Two-dimensional multidirectional crustal stress calculation method and application technology suitable for quasi-static pushing and covering device

Abstract

The invention discloses a two-dimensional multidirectional crustal stress calculation and application method suitable for a quasi-static pushing and covering device, and the method specifically comprises the steps: firstly, arranging the quasi-static pushing and covering device, installing a horizontal actuator on one side of a model box, and supporting the horizontal actuator on an assembly type reaction wall, so as to achieve the quasi-static pushing and covering action of the model box; the stress application is formed by superposing a horizontal tectonic stress and a vertical equivalent self-weight stress; stress cables acting on cable holes in the two sides of the model box provide a stress input source for horizontal tectonic stress, and two sets of vertical actuators acting on the upper portion of the model box apply loads to vertical equivalent self-weight stress; and calculating the ground stress applied by the transverse stress cable and the vertical actuator by combining a test site and the strength of a model similar material. The method is high in practicability, the ground stress application control parameters selected in the formula are visual and effective, and the stress field mapping relation from the engineering field area to the model test is clearer. And the method has wide practicability in the field of tunnel model tests in a high ground stress environment.

Description

Technical Field

[0001] This invention belongs to the technical field of stress system for tunnel model tests, and specifically relates to a two-dimensional multi-directional geostress calculation and application method suitable for quasi-static pushover devices. Background Technology

[0002] As the scale of transportation network construction expands to western my country, the region faces significant challenges. The widespread distribution of high-intensity earthquake zones and complex geological conditions in western China severely restrict the safe construction and operation of highway and railway tunnels. Generally, tunnels in complex and challenging mountainous areas are deep, prone to frequent and intense earthquakes. Therefore, understanding the mechanical morphology of tunnels under the coupled environment of high ground stress and strong earthquakes is crucial for tunnel route selection, construction, and safe operation and maintenance. Researching the seismic response of tunnels under the coupled environment of high ground stress and strong earthquakes, revealing the mechanical properties of tunnels, and proposing corresponding seismic mitigation measures will help improve the theoretical level of seismic design for tunnel engineering in western my country.

[0003] Physical model tests can intuitively and accurately obtain observation results, which is crucial for investigating the impact of strong ground motions on tunnels under high ground stress environments. Physical model test studies on tunnel dynamic response often employ shaking tables and centrifuge shaking tables to conduct corresponding ground motion studies, while tunnel pushover tests, as a quasi-static testing method, are easy to implement. Applying forced displacement to the lateral boundaries of the soil-structure system can directly reflect the soil-structure interaction, which can be used to study the seismic performance of underground structures. Simultaneously, quasi-static seismic resistance methods have become one of the popular trends in physical model tests for seismic resistance of underground structures.

[0004] Currently, most tunnels in the rugged mountainous areas of western my country are buried at great depths, and the problem of high ground stress in the rock mass is particularly prominent during construction. Numerous studies have also shown that the direction and magnitude of ground stress will have a significant impact on the engineering site and underground structure.

[0005] Currently, among the existing model test devices capable of applying high ground stress:

[0006] Chinese Patent Authorization Announcement No. CN112444363, Authorization Announcement Date: March 5, 2021, Invention Title: "A Horizontal Stress Loading Device for a Rigid Model Box for a Vibration Table", This invention designs a rigid model box placed on a vibration table and using a pressure water tank as the stress input source.

[0007] Chinese Patent Authorization Announcement No. CN114859017B, Authorization Announcement Date: October 11, 2022, Invention Title: "An Experimental Device and Method for Controlling the Stress Field and Displacement Field of a Stratum", This invention designs a stress field model box loaded with a jack.

[0008] In existing quasi-static pushover model boxes for simulating tunnel seismic response:

[0009] 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.

[0010] 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.

[0011] Existing designs have addressed the application of in-situ stress and the design of the quasi-static pushover model box, focusing on the methods of applying in-situ stress and the functional uses of the quasi-static pushover model box. However, the following two shortcomings require further consideration:

[0012] 1. Application of geostress

[0013] 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.

[0014] 2. Regarding the operability and control parameters of applying geostress.

[0015] In existing model boxes used for underground engineering that consider the application of in-situ stress, the stress input source mostly relies on a large external stress loading system and heavy jacks to achieve in-situ stress loading. Moreover, it is always impossible to truly quantitatively apply the required stress field size by means of intuitive stress application control parameters, and thus it is impossible to truly realize the expected vector directionality effect of stress field simulation. Summary of the Invention

[0016] 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 three-dimensional multi-directional geostress field, the present invention provides a two-dimensional multi-directional geostress calculation and application method suitable for quasi-static pushover devices.

[0017] The present invention provides a two-dimensional multi-directional geostress calculation and application method applicable to quasi-static pushover devices, specifically as follows:

[0018] The first step is the installation of the pseudo-static pushover device.

[0019] The quasi-static pushover device includes a model box, which is in the form of a steel frame. A horizontal actuator capable of applying forced displacement is installed on one side, and it is supported by a prefabricated reaction wall.

[0020] The stress 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; the vertical equivalent self-weight stress is applied by two sets of vertical actuators acting on the upper part of the model box. The vertical actuators are installed on the vertical actuator reaction beam and act on the distribution beam. The lower part of the distribution beam is equipped with sliding rollers, which act directly on the vertical stress uniform distribution plate and can slide freely.

[0021] Secondly, there is the two-dimensional stress, namely the calculation of the ground stress applied by the transverse stress cable and the vertical actuator.

[0022] To determine the magnitude of the applied ground stress in the stress cable, the horizontal structural stress in the engineering site is set as follows: MPa, the geometric similarity ratio of the model box is C length Based on the principle of similarity, the horizontal stress applied inside the model box can be calculated using dimensional analysis. MPa.

[0023] According to the principle of even stress distribution among n stress cables on each side, the actual stress magnitude of each cable should be: MPa.

[0024] Assume the width and height of the model box are denoted as w. b m and h b m, which is the plate area A on the side of the model box where the stress cable is applied. section =w b h b Therefore, the actual force on each stress cable is calculated to be F. cable = kN, thereby constructing the stress cable tension F cable and model test stress requirements The correspondence is as follows:

[0025]

[0026] Based on the stress similarity ratio, the tension F of the stress cable cable and actual stress at the engineering site The direct correspondence is as follows:

[0027]

[0028] Regarding the magnitude of the applied ground stress by the vertical actuator, the vertical actuator is configured as a jack, and the length and width dimensions of the vertical stress uniform distribution plate are l, respectively.sp w sp .

[0029] Assuming the force applied by the vertical jack is t tons and the unit weight of the soil is γ, what is the vertical self-weight stress of the soil at a tunnel burial depth h in an actual engineering project? The surface force F acting on the loading plate at different tunnel burial depths h will be calculated by directly applying jacks to the tunnel model. sp =t×9.8×10 3 N, stress requirement of self-weight inside the model box The jack force t will have the following relationship:

[0030]

[0031] Based on the similarity ratio C of the heavy model weight The equivalent self-weight stress of the project is calculated based on the burial depth. The jack force t will have the following relationship:

[0032]

[0033] Based on the relationship between density and related surface forces, the relationship between the force t applied by the jack and the actual tunnel burial depth h is calculated as follows:

[0034]

[0035] The relationship between the applied force t of the jack and the actual tunnel burial depth h is incorporated into the self-weight stress requirement within the model box. With respect to the jack force t, the equivalent self-weight stress of the project The self-weight stress is obtained from the formula relating the jack force t. and The direct relationship with the tunnel burial depth h.

[0036] Finally, based on the calculated stress values ​​of the transverse stress cable and the vertical actuator, the application of the horizontal stress of the stress cable and the thrust of the vertical actuator are adjusted.

[0037] Furthermore, all stress cables are restricted by safety limit blocks at both ends of the model box plate to prevent plate failure and damage when the stress cables are stretched. A stress display instrument is installed at the non-loaded end to monitor the tensile stress of the stress cables.

[0038] Furthermore, the bottom 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.

[0039] Furthermore, the ball joint limiting groove is rigidly connected to the limiting bracket, and a roller and a stress application limiting switch are installed between the limiting bracket and the slide rail. The displacement coordination of the side wall of the horizontal stress application box is controlled by the opening and closing of the stress application limiting switch 16.

[0040] Furthermore, under two-dimensional stress conditions, the magnitude and direction of geostress at any angle within a finite range can be achieved, specifically the magnitude of geostress within that finite range. for:

[0041]

[0042] The direction of geostress within this limited range for:

[0043]

[0044] The beneficial technical effects of this invention compared to the prior art are as follows:

[0045] 1. This invention achieves triaxial in-situ stress loading by using the in-situ stress cables on the left and right sides of the model box in the tunnel cross-section direction and the equivalent self-weight stress in the upper part; by selecting appropriate in-situ stress application control parameters, a full-path stress extrapolation calculation formula of "engineering site → control parameters → model area" is constructed, clarifying the stress field mapping relationship from the engineering site to the model test, and providing necessary research methods for the subsequent mechanical behavior of underground structures under different stress states.

[0046] 2. In this invention, the push-over model box adopts the principle of combining stress cables and jacks for ground stress loading, which avoids the reliance on too many jacks, effectively reduces the self-weight of the model box, and makes the ground stress loading process simpler and more efficient.

[0047] 3. This invention utilizes the stress-applying limit switch opening and closing mechanism and the strong lateral reaction force of the ball joint and limit groove combined component, as well as the assembly function of the horizontal actuator, to integrate a dynamic and static dual-purpose model box. It can be used to complete the pseudo-static pushover test of tunnels in high ground stress environment, and can also be used in the dynamic loading test of underground structures, and can be used in conjunction with a shaking table.

[0048] 4. This invention is of practical significance for studying the seismic characteristics of tunnels at different burial depths and corresponding peak ground accelerations in high-stress areas. By using simple stress control indices in the derived formulas to achieve the transformation of stress levels from engineering sites to model tests, the results can provide practical and effective solutions for the seismic design of tunnels in high-stress areas. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the calculation process for the stress extrapolation method.

[0050] Figure 2 This is a schematic diagram of the three-dimensional structure of the pseudo-static push-over device.

[0051] Figure 3 This is a schematic diagram of the overall three-dimensional structure of the model box.

[0052] Figure 4 This is a top view of the model box structure.

[0053] Figure 5 This is a front view structural diagram of the model box.

[0054] Figure 6 This is a schematic diagram of the right-side structure of the model box.

[0055] Figure 7 This is a schematic diagram of a ball joint limiting device.

[0056] Figure 8 This is a schematic diagram of the stress cable and vertical jack loading.

[0057] 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

[0058] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0059] The present invention provides a two-dimensional multi-directional geostress calculation and application method applicable to quasi-static pushover devices, specifically as follows:

[0060] The first step is the installation of the pseudo-static pushover device.

[0061] like Figure 1 , Figure 2 , Figure 4 As shown, the quasi-static pushover device includes a model box, which is in the form of a steel frame. A horizontal actuator 3 capable of applying forced displacement is installed on one side; and it is supported by a prefabricated reaction wall 5.

[0062] The applied stress is formed by the superposition of horizontal structural stress and vertical equivalent self-weight stress. For example... Figure 3 , Figure 6 As shown, the horizontal structural stress is provided by stress cables 15 acting on the cable holes on both sides of the model box. Figure 2 , Figure 5As shown, the vertical equivalent self-weight stress is applied by two sets of vertical actuators 4 acting on the upper part of the model box. The vertical actuators 4 are installed on the vertical actuator reaction beam 6. The vertical actuators 4 act on the distribution beam 7. 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.

[0063] Secondly, there is the two-dimensional stress calculation, which involves calculating the ground stress applied by the transverse stress cable and the vertical actuator. The process is as follows: Figure 1 As shown.

[0064] To determine the magnitude of the applied ground stress in the stress cable, the horizontal structural stress in the engineering site is set as follows: MPa, the geometric similarity ratio of the model box is C length Based on the principle of similarity, the horizontal stress applied inside the model box can be calculated using dimensional analysis. MPa.

[0065] According to the principle of even stress distribution among n stress cables on each side, the actual stress magnitude of each cable should be: MPa.

[0066] Assume the width and height of the model box are denoted as w. b m and h b m, which is the plate area A on the side of the model box where the stress cable is applied. section =w b h b Therefore, the actual force on each stress cable is calculated to be F. cable = kN, thereby constructing the stress cable tension F cable and model test stress requirements The correspondence is as follows:

[0067]

[0068] Based on the stress similarity ratio, the tension F of the stress cable cable and actual stress at the engineering site The direct correspondence is as follows:

[0069]

[0070] Regarding the magnitude of the applied ground stress by the vertical actuator, the vertical actuator is configured as a jack, and the length and width dimensions of the vertical stress uniform distribution plate are l, respectively. sp w sp .

[0071] Assuming the force applied by the vertical jack is t tons and the unit weight of the soil is γ, what is the vertical self-weight stress of the soil at a tunnel burial depth h in an actual engineering project? The surface force F acting on the loading plate at different tunnel burial depths h will be calculated by directly applying jacks to the tunnel model. sp =t×9.8×10 3 N, stress requirement of self-weight inside the model box The jack force t will have the following relationship:

[0072]

[0073] Based on the similarity ratio C of the heavy model weight The equivalent self-weight stress of the project is calculated based on the burial depth. The jack force t will have the following relationship:

[0074]

[0075] Based on the relationship between density and related surface forces, the relationship between the force t applied by the jack and the actual tunnel burial depth h is calculated as follows:

[0076]

[0077] The relationship between the applied force t of the jack and the actual tunnel burial depth h is incorporated into the self-weight stress requirement within the model box. With respect to the jack force t, the equivalent self-weight stress of the project The self-weight stress is obtained from the formula relating the jack force t. and The direct relationship with the tunnel burial depth h.

[0078] Finally, as Figure 8 As shown, based on the calculated stress values ​​of the transverse stress cable and the vertical actuator, the application of the horizontal stress of the stress cable and the thrust of the vertical actuator are adjusted.

[0079] Furthermore, the stress cables 15 are all restricted by safety limit blocks 14 at both ends of the model box plate to prevent the plate from failing and being damaged when the stress cables 15 are tightly stretched, and a stress display instrument is installed at the non-loaded end to monitor the tensile stress of the stress cables.

[0080] Furthermore, such as Figure 3 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, such as... 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.

[0081] Furthermore, such as Figure 7As shown, the ball joint limiting groove 12 is rigidly connected to the limiting bracket 11. A roller 17 and a stress application limiting switch 16 are installed between the limiting bracket 11 and the slide rail 10. The displacement coordination of the side wall of the horizontal stress application box is controlled by the opening and closing of the stress application limiting switch 16.

[0082] Furthermore, under two-dimensional stress conditions, the magnitude and direction of geostress at any angle within a finite range can be achieved, specifically the magnitude of geostress within that finite range. for:

[0083]

[0084] The direction of geostress within this limited range for:

[0085]

[0086] Example:

[0087] Based on the test site and the strength of similar materials used in the model, the geometric similarity ratio of the model was first determined. =0.025 and the high similarity ratio C weight =0.8, the area of ​​the model plates on both sides of the stress cable in the quasi-static push-over test model box mentioned in the invention. =1.5m × 2m = 3m 2 .

[0088] Assuming the horizontal stress to be simulated is 10 MPa, that is =10MPa, and the number of single-sided tension cables n=4, then according to the tension F of the tension cable cable and actual stress at the engineering site Correspondence:

[0089]

[0090] The calculated tensile force of a single horizontal stress cable is 187.5 kN.

[0091] Assuming the tunnel depth h to be simulated is 800m and the rock mass density is 2800kg / m³ 3 The size of the upper model loading plate They are 1m × 2m = 2m respectively 2 The equivalent self-weight stress of the project calculated based on the burial depth. Relationship with jack force t:

[0092]

[0093] The calculated weight of the soil at a depth of 800m is 44.8 tons, corresponding to the vertical self-weight stress of the prototype tunnel. With a magnitude of 270 kPa, the corresponding weight of the jack is 44.8 × 0.8 = 35.84 tons, which can accurately reproduce the two-dimensional geostress distribution field of the engineering area.

[0094] After determining the stress input value of the model, check whether the stress application limit switch 16 is in the maximum width position and ensure that it is closed to prevent the backfilling operation from disturbing the box bodies on both sides; after confirming that the stress application limit switch 16 is closed, perform the stress cable 15 cable connection and keep the safety cable block 14 in a relaxed state.

[0095] Start filling the soil, fill it to the design elevation of the tunnel model, place the tunnel model, and continue filling the soil to the highest design elevation of the soil. Install the vertical stress uniform distribution plate 2, sliding roller 8, distribution beam 7 and vertical actuator 4 in sequence, and install the vertical actuator 4 on the vertical actuator reaction beam 6.

[0096] Turn on the stress application limit switch 16, tighten the stress cable, and pull the horizontal stress to 187.5kN. Then close the sliding function of the limit bracket 11 by closing the stress application limit switch 16. Install the prefabricated reaction wall 5 and the horizontal actuator 3, and set the thrust of the vertical actuator 4 to 35.84 tons to achieve the equivalent stress level in the vertical direction.

[0097] The lateral overburden test was carried out according to the test plan until the test was completed.

[0098] Unload the horizontal reaction wall, horizontal actuator, vertical actuator 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.

[0099] This invention relates to a two-dimensional multi-directional geostress calculation method and application technology applicable to a quasi-static pushover device. The quasi-static pushover device mentioned herein mainly uses a horizontal actuator on the side of the model box as the pushover power source to achieve the pushover action. The horizontal geostress field mentioned herein is loaded by the tensioning of the stress cables on both sides of the model box, while the vertical actuator can achieve the application of a vertically equivalent self-weight stress field.

[0100] The geostress calculation method proposed in this invention is highly practical. The geostress application control parameters selected in the formula are intuitive and effective. It successfully constructs a full-path stress extrapolation calculation method from "engineering site → control parameters → model area" and clarifies the stress field mapping relationship from the engineering site to the model test.

[0101] This invention provides a model box that is simple to manufacture, low in cost, and convenient for applying and reading the geostress field. It can simulate the structural seismic characteristics of tunnels at different burial depths and, through constraint stress application and limit switches, disable the planar rotation function of the ball joint limit groove, and remove the side boundary reaction force and horizontal actuators, achieving a simple and rapid conversion from a quasi-static loading model box to a shaking table model box. It has wide application and practicality in the field of tunnel model testing.

[0102] The specific embodiments described are merely illustrative examples illustrating the spirit of the invention. Those skilled in the art can make various modifications or additions to the specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A method for calculating and applying two-dimensional multi-directional geostress suitable for quasi-static pushover devices, characterized in that, Specifically: The first step is the installation of the quasi-static push-over device; The pseudo-static push-over device includes a model box, which is in the form of a steel frame. A horizontal actuator (3) capable of applying forced displacement is installed on one side; and it is supported by a prefabricated reaction wall (5). The stress application is formed by the superposition of horizontal structural stress and vertical equivalent self-weight stress; the horizontal structural stress is provided by the stress cable (15) acting on the cable holes on both sides of the model box; the vertical equivalent self-weight stress is applied by two sets of vertical actuators (4) acting on the upper part of the model box. The vertical actuators (4) are installed on the vertical actuator reaction beam (6). The vertical actuators (4) act on the distribution beam (7). 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. Secondly, there is the two-dimensional stress, namely the calculation of the ground stress applied by the transverse stress cable and the vertical actuator; To determine the magnitude of the applied ground stress in the stress cable, the horizontal structural stress in the engineering site is set as follows: MPa, the geometric similarity ratio of the model box is C length Based on the principle of similarity, the horizontal stress applied inside the model box can be calculated using dimensional analysis. MPa; According to the principle of even stress distribution among n stress cables on each side, the actual stress magnitude of each cable should be: MPa; Assume the width and height of the model box are denoted as w. b m and h b m, which is the plate area A on the side of the model box where the stress cable is applied. section =w b h b Therefore, the actual force on each stress cable is calculated to be F. cable = kN, thereby constructing the stress cable tension F cable and model test stress requirements The correspondence is as follows: ； Based on the stress similarity ratio, the tension F of the stress cable cable and actual stress at the engineering site The direct correspondence is as follows: ； Regarding the magnitude of the applied ground stress by the vertical actuator, the vertical actuator is configured as a jack, and the length and width dimensions of the vertical stress uniform distribution plate are l, respectively. sp w sp ; Assuming the force applied by the vertical jack is t tons and the unit weight of the soil is γ, what is the vertical self-weight stress of the soil at a tunnel burial depth h in an actual engineering project? The surface force F acting on the loading plate at different tunnel burial depths h will be calculated by directly applying jacks to the tunnel model. sp =t×9.8×10 3 N, stress requirement of self-weight inside the model box The jack force t will have the following relationship: ； Based on the similarity ratio C of the heavy model weight The equivalent self-weight stress of the project is calculated based on the burial depth. The jack force t will have the following relationship: ； Based on the relationship between density and related surface forces, the relationship between the force t applied by the jack and the actual tunnel burial depth h is calculated as follows: ； The relationship between the applied force t of the jack and the actual tunnel burial depth h is incorporated into the self-weight stress requirement within the model box. With respect to the jack force t, the equivalent self-weight stress of the project The self-weight stress is obtained from the formula relating the jack force t. and The direct relationship with the tunnel burial depth h; Finally, based on the calculated stress values ​​of the transverse stress cable and the vertical actuator, the application of the horizontal stress of the stress cable and the thrust of the vertical actuator are adjusted.

2. The method for calculating and applying two-dimensional multi-directional geostress suitable for quasi-static pushover devices according to claim 1, characterized in that, The stress cables (15) are all restricted by safety limit blocks (14) at both ends of the model box plate to prevent the plate from failing and being damaged when the stress cables (15) are tightly stretched. A stress display instrument is installed at the non-loaded end to monitor the tensile stress of the stress cables.

3. The method for calculating and applying two-dimensional multi-directional geostress suitable for quasi-static pushover devices 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 corners 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.

4. The method for calculating and applying two-dimensional multi-directional geostress suitable for quasi-static pushover devices according to claim 3, characterized in that, The ball joint limiting groove (12) is rigidly connected to the limiting bracket (11). A roller (17) and a stress application limiting switch (16) are installed between the limiting bracket (11) and the slide rail (10). The displacement coordination of the side wall of the horizontal stress application box is controlled by the opening and closing of the stress application limiting switch 16.

5. The method for calculating and applying two-dimensional multi-directional geostress suitable for quasi-static pushover devices according to claim 1, characterized in that, Under the aforementioned two-dimensional stress conditions, the magnitude and direction of geostress at any angle within a finite range can be achieved, specifically the magnitude of geostress within that finite range. for: ； The direction of geostress within this limited range for: 。

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