EP3808934A1 - Pretensioning anchor for securing a geological formation - Google Patents
Pretensioning anchor for securing a geological formation Download PDFInfo
- Publication number
- EP3808934A1 EP3808934A1 EP20200534.4A EP20200534A EP3808934A1 EP 3808934 A1 EP3808934 A1 EP 3808934A1 EP 20200534 A EP20200534 A EP 20200534A EP 3808934 A1 EP3808934 A1 EP 3808934A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- anchor
- anchor rod
- coupling
- prestressing
- cladding tube
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
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- 230000008878 coupling Effects 0.000 claims abstract description 186
- 238000010168 coupling process Methods 0.000 claims abstract description 186
- 238000005859 coupling reaction Methods 0.000 claims abstract description 186
- 238000005253 cladding Methods 0.000 claims abstract description 116
- 238000005553 drilling Methods 0.000 claims abstract description 82
- 238000000034 method Methods 0.000 claims abstract description 47
- 239000000725 suspension Substances 0.000 claims description 37
- 239000012530 fluid Substances 0.000 claims description 29
- 125000006850 spacer group Chemical group 0.000 claims description 16
- 238000005755 formation reaction Methods 0.000 description 40
- 239000004568 cement Substances 0.000 description 9
- 238000009434 installation Methods 0.000 description 8
- 239000000463 material Substances 0.000 description 7
- 239000000853 adhesive Substances 0.000 description 6
- 230000001070 adhesive effect Effects 0.000 description 6
- 239000002689 soil Substances 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 4
- 238000007789 sealing Methods 0.000 description 4
- 238000003466 welding Methods 0.000 description 4
- 238000010276 construction Methods 0.000 description 3
- 230000002787 reinforcement Effects 0.000 description 3
- 239000011435 rock Substances 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 241000587161 Gomphocarpus Species 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000011900 installation process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
- E02D5/54—Piles with prefabricated supports or anchoring parts; Anchoring piles
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
- E21D21/0026—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
- E21D21/0033—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts having a jacket or outer tube
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/20—Securing of slopes or inclines
- E02D17/207—Securing of slopes or inclines with means incorporating sheet piles or piles
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/74—Means for anchoring structural elements or bulkheads
- E02D5/80—Ground anchors
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/74—Means for anchoring structural elements or bulkheads
- E02D5/80—Ground anchors
- E02D5/808—Ground anchors anchored by using exclusively a bonding material
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
- E21D20/02—Setting anchoring-bolts with provisions for grouting
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
- E21D21/0026—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
- E21D21/0053—Anchoring-bolts in the form of lost drilling rods
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/74—Means for anchoring structural elements or bulkheads
- E02D5/76—Anchorings for bulkheads or sections thereof in as much as specially adapted therefor
Definitions
- the present invention relates to a prestressing anchor for securing a geological formation, the prestressing anchor having an internally hollow anchor rod and a drill bit attached to a front end of the anchor rod and a cladding tube, and the anchor rod being surrounded by the cladding tube in an area spaced from the drill bit.
- slack soil nails are used, for example. These are non-tensioned systems in which an anchor rod is fastened in a borehole by means of a cement suspension or the like. The hardening cement suspension fills the entire cavity of the borehole remaining around the anchor rod. An anchor plate can be attached to the nail head protruding from the borehole. However, these soil nails are systems that cannot be tensioned.
- prestressing anchors are to be distinguished from these soil nails.
- a part of the anchor rod installed in the borehole must remain as a so-called prestressing section or, in other words, free play section.
- the anchor rod In this free play section, the anchor rod must not come into direct contact with the hardening cement suspension in the borehole. In the free play course, no forces should be diverted from the anchor rod directly into the ground.
- prestressing anchors that a borehole is drilled first, with support tubing being installed in addition to the drill rods when drilling in non-stable material. After completion of the borehole, the drill rod and the drill bit are completely removed from the borehole.
- the anchor rod Only then is the anchor rod inserted into the completed borehole and fixed in an area of the borehole facing away from the borehole mouth, the so-called adhesion section, by means of cement suspension or the like. Towards the mouth of the borehole, the free play section remains, in which the anchor rod is not in contact with the surrounding soil via the cement suspension. This free play section can then be used as a prestressing section for tensioning the prestressing anchor.
- the disadvantage of this technology is the increased effort that results from the fact that you first have to drill the borehole with an ordinary drill rod and an ordinary drill bit and, if necessary, even casing, then remove it from the borehole and then install the prestressing anchor in the borehole.
- Prestressing anchor has been used.
- the anchor rod is used as a drill rod itself, analogous to the self-drilling nail technology described above.
- it carries a drill bit at its front end, which then remains in the borehole together with the anchor rod as a so-called lost drill bit.
- cladding tubes were used in these generic prestressing anchors, which surround the anchor rod in an area arranged at a distance from the drill bit. In the prior art, however, these cladding tubes are only ever arranged in the area between two successive anchor connection sleeves of the anchor rod.
- the object of the invention is to improve a prestressing anchor of the above-mentioned type in such a way that a continuous jacket tube can be installed in an area spaced from the drill bit in order to ensure the formation of the free play section required for tensioning.
- the invention proposes that the cladding tube for co-rotating the cladding tube with the anchor rod during a drilling process by means of at least one coupling of the prestressing anchor in at least one circumferential direction around a longitudinal direction of the anchor rod with the Tie rod is positively coupled or positively coupled.
- the invention thus provides for the prestressing anchor to be designed by means of the coupling in such a way that the cladding tube is rotated along with the anchor rod via the forced coupling during the drilling process.
- This allows the cladding tube to be installed in the borehole in any length in a simple manner, so that a corresponding free play section, as required depending on the application for tensioning the prestressing anchor and for transferring loads in the desired area of the total length, can be implemented.
- the drilling devices or drilling units known and available in the prior art can be used, which can also be used to insert the self-drilling nails mentioned at the beginning into the respective geological formation.
- Prestressing anchors according to the invention can be adapted in a simple manner both with regard to their length and with regard to their diameter to the requirements to be met on site.
- the anchor rod is formed in several parts from two or more anchor rods arranged one behind the other in the direction of longitudinal extension of the anchor rod and two successive anchor rods are connected to one another by means of an anchor connecting sleeve.
- the same also applies to the cladding tube.
- This can also consist of two or more in In the direction of longitudinal extent of the anchor rod, partial casing tubes arranged one behind the other can be formed, in turn, two successive partial casing tubes being connected to one another by means of a casing tube socket.
- this measure allows the length of the prestressing anchors to be formed in the geological formation to be freely adapted to the individual requirements on site by using a corresponding number of anchor rods and partial casing tubes in order to form the total anchor rod and the casing tube required .
- standard lengths of the partial anchor rod and the partial enveloping tube can be used in order to form the anchor rod actually required on site and the correspondingly required enveloping tube in a cost-effective and simple manner.
- Even the standard lengths of the tie rod can be shortened or lengthened at any point, thereby achieving maximum flexibility.
- a further advantage of this preferred embodiment variant is that it is possible to work with relatively short anchor rods and cladding tubes, for example if there is relatively little space on site when installing the prestressing anchor according to the invention in the geological formation.
- prestressing anchors it is preferably provided that at least one of the, preferably all, anchor connection sleeves are arranged within the cladding tube.
- the anchor rod or the anchor rods advantageously have an external thread over their entire length with which they can be screwed into corresponding internal threads of an anchor connecting sleeve in order to connect two successive anchor rods to one another.
- the external thread on the anchor rod can also be used in a manner known per se for screwing on the anchor nut used for tensioning and also for screwing on the drill bit attached to the front end of the anchor rod.
- the thread shape and the direction of rotation during the drilling process should, of course, preferably be coordinated with one another in such a way that the screw connection is not unintentionally unscrewed during the drilling process.
- the cladding tube is composed of several partial cladding tubes and corresponding cladding tube sleeves.
- the casing part tubes also advantageously have an external thread with which they can be screwed into corresponding internal threads of casing tube sleeves in order to connect two successive casing part pipes to one another.
- all screw connections on the prestressing anchor according to the invention are designed in such a way that they are acted upon in the closing direction during the drilling process. This generally prevents the screw connections of the prestressing anchor from being unscrewed inadvertently.
- the anchor rod of a prestressing anchor according to the invention is hollow on the inside.
- the anchor rod or the anchor rods from which it is composed have an inner cavity which is continuous in the longitudinal direction of the anchor rod and through which drilling fluid suspension in the interior of the drilling process passes
- Anchor rod can be transported to the drill bit in order to emerge from the drill bit there and fill the borehole outside the prestressing anchor.
- the drilling fluid suspension advantageously has a dual function. On the one hand, it serves to stabilize the borehole during the drilling process and, above all, to transport the material cut out of the geological formation by means of the drill bit outside the prestressing anchor through the borehole to the borehole mouth.
- the drilling fluid suspension is expediently a cement suspension, liquid concrete or the like.
- pinch seals known per se can be used in these anchor connection sleeves between the anchor rods which meet there. These are available on the market. They seal the anchor connection sleeve or the anchor rods screwed into it from the outside, but do not hinder the transport of the drilling fluid suspension through the anchor rod.
- geological formation which the prestressing anchor is intended to secure, is to be understood in general terms. It can be loose material as well as solid rock as well as mixed forms of it.
- the geological formation to be secured by means of the prestressing anchor can be a An embankment, a slope cut, a rock wall, but also a construction pit wall, to name just a few examples.
- prestressing anchors according to the invention as is known per se in the prior art, plates, mats, grids, concrete facing shells, other reinforcements and the like can be attached to the geological formation in order to secure it in this way.
- the prestressing anchors according to the invention enable the anchor rod that is fixed in the geological formation by means of the adhesive section to be prestressed in order to prevent further deformations of the geological formation to be secured as possible or at least only to a small extent.
- the anchor rod or partial anchor rods, as well as the cladding tube or partial cladding tubes, any anchor connecting sleeves and / or cladding tube sleeves, as well as the couplings for the forced coupling of the cladding tube and anchor rod are advantageously made of metal, preferably steel. In principle, however, it is also conceivable to use other materials, provided they have the strength required on site.
- the coupling which forcibly couples the cladding tube to the anchor rod in the circumferential direction so that the cladding tube is rotated with the anchor rod during the drilling process, can in principle be designed very differently.
- preferred variants of the invention provide that the cladding tube is decoupled from the anchor rod in the direction of longitudinal extent of the anchor rod by means of the coupling.
- the coupling ensures the forced coupling according to the invention between the cladding tube and anchor rod in the circumferential direction, but nevertheless ensures a decoupling of the cladding tube and anchor rod in the longitudinal direction of the anchor rod. This has the advantage that after its installation in the borehole, the cladding tube is decoupled from the anchor rod in the longitudinal direction of the anchor rod during the tensioning process and therefore cannot be tensioned during this tensioning process.
- preferred variants of the invention provide that the cladding tube is sealed against the anchor rod in its end area facing the drill bit to prevent the cladding tube from being filled with drilling fluid suspension is.
- this sealing can be ensured, for example, by appropriate sealing welding of this connection.
- the coupling is designed in such a way that it fills the end of the cladding tube facing the drill bit, in the area around the anchor rod, at least to the extent that or seals that no or at least only an insignificant amount of drilling fluid suspension can penetrate into the cladding tube for the later clamping process.
- the main aim is to prevent the cladding tube from being filled with drilling fluid suspension.
- preferred variants of the invention provide that the coupling is designed in at least two parts.
- Preferred variants of the invention are therefore characterized in that the coupling has a first coupling part formed or fixed on the end of the cladding tube facing the drill bit and a second coupling part fixed on the anchor rod.
- the coupling parts each have at least one form-locking element for forming the positive coupling in the circumferential direction.
- each of the coupling parts has an annular or sleeve-shaped base body and the at least one form-locking element of this coupling part is molded or fixed on the base body and protrudes from the base body in a direction parallel to the longitudinal extension direction of the anchor rod.
- each of the coupling parts has at least two or exactly two form-locking elements, the form-locking elements of the respective coupling part being arranged at a distance from one another on the base body of the respective coupling part and protruding from the base body of this coupling part in the same direction parallel to the longitudinal direction of the anchor rod.
- the coupling parts can be fork-like, the form-locking elements forming corresponding prongs of this imaginary fork, which in the circumferential direction around the anchor rod ensure the corresponding form-fit and thus the forced coupling, in the longitudinal direction of the anchor rod but for decoupling when the prestressing anchor is tensioned be pulled apart between the anchor rod and the cladding tube without offering any resistance.
- the coupling parts each have at least one frictional engagement surface for forming the forced coupling in the circumferential direction, preferably exclusively by means of frictional engagement.
- a mixture of frictional engagement and positive engagement is also conceivable in order to couple the coupling parts to one another in the circumferential direction.
- it can also be a matter of pure form-locking or pure frictional-locking variants.
- each of the coupling parts has an annular or sleeve-shaped base body and, in the first coupling part, the frictional engagement surface is designed as an inwardly facing surface of the annular or sleeve-shaped base body, and in the second coupling part, the frictional engagement surface is designed as one outwardly facing surface of the ring-shaped or sleeve-shaped base body is formed.
- the first coupling part and / or in the case of the second coupling part, the respective frictional engagement surface is or are designed in the form of a truncated cone. At this point, one could also speak of a conical design of the respective frictional engagement surface.
- the shape of the truncated cone is particularly preferably that of a circular truncated cone.
- the truncated cones or circular truncated cones are advantageously designed to taper in the direction of the drill bit both on the first coupling part and on the second coupling part. In other words, it is advantageously provided that the cross-sectional area of the respective truncated cone or cone decreases in the direction of the drill bit.
- both the first coupling part and the second coupling part each have a longitudinal center axis and the longitudinal center axis of the respective coupling part encloses an angle in the range between 1 ° and 10 °, preferably between 2 ° and 5 °, with the frictional engagement surface of the respective coupling part .
- the anchor rod can be passed through the ring or sleeve-shaped base body of the first coupling part.
- the first coupling part is preferably mounted with its base body on the anchor rod so as to be displaceable.
- the second coupling part is preferably fixed on the anchor rod with its ring-shaped or sleeve-shaped base body. This can take place, for example, in that the second coupling part is screwed onto the anchor rod with its ring-shaped or sleeve-shaped base body.
- This screw connection between the external thread of the anchor rod and a corresponding internal thread of the ring-shaped or sleeve-shaped base body of the second coupling part can additionally through a corresponding lock nut must be secured.
- An anchor connection sleeve screwed onto the anchor rod directly behind the base body of the second coupling part can serve as a lock nut.
- a spacer tube is arranged between one of the anchor connection sleeves and the second coupling part fixed to the anchor rod.
- the spacer tube can also act as a type of lock or lock nut for the second coupling part due to its support on the anchor connection sleeve.
- the spacer tube can be used to generate a fixed offset between the partial envelope tubes and the armature sections, which, as explained further below in the description of the figures, can simplify the assembly when installing the armature sections and the partial envelope tubes.
- the second coupling part is arranged inside the cladding tube in a coupling position in which the coupling parts are coupled to one another.
- the two coupling parts of the coupling viewed in the circumferential direction, can engage one another without play.
- the coupling parts engage with one another in the circumferential direction with play in one or the coupling position in which the coupling parts are coupled to one another.
- the anchor rod can initially be rotated a little relative to the cladding tube in the circumferential direction around its longitudinal extension direction until the form-fitting elements of the two coupling parts abut against one another comes. Only when the form-locking elements of the two coupling parts are in contact with one another, seen in the circumferential direction, is the forced coupling between the cladding tube and anchor rod in the circumferential direction, so that from then on the cladding tube is rotated with the anchor rod during the drilling process by means of the coupling.
- the invention also relates to a method for installing a prestressing anchor according to the invention in a geological formation.
- a drill hole is drilled into the geological formation with the drill bit attached to the front end of the anchor rod and, during the drilling process, drilling fluid suspension is conveyed through the internally hollow anchor rod to the drill bit and introduced through the drill bit into the borehole.
- the cladding tube, surrounding the anchor rod can then be installed in the borehole and positively coupled to the anchor rod in the circumferential direction by means of the coupling, the cladding tube then being rotated along with the anchor rod in the circumferential direction when the drilling process is continued.
- the drilling process can then be continued until the prestressing anchor is inserted into the geological formation to the required depth.
- corresponding anchor rods and envelope tubes with corresponding anchor connection sleeves or sleeve sleeves can be mounted one behind the other in order to achieve the length of the adhesion section and the free play section required on site, with the free play section being formed in the duct.
- an anchor plate and an anchor nut can be attached in a known manner to the end of the anchor rod protruding from the borehole mouth in order to tension the prestressing anchor by tightening the anchor nut.
- the clamping forces achieved in this way can be measured in a manner known per se, so that the pretensioning force required in each case can be set.
- Fig. 1 shows the state of a first exemplary embodiment of a prestressing anchor 1 according to the invention, completely installed in the geological formation 2, in which the drilling fluid suspension 9 has already hardened in the borehole 17.
- the drill bit 4 is attached.
- the anchor rod 3 here served as a drill rod.
- the area between the drill bit 4 and the end of the cladding tube 5 facing the drill bit 4 forms the adhesive path in which the anchor rod 3 is connected directly to the geological formation 2 surrounding the borehole by means of the hardened drilling fluid suspension 9.
- the anchor rod 3 is, so to speak, held or anchored in the geological formation 2 in this detention section.
- the anchor rod 3 is hollow on the inside over its entire length, so that during the drilling process the drilling fluid suspension 9, which is still liquid at this point in time, is transported through the anchor rod 3 to the drill bit 4 and can exit via the drill bit 4 into the borehole 17, thereby removing the borehole 17 during the drilling process in the in Fig. 1 to fill the illustrated manner.
- the anchor rod 3 is surrounded by the cladding tube 5.
- the coupling 6 is designed in such a way that the cladding tube 5 is sealed against the anchor rod 3 in its end region 10 facing the drill bit 4, so that the cladding tube 5 is not filled with drilling fluid suspension 9.
- the free play section of the anchor rod 3, which is used to prestress the prestressing anchor 1, is located within the cladding tube 5.
- the prestressing anchor 1 is prestressed in this Embodiment in a manner known per se, in that an anchor plate 19 is pushed in the region of the borehole mouth 18 onto the end of the anchor rod 3 protruding from the borehole mouth 18.
- the anchor rod 3 and thus the prestressing anchor 1 are then prestressed in its longitudinal direction 8 to the required extent.
- the anchor nut 20 is then screwed onto the external thread of the end of the anchor rod 3 protruding from the borehole 17 while maintaining the prestress.
- the coupling 6, which will be explained in detail further below, allows the anchor rod 3 to be decoupled from the cladding tube 5 in the direction of longitudinal extension 8 of the anchor rod 3 during this prestressing process.
- the anchor rod 3 is formed from several anchor rods 15 arranged one behind the other in the direction of longitudinal extension 8 of the anchor rod 3, two successive anchor rods 15 being connected to one another by means of an anchor connecting sleeve 16.
- the anchor connecting sleeves 16 have an internal thread into which the two successive anchor rods 15 to be connected can be screwed with their external thread 21.
- a per se known pinch seal or other sealing elements can be arranged between the two anchor rods 15, within the anchor connection sleeve 16.
- the cladding tube 5 is also constructed from a plurality of partial cladding tubes 22 arranged one behind the other in the direction of longitudinal extent 8 of the anchor rod 3.
- the partial casing pipes 22 arranged one behind the other are connected to one another by means of casing pipe sleeves 23.
- each partial casing pipe 22 has a corresponding external thread at its ends, which can be screwed into a corresponding internal thread of the casing pipe socket 23.
- welded connections or other connections between the cladding part tubes 22 and the cladding tube sockets 23 are also possible. The same naturally also applies to the anchor rods 15 and the anchor connecting sleeves 16.
- the coupling 6, which according to the invention ensures a forced coupling of the cladding tube 5 and anchor rod 3 in the circumferential direction 7 around the longitudinal direction 8 of the anchor rod 3 in order to ensure that the cladding tube 5 rotates with the anchor rod 3 during the drilling process, is also in two parts in this first exemplary embodiment built up. It has a first coupling part 11 and a second coupling part 12.
- the first coupling part 11 is fixed at the end of the cladding tube 5 facing the drill bit 4. This fixation can take place, for example, by welding this first coupling part 11 onto the corresponding jacket tube 5 or jacket part tube 22. This can be carried out even before the partial casing pipes 22 or the casing pipe 5 are transported to the construction site.
- the second coupling part 12 is fixed on the anchor rod 3.
- both coupling parts 11 and 12 each have form-locking elements 13 for forming the positive coupling in the circumferential direction 7.
- FIG. 2 shows, enlarged and in a perspective illustration, the coupling 6 placed on the anchor rod 3, the cladding tube 5 fixed on the base body 14 of the first coupling part 11 not being shown.
- the Figures 3 and 4 show the first coupling part 11 ( Fig. 4 ) and the second coupling part 12 ( Fig. 3 ) of the first embodiment, each in a side view.
- Each of the coupling parts 11 and 12 has an annular or sleeve-shaped base body 14, on which, in this exemplary embodiment, two form-locking elements 13 are fixed or formed. These form-fit elements 13 each protrude from the base body 14 in a direction parallel to the direction of longitudinal extent 8 of the anchor rod 3.
- each of the coupling parts 11 and 12 has two form-locking elements 13, which are arranged at a distance from one another on the respective base body 14 and protrude from the respective base body 14 in the same direction parallel to the longitudinal extension direction 8 of the anchor rod 3.
- Both coupling parts 11 and 12 of the first exemplary embodiment thus have a kind of fork-like structure, so that they can interlock with the form-locking elements 13 in order to do so to be able to bring about the desired positive coupling in the circumferential direction 7.
- Fig. 2 it can be clearly seen that in this embodiment the coupling parts 11 and 12 in the coupling position in which the coupling parts 11 and 12 are coupled to one another, mesh with one another in the circumferential direction 7 with play.
- the anchor rod 3 can be rotated a little with the second coupling part 12 fixed on it in the circumferential direction 7 during the drilling process before the form-locking elements 13 of the second coupling part 12 strike the form-locking elements 13 of the first coupling part 11.
- the coupling 6 creates the forced coupling of the cladding tube 5 and anchor rod 3, which ensures that the cladding tube 5 is rotated with the anchor rod 3 around the longitudinal direction 8 of the anchor rod 3 while the drilling process is continued.
- the first coupling part 11 can be welded to the cladding tube 5 or fastened in some other suitable manner.
- the second coupling part 12 is fixed via the sleeve-like base body 14 of the second coupling part 12, which has an internal thread (not shown here) with which the second coupling part 12 is screwed onto the external thread 21 of the anchor rod 3.
- the anchor connection sleeve 16 arranged directly behind it forms a type of lock nut for the second coupling part 12, which additionally fixes the second coupling part 12 on the anchor rod 3. While the anchor rod 3 is fixed on the second coupling part 12, it is only passed through the base body 14 of the first coupling part 11 so that the anchor rod 3 is in the first Coupling part 11 is slidably mounted.
- the remaining annular gap between the anchor rod 3 and the base body 14 of the first coupling part 11 is made so small in preferred exemplary embodiments that there is no or at least no significant entry of the drilling fluid suspension 9 into the end area 10 and thus into the cavity in the cladding tube 5 during the drilling process comes.
- the coupling 6 is designed overall in such a way that it prevents the cladding tube 5 from being filled with drilling fluid suspension 9 during the drilling process.
- the drill bit 4 is attached to the anchor rod 3 or to the first anchor rod 15.
- the drilling device not shown here, engages in a manner known per se on the rear end of the anchor rod 3 or the anchor rod element 15 facing away from the drill bit 4.
- the anchor rod 3 is used as a drill rod with which the drill bit 4 is rotated in the circumferential direction 7 around the longitudinal extension direction 8 of the anchor rod 3 during the drilling process.
- the drill bit 4 cuts material out of the geological formation 2, so that the borehole 17 is gradually drilled deeper and deeper.
- drilling fluid suspension is passed through the internally hollow anchor rod 3 in a manner known per se Core bit 4 promoted.
- the drilling fluid suspension 9 exits at the front end of the borehole via the drill bit 4 and, as it flows back towards the borehole mouth 18, conveys the material cut out of the geological formation to the borehole mouth 18. This is known per se and does not need to be explained further.
- the spacers 24 that may be used ensure that the anchor rod 3 does not rest against the walls of the already drilled part of the borehole 17 and does not rub during the drilling process. How deep the borehole 17 is initially drilled in this way depends on how long the adhesive path is to be formed.
- a further anchor rod 15 can be attached by means of an anchor connecting sleeve 16 in a manner known per se at the given time, when the first anchor rod 15 is largely sunk in the borehole 17 then continue drilling in the manner described.
- the cladding tube 5 or the first partial cladding tube 22 at the borehole mouth 18 are pushed onto the end section of the anchor rod 3 that is protruding out of the borehole 17 at this point in time.
- the first coupling part 11 with its base body 14 was fastened to the cladding tube 5 in advance.
- the anchor rod 3 is separated in a manner known per se from the drilling device, not shown here.
- the second Coupling part 12 with its base body 14 and the internal thread arranged therein can be screwed onto the external thread 21 of the end of the anchor rod 3 protruding from the borehole 17.
- the second coupling part 12 is, as in Fig. 7 to see, screwed so far onto the anchor rod 3 that the form-locking elements 13 of the two coupling parts 11 and 12 come into engagement with one another.
- the subsequent anchor rod 15 with the anchor connecting sleeve 16 is screwed onto the previous end of the anchor rod 3.
- FIG. 9 yet another cladding part tube 22 can be attached to the first cladding part tube 22 by means of a corresponding cladding tube socket 23.
- the drilling device is again attached to the end of the anchor rod 3 in order to continue the drilling process in that the anchor rod 3 with the drill bit 4 is rotated again in the circumferential direction 7.
- the coupling 6 now ensures a corresponding forced coupling between the cladding tube 5 and anchor rod 3 in the circumferential direction 7, so that the cladding tube 5 is now rotated with the anchor rod 3 when the drilling process is continued.
- a very short partial enveloping tube 22 is used as the first partial enveloping tube 22.
- the second coupling part 12 can then be screwed onto the external thread 21 of the anchor rod 3 within the cladding tube 5 or the cladding part tube 22, for example using a correspondingly long tool.
- the attachment of the next anchor rod 15 by means of the anchor connecting sleeve 16 can also take place within the cladding tube 5.
- Another possibility would also be to initially only place the first coupling part 11 on the end of the anchor rod 3 protruding from the borehole 17, then screw the second coupling part 12 onto the anchor rod 3, and only then push the casing tube 5 on and close it on the first coupling part 11 fasten, in particular weld on.
- both the cladding tube 5 and the anchor rod 3 can be lengthened until the desired lengths are reached by appropriately splitting the partial enveloping tubes 22 and partial anchor rods 15.
- the anchor plate 19 is placed on the end section of the anchor rod 3 protruding from the mouth 18 of the borehole, if necessary after shortening the cladding tube 5 accordingly and after the drilling fluid suspension 9 has hardened.
- the anchor rod 3 and thus the prestressing anchor 1 is prestressed in its longitudinal direction 8 to the required extent.
- the desired prestressing state of the prestressing anchor 1 according to the invention can then be fixed and also checked using known measuring methods.
- Fig. 10 again shows the final state, which Fig. 1 corresponds to.
- FIGS Figures 11 to 20 a variant of a prestressing anchor 1 according to the invention, in which the coupling parts 11 and 12 each have at least one frictional engagement surface 26 and 27 for forming the positive coupling in the circumferential direction 7 by means of frictional engagement.
- This exemplary embodiment is one in which the coupling of the coupling parts takes place exclusively by means of frictional engagement.
- mixed forms of positive couplings based on positive engagement on the one hand and frictional engagement on the other hand in the circumferential direction 7 are also possible.
- Fig. 11 shows a longitudinal section through a borehole 17, at which the prestressing anchor 1 according to the invention of the second embodiment is completely installed and prestressed.
- Fig. 12 shows enlarged the area between the coupling 6 used here and the first anchor connection sleeve 16 following it in the direction of the mouth 18 of the borehole, enlarged in FIG Fig. 12 the cladding tube 5 or the partial cladding tube 22 and also the outer regions of the borehole 17 are not shown.
- Fig. 13 shows the second coupling part 12 of this exemplary embodiment enlarged in a longitudinal section. The first coupling part 11 of this variant is shown in FIG Fig. 14 shown enlarged.
- each of the two coupling parts 11 and 12 of this exemplary embodiment has at least one frictional engagement surface 26 or 27, which is used to form the positive coupling in the circumferential direction 7.
- this forced coupling takes place exclusively by frictional engagement between the two frictional engagement surfaces 26 and 27.
- Both coupling parts 11 and 12 each have an annular or sleeve-shaped base body 14.
- the frictional engagement surface 26 is designed as an inwardly facing surface of the annular or sleeve-shaped base body 14.
- the frictional engagement surface 27 is designed as an outwardly facing surface of the ring-shaped or sleeve-shaped base body 14.
- Both frictional engagement surfaces 26 and 27 are designed in the form of a truncated cone or cone. It is a truncated circular cone. Both circular truncated cones taper in the direction of the drill bit 4.
- the second coupling part 12 screwed onto the anchor rod 3 by means of its internal thread 32 in this exemplary embodiment, is correspondingly pressed into the first Coupling part 11 in the direction of longitudinal extension 8 towards the drill bit 4, there is frictional engagement between the frictional engagement surfaces 26 and 27 and thus between the coupling parts 11 and 12, which on the one hand results in the desired positive coupling in the circumferential direction 7.
- this also enables the casing tube 5 to be decoupled from the anchor rod 3 in the longitudinal direction 8 of the anchor rod 3 when the drill bit 4 with the area of the anchor rod 3 protruding from the casing tube 5 and from the coupling 6 by means of the hardened drilling fluid suspension 9 in the borehole 17 is anchored and the area of the anchor rod 3 within the cladding tube 5 is tensioned by tightening the anchor nut 20 accordingly.
- the angle 31 shown between the respective frictional engagement surfaces 26 and 27 of the respective coupling part 11 and 12 and the respective longitudinal center axis 29 and 30 of the respective coupling part 11 and 12 is advantageously in a range between 1 ° and 10 °, particularly preferably in the range between 2 ° and 5 °. In the exemplary embodiment shown, it is an angle 31 of 3.44 ° in each case.
- the length of the coupling parts 11 and 12 can be between 40 mm and 60 mm, to name just one example.
- the first cladding part tube 22 is advantageously screwed directly onto a corresponding external thread 33 of the first coupling part 11 with its cladding tube socket 23, which in this exemplary embodiment is arranged directly on the cladding part tube 22.
- the coupling part 11 and the corresponding enveloping tube 22 or enveloping tube 5 can also be fixed to one another in a different manner, as has already been explained.
- the coefficient of static friction between these two friction-locking surfaces 26 and 27 can be, for example, of the order of 0.15.
- a second difference between the second exemplary embodiment shown here and the first exemplary embodiment described above is that in this variant implemented here, the cladding tube sleeves 23 are formed on the corresponding partial cladding tubes 22 or at their ends.
- FIG. 12 Another difference to the first embodiment in this second embodiment is the use of the in Fig. 12 Particularly clearly visible spacer tube 28. It is a component arranged between one of the anchor connection sleeves 16 and the second coupling part 12 fixed on the anchor rod 3.
- the spacer tube 28 is advantageously between the in Fig. 12 clearly visible anchor connection sleeve 16 and the second coupling part 12 clamped.
- the anchor rod 3 is expediently passed through the spacer tube 28.
- the spacer tube 28 As explained in detail below, ensures a recurring offset between the respective built-in anchor sections 15 and the respective built-in partial envelope tubes 22. This applies in particular when the anchor segments 15 and the partial envelope tubes 22 are of the same length are.
- Another effect of the spacer tube 28 at the end of the installation is the fact that the rear end of the anchor rod 3 protrudes so far out of the borehole mouth 18 that there is enough protrusion for the assembly of the anchor plate 19 and the anchor nut 20.
- a third advantage is that the spacer tube 28 provides rear support of the second coupling part 12 on the anchor connection sleeve 16, so that the anchor connection sleeve 16 can also act as a lock nut for the second coupling part 12 in its distant arrangement.
- Figs. 15-20 some steps in the installation of a prestressing anchor 1 according to the invention according to the second exemplary embodiment are explained.
- the differences to the first one will essentially be emphasized Embodiment received and otherwise on the above descriptions to the Figures 5 to 10 and thus referred to the first embodiment.
- the drilling device (not shown) engages in a manner known per se on the rear end of the anchor rod 3 or anchor rod element 15 facing away from the drill bit 4.
- the anchor rod 3 is used as a drill rod with which the drill bit 4 is rotated in the circumferential direction 7 during the drilling process.
- Fig. 15 there is still no difference to Fig. 5 so that it does not have to be discussed further here.
- the anchor rod 3 is separated from the drilling device (not shown here) and, as in FIG Fig. 16 shown, the first coupling part 11 is pushed onto the end of the anchor rod 3 or the anchor section 15 protruding from the borehole mouth 18.
- the second coupling part 12 is then screwed with its internal thread 32 onto the external thread 21 of the rear end of the anchor rod 3 protruding from the borehole mouth 18.
- the spacer tube 28 is pushed onto the rear end of the anchor rod 3, so that the situation is achieved as it is in Fig. 17 is shown. Now, on the rear end of the anchor rod 3, as in Fig.
- the next anchor section 15 are screwed on by means of a corresponding anchor connecting sleeve 16.
- a corresponding pinch seal is favorably arranged between the anchor sections 15 within the anchor connection sleeve 16.
- the first Hüllteilrohr 22 on the external thread 33 of the first Coupling part 11 are screwed or fastened in some other way.
- the spacer tube 28 provides as in Fig. 19 easy to see, for the fact that a certain length of the anchor rod 3 always protrudes from the last, just assembled partial envelope tube 22. In particular in the case of partial enveloping tubes 22 and armature sections 15 of the same length, this offset is maintained in a simple manner until the end of the drilling process.
- the drill can be connected to the anchor rod 3 again at the rear end, that is to say the end opposite the drill bit 4.
- the drilling process is now continued in that the anchor rod 3 together with the drill bit 4 and cladding tube 5 is rotated in the circumferential direction 7.
- the forced coupling between the cladding tube 5 and the anchor rod 3 is provided by the friction-locked coupling 6 between the first coupling part 11 and the second coupling part 12.
- the pump pumped in the inner cavity of the anchor rod 3 to the drill bit 4 and through it conveys into the borehole exiting drilling fluid suspension 9, as is generally customary, the drill cuttings separated from the geological formation 2 in the direction of the borehole mouth 18.
- the drilling device can be separated from the anchor rod 3 again, whereupon the next anchor section 15 and then the next jacket tube 22 are installed in the corresponding jacket tube socket 23 by means of a further anchor connection sleeve 16 can. This continues until the borehole 17 has reached the desired depth. Then, as in Fig. 20 shown, at the end of the anchor rod 3 protruding from the borehole mouth 18, the anchor plate 19 is placed and the anchor nut 20 is screwed on. As soon as the drilling fluid suspension 9 has hardened, the anchor rod can be tightened accordingly by tightening the anchor nut 20 3 are stretched within the cladding tube 5 and thus on the prestressing section.
- the clutch 6, which is based on frictional engagement here in this second exemplary embodiment, is decoupled in the direction of longitudinal extension 8 of the anchor rod 3 by pulling the two clutch parts 11 and 12 apart.
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Abstract
Vorspannanker (1) zum Sichern einer geologischen Formation (2), wobei der Vorspannanker (1) einen innen hohlen Ankerstab (3) und eine an einem vorderen Ende des Ankerstabes (3) angebrachte Bohrkrone (4) und ein Hüllrohr (5) aufweist und der Ankerstab (3) in einem von der Bohrkrone (4) distanziert angeordneten Bereich von dem Hüllrohr (5) umgeben ist, wobei das Hüllrohr (5) zum Mitdrehen des Hüllrohres (5) mit dem Ankerstab (3) während eines Bohrvorgangs mittels zumindest einer Kupplung (6) des Vorspannankers (1) in zumindest einer Umfangsrichtung (7) um eine Längserstreckungsrichtung (8) des Ankerstabes (3) herum mit dem Ankerstab (3) zwangskoppelbar oder zwangsgekoppelt ist.Prestressing anchor (1) for securing a geological formation (2), the prestressing anchor (1) having an internally hollow anchor rod (3) and a drill bit (4) attached to a front end of the anchor rod (3) and a cladding tube (5) and the anchor rod (3) is surrounded by the cladding tube (5) in an area spaced apart from the drill bit (4), the cladding tube (5) for rotating the cladding tube (5) with the anchor rod (3) during a drilling process by means of at least one Coupling (6) of the prestressing anchor (1) can be positively coupled or positively coupled to the anchor rod (3) in at least one circumferential direction (7) around a longitudinal direction (8) of the anchor rod (3).
Description
Die vorliegende Erfindung betrifft einen Vorspannanker zum Sichern einer geologischen Formation, wobei der Vorspannanker einen innen hohlen Ankerstab und eine an einem vorderen Ende des Ankerstabes angebrachte Bohrkrone und ein Hüllrohr aufweist und der Ankerstab in einem von der Bohrkrone distanziert angeordneten Bereich von dem Hüllrohr umgeben ist.The present invention relates to a prestressing anchor for securing a geological formation, the prestressing anchor having an internally hollow anchor rod and a drill bit attached to a front end of the anchor rod and a cladding tube, and the anchor rod being surrounded by the cladding tube in an area spaced from the drill bit.
Zum Sichern von geologischen Formationen wie z.B. Böschungen, Felswänden, Hangeinschnitten, Baugrubenwänden und dergleichen sind verschiedene Technologien beim Stand der Technik bekannt, mit denen Platten, Matten, Gitter, Betonvorsatzschalen, sonstige Armierungen und dergleichen an der geologischen Formation befestigt und gesichert werden können. Zum Einsatz kommen z.B. sogenannte schlaffe Bodennägel. Bei diesen handelt es sich um nicht gespannte Systeme, bei denen ein Ankerstab mittels einer Zementsuspension oder dergleichen in einem Bohrloch befestigt wird. Dabei füllt die aushärtende Zementsuspension den gesamten, um den Ankerstab verbleibenden Hohlraum des Bohrlochs aus. Am aus dem Bohrloch herausragenden Nagelkopf kann eine Ankerplatte befestigt werden. Bei diesen Bodennägeln handelt es sich aber eben um nicht spannbare Systeme. Um den Einbauprozess zu beschleunigen, ist es beim Stand der Technik bekannt, solche Bodennägel als sogenannte Selbstbohrnägel mit einer sogenannten verlorenen Bohrkrone am Ankerstab auszurüsten, sodass der Ankerstab mit der Bohrkrone gleich als Bohrwerkzeug zur Herstellung des Bohrlochs verwendet werden kann. Die Bohrkrone verbleibt dabei zusammen mit dem Ankerstab im Bohrloch.Various technologies are known in the prior art for securing geological formations such as embankments, rock walls, slope cuttings, construction pit walls and the like, with which plates, mats, grids, concrete cladding, other reinforcements and the like can be attached and secured to the geological formation. So-called slack soil nails are used, for example. These are non-tensioned systems in which an anchor rod is fastened in a borehole by means of a cement suspension or the like. The hardening cement suspension fills the entire cavity of the borehole remaining around the anchor rod. An anchor plate can be attached to the nail head protruding from the borehole. However, these soil nails are systems that cannot be tensioned. In order to accelerate the installation process, it is known in the prior art to equip such soil nails as so-called self-drilling nails with a so-called lost drill bit on the anchor rod, so that the anchor rod with the drill bit can be used as a drilling tool to produce the borehole. The drill bit remains together with the anchor rod in the borehole.
Von diesen Bodennägeln sind die sogenannten Vorspannanker zu unterscheiden. Bei diesen muss ein Teilbereich des in das Bohrloch eingebauten Ankerstabes als sogenannte Vorspannstrecke bzw. in anderen Worten Freispielstrecke verbleiben. In dieser Freispielstrecke darf der Ankerstab nicht direkt mit der aushärtenden Zementsuspension im Bohrloch in Kontakt kommen. Es sollen in der Freispielstrecke keine Kräfte vom Ankerstab direkt in den Untergrund abgeleitet werden. In der Praxis ist es bei den Vorspannankern in der Regel vorgesehen, dass zunächst ein Bohrloch gebohrt wird, wobei bei Bohrungen in nicht standfestem Material zusätzlich zum Bohrgestänge eine Stützverrohrung eingebaut wird. Nach Fertigstellung des Bohrlochs wird das Bohrgestänge samt Bohrkrone vollständig aus dem Bohrloch entfernt. Erst dann wird der Ankerstab in das fertiggestellte Bohrloch eingesetzt und in einem vom Bohrlochmund abgewandten Bereich des Bohrlochs, der sogenannten Haftstrecke, mittels Zementsuspension oder dergleichen fixiert. Zum Bohrlochmund hin verbleibt dabei die Freispielstrecke, in der der Ankerstab nicht über die Zementsuspension mit dem umgebenden Erdreich in Kontakt steht. Diese Freispielstrecke kann dann als Vorspannstrecke zum Spannen des Vorspannankers eingesetzt werden. Der Nachteil dieser Technologie ist der erhöhte Aufwand, der sich daraus ergibt, dass man zunächst das Bohrloch mit einem gewöhnlichen Bohrgestänge und einer gewöhnlichen Bohrkrone bohren und gegebenenfalls sogar Verrohren muss, dann aus dem Bohrloch entfernen muss, um dann anschließend den Vorspannanker ins Bohrloch einzubauen.The so-called prestressing anchors are to be distinguished from these soil nails. In these, a part of the anchor rod installed in the borehole must remain as a so-called prestressing section or, in other words, free play section. In this free play section, the anchor rod must not come into direct contact with the hardening cement suspension in the borehole. In the free play course, no forces should be diverted from the anchor rod directly into the ground. In practice, it is usually provided with prestressing anchors that a borehole is drilled first, with support tubing being installed in addition to the drill rods when drilling in non-stable material. After completion of the borehole, the drill rod and the drill bit are completely removed from the borehole. Only then is the anchor rod inserted into the completed borehole and fixed in an area of the borehole facing away from the borehole mouth, the so-called adhesion section, by means of cement suspension or the like. Towards the mouth of the borehole, the free play section remains, in which the anchor rod is not in contact with the surrounding soil via the cement suspension. This free play section can then be used as a prestressing section for tensioning the prestressing anchor. The disadvantage of this technology is the increased effort that results from the fact that you first have to drill the borehole with an ordinary drill rod and an ordinary drill bit and, if necessary, even casing, then remove it from the borehole and then install the prestressing anchor in the borehole.
Um diesen Aufwand beim Setzen von Vorspannankern zu reduzieren, sind in der Praxis bereits gattungsgemäße Vorspannanker eingesetzt worden. Bei diesen wird der Ankerstab analog zu der oben geschilderten Technologie der Selbstbohrnägel gleich selbst als Bohrgestänge eingesetzt. Er trägt hierzu an seinem vorderen Ende eine Bohrkrone, die dann zusammen mit dem Ankerstab im Bohrloch als sogenannte verlorene Bohrkrone verbleibt. Um eine Freispielstrecke zu schaffen, wurden bei diesen gattungsgemäßen Vorspannankern Hüllrohre verwendet, welche den Ankerstab in einem von der Bohrkrone distanziert angeordneten Bereich umgeben. Beim Stand der Technik sind diese Hüllrohre allerdings immer nur im Bereich zwischen jeweils zwei aufeinanderfolgenden Ankerverbindungsmuffen des Ankerstabes angeordnet. Dies hat zur Folge, dass beim Aushärten der Zementsuspension im Bohrloch diese Ankerverbindungsmuffen im direkten Kontakt mit der Zementsuspension stehen, fixiert werden und somit ungewollt die auftretenden Kräfte in den Untergrund ableiten. Darüber hinaus besteht das Problem, dass bei dieser bekannten Technologie oft Zementsuspension in das Hüllrohr eindringt, sodass es in der Praxis bisher schwierig ist, tatsächlich eine Freispielstrecke zur Verfügung zu stellen, mit der der Vorspannanker dann ausreichend gespannt werden kann.In order to reduce this effort when setting prestressing anchors, generic ones are already used in practice Prestressing anchor has been used. With these, the anchor rod is used as a drill rod itself, analogous to the self-drilling nail technology described above. For this purpose, it carries a drill bit at its front end, which then remains in the borehole together with the anchor rod as a so-called lost drill bit. In order to create a free play section, cladding tubes were used in these generic prestressing anchors, which surround the anchor rod in an area arranged at a distance from the drill bit. In the prior art, however, these cladding tubes are only ever arranged in the area between two successive anchor connection sleeves of the anchor rod. As a result, when the cement suspension hardens in the borehole, these anchor connection sleeves are in direct contact with the cement suspension, are fixed and thus inadvertently divert the forces that occur into the subsoil. In addition, there is the problem that with this known technology, cement suspension often penetrates into the cladding tube, so that in practice it has been difficult to date to actually provide a free play section with which the prestressing anchor can then be sufficiently tensioned.
Aufgabe der Erfindung ist es, einen Vorspannanker der oben genannten Art dahingehend zu verbessern, dass in einem von der Bohrkrone distanziert angeordneten Bereich ein durchgehendes Hüllrohr eingebaut werden kann, um so die Ausbildung der zum Spannen benötigten Freispielstrecke sicherzustellen.The object of the invention is to improve a prestressing anchor of the above-mentioned type in such a way that a continuous jacket tube can be installed in an area spaced from the drill bit in order to ensure the formation of the free play section required for tensioning.
Die Erfindung schlägt hierzu vor, dass das Hüllrohr zum Mitdrehen des Hüllrohres mit dem Ankerstab während eines Bohrvorgangs mittels zumindest einer Kupplung des Vorspannankers in zumindest einer Umfangsrichtung um eine Längserstreckungsrichtung des Ankerstabes herum mit dem Ankerstab zwangskoppelbar oder zwangsgekoppelt ist.The invention proposes that the cladding tube for co-rotating the cladding tube with the anchor rod during a drilling process by means of at least one coupling of the prestressing anchor in at least one circumferential direction around a longitudinal direction of the anchor rod with the Tie rod is positively coupled or positively coupled.
Die Erfindung sieht somit vor, den Vorspannanker mittels der Kupplung so auszubilden, dass das Hüllrohr über die Zwangskopplung mit dem Ankerstab während des Bohrvorgangs mitgedreht wird. Hierdurch kann das Hüllrohr in beliebiger Länge in einfacher Art und Weise mit in das Bohrloch eingebaut werden, sodass eine entsprechende Freispielstrecke, so wie sie je nach Anwendungsfall zum Spannen des Vorspannankers und zur Lastableitung im gewünschten Bereich der Gesamtlänge benötigt wird, realisierbar ist. Hierdurch ist eine Möglichkeit geschaffen, in vergleichsweise kurzer Zeit und auf relativ einfache Art und Weise Vorspannanker in die zu sichernde geologische Formation einzubauen. Dabei können die beim Stand der Technik bekannten und zur Verfügung stehenden Bohrgeräte bzw. Bohreinheiten verwendet werden, welche auch zum Einbringen der eingangs genannten Selbstbohrnägel in die jeweilige geologische Formation verwendet werden können. Dies führt besonders dann zu einer hohen Effektivität, wenn in eine geologische Formation sowohl Vorspannanker als auch Selbstbohrnägel eingebracht werden sollen.The invention thus provides for the prestressing anchor to be designed by means of the coupling in such a way that the cladding tube is rotated along with the anchor rod via the forced coupling during the drilling process. This allows the cladding tube to be installed in the borehole in any length in a simple manner, so that a corresponding free play section, as required depending on the application for tensioning the prestressing anchor and for transferring loads in the desired area of the total length, can be implemented. This creates the possibility of installing prestressing anchors in the geological formation to be secured in a comparatively short time and in a relatively simple manner. In this case, the drilling devices or drilling units known and available in the prior art can be used, which can also be used to insert the self-drilling nails mentioned at the beginning into the respective geological formation. This leads to a high level of effectiveness especially when both prestressing anchors and self-drilling nails are to be inserted into a geological formation.
Erfindungsgemäße Vorspannanker können in einfacher Art und Weise sowohl bezüglich ihrer Länge als auch bezüglich ihres Durchmessers an die jeweils vor Ort zu erfüllenden Anforderungen angepasst werden. Günstigerweise ist dabei vorgesehen, dass der Ankerstab mehrteilig aus zwei oder mehr in Längserstreckungsrichtung des Ankerstabes hintereinander angeordneten Ankerteilstäben gebildet ist und jeweils zwei aufeinanderfolgende Ankerteilstäbe mittels einer Ankerverbindungsmuffe miteinander verbunden sind. Das Gleiche gilt in bevorzugten Ausgestaltungsformen auch für das Hüllrohr. Auch dieses kann mehrteilig aus zwei oder mehr in Längserstreckungsrichtung des Ankerstabes hintereinander angeordneten Hüllteilrohren gebildet sein, wobei wiederum jeweils zwei aufeinanderfolgende Hüllteilrohre mittels einer Hüllrohrmuffe miteinander verbunden sind. Insbesondere durch diese Maßnahme kann die Länge der jeweils in der geologischen Formation auszubildenden Vorspannanker an die individuell vor Ort anzutreffenden Anforderungen frei angepasst werden, indem man eben eine entsprechende Anzahl von Ankerteilstäben und Hüllteilrohren verwendet, um so den insgesamt benötigten Ankerstab und das insgesamt benötigte Hüllrohr auszubilden. Hierdurch kann auf Standardlängen des Ankerteilstabes und des Hüllteilrohres zurückgegriffen werden, um so in kostengünstiger und einfacher Art und Weise den vor Ort tatsächlich benötigten Ankerstab und das dort entsprechend benötigte Hüllrohr auszubilden. Selbst die Standardlängen des Ankerstabes können an beliebiger Stelle gekürzt oder verlängert werden, wodurch eine maximale Flexibilität erreicht wird. Ein weiterer Vorteil dieser bevorzugten Ausführungsvarianten besteht darin, dass mit relativ kurzen Ankerteilstäben und Hüllteilrohren gearbeitet werden kann, z.B. wenn vor Ort beim Einbau des erfindungsgemäßen Vorspannankers in die geologische Formation, relativ beengte Platzverhältnisse vorherrschen.Prestressing anchors according to the invention can be adapted in a simple manner both with regard to their length and with regard to their diameter to the requirements to be met on site. It is expediently provided that the anchor rod is formed in several parts from two or more anchor rods arranged one behind the other in the direction of longitudinal extension of the anchor rod and two successive anchor rods are connected to one another by means of an anchor connecting sleeve. In preferred embodiments, the same also applies to the cladding tube. This can also consist of two or more in In the direction of longitudinal extent of the anchor rod, partial casing tubes arranged one behind the other can be formed, in turn, two successive partial casing tubes being connected to one another by means of a casing tube socket. In particular, this measure allows the length of the prestressing anchors to be formed in the geological formation to be freely adapted to the individual requirements on site by using a corresponding number of anchor rods and partial casing tubes in order to form the total anchor rod and the casing tube required . As a result, standard lengths of the partial anchor rod and the partial enveloping tube can be used in order to form the anchor rod actually required on site and the correspondingly required enveloping tube in a cost-effective and simple manner. Even the standard lengths of the tie rod can be shortened or lengthened at any point, thereby achieving maximum flexibility. A further advantage of this preferred embodiment variant is that it is possible to work with relatively short anchor rods and cladding tubes, for example if there is relatively little space on site when installing the prestressing anchor according to the invention in the geological formation.
Vor allem ist aber bei bevorzugten Varianten erfindungsgemäßer Vorspannanker bevorzugt vorgesehen, dass zumindest eine der, vorzugsweise alle, Ankerverbindungsmuffen innerhalb des Hüllrohres angeordnet sind. Dies ist auch ein wesentlicher Unterschied zu dem eingangs erläuterten gattungsgemäßen Stand der Technik, bei dem die Ankerverbindungsmuffen eben nicht innerhalb des Hüllrohres angeordnet sind und damit die maximal mögliche Länge der Freispielstrecke stark begrenzt ist. Bei den genannten Varianten der Erfindung ist es möglich, eine Freispielstrecke innerhalb des Hüllrohres auch über mehrere Ankerverbindungsmuffen hinweg auszugestalten.Above all, however, in preferred variants of prestressing anchors according to the invention, it is preferably provided that at least one of the, preferably all, anchor connection sleeves are arranged within the cladding tube. This is also an essential difference to the generic prior art explained at the beginning, in which the anchor connecting sleeves are not arranged within the cladding tube and thus the maximum possible length of the free play section is severely limited. In the aforementioned variants of the invention, it is possible to use a Design free play section within the cladding tube over several anchor connection sleeves.
Der Ankerstab bzw. die Ankerteilstäbe weisen, wie beim Stand der Technik an sich bekannt, günstigerweise über ihre gesamte Länge ein Außengewinde auf, mit dem sie in entsprechende Innengewinde einer Ankerverbindungsmuffe eingeschraubt werden können, um so zwei aufeinanderfolgende Ankerteilstäbe miteinander zu verbinden. Darüber hinaus kann das Außengewinde auf dem Ankerstab in an sich bekannter Weise auch zum Aufschrauben der zum Spannen verwendeten Ankermutter und auch zum Aufschrauben der am vorderen Ende des Ankerstabes angebrachten Bohrkrone verwendet werden. Die Gewindeform und die Drehrichtung beim Bohrvorgang sollen natürlich bevorzugt so aufeinander abgestimmt werden, dass es beim Bohrvorgang nicht zu einem ungewollten Aufschrauben der Schraubverbindung kommt. Das gilt grundsätzlich auch für das Hüllrohr, sofern es aus mehreren Hüllteilrohren und entsprechenden Hüllrohrmuffen zusammengesetzt ist. Auch die Hüllteilrohre weisen günstigerweise ein Außengewinde auf, mit dem sie in entsprechende Innengewinde von Hüllrohrmuffen eingeschraubt werden können, um so zwei aufeinanderfolgende Hüllteilrohre miteinander zu verbinden. Günstigerweise sind alle Schraubverbindungen am erfindungsgemäßen Vorspannanker so ausgeführt, dass sie beim Bohrvorgang in die Schließrichtung beaufschlagt werden. So kann generell ein ungewolltes Aufschrauben von Schraubverbindungen des Vorspannankers verhindert werden. Der Ankerstab eines erfindungsgemäßen Vorspannankers ist innen hohl. In anderen Worten weisen der Ankerstab bzw. die Ankerteilstäbe, aus denen er zusammengesetzt ist, einen in Längserstreckungsrichtung des Ankerstabes durchgehenden inneren Hohlraum auf, durch den hindurch beim Bohrvorgang Bohrspülsuspension im Inneren des Ankerstabes bis zur Bohrkrone transportiert werden kann, um dort aus der Bohrkrone auszutreten und das Bohrloch außerhalb des Vorspannankers zu füllen. Die Bohrspülsuspension hat dabei günstigerweise eine doppelte Funktion. Zum einen dient sie dazu, das Bohrloch beim Bohrvorgang zu stabilisieren und vor allem das mittels der Bohrkrone aus der geologischen Formation herausgeschnittene Material außerhalb des Vorspannankers durch das Bohrloch hindurch zum Bohrlochmund zu transportieren. Darüber hinaus handelt es sich günstigerweise um eine aushärtende Bohrspülsuspension, welche nach Abschluss des Bohrvorgangs aushärtet und so insbesondere in der Haftstrecke eine fixe Verbindung zwischen dem dort blank liegenden Ankerstab und den Bohrlochwänden, also der geologischen Formation, ausbildet. In diesem Sinne handelt es sich bei der Bohrspülsuspension günstigerweise um eine Zementsuspension, um Flüssigbeton oder dergleichen.As is known per se in the prior art, the anchor rod or the anchor rods advantageously have an external thread over their entire length with which they can be screwed into corresponding internal threads of an anchor connecting sleeve in order to connect two successive anchor rods to one another. In addition, the external thread on the anchor rod can also be used in a manner known per se for screwing on the anchor nut used for tensioning and also for screwing on the drill bit attached to the front end of the anchor rod. The thread shape and the direction of rotation during the drilling process should, of course, preferably be coordinated with one another in such a way that the screw connection is not unintentionally unscrewed during the drilling process. In principle, this also applies to the cladding tube, provided it is composed of several partial cladding tubes and corresponding cladding tube sleeves. The casing part tubes also advantageously have an external thread with which they can be screwed into corresponding internal threads of casing tube sleeves in order to connect two successive casing part pipes to one another. Advantageously, all screw connections on the prestressing anchor according to the invention are designed in such a way that they are acted upon in the closing direction during the drilling process. This generally prevents the screw connections of the prestressing anchor from being unscrewed inadvertently. The anchor rod of a prestressing anchor according to the invention is hollow on the inside. In other words, the anchor rod or the anchor rods from which it is composed have an inner cavity which is continuous in the longitudinal direction of the anchor rod and through which drilling fluid suspension in the interior of the drilling process passes Anchor rod can be transported to the drill bit in order to emerge from the drill bit there and fill the borehole outside the prestressing anchor. The drilling fluid suspension advantageously has a dual function. On the one hand, it serves to stabilize the borehole during the drilling process and, above all, to transport the material cut out of the geological formation by means of the drill bit outside the prestressing anchor through the borehole to the borehole mouth. In addition, it is expediently a hardening drilling fluid suspension, which hardens after completion of the drilling process and thus forms a fixed connection between the anchor rod lying bare there and the borehole walls, i.e. the geological formation, in particular in the adhesive section. In this sense, the drilling fluid suspension is advantageously a cement suspension, liquid concrete or the like.
Um ein Austreten der Bohrspülsuspension beim Transport durch den inneren Hohlraum des Ankerstabes hindurch an den Ankerverbindungsmuffen zu verhindern, können in diesen Ankerverbindungsmuffen zwischen den dort jeweils aufeinanderstoßenden Ankerteilstäben an sich bekannte Quetschdichtungen eingesetzt werden. Diese sind am Markt erhältlich. Sie dichten die Ankerverbindungsmuffe bzw. die dort eingeschraubten Ankerteilstäbe nach außen hin ab, behindern aber nicht den Transport der Bohrspülsuspension durch den Ankerstab.In order to prevent the drilling fluid suspension from escaping during transport through the inner cavity of the anchor rod to the anchor connection sleeves, pinch seals known per se can be used in these anchor connection sleeves between the anchor rods which meet there. These are available on the market. They seal the anchor connection sleeve or the anchor rods screwed into it from the outside, but do not hinder the transport of the drilling fluid suspension through the anchor rod.
Der Begriff der geologischen Formation, zu deren Sicherung der Vorspannanker vorgesehen ist, ist allgemein zu verstehen. Es kann sich sowohl um Lockermaterial als auch um Festgestein als auch um Mischformen davon handeln. Die mittels des Vorspannankers zu sichernde geologische Formation kann eine Böschung, ein Hangeinschnitt, eine Felswand, aber auch eine Baugrubenwand sein, um nur einige Beispiele zu nennen. Mit erfindungsgemäßen Vorspannankern können, wie beim Stand der Technik an sich bekannt, Platten, Matten, Gitter, Betonvorsatzschalen, sonstige Armierungen und dergleichen an der geologischen Formation befestigt werden, um diese so zu sichern. Die erfindungsgemäßen Vorspannanker ermöglichen dabei im Gegensatz zu den eingangs genannten Bodennägeln ein Vorspannen des mittels der Haftstrecke in der geologischen Formation fixierten Ankerstabes, um so weitere Verformungen der zu sichernden geologischen Formation möglichst zu unterbinden bzw. zumindest in einem geringen Umfang nur noch zuzulassen.The term geological formation, which the prestressing anchor is intended to secure, is to be understood in general terms. It can be loose material as well as solid rock as well as mixed forms of it. The geological formation to be secured by means of the prestressing anchor can be a An embankment, a slope cut, a rock wall, but also a construction pit wall, to name just a few examples. With prestressing anchors according to the invention, as is known per se in the prior art, plates, mats, grids, concrete facing shells, other reinforcements and the like can be attached to the geological formation in order to secure it in this way. In contrast to the soil nails mentioned at the beginning, the prestressing anchors according to the invention enable the anchor rod that is fixed in the geological formation by means of the adhesive section to be prestressed in order to prevent further deformations of the geological formation to be secured as possible or at least only to a small extent.
Bei erfindungsgemäßen Vorspannankern können alle beim Stand der Technik an sich bekannten, hierfür geeigneten Bohrkronen eingesetzt werden. Der Ankerstab bzw. die Ankerteilstäbe, wie auch das Hüllrohr bzw. die Hüllteilrohre, die gegebenenfalls vorhandenen Ankerverbindungsmuffen und/oder Hüllrohrmuffen, wie auch die Kupplungen zur Zwangskopplung von Hüllrohr und Ankerstab sind günstigerweise aus Metall, vorzugsweise aus Stahl gefertigt. Grundsätzlich ist es aber denkbar, auch andere Materialien einzusetzen, sofern diese die vor Ort benötigte Festigkeit aufweisen.In the case of prestressing anchors according to the invention, all drill bits which are known per se in the prior art and are suitable for this can be used. The anchor rod or partial anchor rods, as well as the cladding tube or partial cladding tubes, any anchor connecting sleeves and / or cladding tube sleeves, as well as the couplings for the forced coupling of the cladding tube and anchor rod are advantageously made of metal, preferably steel. In principle, however, it is also conceivable to use other materials, provided they have the strength required on site.
Die Kupplung, welche das Hüllrohr mit dem Ankerstab in der Umfangsrichtung so zwangskoppelt, dass das Hüllrohr beim Bohrvorgang mit dem Ankerstab mitgedreht wird, kann grundsätzlich sehr unterschiedlich ausgestaltet werden. Z.B. ist es denkbar, zur Ausbildung der Kupplung das Hüllrohr gegebenenfalls unter Verwendung eines dazwischen angeordneten Ringe am Ankerstab zu fixieren, z.B. durch Anschweißen, sodass sich das Hüllrohr zwangsweise beim Bohrvorgang mit dem Ankerstab mitdreht.The coupling, which forcibly couples the cladding tube to the anchor rod in the circumferential direction so that the cladding tube is rotated with the anchor rod during the drilling process, can in principle be designed very differently. For example, it is conceivable, to form the coupling, to fix the cladding tube on the anchor rod, if necessary using a ring arranged between them, for example by welding, so that the cladding tube forcibly engages with the Tie rod rotates.
Bevorzugte Varianten der Erfindung sehen aber vor, dass das Hüllrohr mittels der Kupplung in der Längserstreckungsrichtung des Ankerstabes vom Ankerstab entkoppelt ist. Bei diesen bevorzugten Varianten sorgt die Kupplung zwar in Umfangsrichtung für die erfindungsgemäße Zwangskopplung zwischen Hüllrohr und Ankerstab, sorgt aber trotzdem in Längserstreckungsrichtung des Ankerstabes für eine Entkopplung von Hüllrohr und Ankerstab. Dies hat den Vorteil, dass das Hüllrohr nach seinem Einbau in das Bohrloch beim Spannvorgang in Längserstreckungsrichtung des Ankerstabes vom Ankerstab entkoppelt ist und damit bei diesem Spannvorgang nicht mitgespannt werden kann.However, preferred variants of the invention provide that the cladding tube is decoupled from the anchor rod in the direction of longitudinal extent of the anchor rod by means of the coupling. In these preferred variants, the coupling ensures the forced coupling according to the invention between the cladding tube and anchor rod in the circumferential direction, but nevertheless ensures a decoupling of the cladding tube and anchor rod in the longitudinal direction of the anchor rod. This has the advantage that after its installation in the borehole, the cladding tube is decoupled from the anchor rod in the longitudinal direction of the anchor rod during the tensioning process and therefore cannot be tensioned during this tensioning process.
Damit für den Spannvorgang des Vorspannankers möglichst über die gesamte Länge des Hüllrohres eine entsprechende Freispielstrecke zur Verfügung gestellt werden kann, sehen bevorzugte Varianten der Erfindung vor, dass das Hüllrohr zur Verhinderung des Füllens des Hüllrohres mit Bohrspülsuspension in seinem zur Bohrkrone weisenden Endbereich gegen den Ankerstab abgedichtet ist. Diese Abdichtung kann bei den oben genannten Varianten, bei denen das Hüllrohr fix mit dem Ankerstab mittels Verschweißen verbunden ist, z.B. durch entsprechendes Dichtschweißen dieser Verbindung sichergestellt werden. Es ist aber auch möglich, eine Kupplung, die eine Entkopplung von Ankerstab und Hüllrohr in Längserstreckungsrichtung des Ankerstabes vorsieht, so auszubilden, dass sie für den benötigten Grad der Abdichtung im zur Bohrkrone weisenden Endbereich des Hüllrohres sorgt. Dazu reicht es aus, dass die Kupplung so ausgebildet wird, dass sie das zur Bohrkrone weisende Ende des Hüllrohres, im Bereich um den Ankerstab herum, zumindest so weit ausfüllt, bzw. abdichtet, dass eben keine oder zumindest nur eine für den späteren Spannvorgang unwesentliche Menge an Bohrspülsuspension in das Hüllrohr eindringen kann. Es geht also vor allem darum, zu verhindern, dass das Hüllrohr mit Bohrspülsuspension gefüllt wird.So that a corresponding free play section can be provided for the tensioning process of the prestressing anchor as far as possible over the entire length of the cladding tube, preferred variants of the invention provide that the cladding tube is sealed against the anchor rod in its end area facing the drill bit to prevent the cladding tube from being filled with drilling fluid suspension is. In the above-mentioned variants, in which the cladding tube is fixedly connected to the anchor rod by welding, this sealing can be ensured, for example, by appropriate sealing welding of this connection. However, it is also possible to design a coupling which decouples the anchor rod and the cladding tube in the longitudinal direction of the anchor rod so that it provides the required degree of sealing in the end region of the cladding tube facing the drill bit. For this purpose, it is sufficient that the coupling is designed in such a way that it fills the end of the cladding tube facing the drill bit, in the area around the anchor rod, at least to the extent that or seals that no or at least only an insignificant amount of drilling fluid suspension can penetrate into the cladding tube for the later clamping process. The main aim is to prevent the cladding tube from being filled with drilling fluid suspension.
Insbesondere um die Entkopplung zwischen Hüllrohr und Ankerstab in Längserstreckungsrichtung des Ankerstabes sicherstellen zu können, sehen bevorzugte Varianten der Erfindung vor, dass die Kupplung zumindest zweiteilig ausgebildet ist. Bevorzugte Varianten der Erfindung sind daher dadurch gekennzeichnet, dass die Kupplung ein erstes, am zur Bohrkrone weisenden Ende des Hüllrohres ausgebildetes oder fixiertes Kupplungsteil und ein zweites, am Ankerstab fixiertes Kupplungsteil aufweist.In particular, in order to be able to ensure the decoupling between the cladding tube and the anchor rod in the longitudinal direction of the anchor rod, preferred variants of the invention provide that the coupling is designed in at least two parts. Preferred variants of the invention are therefore characterized in that the coupling has a first coupling part formed or fixed on the end of the cladding tube facing the drill bit and a second coupling part fixed on the anchor rod.
Bei einer ersten Variante der Erfindung kann vorgesehen sein, dass die Kupplungsteile jeweils zumindest ein Formschlusselement zur Ausbildung der Zwangskopplung in Umfangsrichtung aufweisen.In a first variant of the invention it can be provided that the coupling parts each have at least one form-locking element for forming the positive coupling in the circumferential direction.
Die die Zwangskopplung in Umfangsrichtung hervorrufenden Formschlusselemente der beiden Kupplungsteile können grundsätzlich sehr unterschiedlich ausgestaltet werden. Z.B. können sie als Verzahnungen oder andere, zum Eingriff ineinander ausgeformte Elemente ausgebildet sein. Bevorzugte Varianten sind dadurch gekennzeichnet, dass jedes der Kupplungsteile einen ring- oder hülsenförmigen Grundkörper aufweist und das zumindest eine Formschlusselement dieses Kupplungsteils am Grundkörper angeformt oder fixiert ist und in einer Richtung parallel zur Längserstreckungsrichtung des Ankerstabes vom Grundkörper absteht. Eine besonders bevorzugte Variante sieht vor, dass jedes der Kupplungsteile jeweils zumindest zwei oder genau zwei Formschlusselemente aufweist, wobei die Formschlusselemente des jeweiligen Kupplungsteils voneinander distanziert am Grundkörper des jeweiligen Kupplungsteils angeordnet sind und in derselben Richtung parallel zur Längserstreckungsrichtung des Ankerstabes vom Grundkörper dieses Kupplungsteils abstehen. Vereinfacht gesprochen, können die Kupplungsteile gabelartig ausgebildet sein, wobei die Formschlusselemente entsprechende Zinken dieser gedachten Gabel bilden, welche in Umfangsrichtung, um den Ankerstab herum, für den entsprechenden Formschluss und damit die Zwangskopplung sorgen, in Längserstreckungsrichtung des Ankerstabes aber beim Spannen des Vorspannankers zur Entkopplung zwischen Ankerstab und Hüllrohr auseinandergezogen werden, ohne hiergegen Widerstand zu leisten.The positive coupling elements of the two coupling parts that cause the positive coupling in the circumferential direction can in principle be designed very differently. For example, they can be designed as teeth or other elements that are shaped to engage one another. Preferred variants are characterized in that each of the coupling parts has an annular or sleeve-shaped base body and the at least one form-locking element of this coupling part is molded or fixed on the base body and protrudes from the base body in a direction parallel to the longitudinal extension direction of the anchor rod. A particularly preferred variant provides that each of the coupling parts has at least two or exactly two form-locking elements, the form-locking elements of the respective coupling part being arranged at a distance from one another on the base body of the respective coupling part and protruding from the base body of this coupling part in the same direction parallel to the longitudinal direction of the anchor rod. Put simply, the coupling parts can be fork-like, the form-locking elements forming corresponding prongs of this imaginary fork, which in the circumferential direction around the anchor rod ensure the corresponding form-fit and thus the forced coupling, in the longitudinal direction of the anchor rod but for decoupling when the prestressing anchor is tensioned be pulled apart between the anchor rod and the cladding tube without offering any resistance.
Es sind aber auch Varianten der Erfindung möglich, bei denen vorgesehen ist, dass die Kupplungsteile jeweils zumindest eine Reibschlussoberfläche zur Ausbildung der Zwangskopplung in Umfangsrichtung, vorzugsweise ausschließlich, mittels Reibschluss aufweisen. Grundsätzlich ist auch eine Mischung aus Reibschluss und Formschluss denkbar, um die Kupplungsteile in Umfangsrichtung miteinander zu koppeln. Es kann sich, wie gesagt, aber auch um reine Formschluss- oder um reine Reibschlussvarianten handeln. Bei bevorzugten Varianten unter Verwendung eines Reibschlusses ist günstigerweise vorgesehen, dass jedes der Kupplungsteile einen ring- oder hülsenförmigen Grundkörper aufweist und beim ersten Kupplungsteil die Reibschlussoberfläche als eine nach innen weisende Oberfläche des ring- oder hülsenförmigen Grundkörpers ausgebildet ist und beim zweiten Kupplungsteil die Reibschlussoberfläche als eine nach außen weisende Oberfläche des ring- oder hülsenförmigen Grundkörpers ausgebildet ist. Besonders bevorzugte Varianten dieser Art sehen vor, dass beim ersten Kupplungsteil und/oder beim zweiten Kupplungsteil die jeweilige Reibschlussoberfläche in Form eines Kegelstumpfes ausgebildet ist bzw. sind. Man könnte an dieser Stelle auch von einer konusförmigen Ausgestaltung der jeweiligen Reibschlussoberfläche sprechen. Besonders bevorzugt handelt es sich bei der Form des Kegelstumpfes um die eines Kreiskegelstumpfes. Die Kegelstümpfe bzw. Kreiskegelstümpfe sind günstigerweise sowohl am ersten Kupplungsteil als auch am zweiten Kupplungsteil jeweils in Richtung hin zur Bohrkrone verjüngt ausgebildet. In anderen Worten ist also günstigerweise vorgesehen, dass die Querschnittsfläche des jeweiligen Kegelstumpfes bzw. Konus in Richtung hin zur Bohrkrone abnimmt.However, variants of the invention are also possible in which it is provided that the coupling parts each have at least one frictional engagement surface for forming the forced coupling in the circumferential direction, preferably exclusively by means of frictional engagement. In principle, a mixture of frictional engagement and positive engagement is also conceivable in order to couple the coupling parts to one another in the circumferential direction. As mentioned, however, it can also be a matter of pure form-locking or pure frictional-locking variants. In preferred variants using a frictional connection, it is conveniently provided that each of the coupling parts has an annular or sleeve-shaped base body and, in the first coupling part, the frictional engagement surface is designed as an inwardly facing surface of the annular or sleeve-shaped base body, and in the second coupling part, the frictional engagement surface is designed as one outwardly facing surface of the ring-shaped or sleeve-shaped base body is formed. Particularly preferred variants of this type provide that the first coupling part and / or in the case of the second coupling part, the respective frictional engagement surface is or are designed in the form of a truncated cone. At this point, one could also speak of a conical design of the respective frictional engagement surface. The shape of the truncated cone is particularly preferably that of a circular truncated cone. The truncated cones or circular truncated cones are advantageously designed to taper in the direction of the drill bit both on the first coupling part and on the second coupling part. In other words, it is advantageously provided that the cross-sectional area of the respective truncated cone or cone decreases in the direction of the drill bit.
Bevorzugt ist vorgesehen, dass sowohl das erste Kupplungsteil als auch das zweite Kupplungsteil jeweils eine Längsmittelachse aufweisen und die Längsmittelachse des jeweiligen Kupplungsteils mit der Reibschlussoberfläche des jeweiligen Kupplungsteils einen Winkel im Bereich zwischen 1° und 10°, vorzugsweise zwischen 2° und 5°, einschließt.It is preferably provided that both the first coupling part and the second coupling part each have a longitudinal center axis and the longitudinal center axis of the respective coupling part encloses an angle in the range between 1 ° and 10 °, preferably between 2 ° and 5 °, with the frictional engagement surface of the respective coupling part .
Der Ankerstab kann durch den Ring oder hülsenförmigen Grundkörper des ersten Kupplungsteils hindurchgeführt sein. Bevorzugt ist das erste Kupplungsteil dabei mit seinem Grundkörper verschiebbar auf dem Ankerstab gelagert.The anchor rod can be passed through the ring or sleeve-shaped base body of the first coupling part. The first coupling part is preferably mounted with its base body on the anchor rod so as to be displaceable.
Das zweite Kupplungsteil ist mit seinem ring- oder hülsenförmigen Grundkörper bevorzugt auf dem Ankerstab fixiert. Dies kann z.B. dadurch erfolgen, dass das zweite Kupplungsteil mit seinem ring- oder hülsenförmigen Grundkörper auf den Ankerstab aufgeschraubt ist. Diese Schraubverbindung zwischen dem Außengewinde des Ankerstabes und einem entsprechenden Innengewinde des ring- oder hülsenförmigen Grundkörpers des zweiten Kupplungsteils kann zusätzlich durch eine entsprechende Kontermutter gesichert werden. Als Kontermutter kann z.B. eine direkt hinter dem Grundkörper des zweiten Kupplungsteils auf den Ankerstab aufgeschraubte Ankerverbindungsmuffe dienen.The second coupling part is preferably fixed on the anchor rod with its ring-shaped or sleeve-shaped base body. This can take place, for example, in that the second coupling part is screwed onto the anchor rod with its ring-shaped or sleeve-shaped base body. This screw connection between the external thread of the anchor rod and a corresponding internal thread of the ring-shaped or sleeve-shaped base body of the second coupling part can additionally through a corresponding lock nut must be secured. An anchor connection sleeve screwed onto the anchor rod directly behind the base body of the second coupling part can serve as a lock nut.
Besonders bevorzugte Varianten der Erfindung sehen vor, dass zwischen einer der Ankerverbindungsmuffen und dem zweiten, am Ankerstab fixierten, Kupplungsteil ein Distanzrohr angeordnet ist. Das Distanzrohr kann aufgrund seiner Abstützung an der Ankerverbindungsmuffe ebenfalls als eine Art Sperre bzw. Kontermutter für das zweite Kupplungsteil wirken. Besonders bevorzugt kann aber mittels des Distanzrohres ein fixer Versatz zwischen den Hüllteilrohren und den Ankerteilstücken erzeugt werden, welcher, wie weiter hinten in der Figurenbeschreibung noch erläutert, die Montage beim Einbau der Ankerteilstücke und der Hüllteilrohre vereinfachen kann.Particularly preferred variants of the invention provide that a spacer tube is arranged between one of the anchor connection sleeves and the second coupling part fixed to the anchor rod. The spacer tube can also act as a type of lock or lock nut for the second coupling part due to its support on the anchor connection sleeve. Particularly preferably, however, the spacer tube can be used to generate a fixed offset between the partial envelope tubes and the armature sections, which, as explained further below in the description of the figures, can simplify the assembly when installing the armature sections and the partial envelope tubes.
Jedenfalls ist es günstig, wenn das zweite Kupplungsteil in einer Kupplungsstellung, in der die Kupplungsteile miteinander gekuppelt sind, innerhalb des Hüllrohres angeordnet ist. Zur Zwangskopplung von Hüllrohr und Ankerstab können bei Varianten mit Formschluss die beiden Kupplungsteile der Kupplung, in Umfangsrichtung gesehen, ohne Spiel ineinander eingreifen. Insbesondere im Sinne einer besseren und einfacheren Montierbarkeit der Kupplungsteile kann aber auch vorgesehen sein, dass die Kupplungsteile in einer bzw. der Kupplungsstellung, in der die Kupplungsteile miteinander gekuppelt sind, in der Umfangsrichtung mit Spiel ineinander eingreifen. In diesen Ausgestaltungsformen ist dann vorgesehen, dass der Ankerstab in Umfangsrichtung um seine Längserstreckungsrichtung zunächst ein Stück weit relativ zum Hüllrohr gedreht werden kann, bis es zum Anschlag der Formschlusselemente der beiden Kupplungsteile aneinander kommt. Erst wenn die Formschlusselemente der beiden Kupplungsteile, in Umfangsrichtung gesehen, aneinander anliegen, kommt es zu der Zwangskopplung zwischen Hüllrohr und Ankerstab in Umfangsrichtung, sodass ab dann das Hüllrohr beim Bohrvorgang mittels der Kupplung mit dem Ankerstab mitgedreht wird.In any case, it is advantageous if the second coupling part is arranged inside the cladding tube in a coupling position in which the coupling parts are coupled to one another. For the forced coupling of the cladding tube and anchor rod, in the case of variants with a form fit, the two coupling parts of the coupling, viewed in the circumferential direction, can engage one another without play. In particular, in the sense of better and simpler assemblability of the coupling parts, it can also be provided that the coupling parts engage with one another in the circumferential direction with play in one or the coupling position in which the coupling parts are coupled to one another. In these embodiments, it is then provided that the anchor rod can initially be rotated a little relative to the cladding tube in the circumferential direction around its longitudinal extension direction until the form-fitting elements of the two coupling parts abut against one another comes. Only when the form-locking elements of the two coupling parts are in contact with one another, seen in the circumferential direction, is the forced coupling between the cladding tube and anchor rod in the circumferential direction, so that from then on the cladding tube is rotated with the anchor rod during the drilling process by means of the coupling.
Neben dem Vorspannanker an sich betrifft die Erfindung auch ein Verfahren zum Einbau eines erfindungsgemäßen Vorspannankers in eine geologische Formation. Bei diesem Verfahren ist vorgesehen, dass mit der am vorderen Ende des Ankerstabes angebrachten Bohrkrone ein Bohrloch in die geologische Formation gebohrt wird und während es Bohrvorgangs Bohrspülsuspension durch den innen hohlen Ankerstab hindurch zur Bohrkrone befördert und durch die Bohrkrone hindurch in das Bohrloch eingebracht wird. In dem von der Bohrkrone distanzierten Bereich kann dann das Hüllrohr, den Ankerstab umgebend, in das Bohrloch eingebaut und mittels der Kupplung mit dem Ankerstab in der Umfangsrichtung zwangsgekoppelt werden, wobei das Hüllrohr bei Fortsetzung des Bohrvorgangs dann in der Umfangsrichtung mit dem Ankerstab mitgedreht wird. Der Bohrvorgang kann dann so weit fortgesetzt werden, bis der Vorspannanker in der benötigten Tiefe in die geologische Formation eingebracht ist. Soweit benötigt, können hierzu entsprechende Ankerteilstäbe und Hüllteilrohre mit entsprechenden Ankerverbindungsmuffen bzw. Hüllrohrmuffen hintereinander montiert werden, um so die vor Ort benötigte Länge der Haftstrecke und der Freispielstrecke zu realisieren, wobei die Freispielstrecke eben im Hüllrohr ausgebildet wird. Ist die benötigte Länge des Bohrloches hergestellt und der Vorspannanker entsprechend eingebaut, so kann man warten, bis die Bohrspülsuspension ausgehärtet und der vor dem Hüllrohr liegende Abschnitt des Ankerstabes zur Ausbildung der Haftstrecke in der ausgehärteten Bohrspülsuspension verankert ist. Anschließend können am, aus dem Bohrlochmund herausragenden Ende des Ankerstabes in bekannter Art und Weise eine Ankerplatte und eine Ankermutter angebracht werden, um so durch Anziehen der Ankermutter den Vorspannanker zu spannen. Die dabei erzielten Spannkräfte können in an sich bekannter Art und Weise gemessen werden, sodass die jeweils benötigte Vorspannkraft eingestellt werden kann.In addition to the prestressing anchor per se, the invention also relates to a method for installing a prestressing anchor according to the invention in a geological formation. In this method it is provided that a drill hole is drilled into the geological formation with the drill bit attached to the front end of the anchor rod and, during the drilling process, drilling fluid suspension is conveyed through the internally hollow anchor rod to the drill bit and introduced through the drill bit into the borehole. In the area distant from the drill bit, the cladding tube, surrounding the anchor rod, can then be installed in the borehole and positively coupled to the anchor rod in the circumferential direction by means of the coupling, the cladding tube then being rotated along with the anchor rod in the circumferential direction when the drilling process is continued. The drilling process can then be continued until the prestressing anchor is inserted into the geological formation to the required depth. If required, corresponding anchor rods and envelope tubes with corresponding anchor connection sleeves or sleeve sleeves can be mounted one behind the other in order to achieve the length of the adhesion section and the free play section required on site, with the free play section being formed in the duct. Once the required length of the borehole has been made and the prestressing anchor installed accordingly, one can wait until the drilling fluid suspension has hardened and the section of the anchor rod located in front of the cladding tube is used to form the Adhesion line is anchored in the hardened drilling fluid suspension. Subsequently, an anchor plate and an anchor nut can be attached in a known manner to the end of the anchor rod protruding from the borehole mouth in order to tension the prestressing anchor by tightening the anchor nut. The clamping forces achieved in this way can be measured in a manner known per se, so that the pretensioning force required in each case can be set.
Weitere Merkmale und Einzelheiten bevorzugter Ausgestaltungsformen der Erfindung werden beispielhaft in der nachfolgenden Figurenbeschreibung erläutert. Es zeigen:
- Fig. 1
- ein erstes Ausführungsbeispiel eines in eine geologische Formation fertig eingebauten erfindungsgemäßen Vorspannanker in einem Längsschnitt durch das Bohrloch;
- Fig. 2
bis 4 - Detaildarstellungen zur, in diesem Ausführungsbeispiel gemäß
Fig. 1 verwendeten Kupplung; und - Fig. 5
bis 10 - verschiedene Zwischenzustände und den Endzustand beim Einbau des erfindungsgemäßen Vorspannankers gemäß
Fig. 1 in eine geologische Formation; - Fig. 11
- ein zweites Ausführungsbeispiel eines in eine geologische Formation fertig eingebauten erfindungsgemäßen Vorspannankers in einem Längsschnitt durch das Bohrloch;
- Fig. 12
bis 14 - Detaildarstellungen zur in diesem Ausführungsbeispiel gemäß
Fig. 11 verwendeten Kupplung und - Fig. 15
bis 20 - verschiedene Zwischenzustände und den Endzustand beim Einbau des erfindungsgemäßen Vorspannankers gemäß
Fig. 11 in eine geologische Formation.
- Fig. 1
- a first exemplary embodiment of a prestressing anchor according to the invention that is completely installed in a geological formation in a longitudinal section through the borehole;
- Figs. 2 to 4
- Detailed representations for, in this embodiment according to
Fig. 1 clutch used; and - Figures 5 to 10
- various intermediate states and the final state during the installation of the prestressing anchor according to the invention according to FIG
Fig. 1 into a geological formation; - Fig. 11
- a second exemplary embodiment of a prestressing anchor according to the invention that is completely installed in a geological formation in a longitudinal section through the borehole;
- Figures 12-14
- Detailed representations for in this embodiment according to
Fig. 11 used clutch and - Figs. 15-20
- various intermediate states and the final state during the installation of the prestressing anchor according to the invention according to FIG
Fig. 11 in a geological Formation.
In einem von der Bohrkrone 4 distanziert angeordneten Bereich ist der Ankerstab 3 von dem Hüllrohr 5 umgeben. Die Kupplung 6 ist in diesem Ausführungsbeispiel so ausgebildet, dass das Hüllrohr 5 in seinem zur Bohrkrone 4 weisenden Endbereich 10 so gegen den Ankerstab 3 abgedichtet ist, dass das Hüllrohr 5 nicht mit Bohrspülsuspension 9 gefüllt wird. Innerhalb des Hüllrohres 5 befindet sich die Freispielstrecke des Ankerstabes 3, die dem Vorspannen des Vorspannankers 1 dient. Das Vorspannen des Vorspannankers 1 erfolgt in diesem Ausführungsbeispiel in an sich bekannter Art und Weise, indem eine Ankerplatte 19 im Bereich des Bohrlochmundes 18 auf das aus dem Bohrlochmund 18 herausragende Ende des Ankerstabes 3 aufgeschoben wird. Durch Anziehen des Ankerstabes 3 mit einer an sich bekannten Spannvorrichtung wird dann der Ankerstab 3 und damit der Vorspannanker 1 in seiner Längserstreckungsrichtung 8 im benötigten Ausmaß vorgespannt. Anschließend wird unter Aufrechterhaltung der Vorspannung die Ankermutter 20 auf das Außengewinde des aus dem Bohrloch 17 herausragenden Endes des Ankerstabes 3 aufgeschraubt. Die weiter unten noch im Detail erläuterte Kupplung 6 erlaubt bei diesem Vorspannvorgang eine Entkopplung des Ankerstabes 3 vom Hüllrohr 5 in Längserstreckungsrichtung 8 des Ankerstabes 3.In an area arranged at a distance from the
Die beiden später im Detail noch erläuterten Kupplungsteile 11 und 12 dieses ersten Ausführungsbeispiels sind innerhalb des Hüllrohres 5 angeordnet. Der Ankerstab 3 ist im hier gezeigten ersten Ausführungsbeispiel aus mehreren, in Längserstreckungsrichtung 8 des Ankerstabes 3 hintereinander angeordneten Ankerteilstäben 15 ausgebildet, wobei jeweils zwei aufeinanderfolgende Ankerteilstäbe 15 mittels einer Ankerverbindungsmuffe 16 miteinander verbunden sind. Die Ankerverbindungsmuffen 16 weisen hierzu ein Innengewinde auf, in das die beiden miteinander zu verbindenden aufeinanderfolgenden Ankerteilstäbe 15 mit ihrem Außengewinde 21 eingeschraubt werden können. Zwischen den beiden Ankerteilstäben 15 können innerhalb der Ankerverbindungsmuffe 16 jeweils eine an sich bekannte Quetschdichtung oder andere Dichtungselemente angeordnet sein. Diese verhindert das Austreten von Bohrspülsuspension 9 im Stoßbereich zwischen den beiden miteinander verbundenen Ankerteilstäben 15 aus der Ankerverbindungsmuffe 16. Nichtsdestotrotz lässt die Quetschdichtung aber natürlich den Transport der Bohrspülsuspension im inneren Hohlraum des Ankerstabes 3 in Richtung hin zur Bohrkrone 4 zu. Günstig ist jedenfalls, wie hier auch vorgesehen, dass zumindest eine, vorzugsweise alle Ankerverbindungsmuffen 16 innerhalb des Hüllrohres 5 angeordnet sind.The two
Auch das Hüllrohr 5 ist auch in diesem ersten Ausführungsbeispiel aus mehreren in Längserstreckungsrichtung 8 des Ankerstabes 3 hintereinander angeordneten Hüllteilrohren 22 aufgebaut. Die jeweils hintereinander angeordneten Hüllteilrohre 22 sind mittels Hüllrohrmuffen 23 miteinander verbunden. Im gezeigten ersten Ausführungsbeispiel weist jedes Hüllteilrohr 22 dazu an seinen Enden jeweils ein entsprechendes Außengewinde auf, welches in ein entsprechendes Innengewinde der Hüllrohrmuffe 23 eingeschraubt werden kann. Natürlich sind auch Schweißverbindungen oder andere Verbindungen zwischen den Hüllteilrohren 22 und den Hüllrohrmuffen 23 möglich. Das Gleiche gilt natürlich auch für die Ankerteilstäbe 15 und die Ankerverbindungsmuffen 16.In this first exemplary embodiment, the
Der Vollständigkeit halber wird darauf hingewiesen, dass das Bohrloch 17 sowie der darin eingebaute Vorspannanker 1 in den
Die Kupplung 6, welche erfindungsgemäß für eine Zwangskopplung von Hüllrohr 5 und Ankerstab 3 in Umfangsrichtung 7 um die Längserstreckungsrichtung 8 des Ankerstabes 3 sorgt, um so ein Mitdrehen des Hüllrohres 5 mit dem Ankerstab 3 während es Bohrvorgangs sicherzustellen, ist auch in diesem ersten Ausführungsbeispiel zweiteilig aufgebaut. Sie weist ein erstes Kupplungsteil 11 und ein zweites Kupplungsteil 12 auf. Das erste Kupplungsteil 11 ist im hier gezeigten Ausführungsbeispiel am zur Bohrkrone 4 weisenden Ende des Hüllrohres 5 fixiert. Diese Fixierung kann z.B. durch Anschweißen dieses ersten Kupplungsteiles 11 am entsprechenden Hüllrohr 5 bzw. Hüllteilrohr 22 erfolgen. Dies kann schon vor Transport der Hüllteilrohre 22 bzw. des Hüllrohres 5 auf die Baustelle durchgeführt werden. Das zweite Kupplungsteil 12 wird am Ankerstab 3 fixiert. Beide Kupplungsteile 11 und 12 weisen in diesem ersten Ausführungsbeispiel jeweils Formschlusselemente 13 zur Ausbildung der Zwangskopplung in Umfangsrichtung 7 auf.The
In
Zur Fixierung kann das erste Kupplungsteil 11 am Hüllrohr 5 angeschweißt oder in sonstiger geeigneter Art und Weise befestigt sein. Die Fixierung des zweiten Kupplungsteils 12 erfolgt im gezeigten Ausführungsbeispiel über den hülsenartigen Grundkörper 14 des zweiten Kupplungsteils 12, welcher ein hier nicht dargestelltes Innengewinde aufweist, mit dem das zweite Kupplungsteil 12 auf das Außengewinde 21 des Ankerstabes 3 aufgeschraubt ist. Die unmittelbar dahinter angeordnete Ankerverbindungsmuffe 16 bildet für das zweite Kupplungsteil 12 eine Art Kontermutter, welche das zweite Kupplungsteil 12 zusätzlich am Ankerstab 3 fixiert. Während der Ankerstab 3 am zweiten Kupplungsteil 12 fixiert ist, ist er durch den Grundkörper 14 des ersten Kupplungsteils 11 nur hindurchgeführt, sodass der Ankerstab 3 im ersten Kupplungsteil 11 verschiebbar gelagert ist. Der verbleibende Ringspalt zwischen Ankerstab 3 und dem Grundkörper 14 des ersten Kupplungsteils 11 wird in bevorzugten Ausführungsbeispielen so klein ausgeführt, dass es während des Bohrvorgangs zu keinem oder zumindest zu keinem wesentlichen Eintritt der Bohrspülsuspension 9 in den Endbereich 10 und damit in den Hohlraum im Hüllrohr 5 kommt. Grundsätzlich ist es auch denkbar, hier zusätzlich Dichtungen oder dergleichen vorzusehen. Jedenfalls ist in den hier gezeigten Ausführungsbeispielen die Kupplung 6 insgesamt so ausgebildet, dass sie ein Füllen des Hüllrohres 5 mit Bohrspülsuspension 9 während des Bohrvorgangs verhindert.To fix it, the
Anhand der
Zunächst wird, wie in
Zu gegebener Zeit bzw. bei entsprechendem Bohrfortschritt kann dann, wie in
Anschließend an das Aufsetzen des ersten Hüllteilrohres 22 bzw. des Hüllrohres 5 kann, wie in
Bei der beschriebenen Vorgehensweise wird im gezeigten ersten Ausführungsbeispiel als erstes Hüllteilrohr 22 ein sehr kurzes Hüllteilrohr 22 verwendet. Dies hat den Vorteil, dass das zweite Kupplungsteil 12 ganz einfach von Hand auf das hintere Ende des Ankerstabes 3 aufgeschraubt werden kann und auch gut kontrolliert werden kann, dass die erste Ankerverbindungsmuffe 16 ausreichend weit auf das aus dem Bohrloch 17 weisende Ende des Ankerstabes 3 aufgeschraubt werden kann. Nichtsdestotrotz ist es natürlich auch möglich, ein längeres Hüllteilrohr 22 oder das gesamte Hüllrohr 5 in einem Stück in dem Schritt gemäß
Bei Fortsetzung des Bohrvorgangs ausgehend von
Ist dies der Fall, so wird, gegebenenfalls nach entsprechendem Einkürzen des Hüllrohres 5 und nach Aushärten der Bohrspülsuspension 9, die Ankerplatte 19 auf den aus dem Bohrlochmund 18 herausragenden Endabschnitt des Ankerstabes 3 aufgesetzt. Durch Anziehen des Ankerstabes 3 mit einer an sich bekannten Spannvorrichtung wird dann der Ankerstab 3 und damit der Vorspannanker 1 in seiner Längserstreckungsrichtung 8 im benötigten Ausmaß vorgespannt. Durch entsprechendes Anziehen der Ankermutter 20 unter Aufrechterhaltung der Vorspannung kann dann der gewünschte Spannzustand des erfindungsgemäßen Vorspannankers 1 fixiert und über bekannte Messverfahren auch kontrolliert werden.If this is the case, the
Während die Kupplungsteile 11 und 12 beim ersten Ausführungsbeispiel gemäß der
Bei der nachfolgenden Schilderung des zweiten Ausführungsbeispiels und seines Einbaus gemäß der
Wie insbesondere in den
Die in den
Das erste Hüllteilrohr 22 ist günstigerweise mit seiner in diesem Ausführungsbeispiel direkt am Hüllteilrohr 22 angeordneten Hüllrohrmuffe 23 direkt auf ein entsprechendes Außengewinde 33 des ersten Kupplungsteils 11 aufgeschraubt. Natürlich können das Kupplungsteil 11 und das entsprechende Hüllteilrohr 22 bzw. Hüllrohr 5 auch in anderer Art und Weise aneinander fixiert werden, wie dies bereits erläutert wurde.The first
Verwendet man für beide Reibschlussoberflächen 26 und 27 Stahl, so kann der Reibwert der Haftreibung zwischen diesen beiden Reibschlussoberflächen 26 und 27 z.B. in der Größenordnung von 0,15 liegen.If steel is used for both friction-locking
Um den Reibschluss zwischen den beiden Reibschlussoberflächen 26 und 27 und damit zwischen den Kupplungsteilen 11 und 12 zu erreichen, ist günstigerweise vorgesehen, dass der Ankerstab 3 und damit das an ihm befestigte Kupplungsteil 12 mit entsprechend hoher Kraft in das erste Kupplungsteil 11 gedrückt wird.In order to achieve the frictional engagement between the two frictional engagement surfaces 26 and 27 and thus between the
Wie eingangs bereits erläutert, ist günstigerweise bei allen gegebenenfalls realisierten Schraubverbindungen vorgesehen, dass diese in der Umfangsrichtung 7, in der der Ankerstab 3 mit der Bohrkrone 4 beim Bohrvorgang gedreht wird, in Schließrichtung beaufschlagt sind. Dies sorgt dafür, dass beim Bohrvorgang keine Schraubverbindung ungewollt geöffnet werden kann. In diesem Sinne ist es günstig, wenn beim Vorspannanker 1 alle verwendeten Gewindeverbindungen in derselben Drehrichtung eingebaut werden. Dies gilt für das zweite wie auch für das erste, wie auch für andere Ausführungsbeispiele der Erfindung bevorzugt.As already explained at the beginning, it is expediently provided for all possibly implemented screw connections that these are acted upon in the closing direction in the
Ein zweiter Unterschied zwischen dem hier gezeigten zweiten Ausführungsbeispiel und dem vorab geschilderten ersten Ausführungsbeispiel besteht darin, dass in dieser hier realisierten Variante die Hüllrohrmuffen 23 gleich an den entsprechenden Hüllteilrohren 22 bzw. an deren Enden ausgebildet sind. Dies ist eine Variante, die natürlich auch beim ersten Ausführungsbeispiel realisiert werden könnte, genauso wie die beim ersten Ausführungsbeispiel gezeigten Hüllrohrmuffen 23 hier im zweiten Ausführungsbeispiel anwendbar wären.A second difference between the second exemplary embodiment shown here and the first exemplary embodiment described above is that in this variant implemented here, the
Ein weiterer Unterschied zum ersten Ausführungsbeispiel bei diesem zweiten Ausführungsbeispiel besteht in der Verwendung des in
Nachfolgend werden noch anhand der
Ist die gewünschte Tiefe des Bohrlochs 17 zur Ausbildung der Haftstrecke erreicht, so wird der Ankerstab 3 vom hier nicht dargestellten Bohrgerät getrennt und es wird, wie in
In der Stellung gemäß
Der Vollständigkeit halber wird darauf hingewiesen, dass in den gezeigten Darstellungen keine Betonvorsatzschale, kein Armierungsgitter, keine Platte oder dergleichen zwischen Ankerplatte 19 und der geologischen Formation 2 dargestellt ist. All dies kann aber in an sich bekannter Art und Weise natürlich ohne Weiteres vorhanden sein. Die Ankerplatte 19 wird dann nicht direkt auf die geologische Formation 2 sondern eben an die entsprechende Betonvorsatzschale, das entsprechende Gitter etc. aufgesetzt.For the sake of completeness, it is pointed out that in the representations shown, no concrete facing, no reinforcement grid, no slab or the like is shown between
Claims (15)
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ATGM121/2019U AT16940U1 (en) | 2019-10-17 | 2019-10-17 | Prestressing anchor for securing a geological formation |
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Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4204533A1 (en) * | 1992-02-15 | 1993-08-19 | Gd Anker Gmbh & Co Kg | Injection bore anchor - has anchor rod in area adjacent to anchor plate enclosed by tubular cylindrical rubber component |
DE19503122A1 (en) * | 1995-02-01 | 1996-08-08 | Reburg Patentverwertungs Gmbh | Injection anchor |
DE19512119A1 (en) * | 1995-04-04 | 1996-10-10 | Reburg Patentverwertungs Gmbh | Device for draining hollow space surrounded mountain layers |
US6145601A (en) * | 1997-06-18 | 2000-11-14 | Techmo Entwicklungs-Und Vertriebs Gmbh | Method and device for boring holes |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2007053893A1 (en) * | 2005-11-09 | 2007-05-18 | Sandvik Intellectual Property Ab | Self drilling rock bolt |
US20130011204A1 (en) * | 2011-07-07 | 2013-01-10 | Amcon Limited | Method and apparatus for forming pilings and anchors |
-
2019
- 2019-10-17 AT ATGM121/2019U patent/AT16940U1/en not_active IP Right Cessation
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2020
- 2020-10-07 EP EP20200534.4A patent/EP3808934B1/en active Active
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4204533A1 (en) * | 1992-02-15 | 1993-08-19 | Gd Anker Gmbh & Co Kg | Injection bore anchor - has anchor rod in area adjacent to anchor plate enclosed by tubular cylindrical rubber component |
DE19503122A1 (en) * | 1995-02-01 | 1996-08-08 | Reburg Patentverwertungs Gmbh | Injection anchor |
DE19512119A1 (en) * | 1995-04-04 | 1996-10-10 | Reburg Patentverwertungs Gmbh | Device for draining hollow space surrounded mountain layers |
US6145601A (en) * | 1997-06-18 | 2000-11-14 | Techmo Entwicklungs-Und Vertriebs Gmbh | Method and device for boring holes |
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