Roadbed settlement simulation test device based on TLJ type geotechnical centrifuge

Abstract

The utility model discloses a soft soil area roadbed settlement simulation test device based on TLJ type geotechnical centrifuge relates to geotechnical engineering model test device technical field, and horizontal load simulation system includes loading plate, clamping groove and lead block, and the clamping groove is seted up on loading plate, and lead block moves along clamping groove, and lead block is connected with horizontal moving unit, the upper portion of TLJ type geotechnical centrifuge is provided with data acquisition instrument and router A in data transmission system, and roadbed model box and counterweight box are set up in the inside of TLJ type geotechnical centrifuge. The utility model discloses a soft soil area roadbed settlement simulation test device based on TLJ type geotechnical centrifuge, through centrifuge centrifugal effect and horizontal moving system and ground settlement system simulation high -speed train dynamic load and ground settlement, and obtain the change rule of saturated soft soil area roadbed settlement under high -speed train dynamic load through test, has simple structure, convenient operation, high efficiency, good stability etc.

Description

Technical Field

[0001] This utility model relates to the technical field of geotechnical engineering model testing devices, and in particular to a roadbed settlement simulation testing device based on a TLJ-type geotechnical centrifuge in soft soil areas. Background Technology

[0002] In the field of road engineering, subgrade settlement is a crucial factor affecting the strength and stability of subgrades and pavements. Particularly in marine saturated soft soil areas, subgrade instability caused by subgrade settlement is even more pronounced. With the rapid development of transportation infrastructure construction in my country, accurately simulating the subgrade settlement process is essential for optimizing subgrade design and ensuring safe road operation.

[0003] Currently, numerous studies have been conducted on the simulation of roadbed settlement, but existing simulation methods still have significant shortcomings. On the one hand, some studies use on-site monitoring to obtain roadbed settlement data; however, on-site monitoring is constrained by various factors, resulting in long data acquisition cycles, high costs, and significant differences in geological conditions across different regions, making systematic research difficult. On the other hand, common indoor simulation tests often employ fixed-point loading methods, which cannot realistically reproduce the dynamic process of moving loads acting on the roadbed. Under actual traffic loads, fixed-point loading tests cannot reflect the dynamic changes in the stress state of the roadbed over time and space, leading to significant deviations between simulation results and actual conditions. Utility Model Content

[0004] The purpose of this invention is to provide a simulation test device for roadbed settlement in soft soil areas based on a TLJ-type geotechnical centrifuge, and to solve the problems listed in the background art.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] This utility model relates to a roadbed settlement simulation test device based on a TLJ-type geotextile centrifuge in soft soil areas, comprising a TLJ-type geotextile centrifuge, a roadbed model box, a counterweight box, a horizontal load simulation system, a data acquisition system, a data transmission system, and a data receiving system.

[0007] The horizontal load simulation system includes a loading plate, a slot, and a lead block. The slot is provided on the loading plate, and the lead block moves along the slot. The lead block is connected to a horizontal moving unit.

[0008] The upper part of the TLJ geotextile centrifuge is equipped with a data acquisition device and router A in the data transmission system;

[0009] The roadbed model box and the counterweight box are installed inside the TLJ type geotechnical centrifuge;

[0010] The roadbed model box is filled with a roadbed model;

[0011] The loading plate is installed on top of the roadbed model;

[0012] The data acquisition system is used to collect test data of the model of the horizontal load simulation system under operating conditions;

[0013] The data transmission system and the data receiving system are used to transmit and receive the collected test data.

[0014] Preferably, it also includes a roadbed settlement system, which includes a unit block load-bearing plate, a flange bearing seat, bolts and a fixing plate with a sleeve, wherein the flange bearing seat is fixed to the lower surface of the unit block load-bearing plate;

[0015] A ball bearing is installed on the lower surface of the flange bearing housing;

[0016] The end of the bolt passes through the sleeve-mounted fixing plate and is fixedly connected to the ball bearing; the thread of the bolt engages with the sleeve-mounted fixing plate.

[0017] A digital displacement sensor is installed between the opposite surfaces of the flange bearing housing and the sleeve-mounted fixing plate.

[0018] Preferably, the horizontal moving unit includes a pulley fixing device, a pulley, a traction motor, a motor fixing device, and a traction rope. The pulley is fixedly installed on the pulley fixing device, and the traction motor is installed on the motor fixing device. Both the pulley fixing device and the motor fixing device are fixedly installed at the upper opening of the roadbed model box.

[0019] One end of the traction rope is connected to the lead block, the other end of the traction rope is connected to the output shaft of the traction motor, and the middle part of the traction rope abuts against the pulley.

[0020] The traction motor is a self-powered linear permanent magnet traction motor that does not require an external power source.

[0021] Preferably, the roadbed model includes a roadbed and a subgrade laid sequentially from top to bottom, and the loading plate is disposed on the upper surface of the roadbed;

[0022] The soil base is placed on the upper surface of the unit block load-bearing plate.

[0023] Preferably, the data acquisition system includes an LVDT displacement sensor and an earth pressure cell;

[0024] The earth pressure cells are arranged in the contact layer between the roadbed and the subgrade, and are centered at 100mm intervals; the LVDT displacement sensor is arranged on the roadbed surface and connected to the data acquisition instrument via an aviation connector.

[0025] Preferably, the unit block load-bearing plate is a 200*200*5mm steel plate.

[0026] Preferably, the LVDT displacement sensor is fixed on the displacement sensor mounting plate.

[0027] Preferably, the data transmission system includes router A and router B, and router A and router B are electrically connected to the data acquisition system and the data receiving system.

[0028] Preferably, the data receiving system includes a data receiving PC, which is electrically connected to an external power source;

[0029] The data receiving PC is electrically connected to the router A.

[0030] Preferably, the roadbed model box is made of acrylic sheet, and the lower part of the acrylic sheet has four circular holes with a radius of 50mm corresponding to the nut positions.

[0031] Compared with the prior art, the beneficial technical effects of this utility model are as follows:

[0032] 1) The TLJ geotechnical centrifuge in the main structure of this utility model can generate centrifugal force at high speed to simulate the self-weight stress of the prototype, making the stress and strain of the model equivalent to that of the prototype, and can reproduce the characteristics of the prototype in a short time. According to the time similarity law, the TLJ geotechnical centrifuge can quickly simulate the settlement process of the roadbed under long-term load in a test of tens of minutes, which greatly shortens the test cycle and improves the research efficiency compared with traditional roadbed model test devices;

[0033] 2) The horizontal movement system of the load simulation system, together with the motor, pulleys and traction rope fixed on the upper part of the roadbed model box, can realize horizontal movement loading, thereby better simulating the dynamic operation of high-speed trains;

[0034] 3) LVDT displacement sensors, digital displacement sensors and earth pressure cells can monitor the overall settlement and local settlement of the subgrade and the stress of the subgrade body in the subgrade model in real time, so as to monitor the subgrade settlement law and the stress change relationship of the subgrade under centrifugal force during the test. Attached Figure Description

[0035] The present invention will be further described below with reference to the accompanying drawings.

[0036] Figure 1This is a schematic diagram of the overall structure of the roadbed settlement simulation test device based on the TLJ geotechnical centrifuge in soft soil areas according to this utility model;

[0037] Figure 2 This is a schematic diagram of the upper structure of the roadbed model box;

[0038] Figure 3 This is a schematic diagram of the cross-section of the roadbed model;

[0039] Figure 4 This is a schematic diagram of the overall structure of the settling device;

[0040] Figure 5 Schematic diagram of the lower part with sleeve fixing plate;

[0041] Figure 6 This is a schematic diagram of a single unit block settling device.

[0042] Explanation of reference numerals in the attached drawings: 1. TLJ geotechnical centrifuge; 2. Subgrade model box; 3. Subgrade soil model; 4. LVDT displacement sensor; 5. LVDT displacement sensor fixing plate; 6. Loading plate; 7. Slot; 8. Lead block; 9. Pulley fixing structure; 10. Pulley; 11. Traction motor; 12. Traction motor support structure; 13. Data acquisition instrument; 14. Counterweight box; 15. Subgrade; 16. Soil base; 17. Unit block load-bearing plate; 18. Flange bearing seat; 19. Ball bearing; 20. Router A; 21. Router B; 22. Data receiving PC; 23. Traction rope; 24. Bolt; 25. Fixing plate with sleeve; 26. Digital display displacement sensor. Detailed Implementation

[0043] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0044] like Figure 1-6 As shown, the test device for simulating subgrade settlement in soft soil areas based on the TLJ geotechnical centrifuge includes the TLJ geotechnical centrifuge 1, the subgrade model box 2, the counterweight box 14, the horizontal load simulation system, the data acquisition system, the data transmission system and the data receiving system.

[0045] The horizontal load simulation system includes a loading plate 6, a slot 7, and a lead block 8. The loading plate 6 has the slot 7, and the lead block 8 moves along the slot 7. The lead block 8 is connected to the horizontal moving unit. That is, the horizontal load simulation system is used to simulate the settlement of the roadbed itself and the dynamic load of high-speed trains on the track under the action of a geotechnical centrifuge and a motor.

[0046] The upper part of the TLJ type geotextile centrifuge 1 is equipped with a data acquisition instrument 13 and a router A20 in the data transmission system;

[0047] The roadbed model box 2 and the counterweight box 14 are installed inside the TLJ type geotechnical centrifuge 1;

[0048] The roadbed model box 2 is filled with a roadbed model 3;

[0049] The loading plate 6 is installed on top of the roadbed model 3;

[0050] The data acquisition system is used to collect test data of the model of the horizontal load simulation system under operating conditions;

[0051] The data transmission system and the data receiving system are used to transmit and receive the collected test data.

[0052] The roadbed model box 2 is placed on the TLJ geotechnical centrifuge. The roadbed model box 2 is a cuboid of 800×600×600mm and is made of acrylic sheet for easy frontal observation. The lower part of the acrylic sheet has four round holes with a radius of 50mm corresponding to the nut positions, which facilitates manual operation of bolt lifting and lowering.

[0053] like Figure 2 , Figure 3 As shown, it also includes a roadbed settlement system, which includes a unit block load-bearing plate 17, a flange bearing seat 18, bolts 24 and a sleeve-type fixing plate 25. The flange bearing seat 18 is fixed to the lower surface of the unit block load-bearing plate 17.

[0054] A ball bearing 19 is mounted on the lower surface of the flange bearing housing 18;

[0055] The end of the bolt 24 passes through the sleeve fixing plate 25, and the end of the bolt 24 is fixedly connected to the ball bearing 19. The thread of the bolt 24 engages with the sleeve fixing plate 25 to control the up and down movement of the bolt 24.

[0056] A digital displacement sensor 26 is installed between the opposing surfaces of the flange bearing seat 18 and the sleeve-fixed plate 25 to measure the displacement of the unit block load-bearing plate 17.

[0057] Furthermore, a sleeve-mounted fixing plate with a thickness of 800×600×5mm is fixed inside the roadbed model box 2 at a distance of 60mm from the bottom. The sleeve has internal threads. The unit block load-bearing plate is a 200×200×5mm steel plate, which is arranged at the top 85mm of the sleeve-mounted steel plate. Twelve unit block load-bearing plates of the same size are tightly connected. The foundation soil, i.e., soil base 16, is filled and compacted on the upper part of the unit block load-bearing plate. The soil base height is 215mm. Roadbed soil 15 is filled on the upper part of the soil base and compacted in layers. The roadbed soil height is 150mm.

[0058] Earth pressure cells are arranged horizontally and centered every 100mm between the two subgrades. Loading plates 6 are arranged on the top of the subgrade soil. The loading plates 6 are arranged along the length of the model box. A slot is provided at the center line of the upper surface of the loading plates 6.

[0059] Before operating the TLJ-type geotextile centrifuge 1, the bolts 24 on each unit block bearing plate 17 are screwed to the top. Since the bolts 24 are connected to the ball bearings 19, the unit block bearing plate 17 can only move vertically up and down without rotating. Once all 12 unit block bearing plates have risen to the top, the test begins. The readings of the digital displacement sensors 26 and 4 of each unit block are then read to observe the settlement of each unit block and the overall synchronous settlement pattern. Before starting a new test, the bolts 24 on some unit block bearing plates 17 along the transverse or longitudinal direction are pre-rotated downwards to achieve precise unidirectional adjustment. Local settlement patterns are determined through manual compensation. During the test, the sleeve-type fixing plate 25 precisely controls the vertical movement of the bolts 24 and constrains the displacement direction, preventing the bolts 24 from shifting.

[0060] The specific operation embodiment of the TLJ geotextile centrifuge 1 is as follows: Fix the roadbed model box on the TLJ geotextile centrifuge, ensuring a firm installation and closing the centrifuge chamber door. Set the target centrifugal acceleration (or speed), acceleration time, stable running time, deceleration time, etc. on the operating table. Start the centrifuge and gradually increase the speed according to the preset program. Observe parameters such as speed, acceleration, vibration frequency, and bearing temperature to ensure that all indicators are within the normal range. After reaching the target acceleration, enter the stable running state. At this time, the data acquisition system automatically records the data. After reaching the preset running time, start the deceleration program. The centrifuge gradually reduces the speed at the set rate until it is close to a stop. After the speed drops to 0, confirm that the centrifuge has completely stopped rotating and wait 5 to 10 minutes before opening the chamber door.

[0061] like Figure 1 , Figure 2As shown, the horizontal moving unit includes a pulley fixing device 9, a pulley 10, a traction motor 11, a motor fixing device 12, and a traction rope 23. The pulley 10 is fixedly installed on the pulley fixing device 9, and the traction motor 11 is installed on the motor fixing device 12. Both the pulley fixing device 9 and the motor fixing device 12 are fixedly installed at the upper opening of the roadbed model box 2.

[0062] One end of the traction rope 23 is connected to the lead block 8, the other end of the traction rope 23 is connected to the output shaft of the traction motor 11, and the middle part of the traction rope 23 abuts against the pulley 10.

[0063] The traction motor 11 is a self-powered linear permanent magnet traction motor that does not require an external power supply. It can be directly used to control the horizontal movement unit. After the traction motor 11 is working, the lead block 8 moves horizontally along the slot 7 under the drive of the traction rope 23.

[0064] The centrifugal force generated by the TLJ geotechnical centrifuge 1 during high-speed operation simulates the self-weight stress of the prototype roadbed soil, effectively restoring the vertical settlement of the roadbed under actual stress.

[0065] like Figure 1 , Figure 2 , Figure 6 As shown, the data acquisition system includes an LVDT displacement sensor 4 and a data acquisition instrument 13; the earth pressure cell is arranged in the contact layer between the subgrade 15 and the subgrade 16, centered at 100mm intervals, to measure the change of earth pressure during the test; the LVDT displacement sensor 4 is arranged on the subgrade surface and connected to the data acquisition instrument via an aviation plug, the LVDT displacement sensor is fixed on the displacement sensor fixing plate and in contact with the subgrade surface, four of them are arranged at intervals along the length of the model box, used to measure the surface settlement of the subgrade soil.

[0066] according to Figure 1 , Figure 2 As shown, the roadbed model box is installed and the roadbed model is filled. Since the traction motor 5 does not require an external power supply, the traction motor 11 is turned on when the switch is turned on. The traction motor 11 moves the lead block 8 along the slot 7 through the traction rope 23. At the same time, the TLJ type geotechnical centrifuge 1 is started. The speed is gradually increased according to the preset program so that the TLJ type geotechnical centrifuge 1 works normally. The roadbed body begins to settle longitudinally under the action of centrifugal force.

[0067] To make the subgrade settlement measurement more accurate, before starting, the LVDT displacement sensor 4 is brought into close contact with the subgrade surface and the digital display of the digital displacement sensor 26 is checked to see if it is normal. After the TLJ geocentrifuge 1 has finished working, the data received by the data receiving PC 22 is checked to see if it is normal, and then the test data is exported.

[0068] Based on the actual test conditions, repeat the loading process as described above until the required number of tests is reached. After the test, stop the TLJ type geotechnical centrifuge 1 and traction motor 5 by switching them on. The stress-strain relationship of the soil and the change law of subgrade settlement are reflected by the data receiving PC.

[0069] It should be noted that the terms “comprising,” “including,” or any other variations thereof used herein are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0070] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A test device for simulating subgrade settlement in soft soil areas based on a TLJ-type geotextile centrifuge, characterized in that: It includes a TLJ-type geotechnical centrifuge (1), a roadbed model box (2), a counterweight box (14), a horizontal load simulation system, a data acquisition system, a data transmission system, and a data receiving system; The horizontal load simulation system includes a loading plate (6), a slot (7) and a lead block (8). The loading plate (6) has the slot (7) and the lead block (8) moves along the slot (7). The lead block (8) is connected to the horizontal moving unit. The upper part of the TLJ type geotextile centrifuge (1) is equipped with a data acquisition instrument (13) and a router A (20) in the data transmission system; The roadbed model box (2) and the counterweight box (14) are installed inside the TLJ type geotechnical centrifuge (1); The roadbed model box (2) is filled with a roadbed model (3); The loading plate (6) is installed on top of the roadbed model (3); The data acquisition system is used to collect test data of the model of the horizontal load simulation system under operating conditions; The data transmission system and the data receiving system are used to transmit and receive the collected test data.

2. The test device for simulating subgrade settlement in soft soil areas based on a TLJ-type geotextile centrifuge as described in claim 1, characterized in that: It also includes a roadbed settlement system, which includes a unit block load-bearing plate (17), a flange bearing seat (18), bolts (24) and a sleeve-mounted fixing plate (25), wherein the flange bearing seat (18) is fixed to the lower surface of the unit block load-bearing plate (17); A ball bearing (19) is mounted on the lower surface of the flange bearing housing (18); The end of the bolt (24) passes through the sleeve fixing plate (25), and the end of the bolt (24) is fixedly connected to the ball bearing (19). The thread of the bolt (24) meshes with the sleeve fixing plate (25). A digital displacement sensor (26) is installed between the opposing surfaces of the flange bearing housing (18) and the sleeve-mounted fixing plate (25).

3. The test device for simulating subgrade settlement in soft soil areas based on a TLJ-type geotextile centrifuge as described in claim 1, characterized in that: The horizontal moving unit includes a pulley fixing device (9), a pulley (10), a traction motor (11), a motor fixing device (12), and a traction rope (23). The pulley (10) is fixedly installed on the pulley fixing device (9), and the traction motor (11) is installed on the motor fixing device (12). Both the pulley fixing device (9) and the motor fixing device (12) are fixedly installed at the upper opening of the roadbed model box (2). One end of the traction rope (23) is connected to the lead block (8), the other end of the traction rope (23) is connected to the output shaft of the traction motor (11), and the middle part of the traction rope (23) abuts against the pulley (10); The traction motor (11) is a self-powered linear permanent magnet traction motor that does not require an external power supply.

4. The test device for simulating subgrade settlement in soft soil areas based on a TLJ-type geotextile centrifuge as described in claim 2, characterized in that: The roadbed model includes a roadbed (15) and a subgrade (16) laid from top to bottom, and the loading plate (6) is set on the upper surface of the roadbed (15); The soil base (16) is placed on the upper surface of the unit block load-bearing plate (17).

5. The test device for simulating subgrade settlement in soft soil areas based on a TLJ-type geotextile centrifuge as described in claim 4, characterized in that: The data acquisition system includes an LVDT displacement sensor (4) and an earth pressure cell; The earth pressure cells are arranged in the contact layer between the roadbed (15) and the subgrade (16), and the earth pressure cells are arranged centered every 100mm; the LVDT displacement sensor (4) is arranged on the surface of the roadbed (15) and connected to the data acquisition instrument (13) via an aviation plug.

6. The test device for simulating subgrade settlement in soft soil areas based on a TLJ-type geotextile centrifuge as described in claim 2, characterized in that: The unit block load-bearing plate (17) is a 200*200*5mm steel plate.

7. The test device for simulating subgrade settlement in soft soil areas based on a TLJ-type geotextile centrifuge as described in claim 5, characterized in that: The LVDT displacement sensor (4) is fixed on the displacement sensor mounting plate (5).

8. The test device for simulating subgrade settlement in soft soil areas based on a TLJ-type geotextile centrifuge as described in claim 1, characterized in that: The data transmission system includes router A (20) and router B (21), which are electrically connected to the data acquisition system and the data receiving system.

9. The test device for simulating subgrade settlement in soft soil areas based on a TLJ-type geotextile centrifuge as described in claim 8, characterized in that: The data receiving system includes a data receiving PC (22), which is electrically connected to an external power source; The data receiving PC (22) is electrically connected to the router A (20).

10. The test device for simulating subgrade settlement in soft soil areas based on a TLJ-type geotextile centrifuge as described in claim 1, characterized in that: The roadbed model box (2) is made of acrylic sheet, and there are four round holes with a radius of 50mm at the bottom of the acrylic sheet corresponding to the nut position.

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