A quasi-static pushing and covering device for a tunnel in a high ground stress environment

Abstract

The utility model discloses a quasi-static force pushes and covers device of tunnel under high ground stress environment, including model box, stress exerting system and lateral boundary forced displacement exerting system, model box is enclosed by a plurality of side wall steel sheets, and one side of model box is equipped with horizontal actuator, and the assembly type counterforce wall is used as the support, stress exerting system is formed by the superposition of horizontal structural stress and vertical equivalent deadweight stress, and the horizontal structural stress provides stress input source by stress cable that acts on the both sides of model box, and each stress cable is limited by safety limit cable block of model box board both ends, and installs stress digital display instrument at the non -loading end, and the vertical equivalent deadweight stress is by the vertical actuator that acts on the upper portion of model box and is exerted load, and the vertical actuator is installed on the vertical actuator counterforce beam, the utility model discloses simple production, low cost, and ground stress field is added operation and is convenient to read, and can simulate the structural seismic characteristic analysis of different depth tunnel.

Description

Technical Field

[0001] This utility model belongs to the technical field of tunnel model test device, specifically relating to a pseudo-static pushover device for tunnels under high ground stress environment. Background Technology

[0002] Several earthquake disasters have demonstrated the severe damage to tunnels induced by strong earthquakes, and the construction of tunnels in the complex and treacherous mountainous areas of western China inevitably faces the challenge of high ground stress. Studying the response of tunnels to seismic forces under high ground stress, further revealing the deformation and failure modes of tunnels, and proposing corresponding seismic mitigation measures will help improve the theoretical level of seismic mitigation design for tunnel engineering in western my country, and is a necessary condition for ensuring the safe construction and operation of major national lifeline projects. Compared with numerical simulation, conducting tunnel model tests based on reasonable geometric similarity ratios and other basic similarity ratios will help to obtain intuitive and accurate model test observation results, reflect the interaction mechanism between the surrounding rock and the lining, and further reveal the deformation and failure laws of tunnel structures.

[0003] Commonly used research methods for seismic testing of underground structures include shaking table tests, centrifuge shaking table tests, and quasi-static tests. The reactive displacement method is a practical seismic calculation method that effectively simplifies seismic action to static action through the principle of static equivalence. In quasi-static tests of structures, the application of seismic loads is based on the reactive displacement method, specifically manifested in the application of forced horizontal displacement to the external frame structure. By applying forced displacement to the lateral boundaries of the soil-structure system, the interaction between the soil and structure can be directly reflected, which can be used to study the seismic performance of underground structures. Simultaneously, the quasi-static seismic method has become one of the popular trends in physical model testing of underground structures.

[0004] Currently, most tunnels designed for the rugged mountainous areas of western my country have significant burial depths, highlighting the high ground stress in the rock mass within the tunnel as a key construction challenge. Numerous studies have also shown that the direction and magnitude of ground stress significantly influence the deformation of the engineering site and the underground structures situated in high ground stress environments, becoming crucial factors in tunnel deformation and failure modes.

[0005] Currently, among the existing quasi-static pushover test devices that can simulate tunnels:

[0006] Chinese Patent Authorization Announcement No. CN115165282A, Authorization Announcement Date: October 11, 2022, Invention Title: "Pseudostatic Reciprocating Push-over Test Device and Method for Simulating Longitudinal Seismic Response of Tunnels", This invention designs a pseudostatic reciprocating push-over test device and method that can simulate the traveling wave effect of earthquakes.

[0007] Chinese Patent Authorization Announcement No. CN112304665A, Authorization Announcement Date: February 2, 2021, Invention Title: "Model Box and Usage Method for Tunnel Excavation Support and Static Pushover Test", This invention designs a model device and test method that can simulate tunnel excavation and static pushover test.

[0008] Chinese Patent Authorization Announcement No. CN213516368A, Authorization Announcement Date: June 22, 2021, Invention Title: "Model Box for Tunnel Excavation Support and Static Pushover Test", This invention designs a model device that can simulate tunnel excavation support and static pushover test.

[0009] Chinese Patent Authorization Announcement No. CN112254912B, Authorization Announcement Date: July 13, 2021, Invention Title: "An Equipment for Seismic Pushover Test of Multi-Story Underground Structures and a Quasi-Static Loading Method", This invention designs an equipment for seismic pushover test of multi-story underground structures and a quasi-static loading method.

[0010] Existing designs have explored quasi-static pushover principles, including consideration of tunnel construction and the characteristics of traveling wave effects in seismic waves. However, the following two shortcomings require further consideration:

[0011] 1. Application of geostress

[0012] Most existing quasi-static pushover model devices are designed to account for quasi-static pushover under tunnel construction or seismic wave traveling effects, and are no longer applicable to simulation studies of tunnel engineering in western China with extremely high ground stress. Therefore, there is an urgent need to design a quasi-static pushover test device for tunnels under high ground stress to provide support for the seismic performance of deep and large-scale buried tunnels in western China.

[0013] 2. Conversion between static and dynamic model boxes

[0014] Most existing quasi-static pushover model devices are only suitable for quasi-static pushover test research, and their application is somewhat limited. As mentioned above, conventional seismic testing methods for underground structures include shaking table tests in addition to quasi-static tests. How to integrate quasi-static loading model boxes and dynamic loading model boxes, and achieve free conversion between them, is one of the directions worth exploring in promoting model box design. Utility Model Content

[0015] In view of the above-mentioned problems in the existing technology, and in order to overcome the shortcomings and deficiencies of the previous tunnel pushover system in that it could not realize the simulation of ground stress and the static-dynamic conversion, this utility model provides a pseudo-static pushover device for tunnels under high ground stress environment.

[0016] This utility model discloses a pseudo-static pushover device for tunnels under high ground stress conditions, comprising a model box, a stress application system, and a lateral boundary forced displacement application system.

[0017] The model box adopts a steel frame form, which is enclosed by multiple side wall steel plates. A lateral boundary forced displacement application system is installed on one side of the model box. The lateral boundary forced displacement application system includes a horizontal actuator acting on the left side of the model box plate; and it is supported by a prefabricated reaction wall.

[0018] The stress application system is formed by the superposition of horizontal structural stress and vertical equivalent self-weight stress. The horizontal structural stress is provided by stress cables acting on the cable holes on both sides of the model box. Each stress cable is limited by safety limit blocks at both ends of the model box plate, and a stress display instrument is installed at the non-loaded end. The vertical equivalent self-weight stress is applied by vertical actuators acting on the upper part of the model box. The vertical actuators are installed on the vertical actuator reaction beam.

[0019] Furthermore, the vertical actuator acts on the distribution beam, and a sliding roller is configured at the lower part of the distribution beam. The sliding roller acts directly on the vertical stress uniform distribution plate and can slide freely.

[0020] Furthermore, two sets of vertical actuators are provided.

[0021] Furthermore, the lower part of the model box is connected to a base plate, and four ball joint movable devices are set at the corner positions between the model box and the base plate. The lower part of the ball joint of the movable device is installed in the ball joint limiting groove, and the upper part of the ball joint directly acts on the ball joint slide rail reserved at the bottom of the model box. The ball joint limiting groove is rigidly connected to the limiting bracket. The limiting bracket is installed in the slide rail on the base plate through rollers.

[0022] Furthermore, a stress-applying limit switch is installed between the limit bracket and the slide rail.

[0023] Furthermore, at least four sets of horizontal actuators are provided.

[0024] Furthermore, the forced displacement range of the upper horizontal actuator is greater than that of the lower horizontal actuator, thereby achieving the displacement distribution form of the inverted triangle side boundary.

[0025] The beneficial technical effects of this utility model compared with the prior art are as follows:

[0026] 1. This utility model achieves triaxial ground stress loading through the ground stress cables on the left and right sides of the model box in the tunnel cross-section direction and the equivalent self-weight stress at the top. Loading through stress cables avoids excessive reliance on jacks, effectively reduces the self-weight of the model box, and the applied ground stress is directly displayed by a digital display instrument.

[0027] 2. The horizontal stress field of this utility model is loaded by the contraction of the stress cables on both sides of the model box, while the vertical actuator can realize the application of the vertical equivalent self-weight stress field; the model box is simple to manufacture, low in cost, and the application and reading of the stress field are convenient, and it can simulate the structural seismic characteristics analysis of tunnels at different burial depths.

[0028] 3. This utility model integrates a dynamic and static dual-purpose model box by utilizing the stress-applying limit switch opening and closing and the strong lateral reaction force in the ball joint and limit groove combination component and the assembly function of the horizontal actuator. It can perform pushover tests under pseudo-static conditions and also serve as a model box for shaking table tests under constant gravity fields.

[0029] 4. This utility model is of great significance for studying the seismic characteristics of tunnels at different burial depths and corresponding peak ground accelerations in high-stress areas, and for the seismic design of tunnels in high-stress areas. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the pseudo-static pushover device for tunnels under high ground stress conditions according to the present invention.

[0031] Figure 2 This is a schematic diagram of the overall three-dimensional structure of the model box.

[0032] Figure 3 This is a top view of the model box.

[0033] Figure 4 This is a front view structural diagram of the model box.

[0034] Figure 5 This is a schematic diagram of the left-side structure of the model box.

[0035] Figure 6 This is a schematic diagram of the right-side structure of the model box.

[0036] Figure 7 This is a schematic diagram of a ball joint limiting device.

[0037] In the diagram: 1-Side wall steel plate; 2-Vertical stress uniform distribution plate; 3-Horizontal actuator; 4-Vertical actuator; 5-Assembled reaction wall; 6-Vertical actuator reaction beam; 7-Distribution beam; 8-Sliding roller; 9-Base plate; 10-Slide rail; 11-Limiting bracket; 12-Spherical hinge limiting groove; 13-Spherical hinge; 14-Safety cable limiting block; 15-Stress cable; 16-Stress application limit switch; 17-Roller. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and specific implementation methods.

[0039] This utility model discloses a pseudo-static push-over device for tunnels under high ground stress conditions, such as... Figure 1 As shown, it includes a model box, a stress application system, and a lateral boundary forced displacement application system.

[0040] like Figure 2 , Figure 5 As shown, the model box adopts a steel frame structure, which is enclosed by multiple side wall steel plates 1. Figure 4 As shown, a lateral boundary forced displacement application system is installed on one side of the model box. The lateral boundary forced displacement application system includes a horizontal actuator 3 acting on the left side of the model box plate; and is supported by a prefabricated reaction wall 5.

[0041] The stress application system is formed by the superposition of horizontal structural stress and vertical equivalent self-weight stress. For example... Figure 2 As shown, the horizontal structural stress is provided by stress cables 15 acting on the cable holes on both sides of the model box. Each stress cable 15 is limited by safety limiting blocks 14 at both ends of the model box plate to prevent plate failure when the stress cables 15 are tightly stretched. A stress display instrument is installed at the non-loaded end to monitor the cable stress in real time. The vertical equivalent self-weight stress is applied by the vertical actuator 4 acting on the upper part of the model box. The vertical actuator 4 is installed on the vertical actuator reaction beam 6. It should be ensured that the output of the vertical actuator 4 is consistent to ensure the overall structural integrity.

[0042] Furthermore, the vertical actuator 4 acts on the distribution beam 7, and the lower part of the distribution beam 7 is equipped with a sliding roller 8, such as... Figure 3 As shown, the sliding roller 8 acts directly on the vertical stress uniform distribution plate 2 and can slide freely, avoiding the bias pressure caused by the inconsistent shrinkage of the box body when the stress cable shrinks.

[0043] Furthermore, two sets of vertical actuators 4 are provided.

[0044] Furthermore, such as Figure 6 As shown, a base plate 9 is connected to the bottom of the model box. Four ball joints are installed at the corners between the model box and the base plate 9 to allow for limited planar rotation of the side walls of the box, providing the bottom rotational freedom for forced lateral displacement. Figure 7 As shown, the lower part of the ball joint 13 of the ball joint movable device is installed in the ball joint limiting groove 12, and the upper part of the ball joint 13 directly acts on the ball joint slide rail reserved at the bottom of the model box; the ball joint limiting groove 12 is rigidly connected to the limiting support groove 11; the limiting support groove 11 is installed in the slide rail 10 on the base plate 9 through the roller 17.

[0045] Furthermore, such as Figure 7 As shown, a stress application limit switch 16 is installed between the limit bracket 11 and the slide rail 10. The opening and closing of the stress application limit switch 16 can control the displacement coordination of the box side wall under horizontal stress.

[0046] Furthermore, the horizontal actuator 3 shall be provided with no fewer than four sets.

[0047] Furthermore, the forced displacement range of the upper horizontal actuator 3 is greater than that of the lower horizontal actuator 3, thereby realizing the displacement distribution form of the inverted triangle side boundary.

[0048] How to use this utility model:

[0049] Step 1: Check whether the stress application limit switch 16 is in the maximum width position and ensures that it is closed to prevent the backfilling operation from disturbing the box bodies on both sides;

[0050] Step 2: After confirming that the stress application limit switch 16 is closed, perform the stress cable 15 threading connection and keep the safety cable limit block 14 in a relaxed state.

[0051] Step 3: Begin backfilling. Fill to the design elevation of the tunnel model, place the tunnel model in the tunnel, and continue backfilling to the highest design elevation of the soil.

[0052] Step 4: Install the vertical stress uniform distribution plate 2, roller 8, vertical stress distribution beam 7 and vertical actuator 4 in sequence, and install the vertical actuator 4 on the vertical actuator reaction beam 6.

[0053] Step 5: Open the stress application limit switch 16, tighten the stress cable 15, and after pulling the horizontal stress to the predetermined stress value, close the sliding function of the limit bracket 11 by closing the stress application limit switch 16.

[0054] Step 6: Install the prefabricated reaction wall 5 and the horizontal actuator 3, ensuring that the forced displacement range of the upper horizontal actuator 3 is greater than that of the lower horizontal actuator.

[0055] Step 7: Calculate the equivalent vertical stress value according to the actual burial depth of the tunnel, and push the vertical actuator 4 out by a certain amount to achieve the equivalent vertical stress level.

[0056] Step 8: Conduct lateral pushover tests according to the test plan until the test is completed.

[0057] Step 9: Unload the prefabricated reaction wall 5, horizontal actuator 3, vertical actuator 4 and all supporting components, and reopen the stress application limit switch 16, release the tension of the stress cable 15, restore the stress application limit switch 16, excavate the soil and tunnel model, and the test ends.

[0058] The specific embodiments described are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the specific embodiments or use similar methods to replace them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A pseudo-static pushover device for tunnels under high ground stress conditions, characterized in that, Includes a model box, a stress application system, and a lateral boundary forced displacement application system; The model box adopts a steel frame form, which is enclosed by multiple side wall steel plates (1). A lateral boundary forced displacement application system is installed on one side of the model box. The lateral boundary forced displacement application system includes a horizontal actuator (3) acting on the left side of the model box plate; and is supported by a prefabricated reaction wall (5). The stress application system is formed by the superposition of horizontal structural stress and vertical equivalent self-weight stress. The horizontal structural stress is provided by stress cables (15) acting on the cable holes on both sides of the model box. Each stress cable (15) is limited by safety cable limit blocks (14) at both ends of the model box plate, and a stress display instrument is installed at the non-loaded end. The vertical equivalent self-weight stress is applied by the vertical actuator (4) acting on the upper part of the model box. The vertical actuator (4) is installed on the vertical actuator reaction beam (6).

2. The pseudo-static pushover device for tunnels under high ground stress environment according to claim 1, characterized in that, The vertical actuator (4) acts on the distribution beam (7), and the lower part of the distribution beam (7) is equipped with a sliding roller (8). The sliding roller (8) acts directly on the vertical stress uniform distribution plate (2) and can slide freely.

3. The pseudo-static pushover device for tunnels under high ground stress environment according to claim 2, characterized in that, The vertical actuator (4) is provided in two sets.

4. The pseudo-static pushover device for tunnels under high ground stress environment according to claim 1, characterized in that, The model box is connected to a base plate (9) at the bottom. Four ball joint movable devices are set at the corner positions between the model box and the base plate (9). The lower part of the ball joint (13) of the ball joint movable device is installed in the ball joint limiting groove (12), and the upper part of the ball joint (13) directly acts on the ball joint slide rail reserved at the bottom of the model box. The ball joint limiting groove (12) is rigidly connected to the limiting bracket (11). The limiting bracket (11) is installed in the slide rail (10) on the base plate (9) through the roller (17).

5. A pseudo-static pushover device for tunnels under high ground stress environment according to claim 4, characterized in that, A stress-applying limit switch (16) is installed between the limiting bracket (11) and the slide rail (10).

6. The pseudo-static pushover device for tunnels under high ground stress environment according to claim 1, characterized in that, The horizontal actuator (3) shall be provided in no fewer than four sets.

7. A pseudo-static pushover device for tunnels under high ground stress environment according to claim 6, characterized in that, The forced displacement range of the upper horizontal actuator (3) is greater than that of the lower horizontal actuator (3), thereby realizing the displacement distribution form of the inverted triangle side boundary.

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