A method for manufacturing a cross-fault tunnel model under high confining pressure and high ground stress environment

Abstract

The application provides a method for manufacturing a cross-fault tunnel model under high confining pressure and high ground stress environment, comprising the following steps: S1: manufacturing a layered shear box, wherein the layered shear box comprises a plurality of first shear boxes and a plurality of second shear boxes connected through universal connecting pieces; the first shear box comprises a first cavity, and the second shear box comprises a second cavity; S2: filling foam expanded concrete into the first cavity and the second cavity to obtain a fault rock model simulating a tunnel excavation position; S3: opening a surrounding rock hole in the middle of the fault rock model to simulate a tunnel excavation process, thereby obtaining a surrounding rock hole model; S4: placing a tunnel model into the surrounding rock hole, and filling polyurethane expansion material between the tunnel model and the surrounding rock hole, thereby obtaining a cross-fault tunnel model under high confining pressure and high ground stress environment. The method of the application more realistically reproduces the stress state of a tunnel under complex geological environments such as high confining pressure and high ground stress.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of geotechnical engineering, and particularly relates to a cross-fault tunnel model capable of simulating a high confining pressure and high ground stress environment and a manufacturing method thereof. BACKGROUND

[0002] With large-scale development and construction of tunnels in China, how to truly simulate the stress state of a tunnel in the ground in a laboratory has become a problem to be solved in the field of civil engineering technology. In the process of tunnel construction, a tunnel often needs to cross a fault, and the influence of fault activity on the tunnel is extremely complex, especially in a high confining pressure and high ground stress environment, the stability problem of the tunnel is particularly prominent. The traditional laboratory simulation method often cannot accurately reflect these complex geological conditions, resulting in a large difference between the experimental results and the actual engineering conditions. The traditional laboratory simulation method often cannot accurately reproduce the stress state of a tunnel under a complex geological environment such as high confining pressure and high ground stress. For example, in the prior art, the patent document with the application number 201810162269.8 provides a layered shear model soil box and a method for measuring the strain of soil in the model soil box. The model soil box body is composed of layered frames, and a sliding groove, a roller and an arc steel sheet are arranged between adjacent two frames. A counterforce loading device is further arranged for simulating the overburden load of the soil.

[0003] The model soil box simulates the overburden load through the counterforce loading device, and cannot uniformly apply high ground stress to the soil. The deformation and confining pressure in the soil are not the same everywhere, and there will be local stress concentration. Therefore, the model soil box cannot truly simulate the high confining pressure and high ground stress stress state of a tunnel in the environment. Therefore, it is of great significance to provide a cross-fault tunnel model capable of truly simulating a high confining pressure and high ground stress environment and a manufacturing method thereof for improving the design and construction level of tunnel engineering. SUMMARY

[0004] To solve the above problems, the present application provides a manufacturing method of a cross-fault tunnel model capable of simulating a high confining pressure and high ground stress environment. The method can accurately simulate the stress state of a tunnel under a high confining pressure and high ground stress environment by designing a specific model structure and manufacturing process.

[0005] Specifically, the method comprises the following steps:

[0006] S1: manufacturing a layered shear box, the layered shear box comprising a plurality of first shear boxes and a plurality of second shear boxes connected by universal connecting pieces; the first shear box comprising a first cavity, and the second shear box comprising a second cavity;

[0007] S2: filling foam expanded concrete into the first cavity and the second cavity to obtain a fault rock model simulating a tunnel excavation position;

[0008] S3: A surrounding rock hole is opened in the middle of the fault rock model to simulate the tunnel excavation process, and a surrounding rock hole model is obtained;

[0009] S4: The tunnel model is placed in the surrounding rock hole, and the tunnel model and the surrounding rock hole are filled with polyurethane expansion material. The polyurethane expansion material applies pressure to the tunnel model to simulate the high confining pressure environment of the tunnel. The foam expanded concrete expands under the constraint of the first and second shear boxes to simulate the high ground stress environment of the tunnel, and a cross-fault tunnel model under high confining pressure and high ground stress environment is obtained.

[0010] Further, the S2 comprises: S2.1: determining the foam concrete expansion agent addition amount in the foam concrete according to the ground stress at the tunnel excavation location, to obtain the configured foam expanded concrete; the ground stress size is determined by the ground stress detection data of the tunnel excavation location, and the foam concrete expansion agent addition amount is determined by the concrete stress-strain curve;

[0011] S2.2: The configured foam expanded concrete is stirred, and the stirred foam expanded concrete is poured into the layered shear box. After the foam concrete is cured and hardened, the fault rock model is obtained.

[0012] Further, the foam expanded concrete is foam expanded concrete added with HCSA expansion agent produced by Wuhan Sanyuan Special Building Material Co., Ltd.

[0013] Further, the expansion material in S4 is polyurethane expansion material, and the addition amount of the polyurethane expansion material is determined by the confining pressure of the lining, and the confining pressure is determined by the tunnel confining pressure calculation method in the first volume of Highway Tunnel Design Specification (Civil Manual).

[0014] Further, strain gauges are arranged in the multi-fault rock model and the tunnel model.

[0015] Further, the first shear box is surrounded by a plurality of fixedly connected first side plates; the second shear box is surrounded by a plurality of detachably connected second side plates; the universal connecting piece is arranged at the connection of the first side plate or the second side plate, the first side plate surrounds the first cavity, and the second side plate surrounds the second cavity.

[0016] Further, the universal connecting piece comprises a universal ball and an upper ball groove and a lower ball groove accommodating the universal ball, the upper ball groove is arranged at the top connection of the first side plate or the second side plate, the lower ball groove is arranged at the bottom connection of the first side plate or the second side plate, the radius of the upper ball groove and the lower ball groove is greater than the radius of the universal ball, and the total depth of the upper ball groove and the lower ball groove is less than the diameter of the universal ball.

[0017] Further, the first side plate and the second side plate are both acrylic plates, and the second side plates are detachably connected through bolts.

[0018] Further, several second shear boxes are arranged in the middle part of the layered shear box.

[0019] Further, a frame is arranged on the periphery of the layered shear box, the frame comprising an upper bottom plate frame, a lower bottom plate frame, and a support connecting the upper bottom plate frame and the lower bottom plate frame, and an upper bottom plate mounting hole is arranged on the upper bottom plate frame, and a lower bottom plate is fixedly arranged in the lower bottom plate frame.

[0020] The beneficial technical effects of the present application are:

[0021] The method not only considers the influence of rock deposition process on tunnel excavation, but also simulates high confining pressure environment by applying pressure through expanding material, and simulates high ground stress environment by using the expansion of foam expanded concrete under the constraint of the shear box, thereby realizing comprehensive simulation of the real stress state of the tunnel. In addition, by arranging strain gauges, the deformation of the tunnel model and the surrounding rock model can be monitored in real time, providing more reliable data support for tunnel design and construction. By simulating the cross-fault tunnel under high confining pressure and high ground stress environment, the stability and safety of the tunnel under such complex geological conditions can be more accurately evaluated. It provides a reliable basis for subsequent tests.

[0022] Compared with the traditional laboratory simulation method, the method of the present application more realistically reproduces the stress state of the tunnel under complex geological environments such as high confining pressure and high ground stress, thereby greatly improving the accuracy and reliability of the experimental results.

[0023] In addition, the layered shear box and foam expanded concrete provided by the present application have the advantages of simple structure, easy manufacturing and operation, high flexibility and adjustability, and can simulate the stress state of the tunnel under different geological conditions according to actual needs. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The flowchart of the method for manufacturing the cross-fault tunnel model under high confining pressure and high ground stress environment according to the present application;

[0025] Figure 2 The overall structure diagram of the layered shear box according to the present application;

[0026] Figure 3 The top view structure diagram of the layered shear box according to the present application;

[0027] Figure 4 The structure diagram of the layered shear box according to the present application filled with foam expanded concrete;

[0028] Figure 5 : The frame structure diagram of the layer shear box periphery of the present application;

[0029] Figure 6 : The frame structure diagram of the layer shear box periphery of the present application;

[0030] Figure 7 : The first shear box structure diagram of the present application;

[0031] Figure 8 : The second shear box structure diagram of the present application;

[0032] Figure 9 : The second side plate structure diagram of the second shear box of the present application;

[0033] Figure 10 : The universal connecting piece structure diagram of the present application;

[0034] Figure 11 : The first shear box bottom structure diagram of the present application;

[0035] Figure 12 : The layer shear box foam expanded concrete loading physical diagram of the present application;

[0036] In the above diagram: 1 first shear box, 101 first side plate, 2 second shear box, 201 second side plate, 3 universal connecting piece, 301 universal ball, 302 upper ball groove, 303 lower ball groove, 4 foam expanded concrete containing cavity, 5 frame, 501 upper bottom plate, 502 lower bottom plate, 503 upper bottom plate frame, 504 lower bottom plate frame, 505 support column, 6 foam expanded concrete, 7 surrounding rock hole, 8 tunnel model. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0038] In all the embodiments of the present application, the terms are explained as follows unless specifically limited.

[0039] High stress: the stress of the rock deep underground due to the weight of the overlying rock, which usually increases with the increase of the depth.

[0040] Rock deposition: Rock deposition is a process of depositing layers of rock on the surface or near the surface due to weathering, transportation, accumulation, and other geological processes. In simulating the process of rock deposition, the present application fills the cavity of the layered shear box with foam expanded concrete, and uses the expansion characteristics of the concrete to simulate the close-packed state of rock deposition.

[0041] Lining: In the field of civil engineering, especially in geotechnical engineering and tunnel engineering, lining refers to a permanent support structure built around a tunnel, cavern or other underground excavation project using materials such as brick, concrete or reinforced concrete to prevent deformation or collapse of the surrounding rock, and to prevent water seepage, weathering and support the surrounding rock.

[0042] Lining confining pressure: After tunnel excavation, the pressure exerted by the surrounding rock mass on the lining structure.

[0043] With the large-scale development and construction of tunnels in China, how to simulate the stress state of tunnels in the laboratory has become a problem to be solved in the field of civil engineering technology. In the process of tunnel construction, it is often necessary to cross faults, and the impact of fault activity on tunnels is extremely complex, especially in high confining pressure and high geostress environments, the stability of tunnels is particularly prominent. The traditional laboratory simulation method often cannot accurately reflect these complex geological conditions, resulting in a large difference between the experimental results and the actual engineering situation. The traditional laboratory simulation method often cannot accurately reproduce the stress state of tunnels under complex geological environments such as high confining pressure and high geostress. For example, in the prior art, the patent document with application number 201810162269.8 provides a layered shear model soil box and a method for measuring the strain of soil in the model soil box. The model soil box body is composed of layered frames, and adjacent two frames are provided with a sliding groove, a roller and an arc steel sheet, and a counterforce loading device is further provided for simulating the overburden load on the soil.

[0044] The above-mentioned model soil box simulates the overburden load by means of the counterforce loading device, and cannot uniformly apply high geostress to the soil. The deformation and confining pressure inside the soil are not the same everywhere, and there will be local stress concentration, and the high confining pressure and high geostress stress state of the tunnel in the real environment cannot be truly simulated. Therefore, it is of great significance to provide a cross-fault tunnel model and a manufacturing method thereof that can truly simulate the high confining pressure and high geostress environment, for improving the design and construction level of tunnel engineering.

[0045] To solve the above problems, the present application provides a manufacturing method of a cross-fault tunnel model simulating high confining pressure and high geostress environment. The method can accurately simulate the stress state of the tunnel under high confining pressure and high geostress environment by designing a specific model structure and manufacturing process.

[0046] In some embodiments, as shown in Figures 1-12 the specific technical solution of the present application is:

[0047] S1: Fabricate a layered shearing box, the layered shearing box comprising a plurality of first shearing boxes 1 and a plurality of second shearing boxes 2 connected by universal connectors 3; the first shearing box 1 includes a first cavity, and the second shearing box 2 includes a second cavity;

[0048] like Figure 3 As shown, several first shear boxes 1 and second shear boxes 2 are stacked together, and the first cavity and the second cavity together form a foam expansion concrete receiving cavity 4.

[0049] S2: Fill the first cavity and the second cavity with foamed expanded concrete 6 to obtain a fault rock model simulating the tunnel excavation location;

[0050] S3: Open a surrounding rock hole 7 in the middle of the fault rock model to simulate the tunnel excavation process and obtain a surrounding rock hole model;

[0051] S4: The tunnel model 8 is placed into the surrounding rock hole 7, and the space between the tunnel model 8 and the surrounding rock hole 7 is filled with polyurethane expanding material. The polyurethane expanding material applies pressure to the tunnel model 8 to simulate the high confining pressure environment of the tunnel. The foamed expanding concrete 6 expands under the constraint of the first shear box 1 and the second shear box 2 to simulate the high ground stress environment of the tunnel, thus obtaining a cross-fault tunnel model simulating the high confining pressure and high ground stress environment.

[0052] Through the above steps, this application constructs a cross-fault tunnel model capable of simulating high confining pressure and high ground stress environments. During the fabrication process, the design of mutual displacement between layered shear boxes is used to simulate fault activity, and the use of foam-expanded concrete 6, constrained by the layered shear boxes, accurately reproduces the compact packing state of rock deposition. Holes are drilled in the multi-fault rock model to simulate the tunnel excavation process.

[0053] An expanding material is filled between the tunnel model 8 and the surrounding rock borehole 7, as it can apply pressure to the tunnel model, thereby simulating the high confining pressure environment that the tunnel experiences underground. In this embodiment, the confining pressure is determined by referring to the confining pressure calculation method in the "Highway Tunnel Design Code, Volume 1 (Civil Engineering Handbook)".

[0054] Meanwhile, the foamed expansive concrete 6 expands under the constraint of the shear box, effectively simulating the impact of high ground stress environment on the tunnel.

[0055] The simulation method of the present application not only overcomes the limitations of traditional laboratory simulation methods, such as the inability to uniformly apply high ground stress, the inability to truly reflect the stress state of the tunnel in a high confining pressure and high ground stress environment, etc., but also provides a more accurate and reliable simulation method. This is of great significance to improving the design and construction level of tunnel engineering, and helps engineers better predict the behavior of tunnels under actual geological conditions.

[0056] In some embodiments, the S2 comprises,

[0057] S2.1 determining the cement grade of the foam concrete, the addition amount of the foam concrete expander, and the addition amount of the foam according to the ground stress at the tunnel excavation location, to obtain the prepared foam concrete;

[0058] S2.2 stirring the prepared foam concrete and pouring the stirred foam concrete into the layered shear box.

[0059] According to the depth and location of the simulated concrete tunnel, the density of the rock at this depth, the shear wave velocity of the rock at this depth, the ground stress distribution in the rock, and the ground stress size, the cement grade, the addition amount of the foam concrete expander, and the addition amount of the foam are determined. In the experiment, different depths can be used to determine several different addition amounts of the concrete expander according to the in-situ ground stress data at different depths, to simulate different ground stress sizes. According to the rock density and strength at the actual depth, the addition amount of the foam in the foam concrete is changed, which can change the density and strength of the foam concrete. The more foam added, the lower the strength and density. Then add fly ash, silica powder, and slag powder to increase the strength of the concrete material and reduce the density of the concrete material. Add SAP to the concrete material to supplement water in a closed environment. The SAP should be soaked for one hour before the concrete is stirred. According to the 1:50 ratio, 1 part SAP is added to 50 parts water. After the SAP is saturated with water, it is placed in the material. SRA is used to suppress the dry shrinkage of the concrete. Finally, according to the soil data to be simulated, the normal concrete stirring method is used to add water and stir before the experiment. Then pour the stirred concrete into the layered shear box.

[0060] The stress-strain curve of the selected grade of concrete is used to determine the required concrete strength to achieve the required ground stress, and the foam concrete formulation is determined according to the strength. During the experiment, by adjusting the formulation of the foam concrete, the ground stress state at different depths and locations can be simulated, thereby further verifying the stress characteristics of the tunnel model under high confining pressure and high ground stress environment. This provides a more scientific basis for the design and construction of tunnel engineering.

[0061] In some embodiments, the selected foam expanded concrete is a foam expanded concrete added with HCSA expanding agent produced by Wuhan Sanyuan Special Building Material Co., Ltd.

[0062] In some embodiments, the expanding material in S4 is a polyurethane expanding material, and the amount of the polyurethane expanding material added is determined by the confining pressure of the lining.

[0063] The polyurethane expanding material has high strength, high adhesion and good elasticity, and can effectively simulate the actual confining pressure of the lining. When connected, the polyurethane expanding material is first uniformly applied to the outer wall of the tunnel model, and then inserted into the surrounding rock hole. After the polyurethane expanding material is cured, high confining pressure simulation of the tunnel model can be realized. In actual operation, the amount of polyurethane expanding material added can be adjusted to accurately control the size of the lining confining pressure, thereby meeting the simulation needs of different confining pressure conditions in experiments. In addition, the use of polyurethane expanding material can also enhance the connection stability between the tunnel model and the surrounding rock hole model, ensuring the accuracy of the experimental results.

[0064] In some embodiments, strain gauges are arranged in the multi-fault rock model and the tunnel model.

[0065] The strain gauges are arranged to monitor the strain of the tunnel model and the rock model during the simulation experiment. Through the feedback data of the strain gauges, the deformation and stress state of the tunnel model under different ground stresses and confining pressures can be accurately measured and analyzed. These data are crucial for evaluating the stability and safety of the tunnel structure, and provide strong support for the design and optimization of tunnel engineering. At the same time, the arrangement of strain gauges can also realize real-time monitoring of the tunnel model during the simulation experiment, ensuring the accuracy and reliability of the experimental results.

[0066] In some embodiments, as shown in FIG. 1, Figures 2-12 The layered shear box includes a plurality of first shear boxes 1 and a plurality of second shear boxes 2 connected by universal connectors 3. The first shear boxes 1 are surrounded by a plurality of fixedly connected first side plates 101. The second shear boxes 2 are surrounded by a plurality of detachably connected second side plates 201. The universal connectors 3 are arranged at the connection of the first side plates 101 or the second side plates 201. The first side plates 101 and the second side plates 201 form a cavity 4. An upper bottom plate 501 and a lower bottom plate 502 are arranged on the upper opening 401 and the lower opening 402 of the cavity 4, respectively.

[0067] The cavity 4 is filled with foam expanded concrete 6. When the foam concrete expands, the first side plates 101 or the second side plates 201 and the upper bottom plate 501 and the lower bottom plate 502 will generate uniform and isotropic high ground stress on the foam concrete.

[0068] It can be understood that when the foam concrete in the present application expands, it will fill the entire cavity 4, and due to the expansion characteristics of the foam concrete, it will exert uniform pressure on the first side plate 101, the second side plate 201, the upper bottom plate 501 and the lower bottom plate 502. This pressure simulates high ground stress, so that the foam expanded concrete in the cavity is in a similar stress state to the rock deep underground.

[0069] The number of the first shear box 1 and the second shear box 2 can be adjusted according to experimental needs to simulate rock deposition processes of different scales and complexities. For example, a smaller number of shear boxes can be used when simulating shallower deposition layers, while the number of shear boxes can be increased when simulating deeper deposition layers or complex geological structures containing multiple deposition layers.

[0070] The universal joint 3 not only allows relative movement between the first shear box 1 and the second shear box 2 to simulate shear deformation during rock deposition.

[0071] In some embodiments, as shown in Figure 10 and Figure 11 The universal joint 3 includes a universal ball 301 and an upper ball groove 302 and a lower ball groove 303 accommodating the universal ball, the upper ball groove 302 is provided at the top connection of the first side plate 101 or the second side plate 201, the lower ball groove 303 is provided at the bottom connection of the first side plate 101 or the second side plate 201, the radius of the upper ball groove and the lower ball groove is greater than the universal ball, and the total depth of the upper ball groove 302 and the lower ball groove 303 is less than the diameter of the universal ball 301.

[0072] The universal joint 3 can allow relative movement between the shear boxes in multiple directions, thereby more realistically simulating complex shear deformation caused by crustal movement or geological activity during underground rock deposition. This design enables the layered shear box to simulate a more realistic and complex geological environment.

[0073] In some embodiments, the radius of the upper ball groove 302 and the lower ball groove 303 is set to be twice the radius of the universal ball 301, and the depth of the upper ball groove 302 and the lower ball groove 303 is less than 1mm less than the diameter of the universal ball 301.

[0074] This not only ensures that the shear boxes can move relative to each other through the universal joint, but also prevents them from coming apart. At the same time, such a design also makes the entire layered shear box structure more stable and able to withstand greater stress without being damaged.

[0075] In some embodiments, as shown in Figures 7-9 The first side plate and the second side plate are both acrylic plates.

[0076] The use of acrylic plates enables the experimental personnel to clearly observe the expansion process of the foam expanded concrete in the cavity 4 and the relative movement between the shear boxes, thereby facilitating the observation and recording of the experimental results by the experimental personnel. In addition, the acrylic plates also have good transparency and corrosion resistance, which can ensure the accuracy and reliability of the experiment.

[0077] The first shear box 1 is integrally formed with the first side plate 101, and the second shear box 2 is surrounded by the detachable second side plate 201.

[0078] The first shear box 1 is surrounded by the first side plate 101, which is made of acrylic transparent material. The first side plates 101 are integrally formed and fixedly connected, forming a whole structure, which is used to simulate relatively hard rock layers. Such a design enables the first shear box 1 to maintain good integrity and stability when subjected to high ground stress and shear action.

[0079] As shown in Figure 8 The second shear box 2 in the present embodiment includes a detachable second side plate 201 connected by bolts. Such a design facilitates the experimental personnel to adjust the structure and size of the second shear box according to the experimental requirements. For example, when simulating the rock deposition process containing weak interlayer or fracture zone, the experimental personnel can simulate the distribution and characteristics of the weak interlayer or fracture zone by disassembling or adjusting the position and number of the second side plate 201.

[0080] In the present embodiment, the thickness of the acrylic plates of the first shear box 1 and the second shear box 2 reaches 5 cm, so as to ensure that the peripheral shear boxes are absolutely rigid and will not be damaged by the expansion of the concrete during the curing and hardening stage of the foam expanded concrete.

[0081] In some embodiments, a plurality of second shear boxes 2 are arranged in the middle of the layered shear box.

[0082] In the present embodiment, the second shear box 2 is arranged in the layered shear box. After the curing of the foam expanded concrete in the layered shear box is completed, the second shear box 2 is disassembled, so that the foam expanded concrete has an arbitrary deformation range, thereby simulating the fracture zone in the rock layer and more realistically reflecting the complex situation in the underground rock deposition process. At the same time, such a design also provides more experimental flexibility and operability for the experimental personnel, and the position and number of the second shear box can be adjusted according to the specific experimental requirements to achieve the best simulation effect.

[0083] In some embodiments, as shown in Figure 6As shown, the layered shear box is provided with a frame 5, which includes an upper bottom plate frame 503, a lower bottom plate frame 504 and a support column 505 connecting the upper bottom plate frame 503 and the lower bottom plate frame 504, and the upper bottom plate frame 503 is provided with mounting holes corresponding to the upper bottom plate 501, and the upper bottom plate frame 503 is detachably connected with the upper bottom plate 501 through the mounting holes, and the lower bottom plate is fixedly connected with the upper bottom plate frame and the lower bottom plate frame.

[0084] The frame 5 can provide additional support and fixation for the layered shear box, ensuring its stability and safety during experiments. In this embodiment, the upper bottom plate frame 503 and the lower bottom plate frame 504, as well as the support column 505, are all made of reinforced steel, and the lower bottom plate 504 and the support column 505 are fixedly connected by welding, while the upper bottom plate 501 and the upper bottom plate frame 503 are detachably connected, which facilitates the detachable connection of the upper bottom plate 501 through the mounting holes on the upper bottom plate frame 503. This allows the experimenter to easily install and disassemble the layered shear box for experimental operation.

[0085] In summary, the layered shear box for use with foam expanded concrete provided by the present application allows the first shear box and the second shear box to move relative to each other in multiple directions through the use of specially designed universal connecting pieces, thereby simulating the complex shear deformation during the deposition of underground rocks. At the same time, by pouring foam expanded concrete into the cavity and utilizing its expansion characteristics to simulate high ground stress and the tight packing state of rock deposition, the experimental results are more realistic and reliable.

[0086] In addition, the layered shear box in the present application can also simulate the fracture zone in the rock layer by adjusting the number and position of the first shear box and the second shear box, thereby more realistically reflecting the complex conditions during the deposition of underground rocks.

[0087] The cross-fault tunnel model in a high confining pressure and high ground stress environment provided by the present application can provide effective data support for subsequent tests. For example, the tunnel model of the present application can be placed on a shaking table to simulate the response of the tunnel under seismic action, and the deformation and stress conditions of the tunnel model under seismic wave action can be observed. By adjusting the frequency, amplitude and other parameters of the seismic wave, different levels of seismic action can be simulated, thereby evaluating the seismic performance of the tunnel structure under different seismic conditions. Through the above experiments, the stability and safety of the tunnel under different seismic intensities can be evaluated. The shaking table can simulate seismic motion of different frequencies and amplitudes, thereby truly reflecting the influence of earthquakes on tunnels. During the experiment, the deformation of the tunnel, the degree of damage to the lining structure and the response characteristics of the surrounding rock and other key indicators can be observed and recorded. These data can provide important reference for the seismic design and reinforcement of tunnels.

[0088] The simulation method can not only help engineers better understand the behavior of the tunnel under the action of the earthquake, but also provide a scientific basis for the seismic design of the tunnel engineering.

[0089] In summary, the application provides a method for manufacturing a cross-fault tunnel model under high confining pressure and high ground stress environment. The method not only solves the limitations of traditional simulation methods in simulating the stress state of the tunnel under complex geological conditions, but also realizes accurate simulation of the stress characteristics of the tunnel under extreme geological conditions through detailed design and experimental steps. The tunnel model manufacturing method has high flexibility and operability, and can adjust the parameters and structure of the model according to specific experimental requirements to meet the simulation requirements under different experimental conditions.

Claims

1. A method for making a model of a cross-fault tunnel under high confining pressure and high ground stress environment, characterized in that, The method comprises the following steps: S1: make a layered shear box, which comprises a plurality of first shear boxes (1) and a plurality of second shear boxes (2) connected by universal connectors (3); the first shear box (1) comprises a first cavity, and the second shear box (2) comprises a second cavity; S2: fill foam expanded concrete (6) into the first cavity and the second cavity to obtain a fault rock model simulating a tunnel excavation position; S3: open a surrounding rock hole (7) in the middle of the fault rock model to simulate the tunnel excavation process, and obtain a surrounding rock hole model; S4: place a tunnel model (8) into the surrounding rock hole (7), and fill polyurethane expanding material between the tunnel model (8) and the surrounding rock hole (7), so that the polyurethane expanding material applies pressure to the tunnel model (8) to simulate the high surrounding pressure environment of the tunnel; the foam expanded concrete (6) expands under the constraint of the first shear box (1) and the second shear box (2) to simulate the high ground stress environment of the tunnel, and obtain a cross-fault tunnel model under the high surrounding pressure and high ground stress environment; The foam expanded concrete (6) is foam expanded concrete added with HCSA expanding agent produced by Wuhan Sanyuan Special Building Material Co., Ltd.; The first shear box (1) is surrounded by a plurality of first side plates (101) connected fixedly; the second shear box (2) is surrounded by a plurality of second side plates (201) connected detachably; the universal connector (3) is arranged at the connection of the first side plate (101) or the second side plate (201), the first side plate (101) surrounds the first cavity, and the second side plate (201) surrounds the second cavity; The universal connector (3) comprises a universal ball (301) and an upper ball groove (302) and a lower ball groove (303) accommodating the universal ball (301); the upper ball groove (302) is arranged at the top connection of the first side plate (101) or the second side plate (201), the lower ball groove (303) is arranged at the bottom connection of the first side plate (101) or the second side plate (201), the radius of the upper ball groove (302) and the lower ball groove (303) is greater than the radius of the universal ball (301), and the total depth of the upper ball groove (302) and the lower ball groove (303) is less than the diameter of the universal ball (301).

2. The method according to claim 1, wherein the method is characterized by: The S2 comprises: S2.1: determine the foam concrete expanding agent addition amount in the foam concrete according to the ground stress of the tunnel excavation position, and obtain configured foam expanded concrete; the ground stress is determined according to the ground stress detection data of the tunnel excavation position in the field, and the foam concrete expanding agent addition amount is determined according to the concrete stress-strain curve; S2.2: stir the configured foam expanded concrete, pour the stirred foam expanded concrete into the layered shear box, and obtain the fault rock model after the foam expanded concrete is cured and hardened.

3. The method according to claim 1, wherein the method is characterized by: The adding amount of the polyurethane expanding material is determined by the confining pressure, and the confining pressure is determined by a tunnel confining pressure calculation method in the Highway Tunnel Design Specification First Book (Civil Engineering Manual).

4. The method according to claim 1, wherein the method is characterized by: Strain gauges are arranged in the fault rock model and the tunnel model.

5. The method according to claim 1, wherein the method further comprises: 5 setting the pressure in the pressure vessel to a pressure of 10 to 100 MPa, and setting the temperature in the pressure vessel to a temperature of 100 to 300°C. 10 The first side plate (101) and the second side plate (201) are both acrylic plates, and the second side plates (201) are detachably connected through bolts.

6. The method according to claim 1, wherein the method is characterized by: Several second shear boxes (2) are arranged in the middle of the layered shear box.

7. The method according to claim 5, wherein the method further comprises: 5 setting the pressure in the pressure vessel to a pressure of 10 to 100 MPa; and setting the temperature in the pressure vessel to a temperature of 100 to 300°C. 10 A frame (5) is arranged on the periphery of the layered shear box, the frame comprises an upper bottom plate frame (503), a lower bottom plate frame (504) and a support column (505) connecting the upper bottom plate frame (503) and the lower bottom plate frame (504), an upper bottom plate mounting hole is arranged on the upper bottom plate frame (503), and a lower bottom plate (502) is fixedly arranged in the lower bottom plate frame.

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