Narrow foundation pit excavation simulation and test system in super gravity field

Abstract

This invention relates to a simulation and testing system for narrow foundation pit excavation in a hypergravity field, comprising a foundation pit model system, a foundation pit support system, and a measurement system. The foundation pit model system includes a model box, a partition, and an adjusting rod. The partition is vertically positioned inside the model box. One end of the adjusting rod is connected to the partition, and the other end rests against the inner wall of the model box. The adjusting rod is used to adjust the position of the partition. The space between the partition and the model box is used to place test soil, which is formed by consolidating mud in a hypergravity field. The foundation pit support system includes two retaining walls arranged parallel to the excavation trench and a support rod connecting the two retaining walls. The support rod is used to adjust the distance between the two retaining walls. The measurement system is used to measure the strain of the retaining walls, ground settlement, and displacement field changes. This invention can comprehensively measure all aspects of the impact of foundation pit excavation in a hypergravity field and simulate the full excavation and addition of supports to the foundation pit.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of comprehensive pipe gallery engineering in geotechnical and underground engineering, and particularly relates to a narrow foundation pit excavation simulation and test system in a supergravity field. BACKGROUND

[0002] In recent times, with the rapid development of urban underground space, the utilization technology of underground space is also increasingly high. In recent years, a kind of underground comprehensive pipe gallery system has appeared to solve the problem of frequent excavation for maintenance of ground pipeline and underground pipeline. The system not only solves the traffic problem of the ground city, but also is very convenient for the maintenance and repair of municipal facilities such as power, communication, gas and water supply. At the same time, the system has excellent anti-seismic performance and can reduce the damage of various life pipelines such as power and communication in the event of an earthquake. Compared with general foundation pit engineering, the underground comprehensive pipe gallery system has the characteristics of narrow foundation pit, shallow excavation depth and less support. In model experiments, supergravity means is often used to restore the stress level and stress characteristics of the site soil body. A centrifuge is one of the main methods. Centrifugal model test is an advanced physical simulation method in the field of geotechnical engineering, which is very suitable for the research of various foundation pits and can provide important basis for actual engineering construction. The deformation mechanism can be analyzed through centrifugal test to improve the theoretical research level of various foundation pits. The characteristics of the comprehensive pipe gallery make its influence on the surrounding stratum special, and special research is needed. The environmental impact of foundation pit excavation is complex and difficult to measure comprehensively. In the centrifugal experiment, the foundation pit excavation simulation is often only used for symmetrical half excavation research, and the research effect is affected to a certain extent. Therefore, a simulation system for the narrow foundation pit characteristics of the comprehensive pipe gallery is needed, which can comprehensively measure the influence of the foundation pit excavation in the supergravity field and realize the simulation of the overall excavation and the addition of support. SUMMARY

[0003] The purpose of the present application is to provide a narrow foundation pit excavation simulation and test system in a supergravity field to realize the overall excavation simulation of the narrow foundation pit and the research of the comprehensive influence of the measurement results.

[0004] The purpose of the present application can be achieved by the following technical solutions:

[0005] A narrow foundation pit excavation simulation and test system in a supergravity field is composed of a foundation pit model system, a foundation pit support system and a measurement system,

[0006] The foundation pit model system comprises a model box, a partition plate and an adjusting rod. The partition plate is vertically located in the model box. One end of the adjusting rod is connected with the partition plate, and the other end is on the inner wall of the model box. The adjusting rod is used to adjust the position of the partition plate. The space between the partition plate and the model box is used to place test soil. The test soil is formed by consolidating mud in a supergravity field,

[0007] The foundation pit support system comprises two retaining walls arranged in parallel with the excavation trench and support rods connected between the two retaining walls, the retaining walls are installed at the trench after the test soil trench is excavated, the support rods are installed in the foundation pit after the foundation pit is excavated in the test soil, and the distance between the two retaining walls is adjusted.

[0008] The measurement system comprises retaining wall strain measurement devices, stratum settlement measurement devices and displacement field measurement devices, the retaining wall strain measurement devices are installed on the retaining walls for retaining wall strain measurement when the retaining walls are installed at the trench, the stratum settlement measurement devices are used for measuring the settlement of the soil between the retaining walls and the inner wall of the model box after the foundation pit model system is arranged with the foundation pit support system in the supergravity field, and the displacement field measurement devices are used for measuring the displacement change of the foundation pit.

[0009] In an embodiment of the present application, the model box is a hollow rectangular structure, the upper top surface does not exist, the remaining five surfaces can be disassembled, the front side surface is made of an organic glass plate, the connection of each surface is sealed by a sealing strip, and the organic glass plate and the model box are in a detachable structure, the organic glass plate on the front side surface of the model box is disassembled after the soil is preliminarily consolidated, and color wood chips are uniformly scattered on the surface of the soil in contact with the organic glass plate, the color wood chips are scattered between the organic glass plate of the model box and the test soil. The displacement change of the color wood chips serves as the detection object of the displacement field measurement device.

[0010] In an embodiment of the present application, the connection mode of the adjusting rod and the partition plate is welding, one end of the adjusting rod on the inner wall of the model box is provided with a thread and two nuts, and the positions of the two nuts can be adjusted along the thread.

[0011] In an embodiment of the present application, the adjusting rod is vertically distributed in three rows along the depth of the foundation pit, five adjusting rods are arranged in the same horizontal direction in each row, and each adjusting rod is connected to the partition plate at one end and is supported on the side wall of the model box at the other end.

[0012] In an embodiment of the present application, the two retaining walls are rectangular plate structures, one of the retaining walls is provided with a circular groove, the other retaining wall is provided with a threaded hole, one end of the support rod is provided with a thread and a circular nut, the position of the circular nut can be adjusted along the thread, the nut is clamped into the groove of one of the retaining walls, and the other end of the support rod is provided with a thread and is connected to the threaded hole of the other retaining wall.

[0013] In an embodiment of the present application, the support rod, the circular groove and the threaded hole on the retaining wall are three, and the three circular grooves or threaded holes on the retaining wall are arranged in the same horizontal direction.

[0014] In one embodiment of the present application, the stratum settlement measuring device comprises a laser displacement meter, a laser displacement meter rod and a laser displacement meter support, wherein the laser displacement meter support is arranged on the model box when the stratum settlement measuring device is in operation, one end of the laser displacement meter rod is fixed with the laser displacement meter, and the other end is fixed on the laser displacement meter support through a nut and can adjust the position height of the laser displacement meter.

[0015] In one embodiment of the present application, the retaining wall strain measuring device comprises a strain gauge and a data acquisition system, wherein the strain gauge is attached to the retaining wall, and a lead wire connects the strain gauge and the data acquisition system.

[0016] In one embodiment of the present application, the displacement field measuring device comprises a high-definition digital camera, a camera support and a gravity balance plate, wherein the high-definition digital camera is fixed on the camera support, the camera support is fixed on the gravity balance plate, the gravity balance plate is further fixed on a gravity field device, and the gravity field device is a centrifuge. The displacement field measuring result is obtained by processing the photos taken by the high-definition digital camera through a PIV technology.

[0017] In the present application, the retaining wall strain data, the laser displacement meter data and the displacement field photos are collected and stored by the centrifuge data acquisition system.

[0018] In one embodiment of the present application, the test soil is a mud slurry prepared by air-drying, crushing, sieving, soaking and vacuum stirring of soft clay, and is obtained by consolidation in a supergravity field.

[0019] In one embodiment of the present application, the vacuum stirring is performed by a vacuum stirring device, wherein the vacuum stirring device comprises a vacuum box, a stirrer, a stirring paddle, a vacuum machine and a vacuum pipe, the stirring paddle is located in the vacuum box and connected with the stirrer outside the vacuum box, and the vacuum box is connected with the vacuum machine through the vacuum pipe.

[0020] In use, the model box of the present application is placed on a centrifuge device.

[0021] The working process of the present application is as follows:

[0022] The undisturbed soil is dried, crushed, sieved, soaked and stirred in a vacuum to make mud. Silicon oil is applied around the model box to reduce friction between the model box and the test soil. The baffle and adjusting rod are placed in the model box and the distance is adjusted. The prepared mud is poured into the space between the model box and the baffle, and preliminary consolidation is carried out in the centrifugal field. After the soil body is preliminarily consolidated, the organic glass plate on the front side of the model box is removed, and after the surface of the soil body in contact with the glass is evenly sprinkled with colored wood chips, the organic glass plate is installed. A trench is excavated at the predetermined position of the retaining wall, and the retaining wall with strain gauges attached in advance is installed. The centrifuge is started, and the soil body is further consolidated to make the retaining wall closely contact with the surrounding soil. After the surface strain gauges of the retaining wall reach a stable value, the centrifuge is stopped, and the laser displacement meter support and laser displacement meter are installed. Then the centrifuge is started to accelerate, and the initial data is observed and recorded. After the centrifugal acceleration stabilizes for a period of time, the machine is stopped, the foundation pit is excavated, the support rod is installed and the support distance is adjusted, and the centrifuge is started again, and the data is recorded. After the machine is stopped, the excavation and support rod installation of the foundation pit are repeated until the soil is excavated to the predetermined depth, and the deformation and failure of the foundation pit are observed and recorded, and the test is completed.

[0023] Compared with the prior art, the beneficial effects of the present application are that:

[0024] The narrow foundation pit excavation simulation and test system in the supergravity field can provide simulation of comprehensive excavation and support of the narrow foundation pit of the comprehensive pipe gallery in the high-speed centrifugal field, and can measure various data.

[0025] The system has the following characteristics:

[0026] (1) The undisturbed soil is dried, crushed, sieved, soaked and stirred in a vacuum to make mud, and accelerated consolidation in the centrifuge, which not only restores the characteristics of the site soil to a great extent, but also greatly shortens the consolidation time.

[0027] (2) The process of comprehensive excavation and support of the narrow foundation pit can be relatively simple.

[0028] (3) The system can withstand the maximum centrifugal acceleration function, and the function and structure are closely combined. By using the acceleration of the centrifuge to restore the stress level on site, comprehensive test results of various data such as deformation of the retaining wall, settlement of the soil behind the wall and displacement field changes of the entire foundation pit during the comprehensive excavation of the foundation pit under the actual stress level on site can be obtained.

[0029] (4) The equipment required by the present application can be manually processed or purchased, and the equipment processing precision can easily meet the requirements, so the present application is relatively easy to realize and apply to related experimental research.

[0030] (5) By using the excavation of the foundation pit of this system, we can conduct a comprehensive excavation and overall impact study on the characteristics of narrow foundation pits of integrated utility tunnels. Based on theoretical research, we can further verify and deepen the research on the mechanism of integrated utility tunnel system through experiments, and provide good consultation and suggestions for the engineering design, construction and operation of actual integrated utility tunnel systems and similar narrow foundation pits.

[0031] The advantages of this invention system are that it is designed for integrated utility tunnel projects with narrow foundation pits, which have been less studied. It can comprehensively monitor the complex impact process of foundation pit excavation, and can easily simulate the process of full excavation and support addition. The experiment is relatively simple and easy to control. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the main structure of the simulation and testing system for narrow foundation pit excavation in a hypergravity field in Example 1.

[0033] Figure 2 This is a top view of the simulation and testing system for narrow foundation pit excavation in a hypergravity field in Example 1.

[0034] Figure 3 This is a schematic diagram of the vacuum mixer structure in Example 1.

[0035] Figure 4 This is a schematic diagram of the main structure of the support system in Example 1.

[0036] Figure 5 This is a top view of the support system structure in Example 1.

[0037] Figure 6 This is a schematic diagram of the displacement field measuring device from the left side in Example 1.

[0038] Figure 7 This is a top view of the displacement field measuring device in Example 1.

[0039] The following labels are used in the diagram: 1 is the model box; 2 is the partition; 3 is the adjusting rod; 4 is the vacuum chamber; 5 is the mixer; 6 is the stirring paddle; 7 is the vacuum machine; 8 is the vacuum tube; 9 is the retaining wall; 10 is the support rod; 11 is the strain gauge; 12 is the laser displacement device; 13 is the laser displacement device rod; 14 is the laser displacement device bracket; 15 is the high-definition digital camera; 16 is the camera bracket; 17 is the gravity balance plate; 18 is the colored wood chips; 19 is the test soil. Detailed Implementation

[0040] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0041] Example

[0042] A simulation and testing system for narrow foundation pit excavation in a hypergravity field, reference Figure 1、 Figure 2 、 Figure 4 、 Figure 5 , the pit model system, the pit support system, the measuring system, the pit model system includes a model box 1, a partition 2 and an adjusting rod 3, the partition 2 is vertically located in the model box 1, one end of the adjusting rod 3 is connected with the partition 2, and the other end is on the inner wall of the model box 1, the adjusting rod 3 is used for adjusting the position of the partition 2, the space between the partition 2 and the model box 1 is used for placing test soil 19, the test soil 19 is formed by consolidating mud in a supergravity field, the pit support system includes two retaining walls 9 arranged in parallel in the excavation trench and a support rod 10 connected between the two retaining walls 9, when the test soil 19 is excavated in the trench, the retaining wall 9 is installed in the trench, when the pit is excavated in the test soil 19, the support rod 10 is installed in the pit, and the distance between the two retaining walls 9 is adjusted; the measuring system is composed of a retaining wall strain measuring device, a stratum settlement measuring device and a displacement field measuring device, when the retaining wall 9 is installed in the trench, the retaining wall strain measuring device is installed on the retaining wall 9 for retaining wall strain measurement, when the pit support system is arranged in the pit model system in the supergravity field, the stratum settlement measuring device is used for measuring the settlement of the soil body between the retaining wall 9 and the inner wall of the model box 1, and the displacement field measuring device is used for measuring the displacement change of the pit.

[0043] Further reference Figure 1 、 Figure 2 , the model box 1 is a hollow rectangular structure in the middle, the upper top surface does not exist, the remaining five surfaces can be disassembled, the front side is made of organic glass plate, the connection of each surface is sealed by sealing strip, and the organic glass plate and the model box 1 are detachable structure, when the soil body is preliminarily consolidated, stop the machine, remove the organic glass plate on the front side of the model box 1, and uniformly sprinkle colored sawdust 18 on the surface of the soil body in contact with the organic glass plate, the colored sawdust 18 is sprinkled between the organic glass plate of the model box and the test soil 19. The displacement change of the colored sawdust 18 is taken as the detection object of the displacement field measuring device.

[0044] Further reference Figure 2 , the adjusting rod 3 is connected with the partition 2 in a welded manner, one end of the adjusting rod 3 on the inner wall of the model box 1 is provided with threads and two nuts, and the positions of the two nuts can be adjusted along the threads.

[0045] Further reference Figure 2 , the adjusting rod 3 is vertically distributed in three ways along the pit depth, five are arranged in each horizontal direction, one end of each adjusting rod 3 is connected with the partition 2, and the other end is on the side wall of the model box 1.

[0046] Further reference Figure 4 、 Figure 5Two retaining walls 9 are both rectangular plate structures, one of the retaining walls 9 is provided with a circular groove, and the other retaining wall 9 is provided with threaded holes, one end of the support rod 10 is provided with a thread and a circular nut, the circular nut can be adjusted in position along the thread, the nut is clamped into the groove of one of the retaining walls 9, and the other end of the support rod 10 is provided with a thread and is connected to the threaded holes of the other retaining wall 9.

[0047] Further referring to Figure 1 When the stratum settlement measuring device works, the laser displacement sensor support 14 is arranged on the model box 1, one end of the laser displacement sensor rod 13 is fixed with the laser displacement sensor 12, and the other end is fixed on the laser displacement sensor support 14 through a nut and can adjust the position height of the laser displacement sensor 12.

[0048] Further referring to Figure 1 The retaining wall strain measuring device is composed of a strain gauge 11 and a data acquisition system, the strain gauge 11 is attached to the retaining wall 9, and a wire is connected between the strain gauge 11 and the data acquisition system.

[0049] Further referring to Figure 6 、 Figure 7 The displacement field measuring device includes a high-definition digital camera 15, a camera support 16 and a gravity balance plate 17, the high-definition digital camera 15 is fixed on the camera support 16, the camera support 16 is fixed on the gravity balance plate 17, the gravity balance plate 17 is further fixed on a gravity field equipment, and the gravity field equipment refers to a centrifuge. The displacement field measurement result is obtained by processing the photographed photos of the high-definition digital camera 15 through a PIV technology.

[0050] In the present application, the retaining wall strain data, the laser displacement sensor data and the displacement field photos are collected and stored by the centrifuge data acquisition system.

[0051] In the present application, the test soil 19 is a mud prepared by drying, crushing, sieving, soaking and vacuum stirring of soft clay and is obtained by consolidation in a supergravity field.

[0052] Referring to Figure 3 The vacuum stirring device includes a vacuum box 4, a stirrer 5, a stirring paddle 6, a vacuum machine 7 and a vacuum pipe 8, the stirring paddle 6 is located in the vacuum box 4 and is connected with the stirrer 5 located outside the vacuum box 4, and the vacuum box 4 is connected with the vacuum machine 7 through the vacuum pipe 8.

[0053] Specifically, in the present application,

[0054] The model box 1 is cuboid in shape, hollow in the middle, and has a net size of 600mm x 400mm x 700 (length x width x height) and is composed of five side surfaces. The front side surface is a 70mm-thick organic glass surface. The organic glass surface is used to facilitate marking and camera shooting. The other side surfaces are 70mm-thick hard alloy aluminum plates. The model box 1 is internally spaced 200mm from the organic glass surface.

[0055] The partition plate 2 is 10mm thick and separates the model box 1 into a model side and an adjusting rod side. The model side can be used to place the test soil 19 and the retaining wall 9 model.

[0056] The adjusting rod 3 is 30mm in diameter and 190mm in length.

[0057] The test soil 19 is placed in the model side and has a size of 600mm x 200mm x 400 (length x width x height).

[0058] The two retaining wall 9 models are made of aluminum alloy and have a size of 224mm x 200mm x 6.5mm (length x width x thickness). The circular groove on the retaining wall 9 has a diameter of 8mm, and the threaded hole has an outer diameter of 7.3mm. The center of the circular groove and the threaded hole is located 27mm from the upper edge of the retaining wall 9. The three supporting rods 10 are hollow aluminum alloy round pipes, 48mm in length, 7.3mm in outer diameter, and 1mm in wall thickness. The circular nut has an outer diameter of 8mm.

[0059] The laser displacement sensor support 14 is an iron hollow frame with a length of 740mm, an outer width of 50mm, an inner width of 30mm, and a height of 40mm. The laser displacement sensor rod 13 is a circular threaded rod with a length of 260mm and an outer diameter of 23mm. Each rod corresponds to a laser displacement sensor 12. One end of the rod is fixed to the laser displacement sensor 12, and then the rod is fixed to the laser displacement sensor support 14 through a nut and can be adjusted in position and height.

[0060] The gravity balance plate 17 is a solid iron plate with a size of 1000mm x 500mm x 10mm (length x width x height). The camera support 16 is composed of a hollow iron rod with a cross section of 50mm x 50mm. The outer frame size is about 490mm x 600mm x 440mm (length x width x height).

[0061] The vacuum box 4 has a size composed of an upper part 500mm x 500mm x 500 (length x width x height) square space and a lower part 400mm radius semicircular space.

[0062] When in use, the model box of the embodiment is placed on a centrifugal machine device.

[0063] The working process of the embodiment is as follows:

[0064] The original soil is dried, crushed, sieved, soaked, and stirred in a vacuum to make a mud slurry. Silicon oil is applied around the perimeter of the mold box to reduce friction between the mold box and the test soil. The separator and adjustment rod are placed in the mold box and adjusted to the correct distance. The prepared mud slurry is poured into the space between the mold box and the separator, and the soil is initially consolidated in a centrifugal field. After the soil is initially consolidated, the machine is stopped, the front side of the mold box is removed, and the soil surface is evenly coated with colored wood chips. The glass plate is then installed. A trench is dug at the predetermined location of the retaining wall, and the retaining wall with the strain gauges is installed. The centrifuge is started, and the soil is further consolidated so that the retaining wall is in close contact with the surrounding soil. When the strain gauge values on the surface of the retaining wall are stable, the centrifuge is stopped, and the laser displacement meter support and laser displacement meter are installed. The high-definition digital camera and camera support are then installed. The centrifuge is started and accelerated, and initial data are observed and recorded. After the centrifugal acceleration is stable for a period of time, the machine is stopped, the foundation pit is excavated, the support rod is installed, and the distance between the support rods is adjusted. The centrifuge is started again, and data are recorded. After the machine is stopped, the foundation pit is repeatedly excavated and the support rod is installed until the soil is excavated to the predetermined depth. The deformation and failure of the foundation pit are observed and recorded, and the test is complete.

[0065] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. Those skilled in the art can easily make various modifications to the embodiments and apply the general principles described herein to other embodiments without creative effort, and such modifications and applications should be considered within the scope of the invention. Therefore, the invention is not limited to the above-described embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the invention without departing from the scope of the invention should be considered within the scope of the invention.

Claims

1. A simulation and testing system for narrow foundation pit excavation in a hypergravity field, characterized in that, It consists of a foundation pit model system, a foundation pit support system, and a measurement system. The foundation pit model system includes a model box (1), a partition (2), and an adjusting rod (3). The partition (2) is vertically located inside the model box (1). One end of the adjusting rod (3) is connected to the partition (2), and the other end rests against the inner wall of the model box (1). The adjusting rod (3) is used to adjust the position of the partition (2). The space between the partition (2) and the model box (1) is used to place test soil (19). The test soil (19) is formed by the consolidation of mud in a hypergravity field. The foundation pit support system includes two retaining walls (9) set parallel to the excavation trench and a support rod (10) connected between the two retaining walls (9). After the trench is excavated in the test soil (19), the retaining walls (9) are installed in the trench. After the foundation pit is excavated in the test soil (19), the support rod (10) is installed in the foundation pit and the distance between the two retaining walls (9) is adjusted. The measurement system consists of a retaining wall strain measurement device, a ground settlement measurement device and a displacement field measurement device. When the retaining wall (9) is installed in the trench, the retaining wall strain measurement device is installed on the retaining wall (9) for retaining wall strain measurement. In the hypergravity field, after the foundation pit support system is set in the foundation pit model system, the ground settlement measurement device is used to measure the soil settlement between the retaining wall (9) and the inner wall of the model box (1), and the displacement field measurement device is used to measure the displacement change of the foundation pit. The model box (1) is a rectangular structure with a hollow center. The top surface is not present, and the remaining five surfaces are detachable. The front side is made of plexiglass. The connection of each surface is sealed with a sealing strip. The plexiglass is detachable from the model box (1). After the soil has initially solidified, the plexiglass is removed from the front side of the model box (1), and colored wood chips (18) are evenly sprinkled on the soil surface in contact with the plexiglass. The ground settlement measurement device comprises a laser displacement device (12), a laser displacement device rod (13), and a laser displacement device support (14). When the ground settlement measurement device is working, the laser displacement device support (14) is placed on the model box (1). One end of the laser displacement device rod (13) is fixed to the laser displacement device (12), and the other end is fixed to the laser displacement device support (14) by a nut. The position and height of the laser displacement device (12) can be adjusted. The retaining wall strain measurement device consists of a strain gauge (11) and a data acquisition system. The strain gauge (11) is attached to the retaining wall (9), and the wires connect the strain gauge (11) and the data acquisition system.

2. The simulation and testing system for narrow foundation pit excavation in a hypergravity field according to claim 1, characterized in that, The adjusting rod (3) is connected to the partition plate (2) by welding. The end of the adjusting rod (3) that rests on the inner wall of the model box (1) has threads and two nuts. Both nuts can be adjusted along the threads.

3. The simulation and testing system for narrow foundation pit excavation in a hypergravity field according to claim 1, characterized in that, The adjusting rods (3) are vertically distributed in three rows along the depth of the pit, with five rods arranged in each row along the same horizontal direction. Each adjusting rod (3) is connected to the partition plate (2) at one end and rests on the side wall of the model box (1) at the other end.

4. The simulation and testing system for narrow foundation pit excavation in a hypergravity field according to claim 1, characterized in that, Both retaining walls (9) are rectangular plate structures. One retaining wall (9) has a circular groove, and the other retaining wall (9) has a threaded hole. One end of the support rod (10) has a thread and a circular nut. The circular nut can be adjusted along the thread. The nut is inserted into the groove of one of the retaining walls (9). The other end of the support rod (10) has a thread and is threaded to the threaded hole of the other retaining wall (9).

5. The simulation and testing system for narrow foundation pit excavation in a hypergravity field according to claim 1, characterized in that, The displacement field measuring device includes a high-definition digital camera (15), a camera bracket (16), and a gravity balance plate (17). The high-definition digital camera (15) is fixed on the camera bracket (16), the camera bracket (16) is fixed on the gravity balance plate (17), and the gravity balance plate (17) is then fixed on the gravity field device.

6. The simulation and testing system for narrow foundation pit excavation in a hypergravity field according to claim 1, characterized in that, The test soil (19) was obtained by consolidating soft clay into a slurry in a hypergravity field after drying, crushing, sieving, soaking, and vacuum stirring.

7. The simulation and testing system for narrow foundation pit excavation in a hypergravity field according to claim 6, characterized in that, Vacuum mixing is performed by a vacuum mixing device, which includes a vacuum chamber (4), a mixer (5), a stirring paddle (6), a vacuum machine (7), and a vacuum tube (8). The stirring paddle (6) is located in the vacuum chamber (4) and is connected to the mixer (5) located outside the vacuum chamber (4). The vacuum chamber (4) is connected to the vacuum machine (7) through the vacuum tube (8).

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