CN216899889U - Model test device for simulating continuous damage of pile-anchor support foundation pit caused by anchor rod failure - Google Patents
Model test device for simulating continuous damage of pile-anchor support foundation pit caused by anchor rod failure Download PDFInfo
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- CN216899889U CN216899889U CN202123099082.4U CN202123099082U CN216899889U CN 216899889 U CN216899889 U CN 216899889U CN 202123099082 U CN202123099082 U CN 202123099082U CN 216899889 U CN216899889 U CN 216899889U
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Abstract
The utility model discloses a model test device for simulating continuous damage of a pile anchor supporting foundation pit caused by failure of an anchor rod, which comprises a rectangular model box, wherein a sand body is scattered in the model box, a simulation foundation pit is dug in the sand body, one side of the simulation foundation pit is provided with a containment structure, the containment structure is provided with a soil pressure monitoring device and a strain gauge, an anchor rod is connected to a crown beam, the anchor rod is made of steel stranded wires, penetrates through the rear side wall of the model box and is fixedly connected with a hollow bolt which is vertically arranged above the anchor rod by bypassing a fixed pulley, the hollow bolt is fixed at the top of the rear side wall of the model box, a tension meter is connected to a rod section of the anchor rod, which is positioned outside the model box, a guide rail support is arranged outside the model box, and a sanding trolley is arranged on the guide rail support. The method adopts a similar principle to simulate the continuous damage of the pile-anchor supporting foundation pit caused by the local anchor rod failure, and is convenient for exploring the load transfer rule when the continuous damage of the pile-anchor supporting foundation pit caused by the local anchor rod failure is caused.
Description
Technical Field
The utility model relates to a test device in foundation pit engineering, in particular to a model test device for researching the load transfer law when a local anchor rod of a supporting foundation pit fails and the local anchor rod of the foundation pit fails in an anchor rod supporting system.
Background
The anchor bolt support is used as a common foundation pit support system and is mainly used for the situations of large engineering scale, complex surrounding environment and irregular foundation pit shape. In the anchor rod supporting foundation pit, the reasonable use of the anchor rod can effectively control the deformation of the soil body, reduce the internal force of the enclosure structure, reduce the engineering cost and improve the construction efficiency. However, in actual engineering, foundation pit collapse accidents caused by improper design and construction of the anchor rods often occur, such as foundation pit collapse accidents caused by local anchor rod failure all happen in Koron, Japan, Zhengzhou, Nanning places and the like, and huge property loss is caused.
In recent years, numerous scholars have analyzed a large number of bolting project instances or accident cases. For example, the statistical analysis is carried out on 35 bolting engineering cases by International Federation for construction (FIP), wherein the anchor rods in many projects have the risk of failure, and even the existing projects cause structural collapse due to the failure of the anchor rods.
However, the existing foundation pit stability research method is only limited to the two-dimensional condition, the critical state of the foundation pit to be damaged cannot be researched, the development condition of the foundation pit after local damage cannot be researched, the disaster condition of the foundation pit after damage cannot be evaluated, and a systematic foundation pit engineering anti-continuous collapse theory does not exist. In addition, the current research on continuous deep foundation pit failure mainly aims at cantilever type row piles, ring beam type horizontal supporting structure systems and inner support type row pile supporting systems, and pile anchor supporting systems are commonly used in recent years as foundation pit supporting forms, and the mechanism and process of continuous failure caused by local failure and the control of the overall safety of the foundation pit are urgent to be researched. Therefore, it is necessary to provide a model test device and method for simulating continuous failure of a pile-anchor supporting foundation pit caused by local anchor rod failure, so as to disclose a load transfer mechanism of the continuous failure caused by the local anchor rod failure which is still deficient at the present stage.
SUMMERY OF THE UTILITY MODEL
The utility model provides a model test device for simulating continuous damage of a pile-anchor support foundation pit caused by anchor rod failure, aiming at solving the technical problems in the prior art.
The technical scheme adopted by the utility model for solving the technical problems in the prior art is as follows: a model test device for simulating continuous damage of a pile-anchor supporting foundation pit caused by failure of an anchor rod comprises a rectangular model box, wherein a sand body is scattered in the model box, a simulation foundation pit is dug in the sand body, the simulation foundation pit is positioned on the front side of the model box, three sides of the simulation foundation pit are adjacent to the side wall of the model box, one side of the simulation foundation pit is provided with a retaining structure, soil pressure monitoring equipment is installed on the retaining structure, the retaining structure comprises supporting piles and a crown beam, strain gauges are adhered to the inner sides of the supporting piles and the crown beam, and a leakage-proof film is adhered between two adjacent supporting piles on the inner side of the retaining structure; the top beam is supported by a bracket and fixedly connected with the bracket, the bracket is fixed at the top of the inner side of a supporting pile corresponding to the bracket, an anchor rod is connected to the top beam and is made of a steel strand, the anchor rod penetrates out of the rear side wall of the model box and is fixedly connected with a vertically arranged hollow bolt above the anchor rod by bypassing a fixed pulley, the hollow bolt is connected to a support plate, the support plate is fixedly connected to the top of the rear side wall of the model box, a tension meter is connected to a rod section of the anchor rod, which is positioned outside the model box, the fixed pulley is installed outside the rear side wall of the model box, and the left side wall or the right side wall of the model box is made of a toughened glass plate; a guide rail bracket is arranged on the outer side of the model box, a guide rail is laid on the guide rail bracket, the guide rail stretches across the top of the model box, and a sanding trolley is arranged on the guide rail and consists of a wheel shaft system and a sand hopper with a sanding valve; the sanding trolley is provided with a sand conveying grab bucket.
The middle-upper part of the front side wall of the model box is formed by splicing steel plate strips with the same length as the wall length.
All the steel strips are equal in width.
And a gap is reserved between the two ends of the crown beam and the side wall of the model box.
The supporting piles and the crown beam are both made of rigid PVC rectangular hollow pipes.
The guide rail is arranged along the length direction of the model box.
The utility model has the advantages and positive effects that: and by adopting a similar principle, the continuous damage of the pile-anchor supporting foundation pit caused by the local anchor rod failure is simulated, so that the load transfer rule when the continuous damage of the pile-anchor supporting foundation pit caused by the local anchor rod failure is conveniently explored. The pile anchor supporting foundation pit structure has the advantages of small volume, reasonable structure, convenience in test, good reliability, good applicability to pile anchor supporting foundation pits of various sizes, simple structure and low cost.
Drawings
FIG. 1 is a schematic structural diagram of the present invention.
In the figure: 1-a model box; 2-a guide rail bracket; 3-sanding the trolley; 4-sand conveying grab bucket; 5-supporting piles; 6-anchor rod; 7-a crown beam; 8-a tension meter; 9-a hollow bolt; 10-a fixed pulley; 11-axle systems; 12-sanding valve; 13-a sand hopper; 14-steel plate strips; 15-bracket.
Detailed Description
In order to further understand the contents, features and effects of the present invention, the following embodiments are illustrated and described in detail with reference to the accompanying drawings:
referring to fig. 1, a model test device for simulating continuous damage of a pile-anchor supporting foundation pit caused by failure of an anchor rod comprises a rectangular model box 1, a sand body is scattered in the model box 1, a simulation foundation pit is dug in the sand body, the simulation foundation pit is located on the front side of the model box 1, three sides of the simulation foundation pit are adjacent to the side wall of the model box 1, and one side of the simulation foundation pit is provided with a retaining structure.
The earth pressure monitoring equipment is installed on the enclosure structure, the enclosure structure comprises supporting piles 5 and a crown beam 7, strain gauges are pasted on the inner sides of the supporting piles 5 and the crown beam 7, a leakage-proof film is bonded between every two adjacent supporting piles 5, and sand outside the simulated foundation pit can be prevented from leaking from a pile gap.
The crown beam 7 is supported by a bracket 15 and fixedly connected with the bracket 15, the bracket 15 is fixed at the top of the inner side of the supporting pile 5 corresponding to the bracket 15, and the bracket 15 can be made of organic glass and is bonded on the supporting pile 5 by strong glue. The length of the crown beam is slightly shorter than the width of the model box so as to ensure that gaps are reserved between the two ends of the crown beam and the side wall of the model box and avoid friction from influencing the load transmission of a supporting system. The crown beam is perforated according to the anchor rod arrangement mode so as to meet the anchor rod anchoring requirement.
Be connected with stock 6 on crown beam 7, stock 6 adopts the steel strand wires to make, stock 6 wears out the rear side wall of mold box 1 and walk around fixed pulley 10 and be located its top, the hollow bolt 9 rigid coupling of vertical setting, hollow bolt 9 is connected in the backup pad, the backup pad rigid coupling is in the rear side wall top of mold box 1 stock 6 is located be connected with tensiometer 8 on the pole section in the mold box 1 outside, fixed pulley 10 installs the rear side wall outside of mold box 1. The hollow bolt 9 can be rotated to be raised or lowered during the test, so that the anchor rod 6 is stretched or loosened to generate prestress or loosen the axial force of the anchor rod. The tension meter 8 can monitor the axial force of the anchor rod in real time and accurately apply the prestress of the anchor rod.
The middle-upper part of the front side wall of the model box 1 is formed by splicing equal-wall-length steel laths 14, and the widths of all the steel laths 14 are also equal. The assembly structure is adopted to facilitate the excavation of the foundation pit, and the steel plate strips 14 can be taken down one by one in the excavation process of the foundation pit.
The left side wall or the right side wall of the model box 1 is made of toughened glass plates, deformation of soil bodies and structures in the test process can be observed, the other three sides and the bottom of the model box are steel plates, and stiffening ribs are welded on the outer sides of the steel plates to serve as supports, so that rigidity of the model box is guaranteed.
The sand spreading device is characterized in that a guide rail support 2 is arranged on the outer side of the model box 1, a guide rail is paved on the guide rail support 2 and stretches across the top of the model box 1, a sanding trolley 3 is arranged on the guide rail, and the sanding trolley 3 is composed of a wheel shaft system 11 and a sand hopper 13 with a sanding valve 12.
The sanding trolley 12 is provided with a sand conveying grab bucket 4, and the sand conveying grab bucket 4 can convey sand from a sand storage pool to a sand hopper 13.
Because the sanding trolley 12 is positioned on the guide rail bracket 2 and is separated from the model box 1, the disturbance to the model soil during sanding can be avoided, and the sanding trolley can ensure that the sand covers the whole model box and is uniformly scattered during sanding. Before sand sprinkling by a sand rain method, an anchor rod 6 is preset in a model box according to a design position, wherein one end of the anchor rod passes through gaps among model piles and is anchored on a crown beam, and the other end of the anchor rod is finally anchored on a hollow bolt through a fixed pulley.
In this embodiment, the guide rail is provided along the longitudinal direction of the mold box 1. The supporting piles 5 and the crown beams 7 are both made of rigid PVC rectangular hollow pipes.
The device is adopted for testing, and comprises the following steps:
firstly, arranging the support piles, and then arranging the soil pressure monitoring equipment on the building envelope. And (4) pre-arranging the crown beam and the anchor rod in the foundation pit, but not anchoring the outer end of the anchor rod. Then, the sand conveying grab bucket loads sand from the sand storage pool to the sand bucket, a sand spreading valve is opened, and the sand spreading trolley moves back and forth along the length direction of the model box to perform sand rain method sand spreading. And after sanding is finished, taking down the steel strips with the same width one by one, excavating the foundation pit, anchoring the outer end of the anchor rod to the top end of the hollow bolt after excavating to a certain depth, screwing the hollow bolt to apply a certain prestress to the anchor rod, and then continuously excavating the foundation pit to the experimental design depth. And shearing the anchor rods according to the test design sequence until the foundation pit is subjected to continuous collapse damage.
The method can be used for researching the continuous damage of the foundation pit caused by the failure of the local anchor rod so as to reveal the load transfer mechanism caused by the failure of the local anchor rod of the pile anchor supporting foundation pit.
Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and those skilled in the art can make many modifications without departing from the spirit and scope of the present invention as defined in the appended claims.
Claims (6)
1. A model test device for simulating continuous destruction of a pile-anchor support foundation pit caused by failure of an anchor rod is characterized by comprising a rectangular model box,
a sandy soil body is scattered in the model box, a simulation foundation pit is dug in the sandy soil body, the simulation foundation pit is positioned on the front side of the model box, three sides of the simulation foundation pit are adjacent to the side wall of the model box, one side of the simulation foundation pit is provided with a retaining structure, soil pressure monitoring equipment is installed on the retaining structure, the retaining structure comprises supporting piles and a crown beam, strain gauges are adhered to the inner sides of the supporting piles and the crown beam, and a leakage-proof film is adhered between two adjacent supporting piles on the inner side of the retaining structure;
the top beam is supported by a bracket and fixedly connected with the bracket, the bracket is fixed at the top of the inner side of a supporting pile corresponding to the bracket, an anchor rod is connected to the top beam and is made of a steel strand, the anchor rod penetrates out of the rear side wall of the model box and is fixedly connected with a vertically arranged hollow bolt above the anchor rod by bypassing a fixed pulley, the hollow bolt is connected to a support plate, the support plate is fixedly connected to the top of the rear side wall of the model box, a tension meter is connected to a rod section of the anchor rod, which is positioned outside the model box, the fixed pulley is installed outside the rear side wall of the model box, and the left side wall or the right side wall of the model box is made of a toughened glass plate;
a guide rail bracket is arranged on the outer side of the model box, a guide rail is laid on the guide rail bracket, the guide rail stretches across the top of the model box, and a sanding trolley is arranged on the guide rail and consists of a wheel shaft system and a sand hopper with a sanding valve;
the sanding trolley is provided with a sand conveying grab bucket.
2. The model test device for simulating continuous damage of a pile-anchor support foundation pit caused by failure of an anchor rod according to claim 1, wherein the middle upper part of the front side wall of the model box is formed by splicing steel plate strips with the same length as the wall length.
3. The model test device for simulating continuous damage of a pile-anchor support foundation pit caused by failure of an anchor rod according to claim 2, wherein the widths of all the steel plates are equal.
4. The model test device for simulating continuous destruction of a pile-anchor support foundation pit caused by failure of an anchor rod according to claim 1, wherein a gap is reserved between two ends of the crown beam and the side wall of the model box.
5. The model test device for simulating continuous destruction of a pile-anchor support foundation pit caused by anchor rod failure according to claim 1, wherein the support piles and the crown beams are both made of rigid PVC rectangular hollow pipes.
6. The model test device for simulating continuous damage of a pile-anchor support foundation pit caused by failure of an anchor rod according to claim 1, wherein the guide rail is arranged along the length direction of the model box.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123099082.4U CN216899889U (en) | 2021-12-10 | 2021-12-10 | Model test device for simulating continuous damage of pile-anchor support foundation pit caused by anchor rod failure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123099082.4U CN216899889U (en) | 2021-12-10 | 2021-12-10 | Model test device for simulating continuous damage of pile-anchor support foundation pit caused by anchor rod failure |
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| CN216899889U true CN216899889U (en) | 2022-07-05 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202123099082.4U Active CN216899889U (en) | 2021-12-10 | 2021-12-10 | Model test device for simulating continuous damage of pile-anchor support foundation pit caused by anchor rod failure |
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| CN (1) | CN216899889U (en) |
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- 2021-12-10 CN CN202123099082.4U patent/CN216899889U/en active Active
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