CN115419076B - High-pressure rotary spraying recyclable anchor cable supporting construction method for deep foundation pit - Google Patents
High-pressure rotary spraying recyclable anchor cable supporting construction method for deep foundation pit Download PDFInfo
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- CN115419076B CN115419076B CN202210600872.6A CN202210600872A CN115419076B CN 115419076 B CN115419076 B CN 115419076B CN 202210600872 A CN202210600872 A CN 202210600872A CN 115419076 B CN115419076 B CN 115419076B
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- 238000005507 spraying Methods 0.000 title claims abstract description 52
- 238000010276 construction Methods 0.000 title claims abstract description 49
- 238000000034 method Methods 0.000 claims abstract description 36
- 230000008569 process Effects 0.000 claims abstract description 29
- 238000004873 anchoring Methods 0.000 claims description 74
- 239000004568 cement Substances 0.000 claims description 40
- 239000002689 soil Substances 0.000 claims description 26
- 238000005553 drilling Methods 0.000 claims description 21
- 238000003756 stirring Methods 0.000 claims description 17
- 239000002002 slurry Substances 0.000 claims description 13
- 238000002955 isolation Methods 0.000 claims description 9
- 238000002156 mixing Methods 0.000 claims description 7
- 230000002787 reinforcement Effects 0.000 claims description 7
- 238000013461 design Methods 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 238000011049 filling Methods 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 3
- 239000003469 silicate cement Substances 0.000 claims description 3
- 238000005516 engineering process Methods 0.000 abstract description 6
- 239000010410 layer Substances 0.000 description 13
- 238000011084 recovery Methods 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- FGUUSXIOTUKUDN-IBGZPJMESA-N C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 Chemical compound C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 FGUUSXIOTUKUDN-IBGZPJMESA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000004026 adhesive bonding Methods 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009435 building construction Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000004035 construction material Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000007907 direct compression Methods 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000011378 shotcrete Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
Classifications
-
- 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
- E02D17/02—Foundation pits
- E02D17/04—Bordering surfacing or stiffening the sides of foundation pits
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D15/00—Handling building or like materials for hydraulic engineering or foundations
- E02D15/02—Handling of bulk concrete specially for foundation or hydraulic engineering purposes
- E02D15/04—Placing concrete in mould-pipes, pile tubes, bore-holes or narrow shafts
-
- 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
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- Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- Piles And Underground Anchors (AREA)
Abstract
The invention discloses a construction method for high-pressure rotary spraying recyclable anchor cable support of a deep foundation pit, which adopts a high-pressure rotary spraying process and utilizes a drill rod to form an anchor hole, has all advantages of the high-pressure rotary spraying relative to other anchor technologies, brings an anchor assembly into a set anchor position, has simple construction process and high construction efficiency, has firm foundation pit support structure, and can recycle the anchor cable to achieve the aim of reducing construction cost.
Description
Technical Field
The invention relates to a construction method, in particular to a construction method for high-pressure rotary spraying recoverable anchor cable support of a deep foundation pit.
Background
With the development of urban construction industry, deep foundation pit engineering is widely and widely used everywhere, and underground space technology, complex soil layer enclosing technology, high-pressure rotary spraying anchor cable construction technology and the like are increasingly used.
The distance between the foundation pit wall and the surrounding existing building (road) becomes smaller and smaller, and how to ensure the stability of the foundation pit, the structure of the existing building (road) and the planned building and the safety of operators in the construction process becomes a key of engineering.
The high-pressure rotary spraying anchor cable is a novel anchor cable structure formed by combining a large-diameter cement soil pile body and a traditional anchor cable, and is formed by forming holes in soil body and spraying cement slurry in a certain angle by utilizing a rotary spraying drilling machine, fully stirring, and enabling cement and the soil body to interact through a physical-chemical reaction to finally form an anchor body.
In the prior art, when the high-pressure rotary-spraying anchor cable technology supports the pile foundation, the anchor cable is usually anchored in a soil layer and cannot be recycled due to the characteristics of a construction method, and the construction cost is high. Meanwhile, aiming at collapsible soil, the method of excavating earthwork first and then anchoring is easy to cause hole collapse phenomenon in the anchoring process, so that the construction process is complex.
Therefore, the existing high-pressure jet grouting anchor cable construction process needs to be improved, the construction process is simple, the foundation pit supporting structure is firm, and the anchor cable can be recycled so as to achieve the purpose of reducing the construction cost.
Disclosure of Invention
In view of the above, the invention aims to provide a construction method for high-pressure rotary spraying recoverable anchor cable support of a deep foundation pit, which has the advantages of simple construction process, high construction efficiency, firm foundation pit support structure and recoverable anchor cable, so that the aim of reducing construction cost is fulfilled.
The invention discloses a construction method for supporting a recoverable anchor rope by high-pressure jet grouting of a deep foundation pit, which comprises the following steps:
a. Pouring a cast-in-place pile at a set position and pouring a crown beam on the cast-in-place pile;
b. An anchoring via hole is formed in the relevant position of the crown beam;
c. Setting an anchoring position in the soil layer through the anchoring via hole, drilling an anchoring hole for passing through the anchor cable assembly, drilling by adopting a high-pressure rotary spraying process within the range of setting an anchoring body when drilling the anchoring hole, and forming an enlarged end at the bottom of the anchoring body;
the anchor cable assembly is a recyclable anchor cable assembly;
d. In the process of drilling the anchoring holes in the step c, the drill rod simultaneously brings the anchor cable assembly into the anchoring holes, and the bottom anchor head is arranged at the enlarged end of the anchoring body;
e. Withdrawing the drill rod and performing high-pressure jet grouting in the anchoring body area;
f. Tensioning the anchor cable assembly and anchoring after the anchor body is hardened to set indexes;
g. And d, excavating a foundation pit according to the design, pouring a waist beam on the cast-in-place pile at the designed depth position, forming an anchoring via hole on the waist beam, and repeating the steps c to f.
In the step a, a waterproof curtain is formed around the foundation pit by cement stirring piles, and the waterproof curtain is positioned at the outer side of the filling pile.
Further, the recyclable anchor cable assembly comprises an anchor cable, a pulling pin and a bottom anchor head, wherein the bottom anchor head comprises an internal thread anchor device provided with internal threads, the bottom end of the anchor cable is fixedly connected with a connecting section, the connecting section is matched with the internal thread anchor device through threads, and the lift angle of the threads is larger than the self-locking angle;
The pulling pin is inserted into the connecting section along the length direction and locked in the circumferential direction, and can be pulled out to be separated from the female screw anchor and released.
Further, the cross section of pull out the round pin is the polygon, the internal thread ground tackle is equipped with the internal thread that is used for being connected with the linkage segment, and the bottom of internal thread forms and pulls out round pin complex polygon hole, the linkage segment be equipped with be used for with pull out round pin complex polygon hole.
Further, the connecting section is also provided with an operation hole for placing and taking out the pulling pin, a pull wire is arranged along with the anchor cable, one end of the pull wire passes through the operation hole and is fixedly connected with the pulling pin, and the other end of the pull wire is exposed out of the outer anchor head;
the anchor cable is sleeved with an isolation tube, and the stay wire is positioned in the isolation tube.
Further, the bottom anchor head further comprises at least two anchor plates which are parallel along the length direction, the anchor plates are fixedly connected through bolts, the internal thread anchorage device is fixed on the anchor plates, a reinforcement cage is arranged on the anchor plates in a welded connection mode, and the length of the reinforcement cage corresponds to that of the anchor body.
Further, the drill rod is a hollow spiral drill pipe, and nozzles are distributed at the end part of the drill bit and on the side wings;
in step b, the high-pressure jet grouting process comprises the following steps of;
b1, filtering cement paste in a stirring pool, introducing the cement paste into a drill rod by a high-pressure pump through a high-pressure guide pipe, and spraying the cement paste outwards from the nozzle of a drill bit, wherein soil mass on the periphery is synchronously cut in the cement paste spraying process; the drill bit is gradually advanced under power to a designed depth and diameter to form the anchor body.
Further, the cement paste is prepared by mixing and stirring common silicate cement and water, the mixing amount of the anchoring body cement is 20%, and the water-cement ratio is 0.5-0.7;
When the anchoring body is constructed, the drilling speed is less than or equal to 30cm/min, the rotating speed is less than or equal to 20 revolutions/min, the slurry flow is less than or equal to 50L/min, and the pressure of high-pressure rotary spraying stirring is 20Mpa-25Mpa.
Furthermore, when the foundation pit is excavated, the anchor cable is required to be excavated layer by layer according to the designed anchor cable position, the layered thickness is less than or equal to 2m, and when the lower soil is excavated, the prestress rotary spraying anchor cable on the upper layer is required to be tensioned and anchored.
Further, the method also comprises the steps of:
h. before backfilling earthwork, the pull wire is controlled to pull out the pulling pin from the internal thread anchor, the connecting section is separated from the internal thread anchor by utilizing the prestress of the anchor cable and the thread angle between the connecting section and the internal thread anchor being larger than the self-locking angle, and the anchor cable is pulled out after external force is applied;
Or before backfilling earthwork, after the outer anchor head is disassembled to release the anchor cable, the pull wire is controlled to pull out the pull pin from the internal thread anchor, and the anchor cable is pulled out after external force is applied.
The invention has the beneficial effects that: the high-pressure rotary spraying recoverable anchor cable supporting construction method for the deep foundation pit adopts a high-pressure rotary spraying process and utilizes the drill rod to open the anchor holes, has all advantages of the high-pressure rotary spraying relative to other anchor technologies, brings the anchor assembly into a set anchor position, and has the advantages of simple construction process, high construction efficiency, firm foundation pit supporting structure and recoverable anchor cable, so that the aim of reducing the construction cost is fulfilled.
Drawings
The invention is further described below with reference to the drawings and examples.
FIG. 1 is a schematic view of a support structure formed by the method of the present invention;
Fig. 2 is a schematic view of a retractable cord assembly;
FIG. 3 is an enlarged view at A of FIG. 2;
Fig. 4 shows the distribution of anchors and bolts on the anchor plate.
Detailed Description
As shown in fig. 1-4: the deep foundation pit high-pressure rotary spraying recoverable anchor cable supporting construction method comprises the following steps:
a. Pouring a cast-in-place pile 1 at a set position and pouring a crown beam 101 on the cast-in-place pile 1; of course, in the construction, site investigation is required, then, the cast-in-place piles 1 are cast after drilling, and a plurality of cast-in-place piles are cast according to the required quantity and the space, so that the description is omitted; and pouring a crown beam between adjacent cast-in-place piles to serve as a bearing foundation for anchoring prestress, and details are omitted herein; the set position refers to the edge set position of the foundation pit to be excavated, and is not described in detail herein;
b. An anchoring via hole is formed in a relevant position of the crown beam 101, and the anchoring via hole is a hole for passing through a drill rod when the anchoring via hole is drilled and passing through an anchor cable when the anchoring via hole is anchored, and is not repeated herein;
before the anchor holes are positioned, cleaning soil layers on the surfaces of the bored piles, excavating a side slope on one side of the bored piles, and then hanging a net on the side slope for spraying slurry; when the anchoring hole is positioned, hole positions are determined according to the elevation and the horizontal distance required by design, and marks are made by self-spraying paint; after marking, an anchoring via hole is drilled at the marked position to form a drill bit positioning inclined hole, and in order to prevent the soil layer on the surface of the side slope from further weathering, peeling and sporadic falling blocks, a protective layer is formed on the side slope by adopting net hanging and shotcrete, so that the construction safety of the foundation pit can be achieved. In the construction process, the position of the anchor hole is required to be continuously supervised and controlled so as to avoid that a large barrier influences the pore-forming quality and the construction period guarantee, and ensure that the building construction engineering is smoothly developed;
c. Setting an anchoring hole for passing through an anchor rope assembly in a soil layer by drilling the anchoring position through the anchoring via hole, drilling by adopting a high-pressure rotary spraying process within the range of setting an anchoring body 5 when drilling the anchoring hole, and forming an enlarged end 6 at the bottom of the anchoring body 5; the high-pressure rotary spraying process is a process of spraying cement slurry into soil layers and mixing the cement slurry with soil bodies by using a high-pressure rotary nozzle to form a continuous cement anchoring body, and is not described in detail herein; the formation of the expansion end can be controlled by parameters such as rotary spraying pressure and the like, and the expansion end and the anchor body form an integral anchor body together, so that the diameter of the anchor body is larger, the stress level of soil around the anchor cable is effectively reduced, the plastic deformation of the anchor cable is reduced, and meanwhile, the expansion end enables the anchor body to further increase the bearing capacity, so that the length of the anchor body can be further shortened under the condition of the same bearing capacity, construction materials are saved, and the cost is further saved;
of course, anchoring via holes with fixed parameters (such as inclination angle, size and the like) are also required to be formed on the crown beam before the drilling is performed, and the drilling machine is positioned and drilled, so that the description is omitted;
the anchor cable assembly is a recyclable anchor cable assembly; the recoverable anchor cable assembly refers to an anchor cable assembly which releases and takes out an anchor cable from an anchoring state before or during backfilling of foundation pit earthwork, generally adopts threaded connection between the anchor cable and a bottom anchor head, and can be separated from anchoring by rotating the anchor cable when recovery is needed and pulled out by using external force, and the description is omitted here;
d. in the process of drilling the anchoring holes in the step c, the drill rod simultaneously brings the anchor cable assembly into the anchoring holes, and the bottom anchor head is arranged at the enlarged end of the anchoring body; the drill rod is utilized to bring the anchor cable assembly into the anchor cable assembly, and the anchor cable assembly can be realized in a more structural mode in the prior art and is not described in detail herein;
e. withdrawing the drill rod, and performing high-pressure rotary spraying in an anchoring body area, wherein the anchoring body area refers to a length area which is used for anchoring the anchor cable assembly in an anchoring hole and is not described in detail herein; of course, the anchor cable assembly needs to be left at a set position before the drill rod is withdrawn, and high-pressure rotary spraying is continued during withdrawal, so that the uniform stirring of the anchoring body is ensured, the diameter of the anchoring body is ensured, and the set bearing capacity is achieved;
f. the anchor body 5 is hardened to set indexes, and then the anchor cable assembly is tensioned and anchored; setting the index generally means that the hardening index of the anchoring body 5 reaches more than 80% for tensioning and anchoring, and the description is omitted here;
g. c, excavating a foundation pit according to the design, pouring a waist beam on the cast-in-place pile at the designed depth position, and repeating the steps c to f on the waist beam; repeating the steps c to f refers to repeating the anchoring processes of forming the anchoring via hole on the waist beam, drilling the anchoring hole and the like on the crown beam;
and (f) continuing deep digging the foundation pit according to the design requirement and repeating the step f.
In the embodiment, the deep foundation pit is a collapsible soil foundation pit, and in the step a, a waterproof curtain 2 is formed around the foundation pit by cement stirring piles, and the waterproof curtain is positioned at the outer side of the filling pile 1; the outer side refers to the side which is outwards relative to the foundation pit, and is not repeated here; the method is used for preventing or reducing the underground water on the side wall of the foundation pit and the bottom of the foundation pit from flowing into the foundation pit, and ensuring the subsequent construction.
In this embodiment, the recoverable anchor cable assembly includes an anchor cable 3, a pull pin 7 and a bottom anchor head 4, the bottom anchor head 4 includes an internal thread anchor 403 provided with an internal thread, a connecting section 301 is fixedly connected to the bottom end of the anchor cable 3, the connecting section 301 is in threaded fit with the internal thread anchor 403, and a lift angle of the thread is greater than a self-locking angle; the lead angle of the threaded connection is larger than the self-locking angle, and the threaded connection can naturally deviate when axial force (in the length direction) is applied;
The pull pin 7 is inserted into the connecting section 301 along the length direction and locked in the circumferential direction by the internal thread anchor 403, and the pull pin 7 can be pulled out to be separated from the internal thread anchor 403 and released; during anchoring, the pull pin 7 is inserted into the connecting section 301 and the internal thread anchor 403, so that the connecting section 301 and the internal thread anchor 403 are locked in the circumferential direction, and the thread pair is loaded and cannot be pulled out when tensile force in the length direction is applied; when the anchor cable 3 needs to be recovered, the pulling pin 7 is pulled out of the internal thread anchor 403, the relative freedom degree between the connecting section 301 and the internal thread anchor 403 in the circumferential direction is released, and the anchor cable 3 is directly separated from the internal thread anchor under the action of prestress due to the fact that the thread lift angle is larger than the self-locking angle, and the recovery is completed after external force is pulled out; the recovery anchor cable in the prior art is generally connected by screw threads or buckles, and is anchored underground for a long time, the screw threads are tightly combined, and the anchor cable has certain flexibility and unreliable rotation force transmission, so that the rotation anchor cable is laborious during recovery and has poor recovery effect; the invention directly utilizes the prestress effect to directly separate the anchor cable from the bottom anchor head, and the recovery process is simple and easy; of course, the external anchor head is firstly disassembled, the pulling pin is pulled out, and the anchor cable can be easily recycled after the anchor cable is rotated or directly pulled out.
In this embodiment, the cross section of the pull pin 7 is polygonal, the internal thread anchor is provided with an internal thread for connecting with a connecting section, the bottom of the internal thread forms a polygonal hole 4031 matched with the pull pin, and the connecting section is provided with a polygonal hole matched with the pull pin; as shown in the figure, lubricating grease is smeared when the pin and the thread pair are pulled out for use, so that the later pulling out is smooth; the polygonal structure ensures that the pin pulling force is reliable, has more stress surfaces and has better bearing capacity.
In this embodiment, the connection section 301 is further provided with an operation hole 3011 for placing and taking out the pull pin, and the pull wire 8 is provided along with the anchor cable 3, where the pull wire 8 is generally a steel wire or a thin steel strand; one end of the stay wire 8 passes through the operation hole 3011 to be fixedly connected to the pull pin 7, and the stay wire is realized through the existing mechanical connection structure, and the other end of the stay wire is exposed out of the outer anchor head; as shown in the figure, when the bottom anchor head 4 and the anchor cable 3 are implanted, the connecting section 301 is connected with the internal thread anchor device 403 in a threaded manner, the pulling pin is placed in the internal thread anchor device by utilizing the operation hole and extends downwards to form a circumferential fixing mode, the connecting section is of a hollow structure and is used for placing or taking out the pulling pin through the operation hole, a steering block is fixedly arranged in the hollow structure, the steering block is provided with a through hole which is opposite to the pulling pin in the length direction, the pulling wire 8 passes through the through hole of the steering block and is connected with the pulling pin 7, so that the pulling force directly acted on the pulling pin 7 by the pulling wire 8 is in the length direction, and the pulling of the pulling pin is convenient;
The anchor cable 3 is sleeved with the isolation tube 9, the isolation tube 9 is generally a PE tube, the pull wire 7 is positioned in the isolation tube 9, the isolation tube 9 is sleeved on the anchor cable 3 after the pulling pin is placed, the bottom end of the isolation tube is connected with the bottom anchor head 4 to form a seal, and the form of sealing and gluing and the like can be adopted to ensure that the anchor cable cannot be polluted or is poured by an anchoring body, so that the later recovery process is smoothly carried out.
In this embodiment, the bottom anchor head 4 further includes at least two anchor plates 401, 402 juxtaposed along a length direction, the anchor plates 401, 402 are fixedly connected by bolts 404, the internal thread anchor 403 is fixed on the anchor plates 401, 402, a reinforcement cage 405 is welded and connected with the anchor plates, and the length of the reinforcement cage 405 corresponds to the length of the anchor body 5; as shown, the female anchor 403 is fixed between anchor plates 401 and 402, and may be any mechanical fixing method in the prior art, including direct compression fixation by using bolts 404, which is not described herein;
As shown, the anchor disc 401 disposed outside is provided with an anchor cable via hole communicated with the internal thread anchor 403, and the connecting section 301 for the anchor cable 3 passes through and is connected to the internal thread anchor 403, which is not described herein again; the reinforcement cage 405 is used for supporting the anchor cable 3 and for forming an integral body with the anchoring section 6, increasing the anchoring strength.
In the embodiment, the drill rod is a hollow spiral drill pipe, nozzles are distributed at the end part of the drill bit and the side wings, and the front end is generally provided with two side wings to form high-pressure jet grouting; after the cement slurry is filtered in the stirring pool, the cement slurry is introduced into the drill rod by a high-pressure pump through a high-pressure guide pipe and is sprayed outwards from each nozzle of the drill bit, and soil on the periphery is synchronously cut in the cement slurry spraying process; the drill bit is gradually pushed forward under the power pushing until reaching the designed depth and diameter, so as to form an anchoring body; in construction, the high-pressure rotary spraying process has less disturbance to stratum and less influence on surrounding environment, so that the high-pressure rotary spraying mode sprays the mixture to soil body to form a cement soil pile body, and the cement and the soil body interact through physical and chemical reactions to finally form the bearing capacity required by the anchor section for supplying the anchor cable.
In step b, the high-pressure jet grouting process comprises the following steps of;
b1, filtering cement paste in a stirring pool, introducing the cement paste into a drill rod by a high-pressure pump through a high-pressure guide pipe, and spraying the cement paste outwards from the nozzle of a drill bit, wherein soil mass on the periphery is synchronously cut in the cement paste spraying process; the drill bit is gradually pushed forward under the power pushing and reaches the designed depth and diameter, so that the anchoring body is formed;
the bottom anchor head 4 and the anchor cable 3 are placed on the hollow drill rod and reach an anchoring position along with the hollow drill rod, and a structural mode that the bottom anchor head and the anchor cable enter along with the drill rod in the prior art can be adopted, so that the details are not repeated.
In the embodiment, the cement paste is prepared by mixing and stirring common silicate cement and water, the mixing amount of the anchoring body cement is 20%, and the water cement ratio is 0.5-0.7; during actual construction, cement paste is stirred through the paste barrel, so that uniform stirring and proper water-cement ratio are ensured, meanwhile, the cement paste is continuously stirred and used, the cement paste is used in a specified time period, the cement paste is sprayed to a soil body, and the effect of solidifying the body is achieved after physical and chemical reactions.
When the anchoring body is constructed, the drilling speed is less than or equal to 30cm/min, the rotating speed is less than or equal to 20 revolutions/min, the slurry flow is less than or equal to 50L/min, and the pressure of high-pressure rotary spraying stirring is 20Mpa-25Mpa; in this way, the pressure is controlled in the numerical range, and the condition that the ground outside the foundation pit is not influenced and slurry is not overflowed is taken as the premise, and the slurry spraying pressure, the rotation speed of a drill rod and the drilling lifting speed are adjusted in the process of rotary spraying grouting, so that the rotary spraying cylinder is well and uniformly formed; the high-pressure grouting is carried out in the anchoring hole, the advancing and retreating times of the rotary spraying stirring of the expansion head are increased twice compared with the pile body so as to ensure the diameter of the expansion head, and the diameters of the anchoring section and the expansion head can meet the design working condition requirement, and the consolidated body is formed and homogenized.
In the embodiment, when the foundation pit is excavated, the anchor cable is required to be excavated layer by layer according to the designed anchor cable position, the layered thickness is less than or equal to 2m, and when the lower soil is excavated, the prestressed rotary spraying anchor cable on the upper layer is required to be tensioned and anchored.
In this embodiment, the method further includes the steps of:
h. before backfilling earthwork, the pull wire is controlled to pull out the pulling pin from the internal thread anchor, the connecting section is separated from the internal thread anchor by utilizing the prestress of the anchor cable and the thread angle between the connecting section and the internal thread anchor being larger than the self-locking angle, and the anchor cable is pulled out after external force is applied;
as shown in the figure, the stay wire is accompanied with the anchor cable and extends out of a stay wire hole arranged on the external anchor head, and when the pulling pin is required to be pulled out, the anchor cable can be recovered by pulling out by using external force; of course, in order to prevent misoperation, a protection structure may be disposed on the external anchor head, which is not described herein again;
Or before backfilling earthwork, after the outer anchor head is disassembled to release the anchor cable, the pull wire is controlled to pull out the pull pin from the internal thread anchor, and the anchor cable is pulled out after external force is applied, so that the aim of the invention can be realized.
Finally, it is noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the technical solution of the present invention, which is intended to be covered by the scope of the claims of the present invention.
Claims (8)
1. A construction method for supporting a recoverable anchor rope by high-pressure jet grouting of a deep foundation pit is characterized by comprising the following steps: comprises the following steps:
a. Pouring a cast-in-place pile at a set position and pouring a crown beam on the cast-in-place pile;
b. An anchoring via hole is formed in the relevant position of the crown beam;
c. Setting an anchoring position in the soil layer through the anchoring via hole, drilling an anchoring hole for passing through the anchor cable assembly, drilling by adopting a high-pressure rotary spraying process within the range of setting an anchoring body when drilling the anchoring hole, and forming an enlarged end at the bottom of the anchoring body;
the anchor cable assembly is a recyclable anchor cable assembly;
d. In the process of drilling the anchoring holes in the step c, the drill rod simultaneously brings the anchor cable assembly into the anchoring holes, and the bottom anchor head is arranged at the enlarged end of the anchoring body;
e. Withdrawing the drill rod and performing high-pressure jet grouting in the anchoring body area;
f. Tensioning the anchor cable assembly and anchoring after the anchor body is hardened to set indexes;
g. Digging a foundation pit according to the design, pouring a waist beam on the cast-in-place pile at the designed depth position, forming an anchoring via hole on the waist beam, and repeating the steps c to f;
The recyclable anchor cable assembly comprises an anchor cable, a pulling pin and a bottom anchor head, wherein the bottom anchor head comprises an internal thread anchor device provided with internal threads, the bottom end of the anchor cable is fixedly connected with a connecting section, the connecting section is matched with the internal thread anchor device through threads, and the lead angle of the threads is larger than the self-locking angle;
the pulling pin is inserted into the connecting section along the length direction and locked in the circumferential direction, and can be pulled out to be separated from the inner threaded anchor and released;
The connecting section is also provided with an operation hole for placing and taking out the pulling pin, a pulling wire is arranged along with the anchor cable, one end of the pulling wire passes through the operation hole and is fixedly connected with the pulling pin, and the other end of the pulling wire is exposed out of the outer anchor head;
the anchor cable is sleeved with an isolation tube, and the stay wire is positioned in the isolation tube.
2. The deep foundation pit high-pressure rotary spraying recoverable anchor cable support construction method according to claim 1, wherein the construction method comprises the following steps: in the step a, a waterproof curtain is formed around the foundation pit by cement stirring piles, and the waterproof curtain is positioned at the outer side of the filling pile.
3. The deep foundation pit high-pressure rotary spraying recoverable anchor cable support construction method according to claim 1, wherein the construction method comprises the following steps: the cross section of the pulling pin is polygonal, the internal thread anchorage device is provided with an internal thread used for being connected with a connecting section, a polygonal hole matched with the pulling pin is formed at the bottom of the internal thread, and the connecting section is provided with a polygonal hole matched with the pulling pin.
4. The deep foundation pit high-pressure rotary spraying recoverable anchor cable support construction method according to claim 1, wherein the construction method comprises the following steps: the bottom anchor head further comprises at least two anchor plates which are parallel along the length direction, the anchor plates are fixedly connected through bolts, the internal thread anchorage device is fixed on the anchor plates, a reinforcement cage is arranged on the anchor plates in a welded connection mode, and the length of the reinforcement cage corresponds to that of the anchor body.
5. The deep foundation pit high-pressure rotary spraying recoverable anchor cable support construction method according to claim 4, wherein the construction method comprises the following steps: the drill rod is a hollow spiral drill pipe, and nozzles are distributed at the end part of the drill bit and on the side wings;
in step b, the high-pressure jet grouting process comprises the following steps of;
b1, filtering cement paste in a stirring pool, introducing the cement paste into a drill rod by a high-pressure pump through a high-pressure guide pipe, and spraying the cement paste outwards from the nozzle of a drill bit, wherein soil mass on the periphery is synchronously cut in the cement paste spraying process; the drill bit is gradually advanced under power to a designed depth and diameter to form the anchor body.
6. The deep foundation pit high-pressure rotary spraying recoverable anchor cable support construction method according to claim 5, wherein the construction method comprises the following steps: the cement slurry is prepared by mixing and stirring common silicate cement and water, the mixing amount of the anchoring body cement is 20%, and the water cement ratio is 0.5-0.7;
When the anchoring body is constructed, the drilling speed is less than or equal to 30cm/min, the rotating speed is less than or equal to 20 revolutions/min, the slurry flow is less than or equal to 50L/min, and the pressure of high-pressure rotary spraying stirring is 20Mpa-25Mpa.
7. The deep foundation pit high-pressure rotary spraying recoverable anchor cable support construction method according to claim 4, wherein the construction method comprises the following steps: when the foundation pit is excavated, the anchor cable is required to be excavated layer by layer according to the designed anchor cable position, the layered thickness is less than or equal to 2m, and when the lower soil is excavated, the prestress rotary spraying anchor cable on the upper layer is required to be tensioned and anchored.
8. The deep foundation pit high-pressure rotary spraying recoverable anchor cable support construction method according to claim 4, wherein the construction method comprises the following steps: the method also comprises the steps of:
h. before backfilling earthwork, the pull wire is controlled to pull out the pulling pin from the internal thread anchor, the connecting section is separated from the internal thread anchor by utilizing the prestress of the anchor cable and the thread angle between the connecting section and the internal thread anchor being larger than the self-locking angle, and the anchor cable is pulled out after external force is applied;
Or before backfilling earthwork, after the outer anchor head is disassembled to release the anchor cable, the pull wire is controlled to pull out the pull pin from the internal thread anchor, and the anchor cable is pulled out after external force is applied.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113585289A (en) * | 2021-09-18 | 2021-11-02 | 中冶建工集团有限公司 | Support method for collapse soil deep foundation pit |
| CN217782073U (en) * | 2022-05-30 | 2022-11-11 | 中冶建工集团有限公司 | Connecting component suitable for recoverable anchor rope |
| CN115652922A (en) * | 2022-05-30 | 2023-01-31 | 中冶建工集团有限公司 | Recoverable anchor subassembly of prefabricated concrete bottom anchor head |
| CN115652940A (en) * | 2022-05-30 | 2023-01-31 | 中冶建工集团有限公司 | Anchor component capable of recovering anchor cable |
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| EP1486617A1 (en) * | 2000-05-08 | 2004-12-15 | Dywidag-Systems International GmbH | Recoverable injection anchor |
| CN101949151A (en) * | 2010-09-28 | 2011-01-19 | 张继红 | Recyclable locking anchor rod and construction method thereof |
| CN102776881B (en) * | 2012-08-13 | 2015-02-25 | 杭州南联地基基础工程有限公司 | Recyclable post-tensioned prestressing anchor cable pile and construction method thereof |
| CN206298898U (en) * | 2016-11-18 | 2017-07-04 | 苏州市能工基础工程有限责任公司 | Hot melt anchor head |
| CN114134888B (en) * | 2021-10-26 | 2023-01-17 | 泛华建设集团有限公司 | Energy-gathering cutting type recyclable prestressed anchor cable and use method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113585289A (en) * | 2021-09-18 | 2021-11-02 | 中冶建工集团有限公司 | Support method for collapse soil deep foundation pit |
| CN217782073U (en) * | 2022-05-30 | 2022-11-11 | 中冶建工集团有限公司 | Connecting component suitable for recoverable anchor rope |
| CN115652922A (en) * | 2022-05-30 | 2023-01-31 | 中冶建工集团有限公司 | Recoverable anchor subassembly of prefabricated concrete bottom anchor head |
| CN115652940A (en) * | 2022-05-30 | 2023-01-31 | 中冶建工集团有限公司 | Anchor component capable of recovering anchor cable |
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