Device for realizing continuous collapse of cantilever pile support foundation pit in centrifuge test
By designing a combination device of support piles and support shafts in the centrifuge test, the limitation of the cantilever pile support structure in the prior art simulates the continuous collapse of the foundation pit in the sandy environment is solved, and the support piles are automatically achieved. Controllable simulation of damage and continuous collapse improves the accuracy of the test and space utilization.
Patent Information
- Application Number
- CN202420632979.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-29
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2034-03-29
AI Technical Summary
The existing cantilever pile support structure has limitations in the simulation of continuous collapse test of foundation pits, especially in a sandy and soil environment. The rapid inflow of sand and soil after the support pile bends and breaks, resulting in a reduction in subsequent stress, which cannot effectively simulate large-scale continuous collapse.
Design a device, including multiple supporting piles and support shafts, the supporting pile preset section and the receiving cavity, the supporting shaft slides along the inner wall of the receiving cavity, and drives the supporting pile to break simultaneously by soil pressure, simulate continuous collapse, and adopt limit position The device and the hoisting ring system control the movement of the support shaft to ensure that the simulation range of continuous collapse is controllable.
It realizes automatic damage to multiple supporting piles at the same time, simulates continuous collapse, reduces the impact of sand and soil inflow, improves the control and accuracy of the test, saves test space, and improves the economic and scientific research value of the test.
Smart Images
Figure CN222183468U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of foundation pit support, in particular to a device for realizing continuous collapse of a cantilever pile support foundation pit in a centrifuge test. Background Art
[0002] Cantilever pile support is a common foundation pit support method, which is widely used in projects with good soil quality and shallow excavation depth. However, foundation pit damage accidents caused by hidden dangers of support structure occur from time to time. Local damage of cantilever piles will cause more cantilever piles to fail, which may directly lead to continuous large-scale collapse of foundation pits, causing immeasurable casualties and property losses.
[0003] In the prior art, such as the Chinese patent document with application number CN202111496855.4, a support structure and a construction method for preventing large-scale continuous collapse of foundation pit enclosure are disclosed. In this patent document, a support structure is disclosed. This support structure uses herringbone inclined piles as double rows of piles, which can significantly increase the local rigidity of the support structure, interrupt the transmission of possible continuous damage to the pile body, and reduce the possibility of overturning and damage to the foundation pit.
[0004] In the above-mentioned existing technical solutions, these support structures need to undergo certain model tests before use in order to simulate the continuous destruction process, reveal the mechanical mechanism of continuous destruction caused by local destruction, and establish quantitative evaluation indicators and evaluation methods for evaluating the possibility of continuous collapse of foundation pits, so as to propose corresponding prevention methods and emergency rescue measures. However, these current support structures still have certain limitations when performing specific simulations. During the test, since the soil layer is mostly sandy, after the support piles at a certain stage are bent and broken, the sand at that stage quickly flows into the foundation pit, resulting in a reduction in the amount of sand in the adjacent areas, and a reduction in the stress on the subsequent support structures, which makes it impossible to cause large-scale continuous collapse. Utility Model Content
[0005] The utility model provides a device for realizing continuous collapse of a cantilever pile supporting foundation pit in a centrifuge test, aiming to solve the technical problems raised in the above-mentioned background technology.
[0006] In order to solve the above technical problems, the utility model specifically provides the following technical solutions:
[0007] A device for realizing continuous collapse of a cantilever pile support foundation pit in a centrifuge test, wherein the device is placed in a simulated predetermined position, and comprises: a plurality of support piles, all of which are pre-buried in the simulated predetermined position, each of which is provided with a preset cross-section, and each of which is provided with a receiving cavity; a plurality of support shafts, each of which is respectively arranged in the receiving cavity of each support pile, and the support shaft can slide axially along the inner wall of the receiving cavity; when all the support shafts do not slide in the corresponding receiving cavity, each support shaft supports the inner wall of the corresponding receiving cavity; when each support shaft slides to be out of the corresponding receiving cavity, pressure is applied to all the support piles by simulating the soil at the predetermined position to drive each support pile to break simultaneously from the preset cross-section.
[0008] As a preferred solution of the utility model, the supporting pile comprises an upper half pile and a lower half pile, the preset section is the docking surface between the upper half pile and the lower half pile, the upper half pile and the lower half pile are both hollow structures, and the accommodating cavity is the hollow cavity of the upper half pile and the lower half pile.
[0009] As a preferred solution of the present invention, the diameter of the support shaft is not greater than the diameter of the accommodating cavity.
[0010] As a preferred solution of the utility model, the preset section includes three points A, B and C, among which point B is located on the axis line of the hollow cavity, and points A and C are located on both sides of point B respectively. The three points A, B and C are on the same straight line, and there is a set angle between the straight line and the axis line of the hollow cavity.
[0011] As a preferred solution of the utility model, it also includes a limiting device, which is fixedly connected to the end of the supporting shaft, and the limiting device can move the supporting shaft to a certain position in the accommodating cavity and stop.
[0012] As a preferred solution of the utility model, the limiting device includes a fixing frame arranged at one end of the support shaft away from the lower half pile, and a plurality of lifting rings are arranged on the fixing frame, each of the lifting rings is respectively arranged corresponding to each support shaft, and a connecting rope is wound on each lifting ring, and the lifting ring drives the corresponding support shaft to move by winding the connecting rope.
[0013] As a preferred solution of the utility model, the length of the support shaft is not less than one quarter of the length of the supporting pile.
[0014] Compared with the prior art, the utility model has the following beneficial effects:
[0015] 1. The utility model can realize the automatic destruction of multiple support piles at the same time through the cooperation of support piles and support shafts to simulate the situation of continuous collapse. Specifically, all the support piles are first pre-buried in the simulated predetermined position. At this time, each support shaft supports the inner wall of the corresponding accommodating cavity. If a continuous collapse experiment is required, each support shaft only needs to be slid to be separated from the corresponding accommodating cavity. After that, the soil at the simulated predetermined position applies pressure to all the support piles to drive each support pile to break from the preset section at the same time. The entire operation process is less limited by the amount of sand and soil, and the simulation range of continuous collapse is controllable.
[0016] 2. The utility model not only realizes the simultaneous automatic destruction of supporting piles of different numbers and positions, but also can cause less disturbance to the centrifuge in operation.
[0017] 3. The device in the utility model occupies a small space for the model test, which can save the centrifuge model space and improve the utilization rate of the test model space.
[0018] 4. The device and test method in the utility model are simple, economical, versatile, and accurate, and have good economic benefits and scientific research value. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the implementation or the prior art description. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.
[0020] Figure 1 It is a schematic diagram of the overall structure of the utility model;
[0021] Figure 2 It is a structural schematic diagram of the upper half pile and the lower half pile in the utility model when they are overlapped;
[0022] Figure 3 It is a structural schematic diagram of the supporting piles in the utility model when they are arranged in the centrifuge model box.
[0023] The numbers in the figure represent the following:
[0024] 1. Upper half of the pile; 2. Lower half of the pile; 3. Preset section; 4. Limiting device; 5. Support shaft; 6. Support pile; 7. Centrifuge model box; 8. Accommodating chamber; 9. Fixed frame; 10. Lifting ring; 11. Connecting rope. DETAILED DESCRIPTION
[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0026] like Figure 1-Figure 3 As shown, the utility model provides a device for realizing continuous collapse of cantilever pile supporting foundation pit in centrifuge test, and the device for realizing continuous collapse of cantilever pile supporting foundation pit in centrifuge test is placed in a simulated predetermined position (generally, the device is set in a simulated predetermined position in a centrifuge model box 7), and the device includes:
[0027] A plurality of support piles 6, all of which are pre-buried at simulated predetermined positions, each of which is provided with a preset section 3, and each of which is provided with a receiving cavity 8;
[0028] A plurality of support shafts 5, each support shaft 5 is respectively disposed in a receiving cavity 8 of each support pile 6, and the support shaft 5 can slide axially along the inner wall of the receiving cavity 8;
[0029] When all the support shafts 5 are not sliding in the corresponding accommodating chamber 8, each support shaft 5 supports the inner wall of the corresponding accommodating chamber 8;
[0030] When each support shaft 5 slides out of the corresponding accommodation cavity 8 , pressure is applied to all the support piles 6 by simulating the soil at a predetermined position to drive each support pile 6 to break at the preset section 3 at the same time.
[0031] The utility model can realize the automatic destruction of multiple supporting piles 6 at the same time through the cooperation between the supporting piles 6 and the supporting shaft 5 to simulate the situation of continuous collapse. Specifically, all the supporting piles 6 are pre-buried in the simulated predetermined position. At this time, each supporting shaft 5 supports the inner wall of the corresponding accommodating cavity 8. If a continuous collapse experiment is required, each supporting shaft 5 only needs to be slid to be separated from the corresponding accommodating cavity 8. After that, the soil at the simulated predetermined position applies pressure to all the supporting piles 6 to drive each supporting pile 6 to break at the preset section 3 at the same time. The entire operation process is less limited by the amount of sand and soil, and the simulation range of continuous collapse is controllable.
[0032] In the utility model, there are many ways for the support shaft 5 to slide out of the corresponding accommodating cavity 8. For example, an inflatable airbag can be provided in the accommodating cavity 8 to assist in the disengagement. Under normal circumstances, the support shaft 5 is stuck in the accommodating cavity 8. Once the inflatable airbag expands, it will gradually push the support shaft 5 to slide upward. When the support shaft 5 slides to the point where the bottom of the support shaft 5 and the top of the inflatable airbag are flush with the preset section 3, the support pile 6 will be pushed and broken by the soil.
[0033] In some specific embodiments, the supporting pile 6 includes an upper half pile 1 and a lower half pile 2, the preset section 3 is the docking surface between the upper half pile 1 and the lower half pile 2, the upper half pile 1 and the lower half pile 2 are both hollow structures, and the accommodating cavity 8 is the hollow cavity of the upper half pile 1 and the lower half pile 2.
[0034] The fracture in the present invention is relative to the overlap of the upper half pile 1 and the lower half pile 2. The fracture phenomenon occurs when the upper half pile 1 and the lower half pile 2 are separated.
[0035] The supporting piles 6 are arranged in this way so that the upper half of the pile 1 does not need to rely on a large external force to break, and can meet the situation where multiple supporting piles 6 break at the same time.
[0036] In some specific embodiments, the diameter of the support shaft 5 is not larger than the diameter of the accommodating cavity 8. This configuration is to reduce the scraping between the support shaft 5 and the inner wall of the accommodating cavity 8 when the support shaft 5 slides in the accommodating cavity 8, thereby minimizing the situation in which the upper half of the pile 1 is driven by the support shaft 5 and moves therewith.
[0037] In some specific embodiments, the preset section 3 includes three points A, B and C, among which point B is located on the axis of the hollow cavity, point A and point C are located on both sides of point B respectively, and points A, B and C are on the same straight line, which forms a set angle with the axis of the hollow cavity.
[0038] The setting angle is generally 30-120 degrees, but in specific operations, you can refer to Figure 2 Sometimes point A may be higher than point C, and sometimes point A may be lower than point C. Figure 1 What is shown in the figure is the situation where points A, B and C are in a horizontal state (the straight line is perpendicular to the axis of the hollow cavity at this time). In this case, the overlap surface of the upper half pile 1 and the lower half pile 2 is horizontal. The advantage is that the upper half pile 1 and the lower half pile 2 in this state are easy to be pre-buried in the simulated predetermined position, and during the pre-buried process, the upper half pile 1 and the lower half pile 2 will not easily overlap and misalign or the upper half pile 1 will not be placed unstably.
[0039] When point A is higher than point C or point A is lower than point C, you can refer to Figure 2In this case, the overlap surface between the upper half pile 1 and the lower half pile 2 is inclined, which has the advantage that once the support shaft 5 leaves the area where the preset section 3 is located, the upper half pile 1 and the lower half pile 2 will tend to separate, and the amount of sand and soil required for separation is not large.
[0040] When making specific selection, it should be set according to actual needs.
[0041] A technical solution is provided for the problem of how to support the shaft 5 to slide out of the corresponding accommodating cavity 8, which also includes a limit device 4, which is fixedly connected to the end of the support shaft 5. The limit device 4 can move the support shaft 5 to a certain position in the accommodating cavity 8 and stop.
[0042] In some specific embodiments, the limiting device 4 includes a fixing frame 9 arranged at one end of the support shaft 5 away from the lower half pile 2, and a plurality of lifting rings 10 are arranged on the fixing frame 9, each lifting ring 10 is respectively arranged corresponding to each support shaft 5, and a connecting rope 11 is wound around each lifting ring 10, and the lifting ring 10 drives the corresponding support shaft 5 to move by winding the connecting rope 11.
[0043] During specific operation, all the lifting rings 10 can be connected by a driving shaft driven by a motor. Once the driving shaft rotates, all the lifting rings 10 will rotate, so that each corresponding connecting rope 11 can move with the corresponding supporting shaft 5 through winding or lowering operations.
[0044] In some specific embodiments, the length of the support shaft 5 is not less than one quarter of the length of the supporting pile 6. Specifically, both ends of the support shaft 5 should at least exceed the area where point A and point C are located, so that each support shaft 5 can provide support to the inner wall of the corresponding accommodating cavity 8.
[0045] The specific work of this application includes the following steps:
[0046] A1. Connect the upper half pile 1 and the lower half pile 2, fix the steel shaft through the lifting ring 10, and place the test device and the ordinary supporting piles in the predetermined position of the centrifuge model box 7.
[0047] A2. Start the centrifuge and conduct the normal excavation phase of the test. The test device and ordinary support piles together form a cantilever pile support. After excavation reaches the predetermined depth, excavation and monitoring are stopped.
[0048] A3. The steel shaft (i.e., support shaft 5, which is a specific selected component) is lifted by pulling the lifting ring through the manipulator, and the upper half of the pile 1 and the lower half of the pile 2 are separated. Due to the soil pressure behind the pile, the upper half of the pile 1 collapses into the foundation pit, realizing the continuous collapse of the foundation pit supported by the cantilever pile.
[0049] Compared with the prior art, this application has the following beneficial effects:
[0050] 1. It not only realizes the simultaneous automatic destruction of supporting piles of different numbers and positions, but also can cause less disturbance to the running centrifuge.
[0051] 2. The device occupies a small test space of the model (referring to the centrifuge model box 7 in 3), which can save the centrifuge model space and improve the utilization rate of the test model space.
[0052] 3. The device and test method are simple, economical, versatile, and accurate, and have good economic benefits and scientific research value.
[0053] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.
Claims
1. A device for realizing continuous collapse of a cantilever pile supporting foundation pit in a centrifuge test, wherein the test device for realizing continuous collapse of a cantilever pile supporting foundation pit in a centrifuge test is placed in a simulated predetermined position, and is characterized in that: The device includes: A plurality of support piles (6), all of which are pre-buried at simulated predetermined positions, each of which is provided with a preset cross-section (3), and each of which is provided with a receiving cavity (8); A plurality of support shafts (5), each of the support shafts (5) being arranged correspondingly in the accommodating cavity (8) of each of the support piles (6), and the support shaft (5) being capable of axially sliding along the inner wall of the accommodating cavity (8); When all the support shafts (5) are not sliding in the corresponding accommodating cavity (8), each of the support shafts (5) provides support to the inner wall of the corresponding accommodating cavity (8); When each of the support shafts (5) slides to be separated from the corresponding accommodating cavity (8), pressure is applied to all of the support piles (6) by simulating soil at a predetermined position to drive each of the support piles (6) to break simultaneously from the preset section (3).
2. A device for realizing continuous collapse of cantilever pile supporting foundation pit in centrifuge test according to claim 1, characterized in that: The support pile (6) comprises an upper half pile (1) and a lower half pile (2), the preset cross section (3) is a butt joint surface between the upper half pile (1) and the lower half pile (2), the upper half pile (1) and the lower half pile (2) are both hollow structures, and the accommodating cavity (8) is the hollow cavity of the upper half pile (1) and the lower half pile (2).
3. A device for realizing continuous collapse of cantilever pile supporting foundation pit in centrifuge test according to claim 2, characterized in that: The diameter of the support shaft (5) is no greater than the diameter of the accommodating cavity (8).
4. A device for realizing continuous collapse of cantilever pile supporting foundation pit in centrifuge test according to claim 3, characterized in that: The preset cross section (3) includes three points A, B and C. Among the three points, point B is located on the axis of the hollow cavity, and point A and point C are located on both sides of point B respectively. The three points A, B and C are located on the same straight line, and the straight line forms a set angle with the axis of the hollow cavity.
5. The device for realizing continuous collapse of cantilever pile supporting foundation pit in centrifuge test according to claim 4, characterized in that: It also comprises a limiting device (4), wherein the limiting device (4) is fixedly connected to the end of the supporting shaft (5), and the limiting device (4) can move the supporting shaft (5) in the accommodating cavity (8) to a certain position and then stop.
6. The device for realizing continuous collapse of cantilever pile supporting foundation pit in centrifuge test according to claim 5, characterized in that: The limiting device (4) comprises a fixing frame (9) arranged at one end of the supporting shaft (5) away from the lower half pile (2), and a plurality of lifting rings (10) are arranged on the fixing frame (9), each of the lifting rings (10) is respectively arranged corresponding to each of the supporting shafts (5), and a connecting rope (11) is wound around each of the lifting rings (10), and the lifting ring (10) drives the corresponding supporting shaft (5) to move by winding the connecting rope (11).
7. A device for realizing continuous collapse of cantilever pile supporting foundation pit in centrifuge test according to claim 1 or 4, characterized in that: The length of the support shaft (5) is not less than one quarter of the length of the support pile (6).