A tunnel excavation simulation box and simulation device for geotechnical centrifuge tests

Abstract

The utility model relates to a kind of geotechnical centrifugal test tunnel excavation simulation box and simulation device, including box, box is filled with simulation foundation, formation loss simulation mechanism is embedded in simulation foundation;Formation loss simulation mechanism includes outer lining plate is inner lining plate, outer lining plate and inner lining plate are enclosed and are horizontally arranged cylindrical, inner lining plate is arranged in the inside of outer lining plate;Formation loss simulation mechanism includes at least two working sections sequentially connected along length direction;Each working section is provided with softening block and water injection pipe;Softening block is against the inner side wall of outer lining plate;The utility model gradually injects water into each working section along tunnel excavation direction by water injection pipe, so that softening block gradually softens along tunnel excavation direction, when softening block softens, volume reduces, the space between inner lining plate and outer lining plate will reduce accordingly, can effectively simulate formation loss process in tunnel excavation process, the disturbance of simulation process to soil is small, and the success rate of test can be improved.

Description

Technical Field

[0001] This utility model relates to the technical field of tunnel excavation simulation testing, specifically to a geotechnical centrifuge test tunnel excavation simulation box and simulation device. Background Technology

[0002] The demand for subway tunnels and numerous highway and railway tunnels in cities has posed many challenges to geotechnical tunnel construction technology.

[0003] Currently, scientific research and engineering evaluation before and after tunnel excavation can be conducted through model tests. Model tests can vividly and intuitively simulate the entire process of tunnel stress, deformation, and failure, and can also comprehensively and realistically simulate complex geological structures as needed.

[0004] However, most existing tunnel 3D model testing devices use manual excavation, which involves waiting for the soil to consolidate before manually excavating according to preset tunnel parameters such as depth and diameter. This process often causes significant disturbance to the soil and may even lead to soil collapse within the model box, resulting in test failure. Utility Model Content

[0005] Based on the above description, this utility model provides a geotechnical centrifugal test tunnel excavation simulation box and simulation device. Water is gradually injected into each working section along the tunnel excavation direction through a water injection pipe, causing the softened block to gradually soften along the tunnel excavation direction. As the softened block decreases in volume, the space between the inner lining plate and the outer lining plate will decrease accordingly. This can effectively simulate the stratum loss process during tunnel excavation. The simulation process causes little disturbance to the soil and can improve the success rate of the test.

[0006] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: a geotechnical centrifuge test tunnel excavation simulation box, including a box body, the box body is filled with a simulated foundation, and a ground loss simulation mechanism is embedded in the simulated foundation; the ground loss simulation mechanism includes an outer liner plate and an inner liner plate, the outer liner plate and the inner liner plate are both arranged in a horizontally arranged cylindrical shape, and the inner liner plate is arranged inside the outer liner plate;

[0007] The formation loss simulation mechanism includes at least two working sections connected sequentially along its length; in each working section, softening blocks are provided on the outer sidewalls of the left and right sides and the top of the inner liner plate; the softening blocks abut against the inner sidewall of the outer liner plate, thereby forming a water injection layer between the inner liner plate and the outer liner plate; a water injection pipe is provided in the water injection layer in each working section, and the water injection pipe is used to inject water into the water injection layer.

[0008] Based on the above technical solution, the present invention can be further improved as follows.

[0009] Furthermore, soil pressure sensors are embedded in the simulated foundation. All soil pressure sensors are embedded at the same height and are arranged uniformly above the soil loss simulation mechanism along a direction perpendicular to the simulated foundation.

[0010] Furthermore, the housing is equipped with laser displacement sensors, all of which are positioned downwards and at the same height above the simulated foundation. The laser displacement sensors are arranged sequentially and evenly along a direction perpendicular to the simulated foundation.

[0011] Furthermore, strain gauges are provided on the outer side wall of the outer liner, and the strain gauges are arranged sequentially around the formation loss simulation mechanism.

[0012] Furthermore, an observation window is provided on one side of the enclosure, and marker points are affixed to the side of the simulated foundation opposite to the observation window, with the marker points arranged in an array.

[0013] Furthermore, the simulated foundation includes a bedrock layer and a bed soil layer; the bedrock layer is located at the bottom of the box body, a reserved groove is provided at the top of the bedrock layer, the stratum loss simulation mechanism is located inside the bedrock layer, and the bed soil layer covers the top of the stratum loss simulation mechanism.

[0014] Furthermore, the simulation chamber also includes a water tank, which is located on the top of the chamber, and the water injection pipes are connected to the water tank through corresponding solenoid valves.

[0015] Furthermore, the water injection pipe is a perforated pipe with water injection holes evenly arranged on its surface.

[0016] This utility model also proposes a geotechnical centrifuge test tunnel excavation simulation device, including a centrifuge, a counterweight, and a simulation chamber as described in any one of the above; a basket is rotatably mounted on two opposing booms of the centrifuge, and the simulation chamber and the counterweight are respectively mounted on the two baskets.

[0017] Compared with the prior art, the technical solution of this application has the following beneficial technical effects:

[0018] 1. This utility model uses a water injection pipe to gradually inject water into each working section along the tunnel excavation direction, so that the softened block gradually softens along the tunnel excavation direction. When the softened block softens, its volume decreases, and the space between the inner lining plate and the outer lining plate will decrease accordingly. This can effectively simulate the process of soil loss during tunnel excavation. The simulation process causes little disturbance to the soil and can improve the success rate of the test.

[0019] 2. By employing multiple detection methods, it is possible to more comprehensively observe various changes in the strata during the tunnel excavation process. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a geotechnical centrifuge test tunnel excavation simulation box provided in Embodiment 1 of this utility model;

[0021] Figure 2 This is a schematic diagram of the internal structure of the simulation box in Embodiment 1 of this utility model;

[0022] Figure 3 This is a schematic diagram of the formation loss simulation mechanism in Embodiment 1 of this utility model;

[0023] Figure 4 This is a schematic diagram of the connection method between the water injection pipe and the water tank in Embodiment 1 of this utility model;

[0024] Figure 5 This is a schematic diagram of the installation method of the detection mechanism in Embodiment 1 of this utility model;

[0025] Figure 6 This is a schematic diagram of the structure of a geotechnical centrifuge test tunnel excavation simulation device provided in Embodiment 2 of this utility model;

[0026] The attached diagram lists the components represented by each number as follows:

[0027] 1. Centrifuge; 11. Suspended basket; 2. Counterweight; 3. Simulation box; 31. Box body; 311. Observation window; 32. Simulated foundation; 321. Foundation rock layer; 322. Foundation soil layer; 32a. Moderately weathered layer; 32b. Strongly weathered layer; 32c. Completely weathered layer; 32d. Silty clay layer; 32e. Plain fill layer; 33. Formation loss simulation mechanism; 331. Outer lining plate; 332. Inner lining plate; 333. Water injection layer; 334. Softened block; 335. Water injection pipe; 34. Water tank; 35. Solenoid valve; 36. Earth pressure sensor; 37. Laser displacement sensor; 38. Strain gauge; 39. Marker point. Detailed Implementation

[0028] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0030] It is understood that spatial relation terms such as “below,” “under,” “below,” “below,” “above,” “above,” etc., can be used here to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “below,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0031] A geotechnical centrifuge test tunnel excavation simulation box 3 and simulation device include a box body 31 and a water tank 34. The water tank 34 is located on top of the box body 31 and is used to store water needed for the test. The box body 31 is filled with a simulated foundation 32, and a ground loss simulation mechanism 33 is embedded in the simulated foundation 32. The ground loss simulation mechanism 33 is used to simulate the ground loss during the tunnel excavation process, and the changes in the simulated foundation 32 are used to simulate the stress and changes in the ground during the tunnel excavation process.

[0032] The formation loss simulation mechanism 33 includes an outer liner plate 331 and an inner liner plate 332, both of which form a horizontally arranged cylindrical shape. The inner liner plate 332 is disposed inside the outer liner plate 331. In this embodiment, the outer liner plate 331 is made of copper plate, and the inner liner plate 332 is made of stainless steel plate.

[0033] The formation loss simulation mechanism 33 includes at least two working sections connected sequentially along its length. In this embodiment, the formation loss simulation mechanism 33 is configured to include ten working sections. Within each working section, softening blocks 334 are provided on the outer sidewalls of the left and right sides and the top of the inner liner plate 332. The softening blocks 334 abut against the inner sidewall of the outer liner plate 331, thereby forming a water injection layer 333 between the inner liner plate 332 and the outer liner plate 331. In this embodiment, the softening blocks 334 are small sample blocks cast from bentonite, gypsum powder, and water. The size of the blocks is set according to the required formation loss rate of the model. When the softening blocks 334 come into contact with water, they gradually soften.

[0034] Each working section has a water injection pipe 335 installed within its water injection layer 333. The water injection pipe 335 is connected to a water tank 34 via a corresponding solenoid valve 35, used to inject water into the water injection layer 333 to soften the softened block 334 within the corresponding working section. Preferably, the water injection pipe 335 is a perforated pipe with evenly distributed water injection holes on its surface, using pressure to evenly inject water into the water injection layer 333 through these holes.

[0035] The simulated foundation 32 includes a bedrock layer 321 and a soil layer 322. The bedrock layer 321 is located at the bottom of the box 31, and a reserved groove is provided on the top of the bedrock layer 321. The soil loss simulation mechanism 33 is located inside the bedrock layer 321, and the soil layer 322 covers the top of the soil loss simulation mechanism 33. The materials of the bedrock layer 321 and the soil layer 322 are configured according to the actual conditions of the tunnel excavation site, so that the simulated foundation 32 conforms to the actual conditions of the tunnel excavation site as much as possible. In this embodiment, the bedrock layer 321 is a moderately weathered layer 32a, and the soil layer 322, from bottom to top, consists of a strongly weathered layer 32b, a completely weathered layer 32c, a silty clay layer 32d, and a plain fill layer 32e.

[0036] In this embodiment, water is gradually injected into each working section along the tunnel excavation direction through the water injection pipe 335, so that the softened block 334 gradually softens along the tunnel excavation direction. When the softened block 334 softens, its volume decreases, and the space between the inner lining plate 332 and the outer lining plate 331 will decrease accordingly. This can effectively simulate the stratum loss process during tunnel excavation. The simulation process causes little disturbance to the soil and can improve the success rate of the test.

[0037] In addition, various sensors or other detection tools can be installed inside the box 31 to more comprehensively observe the changes in the strata during the tunnel excavation process.

[0038] In this embodiment, soil pressure sensors 36 are embedded in the simulated foundation 32. All soil pressure sensors 36 are buried at the same height, and the soil pressure sensors 36 are evenly arranged in the completely weathered layer 32c above the ground loss simulation mechanism 33 along a direction perpendicular to the simulated foundation 32 to detect the pressure changes in the completely weathered layer 32c during tunnel excavation.

[0039] The housing 31 is equipped with laser displacement sensors 37, all of which are set downwards and at the same height above the simulated foundation 32. The laser displacement sensors 37 are evenly arranged in sequence along a direction perpendicular to the simulated foundation 32 to detect the deformation of the ground at various points during the tunnel excavation process.

[0040] Strain gauges 38 are installed on the outer wall of the outer lining plate 331. The strain gauges 38 are arranged in sequence around the ground loss simulation mechanism 33 to detect the deformation of the tunnel wall during tunnel excavation.

[0041] An observation window 311 is provided on one side of the box 31. Marker points 39 are affixed to the side of the simulated foundation 32 opposite to the observation window 311. The marker points 39 are arranged in an array. Before and after the tunnel excavation, the positions of the marker points 39 can be recorded by cameras, and the deformation of each part of the stratum can be calculated by computer comparison and analysis.

[0042] Example 2

[0043] A geotechnical centrifuge test tunnel excavation simulation device includes a centrifuge 1, a counterweight 2, and a simulation chamber 3 as described in Embodiment 1. Two rotatable baskets 11 are mounted on opposite booms of the centrifuge 1, and the simulation chamber 3 and the counterweight 2 are respectively mounted on the two baskets 11.

[0044] When centrifuge 1 rotates, the two baskets 11 flip to near horizontal. By applying a centrifugal force much greater than gravity to the simulation box 3, the centrifugal force is used to simulate gravity, making the stress and deformation of the smaller model inside the simulation box 3 closer to the actual tunnel excavation environment.

[0045] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A geotechnical centrifuge test tunnel excavation simulation box, characterised in that, The device includes a housing, which is filled with a simulated foundation. A formation loss simulation mechanism is embedded in the simulated foundation. The formation loss simulation mechanism includes an outer liner and an inner liner, both of which form a horizontally arranged cylindrical shape. The inner liner is disposed inside the outer liner. The formation loss simulation mechanism includes at least two working sections connected sequentially along its length; in each working section, softening blocks are provided on the outer sidewalls of the left and right sides and the top of the inner liner plate; the softening blocks abut against the inner sidewall of the outer liner plate, thereby forming a water injection layer between the inner liner plate and the outer liner plate; a water injection pipe is provided in the water injection layer in each working section, and the water injection pipe is used to inject water into the water injection layer.

2. The geotechnical centrifuge test tunnel excavation simulation box according to claim 1, characterized in that, Earth pressure sensors are embedded in the simulated foundation. All earth pressure sensors are buried at the same height and are evenly arranged above the soil loss simulation mechanism along a direction perpendicular to the simulated foundation.

3. The geotechnical centrifuge test tunnel excavation simulation box according to claim 1, characterized in that, The box is equipped with laser displacement sensors, all of which are downward-facing and positioned at the same height above the simulated foundation. The laser displacement sensors are arranged sequentially and evenly along a direction perpendicular to the simulated foundation.

4. The geotechnical centrifuge test tunnel excavation simulation box according to claim 1, characterized in that, Strain gauges are provided on the outer side wall of the outer liner, and the strain gauges are arranged sequentially around the formation loss simulation mechanism.

5. A geotechnical centrifuge test tunnel excavation simulation box according to claim 1, characterized in that, An observation window is provided on one side of the box, and markers are affixed to the side of the simulated foundation opposite to the observation window. The markers are arranged in an array.

6. The geotechnical centrifuge test tunnel excavation simulation box according to claim 1, characterized in that, The simulated foundation includes a bedrock layer and a bed soil layer; the bedrock layer is located at the bottom of the box, and a reserved groove is provided at the top of the bedrock layer; the stratum loss simulation mechanism is located inside the bedrock layer, and the bed soil layer covers the top of the stratum loss simulation mechanism.

7. A geotechnical centrifuge test tunnel excavation simulation box according to claim 1, characterized in that, It also includes a water tank, which is located on the top of the body, and the water inlet pipes are connected to the water tank through corresponding solenoid valves.

8. A geotechnical centrifuge test tunnel excavation simulation box according to claim 1, characterized in that, The water injection pipe is a perforated pipe with water injection holes evenly distributed on its surface.

9. A geotechnical centrifuge test tunnel excavation simulation device, characterized in that, The device includes a centrifuge, a counterweight, and a simulation chamber as described in any one of claims 1 to 8; two opposing booms of the centrifuge are each rotatably mounted with a basket, and the simulation chamber and the counterweight are respectively mounted on the two baskets.

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