Centrifuge test equipment and method for complex fault activation in tunnels induced by earthquake / creep slip

Abstract

Centrifuge experimental equipment and method for activating complex faults in water-rich tunnels induced by earthquakes / creep-slip, characterized by comprising an overweight loading system, an earthquake wave loading system, and a true triaxial loading device; the overweight loading system includes a centrifuge main body, a test hanging basket, and counterweights; the earthquake wave loading system consists of two identical shaking tables, where each shaking table includes a shaking table base, an exciter, a shaking table linear guide rail slide, a shaking table linear guide rail slider, and a shaking table tabletop; the true triaxial loading device includes an external frame, an internal sealed frame, and an earthquake / creep-slip simulation test body; the present invention provides research equipment for activating normal, reverse, and horizontal faults with different attitudes in water-rich tunnels induced by earthquakes / overweights and three-dimensional ground stresses changing with depth, realizing physical tests for activating faults with different attitudes under true three-dimensional stress-water-rich-earthquake / creep-slip-overweight conditions, and capable of simulating the catastrophic processes of normal, reverse, and horizontal faults.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical engineering and test equipment, and particularly to a centrifuge test equipment and method for earthquake / creep-induced activation of complex faults in tunnels. Background Art

[0002] In recent years, the focus of infrastructure construction in China has gradually shifted to the western and southwestern regions. The geological conditions in these regions are complex and changeable. During the construction of tunnels, some geological tectonically active areas will be traversed, and some even need to pass through faults with seismic activities. A large number of national major projects such as the Pinglu Canal are distributed in mountainous areas with active tectonics and developed faults. The route often has to cross active faults and has a large buried depth at the same time. Fault creep refers to the aseismic sliding with a slow rate that occurs in natural tectonic faults. Therefore, studying earthquake / creep-induced activation of complex faults in water-rich tunnels has become an important scientific topic. During an earthquake, the stress state in the earth's crust will change rapidly, resulting in fault sliding and creep, which in turn affects the stability and safety of tunnels. Especially in water-rich areas, the role of groundwater will further exacerbate the interaction between the tunnel and the fault, making the problem more complex.

[0003] At present, the research on earthquake / creep-induced activation of complex faults in water-rich tunnels mainly relies on numerical simulation and theoretical analysis. However, these methods often cannot fully reflect the complexity and nonlinear characteristics in actual engineering. Therefore, the test results have certain limitations and uncertainties. There are many limitations in traditional test equipment and methods for simulating the seismic environment and tunnel structure. Traditional centrifuge equipment can only simulate the activation of faults with a certain specific occurrence. There is a lack of equipment that can simulate three-dimensional in-situ stress, overweight, and groundwater occurrence environment and the coupling conditions of different fault occurrences that can induce fault slip; there is a lack of equipment that can simulate the activation of different fault occurrences such as normal / reverse faults and horizontal faults with different fault dips and other fault occurrences under the action of three-dimensional in-situ stress, seismic force, and groundwater occurrence environment; the traditional tunnel surface force loading experimental system cannot simulate the differences in tunnel disasters caused by different principal stress directions at different depths, and the existing equipment currently cannot simulate the response of tunnels under a multi-field coupling environment of true three-dimensional stress-water-rich-earthquake / creep-overweight. Therefore, developing a test equipment and method that can simulate the activation of complex faults in water-rich tunnels under a real earthquake / creep environment is of great significance for improving the stability and safety of tunnel engineering. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention provides a centrifuge test equipment and method for earthquake / creep-induced activation of complex faults in tunnels, which can be used to carry out centrifuge tests on earthquake / creep-induced activation of complex faults in water-rich tunnels indoors, and realize the test simulation of tunnel specimens under a multi-field coupling environment of true three-dimensional stress-water-rich-earthquake-overweight.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A centrifuge test device for activating complex faults in tunnels induced by earthquakes / creep-slip, comprising an overweight loading system, an earthquake wave loading system, a true three-way loading device for complex fault tunnels, a physical model of a composite lining fault tunnel, and a comprehensive deformation-stress-vibration monitoring system. The overweight loading system includes a centrifuge main body, a test hanging basket, and counterweights. The earthquake wave loading system includes a lower vibration table base, a lower exciter, lower vibration table linear guide rails and sliders, an upper vibration table base, an upper exciter, upper vibration table linear guide rails and sliders, a vibration table surface, and a stop block. The true three-way loading device for complex fault tunnels includes a main frame, a top cover, an oil cylinder, an internal pressure-bearing sealing frame, a pressing head, and a backing plate. The physical model of the composite lining fault tunnel includes a tunnel specimen, a lining, a sheath, and an internal lining plugging. The comprehensive deformation-stress-vibration monitoring system includes embedded optical fibers, water pressure cells, pressure cells, and vibration wave monitors;

[0007] The centrifuge main body provides an overweight centrifugal force through high-speed rotation. The test hanging basket is installed on both sides of the centrifuge main body and has two states: horizontal and vertical. The counterweights and the vibration table are respectively installed on two test hanging baskets;

[0008] The earthquake wave loading system consists of two vibration tables. The vibration table base of the lower vibration table is fixed on the test hanging basket of the centrifuge. The lower exciter is installed and fixed on the lower vibration table base and is in contact with the upper vibration table base at both ends. The lower vibration table linear guide rails and sliders are installed and fixed on the lower vibration table base. One end of the lower vibration table linear guide slider is installed on the lower vibration table linear guide rails, and the other end is installed and fixed on the lower part of the upper vibration table base. The vibration table base of the upper vibration table is connected to the vibration table surface of the lower vibration table through the lower vibration table linear guide. The upper exciter is installed and fixed on the upper vibration table base and is in contact with the upper vibration table surface at both ends. The upper vibration table linear guide rails and sliders are installed and fixed on the upper vibration table base. One end of the upper vibration table linear guide slider is installed on the upper vibration table linear guide rails, and the other end is installed and fixed on the lower part of the upper vibration table surface. The upper vibration table surface is connected to the upper vibration table base through the upper vibration table linear guide. The upper vibration table surface is connected to the true three-way loading device for complex fault tunnels;

[0009] The main frame is installed on the vibrating table surface of the upper vibrating table, and the top cover is installed above the main frame, jointly forming an installation space for the internal sealed frame; the oil cylinders are installed and fixed in the reserved holes of the main frame and the top cover, with 16 oil cylinders installed in all directions, and the oil cylinders are connected to an external controller. The internal pressure-sealed frame is installed in the space formed by the external frame to form a sealed specimen placement space. The pressure head is installed and fixed in the reserved hole of the internal pressure seal and is connected to the oil cylinder. The cushion plate is installed in the internal pressure-sealed frame in contact with the tunnel specimen;

[0010] The tunnel specimen is a scaled-down model of a simulated tunnel with a fault installed in the internal pressure-sealed frame. The lining is installed in the tunnel specimen closely attached to the tunnel specimen. The sheath is installed in the tunnel closely attached to the lining. The inner lining plug is installed in the space formed by the sheath to form a sealed space with the sheath to isolate the internal water from the external water. Wireless sensors are installed between the tunnel specimen, the lining, the sheath, and the inner lining plug. A monitoring camera is installed inside the inner lining plug.

[0011] The deformation-stress-vibration comprehensive monitoring system monitors the deformation, stress, and response under vibration waves of the composite lining fault tunnel physical model.

[0012] The embedded optical fibers are installed in all directions in the tunnel specimen and between the layers of the composite lining. The water pressure cell is placed between the internal pressure-sealed frame and the composite lining fault tunnel physical model. The pressure cell is installed between the oil cylinder and the pressure head. The vibration wave monitor is embedded in the tunnel specimen and installed between the layers of the composite lining.

[0013] A centrifuge test method for earthquake / creep-induced activation of complex faults in water-rich tunnels includes the following steps using the above earthquake / creep-induced tunnel complex fault activation centrifuge test equipment:

[0014] Step 1: Fabricate the tunnel specimen;

[0015] Step 2: Install the lining, sheath, deformation-stress-vibration comprehensive monitoring system, and monitoring camera into the tunnel specimen. After injecting an appropriate amount of water into the space formed by the sheath, install the inner lining plug on both sides of the sheath to form a composite lining fault tunnel physical model, ensuring that the inner lining plug completely seals the tunnel;

[0016] Step 3: Use a lifting device to load the composite lining fault tunnel physical model into the internal sealed frame, and select a suitable cushion plate to ensure that the fault dip angle of the composite lining fault tunnel physical model meets the test requirements after being loaded into the internal sealed frame;

[0017] Step 4: Inject water into the internal pressure-bearing sealing frame to tightly cover the top plate of the internal pressure-bearing sealing frame, closely contact the pressure head with the physical model of the composite-lined fault tunnel, and check the sealing performance of the internal pressure-bearing frame;

[0018] Step 5: Tightly cover the top cover of the external frame and ensure that the upper oil cylinder is connected to the upper pressure head of the internal sealing frame;

[0019] Step 6: If simulating the activation phenomenon of the normal and reverse faults of the water-rich tunnel induced by earthquake and three-dimensional in-situ stress, the following steps can be adopted:

[0020] a. Start the oil cylinder on the true triaxial loading device for the complex fault tunnel to apply preloading to the physical model of the composite-lined fault tunnel;

[0021] b. Read the data of the deformation-stress-vibration integrated monitoring system and the monitoring camera, and judge whether the wireless sensors and the monitoring camera are working properly;

[0022] c. Apply confining pressure. Apply the same confining pressure on the upper and lower sides through the upper and lower oil cylinders, and apply confining pressure that increases sequentially from top to bottom due to different depths in other directions;

[0023] d. After applying the confining pressure, observe the creep-sliding condition of the physical model of the composite-lined fault tunnel. After a period of time, start the exciter of the shaking table, and make the tabletop of the shaking table show high-frequency vibration through the exciter. The tabletop of the shaking table applies seismic waves to the physical model of the composite-lined fault tunnel to realize the activation of the normal and reverse faults of the water-rich tunnel induced by earthquake and three-dimensional in-situ stress;

[0024] Step 7: If simulating the activation phenomenon of the horizontal fault of the water-rich tunnel induced by overweight and three-dimensional stress, the following steps can be adopted:

[0025] a. Start the oil cylinder on the true triaxial loading device for the complex fault tunnel to apply preloading to the physical model of the composite-lined fault tunnel. The preloading should be greater than that in Step 7 to prevent the overall sliding of the physical model of the composite-lined fault tunnel during the test of the centrifuge;

[0026] b. Apply confining pressure according to the test plan;

[0027] c. After applying the confining pressure, read the data of the deformation-stress-vibration integrated monitoring system and the monitoring camera, and judge whether the wireless sensors and the monitoring camera are working properly;

[0028] d. Start the centrifuge and apply a rotational speed within 10g to observe whether there are potential safety hazards in the test;

[0029] e. Slowly increase the rotational speed of the centrifuge to the target speed to realize the activation of the horizontal fault of the water-rich tunnel induced by overweight and three-dimensional stress;

[0030] Step 8: After the physical model of the tunnel with a composite lining and a fault reaches the expected test condition or fails, the experiment ends. First, stop the seismic table and the centrifuge, reduce the pressure to zero, turn off the centrifuge and the shaking table, turn off the true triaxial loading device for the complex fault tunnel, and repair the equipment.

[0031] Step 9: Analyze and process the detection data recorded by the deformation-stress-vibration integrated monitoring system and the monitoring cameras.

[0032] The beneficial effects of the present invention are as follows:

[0033] The present invention can simulate a tunnel specimen with a water-rich fault under a three-dimensional stress state. By adjusting the pressure on the upper and lower sides of the tunnel specimen, the fault of the tunnel specimen can be activated, and further, the tunnel specimen can generate creep along the fault, so as to study the influence of tunnel fault creep on the tunnel and the lining. The water-rich tunnel specimen with a fault of the present invention can be activated by the seismic force generated by the shaking table under the action of three-dimensional stress, so as to simulate the extrusion damage of the lining caused by the slip of the tunnel specimen and the influence of water disasters. The present invention can simulate the creep failure of the fault of the tunnel specimen under the overweight action generated by the high-speed rotation of the centrifuge. The present invention can realize the activation simulation test of faults with different attitudes, and can realize the creep simulation test of normal and reverse faults and horizontal faults. The present invention can simulate the influence of water disasters caused by fault creep on the lining structure in the tunnel under the condition of water covering, as well as the response of the lining and the surrounding rock under the activation of multi-field coupling under the water-rich condition. Through the multi-field coupling of true three-dimensional stress-water-rich-earthquake-overweight, etc., the present invention highly restores the real environment of the tunnel specimen in the laboratory, which is of great significance for improving the stability and safety of tunnel engineering.

[0034] Other features and advantages of the present invention will be partially described in detail in the following specific implementation manners. Brief Description of the Drawings

[0035] Figure 1 It is the overall structure diagram of the centrifuge test equipment for activating complex faults in tunnels induced by earthquakes / creep of the present invention;

[0036] Figure 2 It is the combined structure diagram of the seismic wave loading system and the true triaxial loading device for the complex fault tunnel of the centrifuge test equipment for activating complex faults in tunnels induced by earthquakes / creep of the present invention;

[0037] Figure 3 It is the half-sectional view of the combined structure of the seismic wave loading system and the true triaxial loading device for the complex fault tunnel of the centrifuge test equipment for activating complex faults in tunnels induced by earthquakes / creep of the present invention;

[0038] Figure 4The front sectional view of the combined structure of the seismic wave loading system and the true triaxial loading device for the complex fault tunnel in the centrifuge test equipment induced by earthquake / creep of the present invention;

[0039] Figure 5 The side sectional view of the combined structure of the seismic wave loading system and the true triaxial loading device for the complex fault tunnel in the centrifuge test equipment induced by earthquake / creep of the present invention;

[0040] Figure 6 The horizontal sectional view of the combined structure of the seismic wave loading system and the true triaxial loading device for the complex fault tunnel in the centrifuge test equipment induced by earthquake / creep of the invention;

[0041] Figure 7 The structural schematic diagram of the seismic wave loading system of the centrifuge test equipment for the activation of complex faults in tunnels induced by earthquake / creep of the present invention;

[0042] Figure 8 The sectional schematic diagram of the true triaxial loading device for the complex fault tunnel of the centrifuge test equipment for the activation of complex faults in tunnels induced by earthquake / creep of the present invention;

[0043] Figure 9 The structural schematic diagram of the internal sealing frame of the centrifuge test equipment for the activation of complex faults in tunnels induced by earthquake / creep of the present invention;

[0044] Figure 10 The structural diagram of the composite lining fault tunnel physical model of the centrifuge test equipment for the activation of complex faults in tunnels induced by earthquake / creep of the present invention;

[0045] Figure 11 The stress distribution diagram of the first embodiment of the present invention;

[0046] Figure 12 The stress distribution diagram of the second embodiment of the present invention.

[0047] 1 - Centrifuge main body, 2 - Test hanging basket, 3 - Counterweight, 4 - Lower vibration table base, 5 - Lower exciter, 6 - Lower vibration table linear guide rail slide, 7 - Lower vibration table linear guide rail slider, 8 - Upper vibration table base, 9 - Upper exciter, 10 - Upper vibration table linear guide rail slide, 11 - Upper vibration table linear guide rail slider, 12 - Vibration table surface, 13 - Main frame, 14 - Top cover, 15 - Oil cylinder, 16 - Inner pressure-bearing sealing frame, 17 - Pressure head, 18 - Cushion plate, 19 - Tunnel specimen, 20 - Lining, 21 - Sheath, 22 - Inner lining plugging, 23 - Stopper, Embedded optical fiber 24, Water pressure cell 25, Pressure cell 26, Vibration wave monitor 27. Detailed implementation manners

[0048] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0049] To solve the problems existing in the prior art, such as Figures 1-9 As shown, the present invention provides a centrifuge test device for earthquake / creep-induced complex fault activation in tunnels, including an overweight loading system, a seismic wave loading system, a true three-dimensional loading device for complex fault tunnels, a physical model of a composite lining fault tunnel, and a comprehensive deformation-stress-vibration monitoring system.

[0050] The overweight loading system includes a centrifuge main body 1, a test hanging basket 2, and counterweight blocks 3; the bottom of the centrifuge main body 1 is deeply buried underground, and provides an overweight centrifugal force through high-speed rotation for realizing overweight loading during the test; the test hanging basket 2 is installed on both sides of the centrifuge main body 1 and has a horizontal state and a vertical state for installing the overweight loading system and the physical model of the composite lining fault tunnel; the counterweight blocks 3 and the vibration table are respectively installed on the two test hanging baskets 2 for counterweight during the test.

[0051] The seismic wave loading system includes a lower shaking table base 4, a lower exciter 5, lower shaking table linear guide rails 6, lower shaking table linear guide sliders 7, an upper shaking table base 8, an upper exciter 9, upper shaking table linear guide rails 10, upper shaking table linear guide sliders 11, a shaking table surface 12, and a stop block 23. The lower shaking table base 4 is fixedly installed on a test hanging basket 3 of a centrifuge, and is used for installing and fixing other structures of the shaking table and a true triaxial loading device for a complex fault tunnel. The lower exciter 5 is installed on the lower shaking table base 4 and is restricted by the stop block 23 at both ends. The lower exciter 5 is connected to a control terminal and is used for generating and transmitting seismic waves in one direction. The lower shaking table linear guide rails 6 are fixedly installed on the lower shaking table base 4. One end of the lower shaking table linear guide slider 7 is installed on the lower shaking table linear guide rails 6, and the other end is fixedly installed on the lower part of the upper shaking table base 8. The lower shaking table linear guide rails 6 and the lower shaking table linear guide sliders 7 form a lower shaking table linear guide, which is used to connect the lower shaking table base 4 and the upper shaking table base 8, and is also used for transmitting seismic waves to the upper shaking table base 8 when the lower exciter 5 applies seismic waves. The upper shaking table base 8 is connected to the lower shaking table base 4 through the lower shaking table linear guide, and is used for transmitting seismic waves in one direction. The upper exciter 9 is installed on the upper shaking table base 8, and the upper exciter 9 is connected to the control terminal and is used for generating and transmitting seismic waves in one direction. The upper shaking table linear guide rails 10 are fixedly installed on the upper shaking table base 8. One end of the upper shaking table linear guide slider 11 is installed on the lower shaking table linear guide rails 10, and the other end is fixedly installed on the lower part of the upper shaking table surface 12. The shaking table surface 12 of the upper shaking table is connected to the main frame 13 of the true triaxial loading device for the complex fault tunnel.

[0052] The true triaxial loading device for complex fault tunnels includes a main frame 13, a top cover 14, an oil cylinder 15, an internal pressure-bearing sealing frame 16, a pressure head 17, and a backing plate 18. The main frame 13 is installed and fixed on the vibration table surface 8 of the upper vibration table, and is used to connect the overweight loading system and the true triaxial loading device for complex fault tunnels. The top cover 14 is installed on the upper side of the main frame 13, and together with the main frame 13 forms an installation space for the internal sealing frame. The oil cylinder 15 is installed and fixed in the reserved holes of the main frame 13 and the top cover 14. Sixteen oil cylinders 15 are installed and fixed on each side of the frame structure formed by the main frame 13 and the top cover, and the oil cylinder 15 is connected to the control terminal, and is used to apply loads in various directions during the test. When the oil cylinders 15 of the external frame apply loads, different oil cylinders 15 in the same direction can apply different forces, or can apply the same magnitude of force. The internal pressure-bearing sealing frame 16 is installed in the enclosed space formed by the main frame 13, and is used to install the physical model of the composite lining fault tunnel and achieve sealing under water-rich conditions. The pressure head 17 is installed in the reserved hole of the internal pressure seal 11 and is connected to the oil cylinder 15, and is used to apply the load generated by the oil cylinder 15 to the physical model of the composite lining fault tunnel. The backing plate 18 is installed in the internal pressure-bearing sealing frame 16 and is in contact with the tunnel specimen 19. By replacing the backing plate 18, the inclination angle of the tunnel specimen 19 can be changed, and by adjusting the position where the backing plate 18 is placed, the stress area of the tunnel specimen 19 can also be changed.

[0053] The physical model of the composite lining fault tunnel includes a tunnel specimen 19, a lining 20, a sheath 21, and an inner lining plug 22. The tunnel specimen 19 is a scaled-down model of an actual tunnel with a fault installed in the internal pressure-bearing sealing frame, and the scaling ratio of the model should be greater than the maximum overweight multiple generated by the centrifuge. The lining 20 is installed closely in the tunnel specimen against the tunnel specimen, and is used to maintain the stability of the tunnel specimen 19. The sheath 21 is installed closely in the tunnel specimen 19 against the lining 20, and is used to isolate the connection between the lining 20 and the external environment, reduce the corrosion degree of the lining 20 under water-rich conditions, and also maintain the stability of the tunnel specimen 19 to a certain extent. The inner lining plug 22 is installed in the space formed by the sheath 21 to form a sealed space with the sheath 21 to isolate the internal water and the external water, and is used to seal the tunnel opening of the tunnel specimen 19 to prevent the water injected into the internal sealing frame during the simulation of water-rich conditions from entering the tunnel and causing a large deviation between the test results and the actual project. Wireless sensors are installed between the tunnel specimen 19 and the lining 20, and between the lining 20 and the sheath 21, and are used to monitor the real-time condition of the physical model of the composite lining fault tunnel. A monitoring camera is installed in the sealed space formed by the sheath 21 and the inner lining plug 22, and is used to record the internal condition of the physical model of the composite lining fault tunnel during the test.

[0054] The deformation-stress-vibration comprehensive monitoring system monitors the deformation, stress, and response under vibration waves of the physical model of the composite lining fault tunnel; the deformation-stress-vibration comprehensive monitoring system includes embedded optical fibers 24, water pressure cells 25, pressure cells 26, and vibration wave monitors 27; the embedded optical fibers 24 are installed in all directions within the tunnel specimen 19 and between the lining layers 20 of the composite lining to measure the catastrophic process of the tunnel specimen 19 and the composite lining during the test; the water pressure cells 25 are placed between the internal pressure sealing frame 16 and the physical model of the composite lining fault tunnel to measure the two water pressures; the pressure cells 26 are installed between the oil cylinder 15 and the indenter 17 to monitor the pressure magnitude and creep displacement; the vibration wave monitors 27 are embedded within the tunnel specimen 19 and installed between the lining layers 20 of the composite lining to measure vibration waves.

[0055] The method of the first embodiment of the present invention is as follows:

[0056] A method for simulating the activation of a water-rich tunnel's normal and reverse faults induced by earthquake and three-dimensional in-situ stress uses the above earthquake / creep-induced tunnel complex fault activation centrifuge test equipment, and includes the following steps:

[0057] Step 1, fabricate a tunnel specimen 19 with a horizontal fault strike.

[0058] Step 2, install the lining 20, sheath 21, sensors, and monitoring cameras into the tunnel specimen 19 to form a physical model of the composite lining fault tunnel. After injecting an appropriate amount of water into the space formed by the sheath, seal the inner lining and install it on both sides of the sheath to ensure that the inner lining completely seals the tunnel.

[0059] Step 3, use a lifting device to load the physical model of the composite lining fault tunnel into the internal sealing frame, and select a suitable backing plate 18 so that the fault dip angle of the tunnel specimen 14 of the physical model of the composite lining fault tunnel meets the test requirements after being loaded into the internal sealing frame.

[0060] Step 4, after injecting water into the internal pressure sealing frame 16, tightly cover the top plate of the internal pressure sealing frame 16, and keep the indenter 17 in close contact with the physical model of the composite lining fault tunnel, and check the sealing performance of the internal pressure frame.

[0061] Step 5, tightly cover the top cover of the external frame, and ensure that the upper oil cylinder is connected to the upper indenter of the internal sealing frame.

[0062] Step 6, start the oil cylinder 15 on the complex fault tunnel true triaxial loading device to apply preloading to the physical model of the composite lining fault tunnel.

[0063] Step 7, read the data of the wireless sensors and monitoring cameras, and determine whether the wireless sensors and monitoring cameras are working properly.

[0064] Step 8: Apply confining pressure. The three-dimensional stress is as Figure 11 shown. The lateral shear force increases from top to bottom along the normal direction, and the normal stress is uniformly distributed, entering the accelerated creep stage;

[0065] Step 9: After applying the confining pressure, start the exciter 5 of the shaking table. The control terminal controls the shaking frequency of the shaking table to be 90 Hz. Through the exciter, high-frequency vibration appears on the tabletop of the shaking table. The tabletop 8 of the shaking table applies seismic waves to the physical model of the composite lining fault tunnel, realizing the activation of the normal and reverse faults of the water-rich tunnel induced under the action of simulated earthquake and three-dimensional ground stress;

[0066] Step 10: After the physical model of the composite lining fault tunnel reaches the expected test condition or is damaged, the experiment ends. Turn off the shaking table, reduce the pressure to zero, and repair the equipment for the next use;

[0067] Step 11: Analyze and process the detection data recorded by the sensors and monitoring cameras.

[0068] The method of the second embodiment of the present invention is as follows:

[0069] A method for simulating the activation phenomenon of horizontal faults in water-rich tunnels induced by overweight and three-dimensional stress. Using the above-mentioned centrifuge test equipment for activating complex faults in tunnels induced by earthquake / creep, it includes the following steps:

[0070] Step 1: Fabricate a tunnel specimen 19 with a normal fault;

[0071] Step 2: Install the lining 20, sheath 21, sensors, and monitoring cameras into the tunnel specimen 19 to form a physical model of the composite lining fault tunnel. After injecting an appropriate amount of water into the space formed by the sheath, seal the inner lining and install it on both sides of the sheath to ensure that the inner lining seal 22 completely seals the tunnel;

[0072] Step 3: Use a lifting device to load the physical model of the composite lining fault tunnel into the internal sealed frame, and select a suitable backing plate 18 to ensure that the fault dip angle of the tunnel 14 specimen meets the test requirements after the physical model of the composite lining fault tunnel is loaded into the internal sealed frame;

[0073] Step 4: After injecting water into the internal pressure-bearing sealed frame 16, tightly cover the top plate of the internal pressure-bearing sealed frame 16, and keep the pressure head 17 in close contact with the physical model of the composite lining fault tunnel, and check the sealing performance of the internal pressure-bearing frame;

[0074] Step 5: Tightly cover the top cover of the external frame and ensure that the upper oil cylinder is connected to the upper pressure head of the internal sealed frame;

[0075] Step 6: Start the oil cylinder 15 on the true triaxial loading device for the complex fault tunnel to apply preloading to the physical model of the composite lining fault tunnel. The preloading should be greater than that in Step 7 to prevent the overall sliding of the physical model of the composite lining fault tunnel during the test of the centrifuge.

[0076] Step 7: Apply confining pressure according to the test requirements. As Figure 12 shown, the lateral stress increases from top to bottom along the normal direction, and shear force is applied in the normal direction.

[0077] Step 8: After applying the confining pressure, start the centrifuge main body 1 and apply a rotational speed within 10g to observe whether there are potential safety hazards in the test.

[0078] Step 9: Read the data of the wireless sensors and monitoring cameras to determine whether the wireless sensors and monitoring cameras are working properly.

[0079] Step 10: Apply a rotational acceleration of 80g to the centrifuge main body 1 according to the test plan to simulate the activation of the fault in the tunnel specimen 19 and the appearance of creep along the fault.

[0080] Step 11: Slowly increase the rotational speed of the centrifuge main body 1 to the target speed to achieve the activation of the horizontal fault in the water-rich tunnel induced by simulated overweight and three-dimensional stress.

[0081] Step 13: After the physical model of the composite lining fault tunnel reaches the expected test condition or is damaged, the experiment ends. Reduce the pressure to zero, turn off the centrifuge, and repair the equipment.

[0082] Step 14: Analyze and process the detection data recorded by the sensors and monitoring cameras.

[0083] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A centrifuge test device for activating complex faults in a water-rich tunnel induced by earthquake / creep, characterized in that, The device includes an overweight loading system, a seismic wave loading system, a true triaxial loading device for complex fault tunnels, a physical model of a composite lining fault tunnel, and a comprehensive deformation-stress-vibration monitoring system; the overweight loading system includes a centrifuge main body, a test hanging basket, and counterweight blocks; the seismic wave loading system includes a lower vibration table base, a lower exciter, lower vibration table linear guide rails and sliders, an upper vibration table base, an upper exciter, upper vibration table linear guide rails and sliders, a vibration table surface, and a stop block; the true triaxial loading device for complex fault tunnels includes a main frame, a top cover, an oil cylinder, an internal pressure-bearing sealing frame, a pressure head, and a backing plate; the physical model of the composite lining fault tunnel includes a tunnel specimen, a lining, a sheath, and an internal lining plug; the comprehensive deformation-stress-vibration monitoring system includes embedded optical fibers, water pressure cells, pressure cells, and vibration wave monitors; the centrifuge test equipment for activating complex faults in a water-rich tunnel induced by earthquakes / creep slides activates the fault of the tunnel specimen by adjusting the pressure magnitudes on the upper and lower sides of the tunnel specimen, and further causes the tunnel specimen to creep along the fault; the centrifuge main body provides an overweight centrifugal force through high-speed rotation; the test hanging basket is installed on both sides of the centrifuge main body; the counterweight blocks and the vibration table are respectively installed on the two test hanging baskets; the vibration table base of the lower vibration table is fixed on the test hanging basket of the centrifuge; the lower exciter is installed and fixed on the lower vibration table base and is in contact with the upper vibration table base at both ends; the lower vibration table linear guide rails are installed and fixed on the lower vibration table base; one end of the lower vibration table linear guide slider is installed on the lower vibration table linear guide rails, and the other end is installed and fixed on the lower part of the upper vibration table base; the vibration table base of the upper vibration table is connected to the vibration table surface of the lower vibration table through the lower vibration table linear guide; the upper exciter is installed and fixed on the upper vibration table base and is in contact with the upper vibration table surface at both ends; the upper vibration table linear guide rails are installed and fixed on the upper vibration table base; one end of the upper vibration table linear guide slider is installed on the upper vibration table linear guide rails, and the other end is installed and fixed on the lower part of the upper vibration table surface; the upper vibration table surface is connected to the upper vibration table base through the upper vibration table linear guide; the upper vibration table surface is connected to the true triaxial loading device for complex fault tunnels.

2. The centrifuge test equipment for activating complex faults in water-rich tunnels induced by earthquakes / creep as claimed in claim 1, wherein: The main frame is installed on the vibration table surface; the top cover is installed above the main frame; the oil cylinders are installed and fixed in the reserved space between the main frame and the top cover; multiple oil cylinders are installed on each side; the internal pressure-bearing sealing frame is installed in the space formed by the outer frame to form a sealed specimen placement space; the pressure head is installed and fixed in the reserved hole of the internal pressure-bearing seal and is connected to the oil cylinder; the backing plate is installed in contact with the tunnel specimen in the internal pressure-bearing seal frame.

3. The centrifuge test equipment for activating complex faults in water-rich tunnels induced by earthquakes / creep according to claim 1, characterized in that: The tunnel specimen is a geometrically scaled-down model of a simulated tunnel with a fault installed within an internally pressurized sealed frame; the lining is installed closely within the tunnel specimen against the tunnel specimen; the sheath is installed within the tunnel closely against the lining; the inner lining plug is installed within the space formed by the sheath to form a sealed space isolating the inner water from the outer water; wireless sensors are installed between the tunnel specimen and the lining, and between the lining and the sheath; a monitoring camera is installed within the inner lining plug.

4. The centrifuge test equipment for activating complex faults in a water-rich tunnel induced by earthquake / creep as claimed in claim 1, wherein: The deformation-stress-vibration integrated monitoring system monitors the deformation, stress, and response under vibration waves of the physical model of the composite lining fault tunnel; the embedded optical fibers are installed in all directions within the tunnel specimen and between the various lining layers of the composite lining; the water pressure cell is placed between the internally pressurized sealed frame and the physical model of the composite lining fault tunnel; the pressure cell is installed between the oil cylinder and the pressure head; the vibration wave monitor is embedded within the tunnel specimen and installed between the various lining layers of the composite lining.

5. The experimental method of the centrifuge test equipment for the activation of complex faults in water-rich tunnels induced by earthquakes / creep, as described in claim 1, is characterized in that, It includes the following steps: Step 1, fabricate the tunnel specimen; Step 2, install the lining, sheath, sensors, and monitoring camera into the tunnel specimen, inject an appropriate amount of water into the space formed by the sheath, and then install the inner lining plug on both sides of the sheath to form a physical model of the composite lining fault tunnel, ensuring that the inner lining plug completely seals the tunnel; Step 3, use a lifting device to install the physical model of the composite lining fault tunnel into the internal sealed frame, and select a suitable backing plate to ensure that the fault dip angle of the physical model of the composite lining fault tunnel meets the test requirements after being installed in the internal sealed frame; Step 4, inject water into the internally pressurized sealed frame, tighten the top plate of the internally pressurized sealed frame, and make the pressure head in close contact with the physical model of the composite lining fault tunnel, and check the sealing performance of the internal pressure frame; Step 5, tighten the top cover of the external frame, and ensure that the upper oil cylinder is connected to the upper pressure head of the internal sealed frame; Step 6, if simulating the activation phenomenon of the normal and reverse faults of a water-rich tunnel induced by simulated earthquake and three-dimensional in-situ stress, adopt the following steps: a. Start the oil cylinder on the true triaxial loading device to apply preloading to the physical model of the composite lining fault tunnel; b. Read the data of the wireless sensors and the monitoring camera to determine whether the wireless sensors and the monitoring camera are working properly; c. Apply confining pressure, apply the same confining pressure on the upper and lower sides through the upper and lower oil cylinders, and apply confining pressure that increases sequentially from top to bottom in other directions due to different depths; d. After applying the confining pressure, observe the creep-sliding situation of the physical model of the composite lining fault tunnel. After a period of time, start the exciter of the shaking table, and make the tabletop of the shaking table show high-frequency vibration through the exciter. The tabletop of the shaking table applies seismic waves to the physical model of the composite lining fault tunnel to achieve the activation of the normal and reverse faults of the water-rich tunnel induced by simulated earthquake and three-dimensional in-situ stress; Step 7, if simulating the activation phenomenon of the horizontal fault of a water-rich tunnel induced by simulated overweight and three-dimensional stress, adopt the following steps: a. Start the oil cylinder on the true triaxial loading device to apply preloading to the physical model of the composite lining fault tunnel to prevent the overall sliding of the physical model of the composite lining fault tunnel during the test of the centrifuge; b. Apply confining pressure according to the test plan; c. After applying the confining pressure, read the data of the wireless sensors and monitoring cameras to determine whether the wireless sensors and monitoring cameras are working properly; d. Start the centrifuge and apply a rotational speed within 10g to observe whether there are any potential safety hazards in the experiment; e. Slowly increase the rotational speed of the centrifuge to the target speed to simulate the activation of the horizontal fault in the water-rich tunnel induced by overweight and three-dimensional stress; Step 8: After the physical model of the composite lining fault tunnel reaches the expected test condition or fails, the experiment ends. First, stop the seismic table and the centrifuge, reduce the pressure to zero, turn off the centrifuge and the shaking table, turn off the true triaxial loading device, and repair the equipment; Step 9: Analyze and process the detection data recorded by the wireless sensors and monitoring cameras.

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