CN115573348A - Recyclable prestressed anchor cable for foundation pit support and construction method thereof - Google Patents

Abstract

The invention discloses a recoverable prestressed anchor cable for foundation pit support and a construction method thereof, wherein the recoverable prestressed anchor cable comprises a separable anchor plate and a rubber ring fixed outside the separable anchor plate, and the separable anchor plate is provided with a slurry passing through hole, a grouting through hole and a steel strand installation through hole; a conical breaker is arranged in the grouting through hole, a steel strand penetrates through the steel strand mounting through hole, and a steel strand extrusion head is fixed at the insertion end of the steel strand; a steel strand sleeve is arranged outside the steel strand, and one end of the steel strand sleeve is fixed on the separable anchor plate; the conical breaking device is a hollow pipe, and a grouting pipe is also arranged in the conical breaking device; the separated anchor plate comprises a left anchor plate and a right anchor plate, and the grouting through holes and the steel strand mounting through holes are uniformly divided and arranged on the left anchor plate and the right anchor plate. The invention has simple structure, can realize the recovery of most of the devices of the steel strand, the steel strand extrusion head, the conical mouth breaker and the grouting pipe, can recycle the recovered components, and improves the use value of the anchor cable.

Description

Recyclable prestressed anchor cable for foundation pit support and construction method thereof

Technical Field

The invention relates to the field of civil foundation pit supporting engineering, in particular to a recoverable prestressed anchor cable for foundation pit supporting and a construction method thereof.

Background

The prestressed anchor cable has wide application in the field of civil engineering, is mainly used for slope protection after excavation of cutting in road engineering, and supporting of the inner wall of a foundation pit during excavation of house buildings and large-scale structure foundation pits, and also has a large amount of application in coal mines. The initial prestressed anchor cable is basically an unrecoverable anchor cable which is permanently retained in a soil body. In the aspect of foundation pit support, the multiple anchor rope subassembly that keeps somewhere for a long time can cause the pollution because of corrosion to natural resources such as groundwater in the soil body, also can cause the trouble for the construction of the adjacent building in later stage, becomes the obstacle of construction. And the supporting function of the prestressed anchor cable is not needed any more when the foundation pit is backfilled at the later stage, so that the invention of the recoverable prestressed anchor cable for supporting the foundation pit is very necessary, which is not only beneficial to protecting the natural environment and resources, but also beneficial to saving the cost.

As for some mechanical recoverable prestressed anchor cables disclosed at present, the mechanical recoverable prestressed anchor cables comprise precise components such as detachable threaded connectors and small transmission gears, the components need to be manufactured with high precision, and can be machined and formed by a machine tool with high manufacturing standard; anchor cable installation procedures are more; during recovery, only the steel strand can be recovered generally; the steel strand needs a great amount of manpower to rotate or shake the steel strand with the length of tens of meters by using corresponding tools to make the steel strand withdraw from the anchoring, the operation is not easy, and the recovery time is long. In addition, in the recovery process, the internal precise mechanical components are easy to deform and block due to irregular operation. The mechanical recoverable prestressed anchor cable further comprises a U-shaped recoverable anchor cable, and the bending radius of the steel strand at the U-shaped device at the anchoring end is very small, so that when the anchor cable is long, the steel strand is difficult to pull out manually, and the steel strand is often pulled out slowly by using a jack, so that the recovery time is long.

Compared with the mechanical type, the hot-melt type recoverable prestressed anchor cable needs to manufacture a special anchor device embedded with hot-melt materials, and parts such as an electric heating ring, a lead wire, a wire protecting pipe and the like are added, so that only steel strands can be recovered during recovery, and the recovery rate is low. The precision that adds hot melt material and installation wire in ground tackle requires highly, if not install in place, perhaps send the hole in-process at the anchor rope, because of reasons such as collision, extrusion cause the wire damage fracture, the joint drops, hot melt material leaks, aversion scheduling problem, can make the wire not circular telegram, and hot melt material is insufficient, fusing position is inaccurate, the phenomenon of unable effective fusing appears, can only carry out the anchor rope with the help of manual work and mechanical system again and retrieve, even unable recovery.

In conclusion, the existing various recyclable anchor cable products have the problems of high requirements on manufacturing and mounting precision and low recovery rate. The operation is not easy during construction, and part of the steel strand and the matching appliances can not be recycled and can not be used repeatedly.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a recyclable prestressed anchor cable for foundation pit support and a construction method thereof.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows: the anchor plate comprises a separable anchor plate and a rubber ring fixed outside the separable anchor plate, wherein the separable anchor plate is provided with a slurry through hole, a grouting through hole and a steel strand mounting through hole; a conical breaker is arranged in the grouting through hole, a steel strand penetrates through the steel strand mounting through hole, and a steel strand extrusion head is fixed at the insertion end of the steel strand; a steel strand sleeve is arranged outside the steel strand, and one end of the steel strand sleeve is fixed on the separable anchor plate; the conical breaking device is a hollow pipe, and a grouting pipe is also arranged in the conical breaking device; the steel strand extrusion head is cylindrical, and the contact end of the steel strand extrusion head and the separable anchor plate is a plane; the separable anchor plate comprises a left anchor plate and a right anchor plate, the grouting through holes and the steel strand mounting through holes are uniformly arranged on the left anchor plate and the right anchor plate in a split mode, and the left anchor plate and the right anchor plate are also respectively provided with a plurality of grouting through holes; one end of the steel strand is fixed at one end of the separable anchor plate through the steel strand extrusion head, and the other end of the steel strand is fixed on the anchor beam through an external clamping piece anchorage device.

Furthermore, the conical mouth-breaking device comprises a straight cylinder part, a guide part and an expansion part which are connected in sequence, the conical mouth-breaking device is a hollow pipe, and a grouting pipe is fixed in the conical mouth-breaking device; the grouting through hole comprises a guide straight hole and a guide hole connected with the guide straight hole, and the inclination of the guide hole is the same as that of the guide part; and a chamfer for installing the steel strand is arranged on the fixed side of the steel strand installing through hole.

Furthermore, the left anchor plate and the right anchor plate are semicircular, and the left anchor plate and the right anchor plate are jointed to form a cylinder; the grouting through hole is provided with one position, the steel strand mounting through hole is provided with two positions, the two steel strand mounting through holes are symmetrically distributed on two sides of the grouting through hole, and the grouting through hole and the steel strand mounting through hole are uniformly divided and arranged on the left anchor plate and the right anchor plate.

Further, rubber plugs are arranged among the guide portion, the expansion portion and the grouting pipe, the rubber plugs are provided with through holes for installing the grouting pipe, the shapes of the rubber plugs and the conical breaking device are the same, and the outer diameter of each rubber plug is smaller than or equal to the inner diameter of the conical breaking device.

Further, the steel strand sleeve is bonded and fixed on the separable anchor plate.

Furthermore, the tail end of the expansion part is provided with a partition plate, the partition plate is provided with a through hole for installing a grouting pipe, and the partition plate is respectively connected with the expansion part and the grouting pipe in a sealing manner.

Furthermore, the rubber ring is made of water-absorbing expansion rubber, and the inner ring surface of the rubber ring is fixedly bonded with the outer part of the separable anchor plate.

Furthermore, one surface of the separable anchor plate, which is attached to the rubber ring, is a circular table surface; the inner ring surface of the rubber ring is a circular table surface, the outer side of the rubber ring is a circular ring surface, and the small radius end of the circular table surface is positioned at the insertion end of the separable anchor plate.

Furthermore, a plurality of uniformly distributed strip-shaped open grooves are formed in the rubber ring and are positioned at the corners of the outer ring surface and the upper side surface of the rubber ring; the vertical section of the strip-shaped open slot is triangular.

The construction method of the recoverable prestressed anchor cable comprises the following steps:

s1: assembling a prestressed anchor cable:

firstly, bonding and fixing a steel strand sleeve in a steel strand mounting through hole of a separable anchor plate, then penetrating a steel strand through the steel strand sleeve and the separable anchor plate, and fixing an inserting end of the steel strand by using a steel strand extrusion head; separating the separable anchor plates, installing the conical crevasse through the grouting through hole, and combining and fixing the separable anchor plates by using a rubber ring;

s2: foundation pit pore-forming, installation prestressed anchorage cable, the slurry that pours:

before excavation of the foundation pit, confirming the depth, the diameter and the excavation angle of the foundation pit of the unrecyclable anchor cable; excavating in the design range of the foundation pit, and when excavating to the designed elevation of the prestressed anchor cable, adopting a drilling machine to form a hole; after hole forming is completed, the assembled prestressed anchor cable is placed in a designed position in the hole, grouting operation is carried out from the outside through a grouting pipe, and after grouting is full on one side of the separable anchor plate, slurry enters the foundation pit on the other side of the separable anchor plate from a slurry through hole in the separable anchor plate until grouting is full in the foundation pit;

s3: installing an anchor beam and tensioning a steel strand:

when the slurry is solidified to reach the designed strength, tensioning the steel strand, anchoring the steel strand on an anchor beam by using a clip anchorage when the steel strand is tensioned to the designed tonnage, realizing support for the foundation pit and completing the installation of the prestressed anchor cable;

s4: continuing subsequent foundation pit excavation, repeating S1-S3, and completing installation of all prestressed anchor cables;

s5: backfilling a foundation pit, and recovering a prestressed anchor cable:

tensioning the conical crevasse device at a tensioning end by using tensioning equipment to enable the conical crevasse device to move forwards, expanding the separable anchor plates by the conical crevasse device, extruding the rubber ring on the outer side to enable the rubber ring to deform, continuously expanding a gap at the joint of the two anchor plates in the separable anchor plates by the conical crevasse device until the conical crevasse device can be pulled out from the grouting through hole, retracting the steel strand into the steel strand sleeve under the action of tensioning force, and then manually pulling out and recovering the steel strand; the method for calculating the retraction amount of the steel strand which is not released during anchor withdrawal under the action of a certain internal tension force comprises the following steps:

in the above formula, F represents the internal tensile force of the steel strand; l represents the calculated length of the steel strand; EA represents the tensile stiffness of the steel strand.

The invention has the following advantages:

1. the invention realizes the support of the inner wall of the foundation pit by the combination of the steel strand, the steel strand sleeve, the separable anchor plate, the rubber ring, the steel strand extrusion head, the conical breaker, the grouting pipe and the clip anchorage device, and realizes the recycling of most structures of the anchor cable by utilizing the corresponding functions of the components consisting of the separable anchor plate, the rubber ring and the conical breaker.

2. The invention can provide effective pre-pressing stress for the inner wall of the foundation pit, and plays a role in supporting; the steel strand wire fixing device is simple in structure, is not prone to large deformation in the service stage, and is not prone to the problem that steel strands are stuck and cannot be recycled in recycling.

3. When the conical mouth-breaking device is tensioned, the separable anchor plate at the fixed end is expanded, and the steel strand and the extrusion head of the steel strand which are not tensioned automatically separate from the separable anchor plate at the fixed end under the action of internal tension force enter the PVC sleeve and can be directly dragged out of the hole. The method is simple, high in recovery reliability and good in robustness, and avoids the difficult operation of withdrawing the anchor in a mode of manually rotating the steel strand to recover or shaking the steel strand.

4. The anchor cable assembly can be recycled except the separable anchor plate and the rubber ring, so that the recovery rate is high; the invention can realize the recovery of most of the tools of the steel strand, the steel strand extrusion head, the conical mouth-breaking device and the grouting pipe, and the recovered parts can be recycled, thereby improving the use value of the anchor cable, saving materials and reducing cost.

5. After the recycled components are subjected to simple deslagging, the recycled steel strands and the steel strand extrusion heads thereof are sleeved with PVC pipes and combined with recycled conical breakers, and the recycled steel strands and the fixed end separable anchor plates can be recombined and reused with the replaced plastic grouting pipes and the replaced fixed end separable anchor plates, so that the recycling times of the steel strands are increased, and the recycling process is economic.

6. The invention does not need to design and customize a special anchorage device, and avoids the procedure of casting a new anchorage device in a factory workshop. The separable anchor plate can be manufactured on site, the existing anchor plate is simply half-cut, and the fixed end can be assembled by sleeving the rubber ring after machining and transformation.

7. The integral structure of the anchor cable is not complex, the assembly is simple, professional training is not needed, and the operation is quick; in the process of feeding into the hole and tensioning, the fixed end steel strand cannot be separated from the separable anchor plate and fall off due to the adoption of the squeezed extrusion sleeve, and the phenomenon that the steel strand is clamped with an internal component cannot occur.

8. When the device is recycled, the stretching equipment is used for stretching the conical hole breaker, so that the separable anchor plate is opened to form a gap large enough, the steel strand which is not stretched is conveniently automatically retracted under the action of the stretching force in the steel bundle to be separated from the separable anchor plate, enters the PVC sleeve and is directly dragged out of the hole, and the method is simple, high in recycling reliability, good in robustness and high in recycling speed.

9. The anchor cable is anchored not by the clamping piece but by the end part bearing, so that the unrecoverable separable anchor plate can be made very thin, the cost and the expense of the separable anchor plate are low, and the influence of the unrecoverable part on the environment is small.

10. After the recycled components are subjected to simple deslagging, the recycled steel strand and the extrusion head thereof are only required to be sleeved with the steel strand sleeve and combined with the recycled conical mouth breaker, and the recycled components can be recombined with the grouting pipe and the separable anchor plate which are replaced again for reuse.

Drawings

FIG. 1 is a first schematic view of the present invention;

FIG. 2 is a second external view of the present invention;

FIG. 3 is a front view of the present invention;

FIG. 4 is a cross-sectional view taken along line B-B of FIG. 3;

FIG. 5 is a schematic diagram of the operation of the present invention;

FIG. 6 isbase:Sub>A cross-sectional view taken along line A-A of FIG. 5;

fig. 7 is a schematic view of the installation of the present invention.

Wherein the symbols of the components are as follows;

1. a rubber ring; 2. a separable anchor plate; 3. a conical disruptor; 4. steel strand wires; 5. a steel strand extrusion head; 6. grouting pipes; 7. passing through the slurry through hole; 8. sleeving a steel strand; 9. a mountain body; 10. a hole wall; 11. an anchor beam; 12. a clamping piece anchorage device.

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined by the appended claims, and all changes that can be made by the invention using the inventive concept are intended to be protected.

As shown in fig. 1 to 7, the recoverable prestressed anchor cable for foundation pit support comprises a separable anchor plate 2 and a rubber ring 1 fixed outside the separable anchor plate 2, wherein the separable anchor plate 2 is provided with a slurry through hole 7, a grouting through hole and a steel strand installation through hole; the steel strand installation through hole is provided with the steel strand in a penetrating way, and the inserting end of the steel strand 4 is fixed with a steel strand extrusion head 5.

The steel strand 4 is externally provided with a steel strand sleeve 8, and one end of the steel strand sleeve 8 is fixed on the separable anchor plate 2. The steel strand sleeve 8 is bonded and fixed on the separable anchor plate 2, the steel strand sleeve 8 is preferably a PVC pipe, and the steel strand sleeve 8 is bonded and fixed at the lower end of the separable anchor plate 2 and concentrically arranged with the steel strand mounting through hole.

A conical breaking device 3 is arranged in the grouting through hole, the conical breaking device 3 is a hollow pipe, a grouting pipe 6 is also arranged in the conical breaking device 3, and the grouting pipe 6 is preferably a plastic hose; the steel strand extrusion head 5 is cylindrical, and the contact end of the steel strand extrusion head 5 and the separable anchor plate 2 is a plane. The conical breaker 3 comprises a straight cylinder part, a guide part and an expansion part which are connected in sequence, the conical breaker 3 is a hollow pipe, and a grouting pipe 6 is fixed in the conical breaker 3; the grouting through hole comprises a guide straight hole and a guide hole connected with the guide straight hole, and the inclination of the guide hole is the same as that of the guide part; and a chamfer angle for installing the steel strand 4 is arranged at the fixed side of the steel strand installing through hole. The tail end of the expansion part is provided with a partition board, the partition board is provided with a through hole for installing the grouting pipe 6, and the partition board is respectively connected with the expansion part and the grouting pipe 6 in a sealing mode.

The separable anchor plate 2 comprises a left anchor plate and a right anchor plate, the grouting through holes and the steel strand mounting through holes are uniformly divided and arranged on the left anchor plate and the right anchor plate, and the left anchor plate and the right anchor plate are also respectively provided with a plurality of grout passing through holes 7; the left anchor plate and the right anchor plate are semicircular, and the left anchor plate and the right anchor plate are attached to form a cylinder; the grouting through hole is provided with one position, the steel strand mounting through hole is provided with two positions, the two steel strand mounting through holes are symmetrically distributed on two sides of the grouting through hole, and the grouting through hole and the steel strand mounting through hole are uniformly divided and arranged on the left anchor plate and the right anchor plate.

In this embodiment, rubber plugs are arranged between the guiding portion, the enlarging portion and the grouting pipe 6, the rubber plugs are provided with through holes for installing the grouting pipe 6, the rubber plugs and the conical breaking device 3 are in the same shape, and the outer diameter of the rubber plugs is smaller than or equal to the inner diameter of the conical breaking device 3. The rubber buffer can play certain supporting role to 3 inner walls of toper breaker, has certain elasticity simultaneously, can play certain buffering and inhale shake effect at 3 clash detachable anchor slab 2 of toper breaker, plays certain support and guard action to slip casting pipe 6 simultaneously.

In this embodiment, the rubber ring 1 is made of water-swellable rubber, and the inner annular surface of the rubber ring 1 is bonded and fixed to the outside of the separable anchor plate 2. The upper side and the lower side of the rubber ring 1 are contacted with concrete, the outer ring surface of the rubber ring 1 is contacted with a foundation pit hole, the rubber ring 1 absorbs moisture in the concrete and soil, so that the upper side and the lower side and the outer ring surface of the rubber ring 1 absorb water and expand, and the inner ring surface of the rubber ring 1 is contacted with the separable anchor plate 2; the unable moisture absorption of inner ring face of event rubber circle 1, thereby the elasticity that provides is unchangeable, and the upper and lower side and the outer annular absorption inflation of rubber circle 1, the elastic force of providing will corresponding reduction, thereby whole rubber circle 1 reduces separable anchor slab 2's elastic constraint power, when retrieving and haul out toper breaker 3, more be favorable to pulling out of toper breaker 3, before guaranteeing not to haul out toper breaker 3 simultaneously, provide certain prestressing force and close separable anchor slab 2, make steel strand wires 4 be in the atress state of drawing closely always, make steel strand wires 4's normal work not receive the influence.

In the embodiment, one surface of the separable anchor plate 2, which is attached to the rubber ring 1, is a circular table surface; the inner ring surface of the rubber ring 1 is a circular table surface, the outer side of the rubber ring 1 is a circular ring surface, and the small radius end of the circular table surface is positioned at the insertion end of the separable anchor plate 2. The outside of detachable anchor slab 2 is the round platform face, the interior anchor slab that cooperates rubber circle 1 can play the polymerization fixed action to detachable anchor slab 2, can be fixed into a whole with the left anchor slab and the right anchor slab of installation toper breaker 3 and steel strand wires 4, and interior anchor slab is the rubber circle 1 of round platform face receiving radial effort, when the decomposition effort to detachable anchor slab 2 when toper breaker 3 is dragged out, rubber circle 1 takes place to past deformation easily, when making toper breaker 3 retrieve, it is easier, but also do not influence the normal prestressed anchorage of steel strand wires 4 and steel strand wires extrusion head 5.

In the embodiment, a plurality of uniformly distributed strip-shaped open grooves are formed in the rubber ring 1, and the strip-shaped open grooves are positioned at the corners of the outer ring surface and the upper side surface of the rubber ring 1; the vertical section of the strip-shaped open slot is triangular. The strip-shaped open slot is beneficial to the upward deformation of the outer ring of the rubber ring 1, so that the conical breaking device 3 can trigger the separable anchor plate 2 and the rubber ring 1 more easily, and the conical breaking device 3 and the steel strand 4 can be taken out more easily.

The construction method of the recoverable prestressed anchor cable comprises the following steps:

s1: assembling a prestressed anchor cable:

firstly, a steel strand sleeve 8 is bonded and fixed in a steel strand mounting through hole of a separable anchor plate 2, then a steel strand 4 penetrates through the steel strand sleeve 8 and the separable anchor plate 2, and an inserting end of the steel strand 4 is fixed by a steel strand extrusion head 5; separating the separable anchor plate 2, installing the conical mouth-breaking device 3 through the grouting through hole, and combining and fixing the separable anchor plate 2 by using the rubber ring 1;

s2: foundation pit pore-forming, installation prestressed anchorage cable, the slurry that pours:

before excavation of the foundation pit, confirming the depth, the diameter and the excavation angle of the foundation pit of the unrecyclable anchor cable; excavating in the design range of the foundation pit, and when excavating to the designed elevation of the prestressed anchor cable, adopting a drilling machine to form a hole; after hole forming is completed, the assembled prestressed anchor cable is placed in a designed position in the hole, grouting operation is carried out from the outside through a grouting pipe, and after grouting is full on one side of the separable anchor plate 2, slurry enters the foundation pit on the other side of the separable anchor plate from the slurry through hole 7 in the separable anchor plate 2 until grouting is full in the foundation pit;

s3: installing an anchor beam 11, tensioning a steel strand:

when the slurry is solidified to reach the designed strength, tensioning the steel strand 4, and anchoring the steel strand on an anchor beam 11 by using a clip anchorage 12 when the steel strand is tensioned to the designed tonnage, so as to support the foundation pit and complete the installation of the prestressed anchor cable;

s4: continuing subsequent foundation pit excavation, repeating S1-S3, and completing installation of all prestressed anchor cables;

s5: backfilling a foundation pit, and recovering a prestressed anchor cable:

tensioning the conical breaker 3 at a tensioning end by using tensioning equipment to enable the conical breaker 3 to move forwards, expanding the separable anchor plate 2 by using the conical breaker 3, extruding the rubber ring 1 on the outer side to deform the rubber ring, continuously expanding a gap between the joint parts of the two anchor plates in the separable anchor plate 2 by using the conical breaker 3 until the conical breaker 3 can be pulled out of the grouting through hole, retracting the steel strand 4 into the steel strand sleeve 8 under the action of tensioning force, and subsequently manually pulling out the steel strand 4 to recover the steel strand 4; the method for calculating the retraction amount of the steel strand which is not released during anchor withdrawal under the action of a certain internal tension comprises the following steps:

in the above formula, F represents the internal tensile force of the steel strand; l represents a calculated length of the steel strand; EA represents the tensile stiffness of the steel strand. For example: the 2 phi s15.2 steel strand with the length of 10m has the elastic modulus that the retraction amount when the anchor is withdrawn under the action of 20t internal tension is as follows:

Claims (10)

1. the utility model provides a recoverable prestressed anchorage cable for excavation supporting which characterized in that: the anchor plate comprises a separable anchor plate (2) and a rubber ring (1) fixed outside the separable anchor plate (2), wherein a grout passing through hole (7), a grouting through hole and a steel strand installation through hole are formed in the separable anchor plate (2); a conical breaker (3) is arranged in the grouting through hole, a steel strand (4) penetrates through the steel strand mounting through hole, a steel strand extrusion head (5) is fixed at the insertion end of the steel strand (4), a steel strand sleeve (8) is arranged outside the steel strand (4), and one end of the steel strand sleeve (8) is fixed on the separable anchor plate (2); the conical breaking device (3) is a hollow pipe, and a grouting pipe (6) is also arranged in the conical breaking device (3); the steel strand extrusion head (5) is cylindrical, and the contact end of the steel strand extrusion head (5) and the separable anchor plate (2) is a plane;

the separable anchor plate (2) comprises a left anchor plate and a right anchor plate, the grouting through holes and the steel strand mounting through holes are uniformly divided and arranged on the left anchor plate and the right anchor plate, and a plurality of grout passing through holes (7) are respectively formed in the left anchor plate and the right anchor plate;

one end of the steel strand (4) is fixed at one end of the separable anchor plate (2) through the steel strand extrusion head (5), and the other end of the steel strand (4) is fixed on the anchor beam (11) through the external clip anchorage device (12).

2. The recoverable prestressed anchorage cable for foundation pit support according to claim 1, wherein said cone-shaped breaker (3) comprises a straight body, a guide portion and an expansion portion connected in sequence, said cone-shaped breaker (3) is a hollow tube, said grouting pipe (6) is fixed in said cone-shaped breaker (3); the grouting through hole comprises a guide straight hole and a guide hole connected with the guide straight hole, and the inclination of the guide hole is the same as that of the guide part; and a chamfer for installing the steel strand (4) is arranged at the fixed side of the steel strand installing through hole.

3. The recoverable prestressed anchor rope for foundation pit support according to claim 1, wherein said left anchor plate and said right anchor plate are semicircular, and said left anchor plate and said right anchor plate are fitted to form a cylindrical shape; the grouting through hole is provided with one position, the steel strand mounting through hole is provided with two positions, the two positions are symmetrically distributed on two sides of the grouting through hole, and the grouting through hole and the steel strand mounting through hole are uniformly divided and arranged on the left anchor plate and the right anchor plate.

4. The recoverable prestressed anchor cable for foundation pit support according to claim 2, wherein a rubber plug is arranged between the guide portion, the expansion portion and the grouting pipe (6), the rubber plug is provided with a through hole for installing the grouting pipe (6), the rubber plug and the conical breaker (3) are identical in shape, and the outer diameter of the rubber plug is smaller than or equal to the inner diameter of the conical breaker (3).

5. The recoverable prestressed anchor rope for foundation pit support according to claim 1, wherein said steel strand sleeve (8) is adhesively fixed to said separable anchor plate (2).

6. The recoverable prestressed anchor rope for foundation pit support according to claim 2, wherein said enlarged portion has a partition at its end, said partition having a through hole for installing said grouting pipe (6), said partition being hermetically connected to said enlarged portion and said grouting pipe (6), respectively.

7. The recoverable prestressed anchor rope for foundation pit support according to claim 1, wherein said rubber ring (1) is a water-swelling rubber, and an inner circumferential surface of said rubber ring (1) is adhesively fixed to an outer portion of said separable anchor plate (2).

8. The recoverable prestressed anchor cable for foundation pit support according to claim 1, wherein one surface of said separable anchor plate (2) attached to said rubber ring (1) is a round table surface; the inner ring surface of the rubber ring (1) is a circular table surface, the outer side of the rubber ring (1) is a circular ring surface, and the small radius end of the circular table surface is located at the insertion end of the separable anchor plate (2).

9. The recoverable prestressed anchor cable for foundation pit support according to claim 8, wherein said rubber ring (1) is provided with a plurality of uniformly distributed bar-shaped open slots, said bar-shaped open slots are located at the corners of the outer annular surface and the upper side surface of the rubber ring (1); the vertical section of the strip-shaped open slot is triangular.

10. A construction method for the recoverable prestressed anchor rope of claims 1-9, comprising the steps of:

s1: assembling a prestressed anchor cable:

firstly, a steel strand sleeve (8) is bonded and fixed in a steel strand mounting through hole of a separable anchor plate (2), then a steel strand (4) penetrates through the steel strand sleeve (8) and the separable anchor plate (2), and an inserting end of the steel strand (4) is fixed by a steel strand extrusion head (5); separating the separable anchor plate (2), installing the conical breaking device (3) through the grouting through hole, and combining and fixing the separable anchor plate (2) by using the rubber ring (1);

s2: foundation pit pore-forming, installation prestressed anchorage cable, the slurry that pours:

before excavation of the foundation pit, confirming the depth, the diameter and the excavation angle of the foundation pit of the unrecyclable anchor cable; excavating in the design range of the foundation pit, and when excavating to the designed elevation of the prestressed anchor cable, adopting a drilling machine to form a hole; after hole forming is completed, the assembled prestressed anchor cable is placed in a designed position in a hole, grouting operation is carried out from the outside through a grouting pipe, when one side of the separable anchor plate (2) is full, slurry enters a foundation pit on the other side of the separable anchor plate from a slurry through hole (7) in the separable anchor plate (2) until the foundation pit is full in grouting;

s3: installing an anchor beam (11), tensioning the steel strand:

when the slurry is solidified to reach the designed strength, the steel strand (4) is tensioned, and when the steel strand is tensioned to the designed tonnage, the steel strand is anchored on an anchor beam (11) by a clip anchorage device (12), so that the foundation pit is supported, and the installation of a prestressed anchor cable is completed;

s4: continuing subsequent foundation pit excavation, repeating S1-S3, and completing installation of all prestressed anchor cables;

s5: backfilling a foundation pit, and recovering a prestressed anchor cable:

tensioning the conical mouth breaker (3) at a tensioning end by using tensioning equipment to enable the conical mouth breaker (3) to move forwards, expanding the separable anchor plate (2) by the conical mouth breaker (3), extruding the rubber ring (1) on the outer side to deform the rubber ring, continuously expanding a gap at the joint of the two anchor plates in the separable anchor plate (2) by the conical mouth breaker (3) until the conical mouth breaker (3) can be pulled out from the grouting through hole, retracting the steel strand (4) into the steel strand sleeve (8) under the action of tensioning force, and then manually pulling out and recovering the steel strand (4); the method for calculating the retraction amount of the steel strand which is not released during anchor withdrawal under the action of a certain internal tension comprises the following steps:

in the above formula, F represents the internal tensile force of the steel strand; l represents the calculated length of the steel strand; EA represents the tensile stiffness of the steel strand.

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