阅读说明：本技术 一种预应力锚索结构及预应力锚索施工方法 (Prestressed anchor cable structure and prestressed anchor cable construction method ) 是由 严毅 郝非 李宗鹏 杜士亮 毋铭 彭建民 何冠儒 黄镜儒 于 2019-09-27 设计创作，主要内容包括：本发明提供了一种预应力锚索结构及预应力锚索施工方法。该结构包括：锚索成孔套管、锚索、注浆管、锚索定位托架、锚具；其中,锚索成孔套管设置于土层中锚索孔内且外壁抵接在土层上,用以临时支撑土层以保证锚索孔的直线性；锚索、注浆管和锚索定位支架设置在锚索成孔套管内,并且,锚索的尾部伸出冠梁并连接在锚具上锁定；若干个锚索定位托架在锚索成孔套管内沿锚索的长度方向并排设置,用以固定锚索以防止锚索在土层中下沉或者下挠；注浆管进行锚索的注浆,用以固定锚索在土层中的位置,锚具进行锚索的张拉锁定和复拉达到设计要求。本发明可控制锚索的变形并减少预应力损失,且施工速度快且操作方便,锚索变形小,基坑边坡变形及安全有保证。(The invention provides a prestressed anchor cable structure and a prestressed anchor cable construction method. The structure includes: the anchor cable positioning device comprises an anchor cable hole-forming sleeve, an anchor cable, a grouting pipe, an anchor cable positioning bracket and an anchor; the anchor cable pore-forming sleeve is arranged in an anchor cable hole in a soil layer, and the outer wall of the anchor cable pore-forming sleeve is abutted against the soil layer and used for temporarily supporting the soil layer so as to ensure the linearity of the anchor cable hole; the anchor cable, the grouting pipe and the anchor cable positioning bracket are arranged in the anchor cable hole forming sleeve, and the tail part of the anchor cable extends out of the crown beam and is connected to the anchor device for locking; the anchor cable positioning brackets are arranged in the anchor cable hole forming sleeve side by side along the length direction of the anchor cable and used for fixing the anchor cable so as to prevent the anchor cable from sinking or warping in a soil layer; the grouting pipe is used for grouting the anchor cable to fix the position of the anchor cable in the soil layer, and the anchor device is used for tensioning, locking and redrawing the anchor cable to meet the design requirement. The invention can control the deformation of the anchor cable and reduce the prestress loss, and has the advantages of high construction speed, convenient operation, small deformation of the anchor cable and guarantee of the deformation and the safety of the foundation pit slope.)

1. A prestressed anchorage cable structure, comprising: the anchor cable positioning device comprises an anchor cable hole-forming sleeve, an anchor cable, a grouting pipe, an anchor cable positioning bracket and an anchor; wherein the content of the first and second substances,

the anchor cable pore-forming sleeve is arranged in an anchor cable hole in a soil layer, and the outer wall of the anchor cable pore-forming sleeve is abutted against the soil layer and used for temporarily supporting the soil layer so as to ensure the linearity of the anchor cable hole;

the anchor cable, the grouting pipe and the anchor cable positioning bracket are arranged in the anchor cable hole forming sleeve, the tail part of the anchor cable extends out of the crown beam and is locked on an anchor device, and the anchor device is used for tensioning, locking and redrawing the anchor cable to meet the preset requirement;

the anchor cable positioning brackets are arranged in the anchor cable hole forming sleeve side by side along the length direction of the anchor cable, and a plurality of notches are formed in the axial direction of the anchor cable positioning brackets and used for fixing the anchor cable to prevent the anchor cable from sinking or warping in a soil layer; the grouting pipe is used for grouting the anchor cable so as to fix the position of the anchor cable in a soil layer.

2. The prestressed anchor rope structure of claim 1,

and a supporting water-stopping structure is arranged on the side wall of the soil layer and is used for supporting and stopping the soil layer.

3. The prestressed anchor rope structure of claim 2,

the crown beam is arranged above the supporting water-stopping structure, and the side wall of the crown beam is pressed against the soil layer to fix the anchorage device.

4. The prestressed anchor rope structure of claim 3, wherein a tie plate is provided at a connecting position between said crown beam and said anchor.

5. The prestressed anchor rope structure of claim 4, wherein the tail portion of said anchor rope extends from said anchor rope boring sleeve and is sequentially inserted through said crown beam and said bolster plate.

6. The prestressed anchor rope structure of any one of claims 1 to 5, wherein said anchor rope is a strand consisting of a plurality of steel strands.

7. A construction method of a prestressed anchor cable is characterized by comprising the following steps:

an anchor cable hole forming step, wherein an anchor cable hole forming sleeve is adopted to drill at a preset position in a soil layer so as to obtain an anchor cable hole, and the anchor cable hole forming sleeve is arranged in the anchor cable hole;

an anchor cable lowering step, namely winding and binding an anchor cable and a grouting pipe on an anchor cable positioning bracket to fix the anchor cable at a notch of the anchor cable positioning bracket, fixing the grouting pipe at a positioning hole formed in the middle of the anchor cable positioning bracket to form an anchor cable bundle, and feeding the bound anchor cable bundle into an anchor cable hole through an anchor cable hole-forming sleeve;

grouting, namely injecting cement slurry into the anchor cable hole through a grouting pipe so that the anchor section and the free section of the anchor cable are fully filled with the cement slurry, and gradually drawing out an anchor cable hole-forming sleeve in the grouting process;

a casing extraction step, namely after the anchor cable pore-forming casing is extracted and before the cement slurry is initially set, temporarily fixing the anchor cable bundle to prevent the anchor cable bundle from downwarping caused by hole collapse of the anchor cable hole and sinking of the anchor cable bundle;

tensioning the anchor cable, namely pre-tensioning the anchor cable through an anchorage device arranged outside an anchor cable hole after the cement paste reaches a preset age;

an anchor cable locking step, namely performing prestress tensioning locking on the anchor cable after pre-tensioning;

and excavating the foundation pit, namely after tensioning and locking the anchor cable, excavating the earth of the foundation pit, and redrawing the anchor cable in the period to control the deformation of the foundation pit.

8. The prestressed anchor rope construction method as claimed in claim 7,

in the grouting step, the anchor cable hole-forming sleeve is gradually drawn out, and meanwhile, orifice grout supplement and secondary grouting are carried out, so that the grouting quality of the anchor cable is ensured.

9. The prestressed anchor rope construction method as claimed in claim 7,

in the anchor cable locking step, the anchor cables are subjected to interval lock jumping locking so as to ensure that all strands of steel strands of all the anchor cables are stressed uniformly and the locking load value is balanced.

10. The prestressed anchor rope construction method as claimed in any one of claims 7 to 9,

in the anchor cable tensioning step, the anchor cable is pre-tensioned at a preset locking value, and the load is maintained for not less than 15min, so that the sufficient extension of the free section of the anchor cable is ensured, and the creep deformation of the anchor cable is reduced.

Technical Field

The invention relates to the technical field of constructional engineering, in particular to a prestressed anchor cable structure and a prestressed anchor cable construction method.

Background

In the deep foundation pit construction process of urban building engineering, the foundation pit supporting type of the support piles, the stirring pile waterproof curtain and the prestressed anchor cables is an economical and reasonable foundation pit supporting scheme. Due to the fact that deep soft soil layers are arranged in river and coastal alluvial areas, the total length of the anchor cable is long, the anchoring section and the free section are located in the soft soil layers, deformation values and elongation values of the anchor cable are large in the anchor cable construction pore-forming, anchor cable laying, grouting and prestress tensioning processes, and meanwhile due to the fact that the soil layers are soft, the soil body is deformed and the stress conditions are complex, the anchor cable prestress loss is prone to occurring. Therefore, the deep foundation pit of the pile-anchor support type in the coastal soft soil area is easy to deform to a large extent, so that the potential safety hazard of the foundation pit is caused, and the normal use of the foundation pit is influenced.

Disclosure of Invention

In view of the above, the invention provides a prestressed anchor cable structure and a prestressed anchor cable construction method, and aims to solve the problems that deformation values and elongation values of anchor cables are large and the anchor cables lose prestress due to the fact that deep soft soil layers exist in rivers and coastal alluvial areas.

In one aspect, the present invention provides a prestressed anchor cable structure, including: the anchor cable positioning device comprises an anchor cable hole-forming sleeve, an anchor cable, a grouting pipe, an anchor cable positioning bracket and an anchor; the anchor cable pore-forming sleeve is arranged in an anchor cable hole in a soil layer, and the outer wall of the anchor cable pore-forming sleeve is abutted against the soil layer and used for temporarily supporting the soil layer so as to ensure the linearity of the anchor cable hole; the anchor cable, the grouting pipe and the anchor cable positioning bracket are arranged in the anchor cable hole forming sleeve, the tail part of the anchor cable extends out of the crown beam and is locked on an anchor device, and the anchor device is used for tensioning, locking and redrawing the anchor cable to meet the preset requirement; the anchor cable positioning brackets are arranged in the anchor cable hole forming sleeve side by side along the length direction of the anchor cable, and a plurality of notches are formed in the axial direction of the anchor cable positioning brackets and used for fixing the anchor cable to prevent the anchor cable from sinking or warping in a soil layer; the middle position of the anchor cable positioning bracket is also provided with a positioning hole for fixing the grouting pipe, and the grouting pipe is used for grouting the anchor cable so as to fix the position of the anchor cable in a soil layer.

Further, in the prestressed anchor cable structure, a supporting water stopping structure is arranged on the side wall of the soil layer and is used for supporting and stopping the soil layer.

Further, in the prestressed anchor cable structure, the crown beam is arranged above the supporting water-stopping structure, and the side wall of the crown beam is pressed against the soil layer to fix the anchor.

Further, in the prestressed anchor cable structure, a base plate is arranged at the connecting position between the crown beam and the anchor.

Further, in the above prestressed anchor cable structure, the tail portion of the anchor cable extends out of the anchor cable hole-forming sleeve and sequentially penetrates through the crown beam and the base plate.

Further, in the prestressed anchor cable structure, the anchor cable is a wire harness formed by a plurality of steel strands.

On the other hand, the invention also provides a construction method of the prestressed anchor cable, which comprises the following steps: an anchor cable hole forming step, wherein an anchor cable hole forming sleeve is adopted to drill at a preset position in a soil layer so as to obtain an anchor cable hole, and the anchor cable hole forming sleeve is arranged in the anchor cable hole; an anchor cable lowering step, namely winding and binding an anchor cable and a grouting pipe on an anchor cable positioning bracket to fix the anchor cable at a notch of the anchor cable positioning bracket, fixing the grouting pipe at a positioning hole formed in the middle of the anchor cable positioning bracket to form an anchor cable bundle, and feeding the bound anchor cable bundle into an anchor cable hole through an anchor cable hole-forming sleeve; grouting, namely injecting cement slurry into the anchor cable hole through a grouting pipe so that the anchor section and the free section of the anchor cable are fully filled with the cement slurry, and gradually drawing out an anchor cable hole-forming sleeve in the grouting process; a casing extraction step, namely after the anchor cable pore-forming casing is extracted and before the cement slurry is initially set, fixing the anchor cable bundle to prevent the anchor cable bundle from downwarping caused by hole collapse of the anchor cable hole and sinking of the anchor cable bundle; tensioning the anchor cable, namely pre-tensioning the anchor cable through an anchorage device arranged outside an anchor cable hole after the cement paste reaches a preset age; an anchor cable locking step, namely performing prestress tensioning locking on the anchor cable after pre-tensioning; and excavating the foundation pit, namely after tensioning and locking the anchor cable, excavating the earth of the foundation pit, and redrawing the anchor cable in the period to control the deformation of the foundation pit.

Further, in the grouting step, the grouting of the hole opening and the secondary grouting are performed while the anchor cable hole-forming sleeve is gradually drawn out, so that the grouting quality of the anchor cable is ensured.

Further, in the anchor cable locking step, the pre-stressed anchor cable construction method performs interval lock-jumping locking on the anchor cables so as to ensure that all strands of steel strands of all the anchor cables are stressed uniformly and the locking load value is balanced.

Further, in the anchor cable tensioning step, the anchor cable is pre-tensioned to a preset locking value, and the load holding time is not less than 15min, so that the free section of the anchor cable is fully extended, and creep deformation of the anchor cable is reduced.

According to the prestressed anchor cable structure and the prestressed anchor cable construction method, the anchor cable hole forming sleeve is arranged in the anchor cable hole, so that a soil layer on the inner wall of the anchor cable hole is temporarily supported to ensure the linearity of the anchor cable hole, the hole forming quality is guaranteed, the disturbance damage to a soft soil layer is reduced, and hole collapse is avoided; meanwhile, the anchor cable hole-forming sleeve has high rigidity, so that the linear radian of the anchor cable hole caused by the self weight of a drill bit and a drill rod in the hole-forming process can be reduced, the disturbance damage to a soft soil layer is avoided, the deformation value and the elongation value of the anchor cable are prevented from being increased in the hole-forming, anchor cable laying, grouting and prestress tensioning processes, and the loss of the prestress of the anchor cable can be avoided; adopting an anchorage device to perform tensioning locking and redrawing on the anchor cable so as to meet the design requirement; meanwhile, an anchor cable positioning bracket is arranged on the anchor cable to fixedly support the anchor cable and the grouting pipe so as to prevent the anchor cable from sinking or warping in the soil layer; and grouting the anchor cable by adopting a grouting pipe to fix the position of the anchor cable in the soil layer. Compared with the prior art, the deformation of the anchor cable can be controlled, the prestress loss is reduced, the construction speed is high, the operation is convenient, and the standardized components are quickly installed; meanwhile, the anchor cable has small deformation, and the deformation and the safety of the foundation pit slope are ensured.

Further, cement grout is injected into the anchor cable hole through the grouting pipe, the anchoring section and the free section of the anchor cable are fully filled with the cement grout, the anchor cable hole-forming sleeve is slowly drawn out in combination with the grouting condition in the grouting process, in addition, in the grouting process, in order to avoid the downward deflection of the anchor cable bundle caused by the hole collapse of the anchor cable hole and the sinking of the anchor cable bundle, the anchor cable bundle is temporarily fixed, so that the deformation of the anchor cable and the deformation of the foundation pit side slope are reduced, and the construction safety is ensured; after the cement paste reaches the preset age, pretensioning is carried out on the anchor cable, the prestress relaxation of the anchor cable is reduced, the sufficient extension of the free section of the anchor cable is ensured, and the creep deformation of the anchor cable is reduced; and the anchor cable is subjected to prestress tensioning locking after pretensioning, and is subjected to redraw after locking, so that the deformation and elongation values of the anchor cable are effectively reduced, and the prestress loss of the anchor cable is reduced.

Particularly, interval lock jumping is adopted during prestress tensioning locking, so that the uniform stress of each anchor cable is ensured, the locking load value is balanced, the locking load of the anchor cable is ensured to reach 1.2-1.3 times of the designed locking load value, and the locking of the over-force value is carried out.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1 is a schematic structural diagram of a prestressed anchor cable structure according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view taken at the location A-A in FIG. 1;

fig. 3 is a flowchart of a prestressed anchor cable construction method according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

Prestressed anchorage cable structure embodiment:

referring to fig. 1 to 2, there are shown schematic structural views of a prestressed anchor cable structure provided by an embodiment of the present invention. As shown, the structure includes: the anchor cable positioning device comprises an anchor cable hole-forming sleeve 1, an anchor cable 2, a grouting pipe 3, an anchor cable positioning bracket 4, a base plate 5, an anchor 6, a supporting water-stopping structure 7 and a crown beam 8; wherein the content of the first and second substances,

the anchor rope pore-forming sleeve 1 is arranged in an anchor rope hole in a soil layer, and the outer wall of the anchor rope hole is abutted against the soil layer to support the soil layer. Specifically, the anchor cable hole forming sleeve 1 is arranged in the anchor cable hole to support a soil layer on the inner wall of the anchor cable hole so as to ensure the linearity of the anchor cable hole, thereby ensuring the hole forming quality, reducing disturbance damage to a soft soil layer and avoiding hole collapse; meanwhile, the anchor cable hole forming sleeve 1 is high in rigidity, and the linear radian of the anchor cable hole caused by the self weight of a drill bit and a drill rod in the hole forming process can be reduced. Wherein, anchor rope pore-forming sleeve pipe 1 can be the steel casing pipe to guarantee its rigidity, especially to the river and the coastal alluvial area have deep soft soil layer, can further ensure the pore-forming quality, avoid the disturbance destruction to soft soil layer, and then avoid in pore-forming, anchor rope, slip casting, prestressing force stretch-draw in-process the grow of deformation value and elongation value of anchor rope 2, and can avoid the loss of the prestressing force of anchor rope 2.

The anchor cable 2, the grouting pipe 3 and the anchor cable positioning bracket 4 are all arranged in the anchor cable hole-forming sleeve 1, the tail part of the anchor cable 2 extends out of the crown beam 8 and locks the anchor 6, and the anchor 6 is used for tensioning, locking and redrawing the anchor cable 2 to meet the preset requirement. Specifically, the anchor cable 20 is divided into a tension section, a free section, and an anchor section in this order from the tail portion to the front end. The free section and the anchoring section are embedded in the anchor cable hole forming sleeve 1, namely the inside of the anchor cable hole. The anchor cable 2 is a wire bundle composed of a plurality of steel strands. The side surface of each steel strand in the free section can be wrapped with a hose. The arrangement of the hose ensures that the steel strands in the free section 22 interval cannot be fixed by the anchor cable pore-forming sleeve 1, so that the steel strands in the free section interval can be stretched in the hose in the process of pre-stress stretching of the anchor cable 2. The steel strands in the free section interval can be parallel to each other and arranged at a certain distance, and preferably, the steel strands can be uniformly distributed in a circular shape. The tail part of the anchor cable 2 extends out of the anchor cable hole-forming sleeve 1, sequentially penetrates through the crown beam 8 and the base plate 5 and then is connected to an anchorage device 6 outside the anchor cable hole-forming sleeve 1, so that the anchor cable 2 is tensioned, locked and redrawn through the anchorage device 6, and the anchor cable 2 can meet preset requirements, the preset requirements can be determined according to actual conditions, and no limitation is imposed on the anchor cable 2 in the embodiment. Slip casting pipe 3 sets up in anchor rope pore-forming sleeve pipe 1 and sets up in the inside that many steel strands enclosed the circular structure of establishing, and with parallel interval setting between the steel strand wires.

The anchor cable positioning brackets 4 are arranged in the anchor cable pore-forming sleeve 1 side by side along the length direction of the anchor cable 2, and a plurality of notches 41 are axially arranged on the anchor cable positioning brackets 4 and used for fixing the anchor cable 2 to prevent the anchor cable 2 from sinking or warping in a soil layer; the middle position of the anchor cable positioning bracket 4 is further provided with a positioning hole 42 for fixing the grouting pipe 3, and the grouting pipe 3 is used for grouting the anchor cable 2 to fix the position of the anchor cable 2 in the soil layer. Specifically, the anchor cable positioning bracket 4 may be provided at the anchoring section to support the plurality of steel strands and the grout pipe 3 at the anchoring section of the anchor cable 2. The anchor cable positioning brackets 4 can be made of wide and thick circular sheet-shaped plastic brackets, and the space between the anchor cable positioning brackets 4 is encrypted by combining the situation of entering the soil layer, so that the anchor cable 2 is ensured not to sink into the soft soil layer, and preferably, the space between the anchor cable positioning brackets 4 can be 1m-1.5 m. The steel strand wires of the anchor cable 2 can be fixed at the position of the notch 41 through binding, and the grouting pipes 3 can be fixed at the position of the positioning holes 42 through binding, so that the three types of whole bodies can be conveniently conveyed into the anchor cable holes through the anchor cable hole-forming sleeve 1. The setting of anchor rope location bracket 4 can be so that the steel strand wires that constitute anchor rope 2 can not twine together, make anchor rope 2 can keep the shape in the installation, and so as to avoid the contact between slip casting pipe 3 and anchor rope 2 to be connected, exist mutually independently between slip casting pipe 3 and the anchor rope 2 promptly, and then anchor rope 2 buries underground in the thick liquid when being convenient for follow-up slip casting in order to prevent anchor rope 2 from sinking or downwarping in the soil layer, and slip casting pipe 3 promotes and rotates along with the slip casting simultaneously, slip casting pipe 3 is taken out while slip casting promptly, and then avoid the damage of slip casting pipe 3 and slip casting pipe 3 to bury and lead to the thick liquid shrink in the thick liquid and cause the problem that needs supplementary slip casting, the intensity of the anchor rope body has been improved, and slip casting makes anchor rope 2 fix the settlement position in the soil layer. The notches 41 are arranged in one-to-one correspondence with the steel strands and are uniformly distributed along the circumferential direction of the anchor cable positioning bracket 4.

And a supporting and water-stopping structure 7 is arranged on the side wall (the right side wall shown in figure 1) of the soil layer and is used for supporting and stopping the soil layer. In particular, the supporting and water-stopping structure 7 may support a structure of a pile, i.e., a water-stopping curtain combination, so as to prevent the side edges of the soil layer from collapsing and stop water thereof.

And a crown beam 8 is arranged above the supporting and water-stopping structure 7, and the side wall of the supporting and water-stopping structure is pressed on a soil layer to fix the anchorage device 6. Specifically, the crown beam 8 may be a reinforced concrete continuous beam disposed at the top of the support water stop structure 7, and has one function of connecting all pile foundations together to prevent the foundation pit, i.e., the top edge of the soil layer, from collapsing, and the other function of fixing the anchor 6 by assuming the horizontal extrusion force and the vertical shearing force during the construction such as drilling and grouting. Wherein, a backing plate 5 is arranged at the connecting position between the crown beam 8 and the anchorage device 6 for supporting the anchorage device 6.

In summary, in the prestressed anchor cable structure provided by this embodiment, the anchor cable hole-forming sleeve 1 is arranged in the anchor cable hole to temporarily support the soil layer on the inner wall of the anchor cable hole to ensure the linearity of the anchor cable hole, thereby ensuring the hole-forming quality, reducing disturbance damage to the soft soil layer, and avoiding hole collapse; meanwhile, the anchor cable hole-forming sleeve 1 has high rigidity, can reduce the linear radian of the anchor cable hole caused by the self weight of a drill bit and a drill rod in the hole-forming process, particularly for a river and a deep soft soil layer in a coastal alluvial area, avoids the deformation value and the elongation value of the anchor cable 2 from being increased in the hole-forming, anchor cable laying, grouting and prestress tensioning processes, and can avoid the loss of prestress of the anchor cable 2; adopting an anchorage device 6 to perform tensioning locking and redrawing on the anchor cable 2 so as to meet the design requirement; meanwhile, an anchor cable positioning bracket 4 is arranged on the anchor cable 2 to fixedly support the anchor cable 2 and the grouting pipe 3 so as to prevent the anchor cable 2 from sinking or warping in the soil layer; and grouting the anchor cable by adopting the grouting pipe 3 so as to fix the position of the anchor cable in the soil layer. Compared with the prior art, the structure can control the deformation of the anchor cable 2 and reduce the prestress loss, and has the advantages of high construction speed, convenient operation and quick installation of standardized components; meanwhile, the anchor cable 2 is small in deformation, and the deformation and safety of the foundation pit slope are guaranteed.

Further, the supporting water-stopping structure 7 and the crown beam 8 are arranged on the side wall of the soil layer to bear horizontal leaning force and vertical shearing force to prevent the soil layer from collapsing. Compared with the prior art, the deformation of the anchor cable 2 can be controlled, the prestress loss is reduced, the construction speed is high, the operation is convenient, and the standardized components are quickly installed; meanwhile, the anchor cable 2 is small in deformation, and the deformation and safety of the foundation pit slope are guaranteed.

The method comprises the following steps:

referring to fig. 3, it is a flowchart of a prestressed anchor cable construction method according to an embodiment of the present invention. As shown, the method comprises the following steps:

and an anchor cable hole forming step S1, drilling holes at preset positions in the soil layer by using the anchor cable hole forming sleeves to obtain anchor cable holes, wherein the anchor cable hole forming sleeves are arranged in the anchor cable holes.

Specifically, anchor rope pore-forming can adopt anchor rope pore-forming sleeve pipe 1 to carry out the pore-forming to obtain anchor rope hole and anchor rope pore-forming sleeve pipe 1 sets up downthehole in order to support the soil layer temporarily of anchor rope, and guarantee the linearity in anchor rope hole, can ensure the pore-forming quality, reduce the disturbance to soft soil layer and destroy, avoid collapsing the hole. Meanwhile, the anchor cable hole forming sleeve 1 is high in rigidity, and the linear radian of the anchor cable hole caused by the self weight of a drill bit and a drill rod in the hole forming process can be reduced.

And an anchor cable lowering step S2, wherein the anchor cable and the grouting pipe are wound and bound on the anchor cable positioning bracket, so that the anchor cable is fixed at the notch of the anchor cable positioning bracket, the grouting pipe is fixed at the positioning hole formed in the middle of the anchor cable positioning bracket to form an anchor cable bundle, and the bound anchor cable bundle is conveyed into the anchor cable hole through the anchor cable hole-forming sleeve.

Specifically, each steel strand of the anchor cable 2 and the grouting pipe 3 are respectively bound and fixed at the notch 41 and the positioning hole 42 of the anchor cable positioning bracket 4, so that the anchor cable 2 is fixed through the anchor cable positioning bracket 4, and the anchor cable 2 is prevented from sinking or warping in the soil layer; and the grouting pipe 3 can be adopted to perform grouting on the anchor cable 2 so as to fix the position of the anchor cable 2 in the soil layer. The anchor cable positioning brackets 4 can be round and thick sheet-shaped plastic brackets, the distance between the anchor cable positioning brackets 4 is encrypted by combining the condition of entering the soil layer, and the distance between the anchor cable positioning brackets 4 can be 1m-1.5m so as to ensure that the anchor cable 2 does not sink into the soft soil layer. And then the bound anchor cable bundle is fed into the anchor cable hole through the anchor cable hole-forming sleeve 1.

And a grouting step S3, injecting cement grout into the anchor cable hole through the grouting pipe so that the anchor section and the free section of the anchor cable are filled with the cement grout, and gradually drawing out the anchor cable hole-forming sleeve in the grouting process.

Specifically, cement grout is injected into the anchor cable hole through the grouting pipe 3, and the anchoring section and the free section of the anchor cable 2 should be fully filled with the cement grout. Wherein, the free section is protected by an anchor cable pore-forming sleeve 1 to ensure that the steel strand is separated from the cement paste. In the grouting process, the anchor cable hole-forming sleeve 1 is slowly drawn out in combination with the grouting condition, and meanwhile, orifice grouting and secondary grouting are timely performed, so that the grouting quality of the anchor cable is ensured.

And a casing extracting step S4, wherein the anchor cable bundle is fixed after the anchor cable hole-forming casing is extracted and before the cement slurry is initially set, so that the anchor cable bundle is prevented from being downwarped due to hole collapse of the anchor cable hole and sinking of the anchor cable bundle.

Specifically, after the anchor cable hole-forming sleeve 1 is drawn out and before the cement slurry is initially set, the anchor cable bundle should be temporarily fixed to prevent the anchor cable bundle from being downwarped due to hole collapse of the anchor cable hole and sinking of the anchor cable bundle.

And an anchor cable tensioning step S5, pre-tensioning the anchor cable through an anchor device arranged outside the anchor cable hole after the cement paste reaches the preset age.

Specifically, when the anchor cable cement paste reaches the preset age, tensioning of the anchor cable 2 should be performed fully. The pretension of the anchor cable 2 is required to be loaded at a designed locking value for not less than 15min, so that the sufficient extension of the free section of the anchor cable 2 is ensured, and the creep deformation of the anchor cable 2 is reduced; the preset age may be determined according to actual conditions, and is not limited in this embodiment.

And an anchor cable locking step S6, pre-stressing, tensioning and locking the anchor cable.

Specifically, the prestressing tensioning of the anchor cable 1 is locked and performed after the prestressing tensioning is completed. The tensioning locking needs to jump at intervals, so that the steel strands of each anchor cable 2 are uniformly stressed, and the locking load value is balanced; the locking load of the anchor cable 2 should be 1.2-1.3 times of the designed locking load value. Wherein, the design locking load value can be determined according to the actual situation.

And a foundation pit excavation step S7, after the anchor cables are tensioned and locked, performing foundation pit earth excavation, and redrawing the anchor cables during the foundation pit earth excavation to control the deformation of the foundation pit.

Specifically, after the anchor cable 2 is locked, during the excavation of the foundation pit, due to the influences of soil stress variation, underground water level variation, earth excavation sequence and depth and the like, the stress of the anchor cable 2 can be changed, and the increase and the decrease are also caused. Aiming at the situation that the stress reduction loss of the anchor cable 2 is greatly reduced to 30%, the anchor cable 2 is required to be redrawn in time, and the deformation of the foundation pit is effectively controlled.

In summary, in the prestressed anchor cable construction method provided by this embodiment, the anchor cable hole-forming sleeve 1 is arranged in the anchor cable hole to temporarily support the soil layer on the inner wall of the anchor cable hole so as to ensure the linearity of the anchor cable hole, ensure the hole-forming quality, reduce disturbance damage to the soft soil layer, and avoid hole collapse; meanwhile, the anchor cable hole-forming sleeve 1 has high rigidity, so that the linear radian of the anchor cable hole caused by the self weight of a drill bit and a drill rod in the hole-forming process can be reduced, the disturbance damage to a soft soil layer is avoided, the deformation value and the elongation value of the anchor cable 2 are prevented from being increased in the hole-forming, anchor cable laying, grouting and prestress tensioning processes, and the loss of the prestress of the anchor cable 2 can be avoided; adopting an anchorage device 6 to perform tensioning locking and redrawing on the anchor cable 2 so as to meet the design requirement; meanwhile, an anchor cable positioning bracket 4 is arranged on the anchor cable 2 to fixedly support the anchor cable 2 and the grouting pipe 3 so as to prevent the anchor cable 2 from sinking or warping in the soil layer; and grouting the anchor cable by adopting the grouting pipe 3 so as to fix the position of the anchor cable in the soil layer. Compared with the prior art, the deformation of the anchor cable 2 can be controlled, the prestress loss is reduced, the construction speed is high, the operation is convenient, and the standardized components are quickly installed; meanwhile, the anchor cable 2 is small in deformation, and the deformation and safety of the foundation pit slope are guaranteed.

Further, cement grout is injected into the anchor cable hole through the grouting pipe 3, the anchoring section and the free section of the anchor cable 2 are fully filled with the cement grout, the anchor cable hole-forming sleeve 1 is slowly drawn out in combination with the grouting condition in the grouting process, and in the grouting process, in order to avoid downward deflection of the anchor cable bundle caused by hole collapse of the anchor cable hole and sinking of the anchor cable bundle, the anchor cable bundle is temporarily fixed, so that deformation of the anchor cable and deformation of a foundation pit slope are reduced, and the construction safety is ensured; after the cement paste reaches the preset age, pretensioning is carried out on the anchor cable, the prestress relaxation of the anchor cable is reduced, the sufficient extension of the free section of the anchor cable is ensured, and the creep deformation of the anchor cable is reduced; the anchor cable is subjected to prestress tensioning locking after pretensioning, and is subjected to redraw after locking, so that the deformation and elongation values of the anchor cable are effectively reduced, and the prestress loss of the anchor cable is reduced; that is to say, in this application through the setting of anchor rope pore-forming sleeve pipe 1 and slowly take out anchor rope pore-forming sleeve pipe 1 and fix the anchor rope bundle temporarily when slip casting, combine to carry out pretension to the anchor rope and reduce the prestressing force relaxation of anchor rope, jump again and draw, the locking of excess force value to control the deformation of anchor rope in each step, with the deformation of whole control anchor rope in the slip casting process, and then reach the purpose that reduces prestressing force loss.

Particularly, interval lock jumping is adopted during prestress tensioning locking, so that the uniform stress of each anchor cable is ensured, the locking load value is balanced, the locking load of the anchor cable is ensured to reach 1.2-1.3 times of the designed locking load value, and the locking of the over-force value is carried out.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.