CN113668525A - Construction method of anti-floating anchor rod with water-drop-shaped enlarged head based on PSB finish-rolled deformed steel bar - Google Patents
Construction method of anti-floating anchor rod with water-drop-shaped enlarged head based on PSB finish-rolled deformed steel bar Download PDFInfo
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- CN113668525A CN113668525A CN202111031879.2A CN202111031879A CN113668525A CN 113668525 A CN113668525 A CN 113668525A CN 202111031879 A CN202111031879 A CN 202111031879A CN 113668525 A CN113668525 A CN 113668525A
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- 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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- 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
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D31/00—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution
- E02D31/02—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution against ground humidity or ground water
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D31/00—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution
- E02D31/10—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution against soil pressure or hydraulic pressure
- E02D31/12—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution against soil pressure or hydraulic pressure against upward hydraulic pressure
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Abstract
The invention belongs to the technical field of anti-floating anchor rods, and discloses a construction method of a drop-shaped enlarged footing anti-floating anchor rod based on PSB finish-rolled deformed steel bars, which aims to solve the problem that an anchoring body at a step of a large section of an enlarged footing of the conventional anti-floating anchor rod is easy to shear and crack. The invention comprises an anchor hole arranged in a soil body or a rock body, wherein PSB finish rolling deformed steel bars are sleeved in the anchor hole, an anchoring body is formed between the anchor hole and the PSB finish rolling deformed steel bars in a pouring way, the anchor hole comprises a non-expanding head section, a water drop-shaped expanding head section and an equal-diameter expanding head section which are sequentially communicated from top to bottom, and the diameter of the non-expanding head section of the anchor hole is gradually and smoothly expanded to the diameter of the equal-diameter expanding head section by the water drop-shaped expanding head section. According to the invention, the design of the water drop type head expanding section enables the anchoring body not to form a step surface, so that the shearing stress borne by the anchoring body is reduced, the generation of cracks of the anchoring body is controlled, the corrosion of PSB finish-rolled deformed steel bar is avoided, and the purpose of prolonging the service life of the anti-floating anchor rod is achieved.
Description
Technical Field
The invention belongs to the technical field of anti-floating anchor rods, and particularly relates to a construction method of a drop-shaped enlarged footing anti-floating anchor rod based on PSB finish-rolled deformed steel bars.
Background
The anti-floating anchor rod is a structural member arranged for resisting upward displacement of a building on the anti-floating anchor rod, is related to the height and change of an underground water level, and is opposite to the stress direction of a compression-resistant pile.
Anti-floating anchor includes ordinary anti-floating anchor and enlarged footing anti-floating anchor, and in order to improve the anti-floating ability of anti-floating anchor, enlarged footing anti-floating anchor has appeared, and enlarged footing anti-floating anchor is with the biggest difference of ordinary anti-floating anchor: the bottom of the anchor hole is provided with the enlarged head, and an enlarged head section is formed at the bottom of the anchor hole after pouring is finished, so that the anti-pulling capacity of the anti-floating anchor rod is improved. For example, the patent with application number 201220060959.0 discloses a bottom-expanded prestressed expanded head anti-floating anchor rod, which comprises a metal corrugated pipe penetrating through a waterproof bottom plate, wherein the metal corrugated pipe extends into the lower end part of an anchor rod hole at the lower part of the waterproof bottom plate, and the lower end part of the anchor rod hole is a rod end expanded head; a steel sleeve is embedded outside the metal corrugated pipe in the waterproof bottom plate; the metal corrugated pipe is penetrated with a steel strand, the upper end of the steel strand is fixed on the anchorage device, the lower end of the steel strand is anchored on the anchoring plate in the rod end expansion head, and the anchoring plate is arranged on the anchoring head; and a secondary grouting guide pipe is arranged between the metal corrugated pipe and the steel sleeve.
For another example, the invention patent with application number 201922255034.6 discloses a PSB finish rolling deformed steel bar expansion head anti-floating anchor rod structure, which comprises an expansion head hole, a non-expansion head hole, a PSB finish rolling deformed steel bar anchor rod body, a supporting body, a matched anchor plate and an anchor head; the PSB finish-rolled deformed steel anchor rod body is a round rod, a first through hole and a second through hole are formed in the matched anchor plate and the anchor head, the matched anchor plate and the anchor head are arranged at the upper end part of the PSB finish-rolled deformed steel anchor rod body and are matched with the outer circumferential surface of the PSB finish-rolled deformed steel anchor rod body through the first through hole and the second through hole respectively, the matched anchor plate is arranged at the lower end of the anchor head, and the upper surface of the matched anchor plate is attached to the lower surface of the anchor head; the expanded head hole and the non-expanded head hole are formed in a soil body or a rock body at the lower part of a building foundation or a water-resistant plate, the expanded head hole is communicated with the non-expanded head hole, the expanded head hole is arranged at the lower end of the non-expanded head hole, and the PSB finish-rolled deformed steel bar anchor rod body is arranged inside the expanded head hole and the non-expanded head hole and is communicated with the expanded head hole and the non-expanded head hole; and cement grout or filling concrete is injected into the enlarged head hole and the non-enlarged head hole.
For another example, the invention patent with application number 202021002179.1 discloses an anti-cracking prestressed enlarged footing anti-floating anchor rod and a construction method of an anti-cracking PSB finish-rolled deformed steel bar-based water-droplet-shaped enlarged footing anti-floating anchor rod, which comprises an anchor hole formed in a soil body, wherein the anchor hole comprises an enlarged head section and a non-enlarged head section, the diameter of the enlarged head section is larger than that of the non-enlarged head section, finish-rolled deformed steel bars are arranged in the anchor hole, concrete is poured between the anchor hole and the finish-rolled deformed steel bars, a steel sleeve is sleeved on the top section of the anchor hole, an anchor plate is fixedly connected to the top of the steel sleeve, and the top of the finish-rolled deformed steel bars sequentially penetrates through the steel sleeve and the anchor plate and is in threaded connection with a nut for applying prestress.
As the enlarged head large anti-floating anchor rod as described by the example, the anchor hole comprises the free section and the anchoring section, the diameter of the anchoring section is larger than that of the free section so as to form the enlarged head, however, a step is formed between the enlarged head section (anchoring section) and the non-enlarged head section (free section) in the prior art, and no smooth transition exists between the enlarged head section and the non-enlarged head section, so that the problem that the anchoring body (grouting body) is easily sheared and cracked at the step due to stress concentration is caused, the problem that PSB finish rolling deformed steel bar corrodes exists after the anchoring body is cracked at the step, and the service life of the anti-floating anchor rod is shortened.
Disclosure of Invention
The invention provides a construction method of a drop-shaped enlarged head anti-floating anchor rod based on PSB finish-rolled deformed steel bar, aiming at solving the problem that an anchoring body at the step of the enlarged head large section of the existing anti-floating anchor rod is easy to shear and crack, and the drop-shaped enlarged head anti-floating anchor rod enables the enlarged head section and the non-enlarged head section to be in smooth transition, so that the shear stress borne by the anchoring body is reduced, the generation of cracks of the anchoring body is controlled, the PSB finish-rolled deformed steel bar is prevented from being corroded, and the purpose of prolonging the service life of the anti-floating anchor rod is achieved.
In order to solve the technical problem, the technical scheme adopted by the invention is as follows:
a construction method of a water-drop-shaped enlarged footing anti-floating anchor rod based on PSB finish-rolled deformed steel bar comprises an anchor hole formed in a soil body or a rock body, the PSB finish-rolled deformed steel bar is sleeved in the anchor hole, and an anchoring body is formed between the anchor hole and the PSB finish-rolled deformed steel bar in a pouring mode; the construction method of the anti-floating anchor rod with the water-drop-shaped enlarged head based on PSB finish-rolled deformed steel bars comprises the following steps:
(1) pile position arrangement: determining the position of an anti-floating anchor rod in a construction area;
(2) drilling a hole to form an anchor hole along the pipe: after the position of the anchor rod hole is determined, drilling the hole with a hydraulic anchor rod drilling machine along with a pipe to form an anchor hole;
(3) cleaning holes and lifting the drill: after the anchor hole is formed, high-pressure air is used for removing residues in the hole until the mouth of the anchor hole returns to the air and the hand feeling is free of dust;
(4) anchor rod preparation, installation: setting the length of the PSB finish-rolled deformed steel bar according to design requirements, mounting a plurality of supporting bodies on the PSB finish-rolled deformed steel bar, and placing the PSB finish-rolled deformed steel bar into an anchor hole after checking and acceptance;
(5) tube drawing; after the PSB finish-rolled deformed steel bar is placed, a hydraulic pipe drawer is used for pulling out the sleeve, so that the PSB finish-rolled deformed steel bar is prevented from being pulled out when the sleeve is pulled out;
(6) high-pressure rotary spraying: adopting high-pressure rotary jet grouting: moving the spraying trolley to a hole forming position, firstly carrying out slurry and gas trial spraying on the ground, lowering the spraying pipe to the designed depth after checking that all process parameters meet the design requirements, firstly sending high-pressure water, then sending slurry, then carrying out rotary spraying on the bottom for 1 minute, and spraying slurry while rotating after the preset spraying pressure and spraying amount are reached; lifting from bottom to top according to the designed lifting mode and speed; when the construction of the equal-diameter expanding head section is finished, the grouting pressure is changed to construct the water-drop-shaped expanding head section, the grouting pressure is gradually reduced along with the lifting of the injection pipe, and the grouting pressure is gradually reduced to 1Mpa when the construction of the water-drop-shaped expanding head section is finished; continuously installing the pressure construction with the grouting pressure of 1Mpa at the non-expansion section until the design elevation; when the high-pressure rotary spraying forms the anchoring body: the water-cement ratio of the slurry is not more than 0.6; slurry flow rate: 60-100L/min; nozzle aperture: phi is 3 mm; lifting speed of the injection pipe: 0.1-0.2 m/min; nozzle rotation speed: 20 r/mmin; wherein, when the equal diameter expanding head section is sprayed, the grouting pressure of the grout is 20-30 Mpa.
(7) After the high-pressure rotary jet injection is finished, static pressure filling grouting is carried out in the injection hole immediately until the grout surface does not sink any more; checking after two hours of grouting, and if cement slurry is lost, performing slurry supplement;
(8) applying prestress: the prestress can be applied after the strength of the cushion concrete reaches 75 percent.
The construction method of the anti-floating anchor rod with the water-drop-shaped enlarged head based on PSB finish-rolled deformed steel bars comprises the following steps:
(1) pile position arrangement: determining the position of an anti-floating anchor rod in a construction area;
(2) drilling a hole to form an anchor hole along the pipe: after the position of the anchor rod hole is determined, drilling the hole with a hydraulic anchor rod drilling machine along with a pipe to form an anchor hole;
(3) cleaning holes and lifting the drill: after the anchor hole is formed, high-pressure air is used for removing residues in the hole until the mouth of the anchor hole returns to the air and the hand feeling is free of dust;
(4) anchor rod preparation, installation: setting the length of the PSB finish-rolled deformed steel bar according to design requirements, mounting a plurality of supporting bodies on the PSB finish-rolled deformed steel bar, and placing the PSB finish-rolled deformed steel bar into an anchor hole after checking and acceptance;
(5) tube drawing; after the PSB finish-rolled deformed steel bar is placed, a hydraulic pipe drawer is used for pulling out the sleeve, so that the PSB finish-rolled deformed steel bar is prevented from being pulled out when the sleeve is pulled out;
(6) high-pressure rotary spraying: adopting high-pressure rotary jet grouting: moving the spraying trolley to a hole forming position, firstly carrying out slurry and gas trial spraying on the ground, lowering the spraying pipe to the designed depth after checking that all process parameters meet the design requirements, firstly sending high-pressure water, then sending slurry, then carrying out rotary spraying on the bottom for 1 minute, and spraying slurry while rotating after the preset spraying pressure and spraying amount are reached; lifting from bottom to top according to the designed lifting mode and speed; when the construction of the equal-diameter expanding head section is finished, the grouting pressure is changed to construct the water-drop-shaped expanding head section, the grouting pressure is gradually reduced along with the lifting of the injection pipe, and the grouting pressure is reduced to 1Mpa when the construction of the water-drop-shaped expanding head section is finished; continuously installing the pressure construction with the grouting pressure of 1Mpa at the non-expansion section until the design elevation; when the high-pressure rotary spraying forms the anchoring body: the water-cement ratio of the slurry is not more than 0.6; slurry flow rate: 60-100L/min; nozzle aperture: phi is 3 mm; lifting speed of the injection pipe: 0.1-0.2 m/min; nozzle rotation speed: 20 r/mmin; wherein, when the equal diameter expanding head section is sprayed, the grouting pressure of the grout is 20-30 Mpa.
(7) After the high-pressure rotary jet injection is finished, static pressure filling grouting is carried out in the injection hole immediately until the grout surface does not sink any more; checking after two hours of grouting, and if cement slurry is lost, performing slurry supplement;
(8) applying prestress: the prestress can be applied after the strength of the cushion concrete reaches 75 percent.
In some embodiments, the periphery of the PSB finish rolled deformed steel bar is sleeved with an anti-corrosion sleeve, the anti-corrosion sleeve is filled with anti-corrosion grease, and the lower end of the anti-corrosion sleeve is provided with a flexible sealing ring for preventing the anti-corrosion grease from flowing out.
In some embodiments, the lower end of the corrosion protection sleeve extends to a drop-shaped enlarged head section of the anchor eye.
In some embodiments, a plurality of supporting bodies are arranged on the PSB finish-rolled deformed steel bar in the equal-diameter expansion head section, or a bearing plate and an anchor head are sleeved on the lower end of the PSB finish-rolled deformed steel bar in the equal-diameter expansion head section.
In some embodiments, a cushion layer is poured at the upper end of the anchor hole, and the cushion layer is characterized in that an anchor pier with the upper end size larger than the lower end size is poured at the position of the cushion layer corresponding to the center of the anchor hole, the size of the lower end of the anchor pier is larger than or equal to the diameter of the anchor hole, the center of the anchor pier corresponds to the center of the anchor hole, the lower end of the PSB finish-rolled deformed steel bar penetrates through the anchor pier and extends into the anchor hole, a spiral rib is further arranged in the anchor pier, and a central hole for the PSB finish-rolled deformed steel bar to penetrate through is formed in the middle of the spiral rib.
In some embodiments, at least two diagonal reinforcements are connected to the periphery of the spiral reinforcement, one end of each diagonal reinforcement is connected to the lower end of the spiral reinforcement, and the other end of each diagonal reinforcement is connected to a horizontal reinforcement implanted in the horizontal section of the cushion layer.
In some embodiments, the diagonal draw bars are symmetrically connected to the periphery of the spiral bars.
In some embodiments, the upper end of the PSB finish-rolled deformed steel bar passes through the central hole of the spiral rib and out of the cushion layer and is sleeved with a pre-stressed mating anchor plate, the pre-stressed mating anchor plate is provided with a pre-stressed mating anchor head, and the lower end surface of the pre-stressed mating anchor plate is in contact with the upper end surface of the cushion layer.
In some embodiments, the PSB finish-rolled deformed steel bar at the upper end of the prestressed mating anchor head is further sleeved with a mating anchor plate and a mating anchor head.
In some embodiments, a foundation or water-resistant plate is further poured above the cushion layer, and the prestress mating anchor plate and the mating anchor plate are positioned in the foundation or water-resistant plate.
Compared with the prior art, the invention has the following beneficial effects:
according to the construction method of the anti-floating anchor rod with the water-drop-shaped enlarged head based on the PSB finish rolled deformed steel bar, the water-drop-shaped enlarged head section is arranged between the non-enlarged head section and the equal-diameter enlarged section, so that the diameter of the anchor hole is gradually and smoothly transited from the bottom of the non-enlarged head section to the top of the equal-diameter enlarged head section, the anchoring body cannot form a step surface, the shearing stress on the anchoring body is reduced, the generation of cracks of the anchoring body is controlled, the PSB finish rolled deformed steel bar is prevented from being corroded, and the purpose of prolonging the service life of the anti-floating anchor rod is achieved. Meanwhile, by utilizing the construction method of the invention and utilizing high-pressure grouting to control the technological parameters during grouting, the method has the characteristics of good molding quality and high molding speed of the water drop-shaped expansion section and the equal-diameter expansion section, thereby ensuring that the anchoring body cannot form a step surface which is easy to generate cracks.
Meanwhile, the anchor piers corresponding to the anchor hole positions are arranged in the middle of the cushion layer, the spiral ribs are arranged in the anchor piers, the anchor piers can provide good support when prestress is applied to PSB finish rolling deformed steel bars, and the spiral ribs and the diagonal draw steel bars can restrict horizontal deformation of anchor pier concrete, so that the overall strength of the anchor piers is greatly improved, and shear damage caused by insufficient shear strength of concrete (cushion layer) is avoided. Through when exerting prestressing force, the effort that prestressed anchorage board fed back to the anchor block passes through the effect of spiral muscle, diagonal reinforcement and horizontal muscle and concreting, progressively transmits whole bed course with the concentrated atress of anchor block part to avoided the easy problem of damaging of bed course, avoided the prestressing force loss's that brings because of the bed course damage problem simultaneously. And the damage of the cushion layer can directly result in the loss of the applied prestress, so that the prestress of the anti-floating anchor rod cannot meet the design requirement, and a larger potential safety hazard is caused.
Drawings
FIG. 1 is a schematic structural diagram of an embodiment of the present invention;
fig. 2 is a schematic structural view of another embodiment of the anti-floating anchor according to the present invention at a cushion layer;
the labels in the figure are: 1. anchor eye, 101, non-enlarged head section, 102, water drop shape enlarged head section, 103, equal diameter enlarged head section, 2, PSB finish rolling deformed steel bar, 3, anticorrosive casing, 4, flexible sealing gasket, 5, supporting body, 6, cushion layer, 7, prestress supporting anchor plate, 8, prestress supporting anchor head, 9, supporting anchor plate, 10, supporting anchor head, 11, foundation or water-resistant plate, 12, anchor pier, 13, spiral rib, 14, diagonal reinforcement, 15, horizontal rib.
Detailed Description
The present invention will be further described with reference to the following examples, which are intended to illustrate only some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, other embodiments used by those skilled in the art without any creative effort belong to the protection scope of the present invention.
With reference to the attached drawing 1, the construction method of the anti-floating anchor rod with the water-drop-shaped enlarged head based on the PSB finish-rolled deformed steel bars, disclosed by the invention, comprises an anchor hole 1 formed in a soil body or a rock body, the PSB finish-rolled deformed steel bars 2 are sleeved in the anchor hole 1, an anchoring body is formed between the anchor hole 1 and the PSB finish-rolled deformed steel bars 2 in a pouring manner, the anchor hole 1 comprises a non-enlarged head section 101, a water-drop-shaped enlarged head section 102 and an equal-diameter enlarged head section 103 which are sequentially communicated from top to bottom, and the diameter of the non-enlarged head section 101 of the anchor hole is gradually and smoothly enlarged to the diameter of the equal-diameter enlarged head section by the water-drop-shaped enlarged head section 102. The PSB finish-rolled deformed steel bar 2 can be a common steel bar or a PSB finish-rolled deformed steel bar. According to the construction method of the anti-floating anchor rod with the water-drop-shaped enlarged head based on the PSB finish rolled deformed steel bar, the water-drop-shaped enlarged head section is arranged between the non-enlarged head section and the equal-diameter enlarged section, so that the diameter of the anchor hole is gradually and smoothly transited from the bottom of the non-enlarged head section to the top of the equal-diameter enlarged head section, the anchoring body cannot form a step, the shearing stress on the anchoring body is reduced, the generation of cracks of the anchoring body is controlled, the PSB finish rolled deformed steel bar is prevented from being corroded, and the purpose of prolonging the service life of the anti-floating anchor rod is achieved.
The drop-shaped enlarged head section disclosed by the invention means that the diameter of the anchor hole is gradually changed, so that the sudden change of the diameter is avoided, and a step surface cannot be formed on the poured anchor body.
The construction method of the anti-floating anchor rod with the water-drop-shaped enlarged head based on PSB finish-rolled deformed steel comprises the following steps:
(1) pile position arrangement: determining the position of an anti-floating anchor rod in a construction area;
(2) drilling a hole to form an anchor hole along the pipe: after the position of an anchor rod hole is determined, a hydraulic anchor rod drilling machine is used for drilling along with a pipe (a drill rod is added and a sleeve pipe is added at the same time) to form the anchor hole, high-pressure air generated by an air compressor is used for deslagging, and the hole forming depth is required to be larger than the design depth of 200 mm; when the design depth is reached but the bottom of the soft layer is the weak layer, the drilling process is continued to penetrate through the lower soft layer and enter the lower stable rock-soil layer by more than 1.0m (namely, the bearing stratum). After the designed depth is reached, the drilling cannot be stopped immediately, the drilling is stabilized for 1-2 min, and the situation that the designed diameter of the anchor rod and the grouting filling degree cannot be reached at the bottom end is prevented.
(3) Cleaning holes and lifting the drill: after the anchor hole is formed, high-pressure air is used for removing residues in the hole until the mouth of the anchor hole returns to the air and the hand feeling is free of dust; and the existence of sediments in the hole is avoided, and whether the hole depth and the skewness of the anchor hole meet the requirements or not is detected.
(4) Anchor rod preparation, installation: setting the length of the PSB finish-rolled deformed steel bar according to design requirements, mounting a plurality of supporting bodies on the PSB finish-rolled deformed steel bar, and placing the PSB finish-rolled deformed steel bar into an anchor hole after checking and acceptance; the PSB finish rolling deformed steel bar is corresponding to the center of the positive anchor hole, the length of the PSB finish rolling deformed steel bar is correctly calculated, and the anchoring length in the bottom plate is ensured.
(5) Tube drawing; after the PSB finish-rolled deformed steel bar is placed, a hydraulic pipe drawer is used for pulling out the sleeve, so that the PSB finish-rolled deformed steel bar is prevented from being pulled out when the sleeve is pulled out;
(6) high-pressure rotary spraying: adopting high-pressure rotary jet grouting: moving the spraying trolley to a hole forming position, firstly carrying out slurry and gas trial spraying on the ground, lowering the spraying pipe to the designed depth after checking that all process parameters meet the design requirements, firstly sending high-pressure water, then sending slurry, then carrying out rotary spraying on the bottom for 1 minute, and spraying slurry while rotating after the preset spraying pressure and spraying amount are reached; lifting from bottom to top according to the designed lifting mode and speed; when the construction of the equal-diameter expanding head section is finished, the grouting pressure is changed to construct the water-drop-shaped expanding head section, the grouting pressure is gradually reduced along with the lifting of the injection pipe, and the grouting pressure is gradually reduced to 1Mpa when the construction of the water-drop-shaped expanding head section is finished; continuously installing the pressure construction with the grouting pressure of 1Mpa at the non-expansion section until the design elevation; when the high-pressure rotary spraying forms the anchoring body: the water-cement ratio of the slurry is not more than 0.6; slurry flow rate: 60-100L/min; nozzle aperture: phi is 3 mm; lifting speed of the injection pipe: 0.1-0.2 m/min; nozzle rotation speed: 20 r/mmin; wherein, when the equal diameter expanding head section is sprayed, the grouting pressure of the grout is 20-30 Mpa.
(7) After the high-pressure rotary jet injection is finished, static pressure filling grouting is carried out in the injection hole immediately until the grout surface does not sink any more; checking after two hours of grouting, and if cement slurry is lost, performing slurry supplement;
(8) applying prestress: the prestress can be applied after the strength of the cushion concrete reaches 75 percent. Wherein the pre-stressed mating anchor head 8 is locked after the pre-stress is applied.
In some embodiments, the periphery of the PSB finish-rolled deformed steel bar 2 is sleeved with an anti-corrosion sleeve 3, the anti-corrosion sleeve 3 is filled with anti-corrosion grease, and the lower end of the anti-corrosion sleeve 3 is provided with a flexible sealing ring 4 for preventing the anti-corrosion grease from flowing out. Wherein, the corrosion-proof sleeve 3 and the flexible sealing ring 4 are both products in the prior art, and can be understood and understood by those skilled in the art, and are not described in detail herein. The corrosion-resistant sleeve 3, the corrosion-resistant grease and the flexible sealing ring 4 are arranged to facilitate corrosion-resistant protection of the PSB finish-rolled deformed steel bar.
In some embodiments, the lower end of the corrosion protection sleeve 3 extends to the drop-shaped enlarged head section 102 of the anchor eye 1. Compared with the prior art, the invention can also reduce the length (depth) of the equal-diameter expanding head section 103 under the action of the holding force of the water-drop-shaped expanding head section 102, thereby being convenient for improving the construction efficiency of the anti-floating anchor rod.
In the prior art, the non-expansion head section is not considered when calculating the holding power due to the decision of geological conditions (soft soil layers), so that the anchoring sections (holding power sections) are all in the expansion head section, the design length (depth) of the expansion head section is longer, and the construction speed of an anchor hole is lower. Due to the design of the water-drop-shaped enlarged head section 102, part of the soft soil layer can be used as a supporting section or supplement of the supporting section, so that the length (depth) of the equal-diameter enlarged head section is reduced, and the forming speed of the anchor hole is increased.
In some embodiments, when the anti-floating anchor is a tension-compression type prestressed anti-floating anchor, a plurality of supporting bodies 5 are disposed on the PSB finish-rolled deformed steel bar 2 located in the equal-diameter enlarged head section 103. When the anti-floating anchor rod is a pressure type anti-floating anchor rod, the lower end of the PSB finish-rolled deformed steel bar 2 positioned at the equal-diameter enlarged head section 103 is sleeved with a bearing plate and an anchor head.
In some embodiments, a cushion layer 6 is poured on the upper end of the anchor hole 1, an anchor pier 12 with the upper end size larger than the lower end size is poured on the cushion layer 6 corresponding to the center of the anchor hole 1, the lower end size of the anchor pier 12 is larger than or equal to the diameter of the anchor hole 1, the center of the anchor pier 12 corresponds to the center of the anchor hole 1, wherein the anchor pier 12 can be in a circular truncated cone shape, a prismatic shape and the like, for convenience of construction, as a preferred mode of the invention, the anchor pier 12 is in a circular truncated cone shape with a large upper end and a small lower end, the lower end of the PSB finish-rolled deformed steel bar 2 penetrates through the anchor pier 12 and extends into the anchor hole 1, a spiral rib 13 is further arranged in the anchor pier 12, and the middle part of the spiral rib 13 is provided with a central hole for the PSB finish-rolled deformed steel bar 2 to penetrate through.
In some embodiments, at least two diagonal reinforcements 14 are connected to the periphery of the spiral reinforcement 13, one end of each diagonal reinforcement 14 is connected to the lower end of the spiral reinforcement 13, and the other end of each diagonal reinforcement 14 is connected to a horizontal reinforcement 15 embedded in the horizontal section of the cushion layer 6.
In a preferred embodiment of the present invention, the diagonal reinforcement 14 is disposed along a direction parallel to the outer surface of the anchor pier 12, that is, the diagonal reinforcement 14 is disposed along the slope of the outer surface of the anchor pier 12. The stress of the diagonal reinforcing steel bars 14 and the anchor pier 12 is more uniform, and the bearing capacity is further improved.
In some embodiments, to improve the uniformity of the force, the diagonal draw bars 14 are symmetrically connected to the periphery of the spiral bars 13.
In some embodiments, the PSB finish-rolled deformed steel bar 2 of the anti-floating anchor rod has an upper end passing through the center hole of the spiral rib 13 and penetrating through the cushion layer 6 and sleeved with a pre-stress mating anchor plate 7, the pre-stress mating anchor rod 7 is provided with a pre-stress mating anchor head 8, and a lower end surface of the pre-stress mating anchor plate 7 is in contact with an upper end surface of the cushion layer 6.
In some embodiments, the PSB finish-rolled deformed steel bar 2 at the upper end of the prestressed complementary anchor head 8 is further provided with a complementary anchor plate 9 and a complementary anchor head 10.
In some embodiments, a foundation or water-resistant plate 11 is further poured above the cushion layer 6, and the prestressed complementary anchor plate 9 and the complementary anchor plate 10 are positioned in the foundation or water-resistant plate 11.
According to the invention, the anchor piers corresponding to the anchor hole positions are arranged in the middle of the cushion layer, and the spiral bars are arranged in the anchor piers, so that the anchor piers can provide good support when prestress is applied to PSB finish rolling deformed steel bars, and the spiral bars and the diagonal draw bars can restrict horizontal deformation of anchor pier concrete, thereby greatly improving the overall strength of the anchor piers and avoiding shear damage caused by insufficient shear strength of concrete (cushion layer). Through when exerting prestressing force, the effort that prestressed anchorage board fed back to the anchor block passes through the effect of spiral muscle, diagonal reinforcement and horizontal muscle and concreting, progressively transmits whole bed course with the concentrated atress of anchor block part to avoided the easy problem of damaging of bed course, avoided the prestressing force loss's that brings because of the bed course damage problem simultaneously. And the damage of the cushion layer can directly result in the loss of the applied prestress, so that the prestress of the anti-floating anchor rod cannot meet the design requirement, and a larger potential safety hazard is caused.
Claims (10)
1. The construction method of the anti-floating anchor rod with the water-drop-shaped enlarged head based on the PSB finish-rolled deformed steel bar is characterized in that the anti-floating anchor rod with the water-drop-shaped enlarged head based on the PSB finish-rolled deformed steel bar comprises an anchor hole formed in a soil body or a rock body, the PSB finish-rolled deformed steel bar is sleeved in the anchor hole, and an anchoring body is formed between the anchor hole and the PSB finish-rolled deformed steel bar in a pouring mode; the construction method of the anti-floating anchor rod with the water-drop-shaped enlarged head based on PSB finish-rolled deformed steel bars comprises the following steps:
(1) pile position arrangement: determining the position of an anti-floating anchor rod in a construction area;
(2) drilling a hole to form an anchor hole along the pipe: after the position of the anchor rod hole is determined, drilling the hole with a hydraulic anchor rod drilling machine along with a pipe to form an anchor hole;
(3) cleaning holes and lifting the drill: after the anchor hole is formed, high-pressure air is used for removing residues in the hole until the mouth of the anchor hole returns to the air and the hand feeling is free of dust;
(4) anchor rod preparation, installation: setting the length of the PSB finish-rolled deformed steel bar according to design requirements, mounting a plurality of supporting bodies on the PSB finish-rolled deformed steel bar, and placing the PSB finish-rolled deformed steel bar into an anchor hole after checking and acceptance;
(5) tube drawing; after the PSB finish-rolled deformed steel bar is placed, a hydraulic pipe drawer is used for pulling out the sleeve, so that the PSB finish-rolled deformed steel bar is prevented from being pulled out when the sleeve is pulled out;
(6) high-pressure rotary spraying: adopting high-pressure rotary jet grouting: moving the spraying trolley to a hole forming position, firstly carrying out slurry and gas trial spraying on the ground, lowering the spraying pipe to the designed depth after checking that all process parameters meet the design requirements, firstly sending high-pressure water, then sending slurry, then carrying out rotary spraying on the bottom for 1 minute, and spraying slurry while rotating after the preset spraying pressure and spraying amount are reached; lifting from bottom to top according to the designed lifting mode and speed; when the construction of the equal-diameter expanding head section is finished, the grouting pressure is changed to construct the water-drop-shaped expanding head section, the grouting pressure is gradually reduced along with the lifting of the injection pipe, and the grouting pressure is gradually reduced to 1Mpa when the construction of the water-drop-shaped expanding head section is finished; continuously installing the pressure construction with the grouting pressure of 1Mpa at the non-expansion section until the design elevation; when the high-pressure rotary spraying forms the anchoring body: the water-cement ratio of the slurry is not more than 0.6; slurry flow rate: 60-100L/min; nozzle aperture: phi is 3 mm; lifting speed of the injection pipe: 0.1-0.2 m/min; nozzle rotation speed: 20 r/mmin; wherein, when the equal diameter expanding head section is sprayed, the grouting pressure of the grout is 20-30 Mpa;
(7) after the high-pressure rotary jet injection is finished, static pressure filling grouting is carried out in the injection hole immediately until the grout surface does not sink any more; checking after two hours of grouting, and if cement slurry is lost, performing slurry supplement;
(8) applying prestress: the prestress can be applied after the strength of the cushion concrete reaches 75 percent.
2. The construction method of the PSB finish-rolled deformed steel bar-based water drop-shaped enlarged footing anti-floating anchor rod according to claim 1, is characterized in that an anti-corrosion sleeve is sleeved on the periphery of the PSB finish-rolled deformed steel bar, anti-corrosion grease is filled in the anti-corrosion sleeve, and a flexible sealing ring for preventing the anti-corrosion grease from flowing out is installed at the lower end of the anti-corrosion sleeve.
3. The construction method of the PSB finish-rolled deformed steel bar-based water droplet-shaped enlarged head anti-floating anchor rod according to claim 2, wherein the lower end of the corrosion-resistant sleeve extends to the water droplet-shaped enlarged head section of the anchor hole.
4. The construction method of the anti-floating anchor rod with the water drop-shaped enlarged head based on the PSB finish-rolled deformed steel bar as claimed in any one of claims 1 to 3, wherein a plurality of supporting bodies are provided on the PSB finish-rolled deformed steel bar in the equal-diameter enlarged head section, or a bearing plate and an anchor head are sleeved on the lower end of the PSB finish-rolled deformed steel bar in the equal-diameter enlarged head section.
5. The construction method of the anti-floating anchor rod with the water drop-shaped enlarged footing based on the PSB finish-rolled deformed steel bar as claimed in any one of claims 1-3, wherein a cushion layer is poured on the upper end of the anchor hole, an anchor block with the size of the upper end larger than that of the lower end is poured on the cushion layer corresponding to the center of the anchor hole, the size of the lower end of the anchor block is larger than or equal to the diameter of the anchor hole, the center of the anchor block and the center of the anchor hole correspond to each other, the lower end of the PSB finish-rolled deformed steel bar penetrates through the anchor block and extends into the anchor hole, a spiral rib is further arranged in the anchor block, and the middle of the spiral rib is provided with a central hole for the PSB finish-rolled deformed steel bar to penetrate through.
6. The construction method of the PSB finish-rolled deformed steel bar-based water droplet-shaped enlarged footing anti-floating anchor rod of claim 5, wherein the periphery of the spiral rib is connected with at least two diagonal reinforcing bars, one end of each diagonal reinforcing bar is connected with the lower end of the spiral rib, and the other end of each diagonal reinforcing bar is connected with a horizontal rib implanted into the horizontal section of the cushion layer.
7. The construction method of the PSB finish-rolled deformed steel bar-based water droplet-shaped enlarged footing anti-floating anchor rod of claim 6, wherein the diagonal reinforcing bars are symmetrically connected to the periphery of the spiral bars.
8. The construction method of the PSB finish-rolled deformed steel bar-based water droplet-shaped enlarged footing anti-floating anchor rod according to claim 6, wherein the upper end of the PSB finish-rolled deformed steel bar passes through the center hole of the spiral rib and out of the cushion layer and is sleeved with a pre-stressed mating anchor plate, the pre-stressed mating anchor rod is provided with a pre-stressed mating anchor head, and the lower end surface of the pre-stressed mating anchor plate is in contact with the upper end surface of the cushion layer.
9. The construction method of the PSB finish-rolled deformed steel bar-based water droplet-shaped enlarged footing anti-floating anchor rod of claim 8, wherein the PSB finish-rolled deformed steel bar positioned at the upper end of the prestressed mating anchor head is further sleeved with a mating anchor plate and a mating anchor head.
10. The construction method of the PSB finish-rolled deformed steel bar-based water droplet-shaped enlarged footing anti-floating anchor rod according to claim 9, wherein a foundation or a water-resistant plate is further poured above the cushion layer, and the pre-stressed mating anchor plate and the mating anchor plate are located in the foundation or the water-resistant plate.
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| CN114482142A (en) * | 2022-02-14 | 2022-05-13 | 青岛理工大学 | Major diameter finish rolling screw-thread steel anti-floating anchor rod |
| CN115369929A (en) * | 2022-09-22 | 2022-11-22 | 中国五冶集团有限公司 | Post-cast anti-floating anchor rod construction method |
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