Vibration table test device and test method for seismic dynamic response of fault-crossing mountain tunnel

Abstract

The invention discloses a vibration table test device and a test method for seismic dynamic response of a fault-crossing mountain tunnel. The test device comprises an earthquake simulation vibration table, a laminated shear model box, surrounding rock, a fault fracture zone, a tunnel model and a monitoring and measuring system. Wherein the earthquake simulation vibration table inputs earthquake waves and provides earthquake power; the bottom of the laminated shear model box is fixed on the earthquake simulation vibration table, and the laminated shear model box is filled with surrounding rocks and fault fracture zones; the fault dip angle is 90 degrees, and left and right surrounding rock elevations are inconsistent; the tunnel model comprises a non-shock-absorption layer and a shock-absorption layer which are buried in the surrounding rock in the model box in parallel and perpendicularly intersect with a fault fracture zone. The monitoring and measuring system is used for measuring tunnel acceleration and strain, surrounding rock acceleration, fault acceleration and the like in the seismic oscillation process. The test device can simulate the dynamic response process of the fault-crossing mountain tunnel under the action of an earthquake, and time evolution and spatial distribution characteristics of tunnel earthquake response are determined.

Description

Technical Field

[0001] The present invention relates to the field of tunnel engineering, in particular to a tunnel shaking table test, and specifically to a shaking table test device and a test method for a cross-fault mountain tunnel earthquake dynamic response. Background Art

[0002] In recent years, in order to promote economic and social development and facilitate people's travel, my country has built a large number of cross-regional high-speed railways. According to statistics, by the end of 2022, my country's high-speed railway operating mileage has reached 42,000 kilometers, of which the total length of tunnel sections is 7,032 kilometers, ranking first in the world, and will continue to grow at a relatively fast pace in the future.

[0003] At the same time, my country is located between the Pacific Rim Seismic Belt and the Eurasian Seismic Belt. Due to the compression of the plates, the seismic fault zones in the country are very active. A large number of built and planned high-speed rail tunnels are located in the southwest, northwest, north China and other regions with frequent seismic activities. According to records, there are many cases of tunnel damage caused by earthquakes, such as arch collapse, side wall misalignment, and invert arch uplift. Earthquake damage survey data also show that the cross-fault section is the most severely damaged part of the tunnel. It can be seen that underground tunnels, especially cross-fault tunnels, still face major safety risks under the action of earthquakes.

[0004] High-speed railway tunnels have the characteristics of large cross-section, long distance, and high construction and operation standards. Earthquakes are sudden, destructive, and have a wide impact. Once a high-speed railway tunnel is damaged in an earthquake, it will not only cause inconvenience to the daily travel of the people, but also have a serious adverse impact on the normal operation of the national railway transportation network. Therefore, it is of great significance to study the seismic response characteristics of cross-fault tunnels, reveal the tunnel earthquake damage mechanism, and explore tunnel seismic control methods.

[0005] As an effective method to study the seismic response of cross-fault tunnels, the shaking table test has been fruitfully studied in recent years. However, by summarizing the existing research work, it is found that there are still the following deficiencies:

[0006] (1) The model box is basically a rigid model box, whose fixed boundary will lead to obvious seismic wave reflection phenomenon and cannot meet the boundary requirements of the infinite domain of rock and soil mass;

[0007] (2) Faults are mainly normal faults or reverse faults, and the consideration of horizontal strike-slip faults is very limited;

[0008] (3) The ground surface in the model is basically assumed to be a horizontal plane, without considering the influence of terrain, which is often quite different from the actual mountain tunnel engineering scenario.

[0009] Therefore, it is urgent to design a shaking table test device and test method for the seismic response of cross-fault mountain tunnels that can overcome the rigid boundary effect of the model box and realize the simulation of horizontal strike-slip faults and terrain differences, so as to improve the disaster reduction and prevention capabilities of high-speed railway tunnels in my country's high-intensity earthquake zones and ensure the safe construction and operation of high-speed railway tunnels. Summary of the invention

[0010] The purpose of the present invention is to provide a shaking table test device and test method for the earthquake dynamic response of a cross-fault mountain tunnel in view of the existing deficiencies, so as to provide a test platform for studying the earthquake response characteristics and earthquake damage mechanism of the cross-fault tunnel.

[0011] The present invention adopts the following technical solutions to solve the above technical problems:

[0012] In a first aspect, the present invention provides a shaking table test device for earthquake dynamic response of a cross-fault mountain tunnel, comprising an earthquake simulation shaking table, a laminated shear model box, surrounding rock, a fault fracture zone, a tunnel model and a monitoring and measurement system.

[0013] The laminated shear model box is fixedly mounted on the earthquake simulation vibration table; the earthquake simulation vibration table is used to input earthquake waves to drive the laminated shear model box to vibrate;

[0014] The surrounding rock and the fault fracture zone are filled in the laminated shear model box, and the tunnel model is buried in the surrounding rock and intersects with the fault fracture zone;

[0015] The monitoring and measuring system is used to collect data of the surrounding rock, fault fracture zone and tunnel model;

[0016] The laminated shear model box has an opening at the top, and its bottom is fixed on an earthquake simulation vibration table. Sponges and rubber films are sequentially pasted on the inner wall of the box.

[0017] The effect produced by the above settings: The test device provided by the present invention drives the laminated shear model box to vibrate through the earthquake simulation vibration table to simulate the earthquake, uses the surrounding rock, fault fracture zone, and tunnel model to simulate the cross-fault mountain tunnel, and the monitoring and measurement system collects data, thereby providing a test platform for studying the seismic response characteristics and earthquake damage mechanism of the cross-fault tunnel. In addition, the laminated shear model box with sponge and rubber film sequentially pasted on the inner wall of the box is a flexible model box, which can effectively overcome the boundary effect of the traditional rigid model box, realize the simulation of the vibration shear deformation of the rock and soil body, and meet the requirements of the infinite domain of the site.

[0018] Preferably, the surrounding rock and fault fracture zone are the constraint materials of the tunnel and also the propagation medium of seismic waves. The selection and preparation method of similar materials are determined according to the properties and similarity ratio of the prototype material, and are loaded into the model box after preparation.

[0019] The surrounding rock comprises an upper plate surrounding rock and a lower plate surrounding rock respectively arranged on both sides of the laminated shear model box; the fault fracture zone is arranged through and between the upper plate surrounding rock and the lower plate surrounding rock.

[0020] Preferably, the fault dip angle of the fault fracture zone is 90°.

[0021] The effect of the above settings: The fault dip angle of 90° is to simulate the fault type of horizontal strike-slip fault.

[0022] Preferably, the surface elevations of the upper wall surrounding rock and the lower wall surrounding rock on both sides of the fault fracture zone are inconsistent.

[0023] The effect of the above settings: The inconsistent elevations are to simulate the real mountain slope environment.

[0024] Preferably, the earthquake simulation vibration table is used to input seismic waves and provide seismic power, and the loading direction is consistent with the direction of the fault fracture zone and perpendicular to the direction of the tunnel.

[0025] Preferably, the tunnel model comprises two tunnels, one without a shock-absorbing layer and the other with a shock-absorbing layer, which are arranged in parallel, and each tunnel is assembled by bonding a plurality of segments.

[0026] The effect of the above settings: Two tunnels with and without a shock-absorbing layer are set up in order to investigate the shock-absorbing effect of the shock-absorbing layer on the strike-slip fault.

[0027] Preferably, the tunnel model is a scaled model, the model size and material are determined according to the prototype tunnel and the similarity ratio, and the manufactured tunnel is buried in the surrounding rock inside the model box and intersects the fault fracture zone vertically.

[0028] The effect produced by the above settings is that the fault fracture zone is parallel to the vibration direction, and the tunnel direction intersects the fault vertically in order to simulate the impact of the dislocation of the rock and soil on both sides of the fault on the tunnel.

[0029] Preferably, the monitoring and measuring system comprises a sensor, a data acquisition device and a computer, wherein the sensor is connected to the data acquisition device, the data acquisition device is connected to the computer, and the computer is loaded with a control system for data acquisition, analysis and management.

[0030] Preferably, the sensor comprises an accelerometer and a strain gauge.

[0031] The accelerometers are arranged on the invert in each tunnel segment, arranged vertically at intervals in the surrounding rock and fault fracture zone, and arranged vertically at intervals on the side wall of the model box parallel to the vibration direction;

[0032] The accelerometers installed in the tunnel are used to collect the acceleration response of the tunnel during the earthquake motion;

[0033] The accelerometers installed in the surrounding rock and fault fracture zone are used to collect the acceleration response at different depths in the surrounding rock and fault fracture zone to study the propagation law of seismic waves;

[0034] The accelerometers installed on the side walls of the model box are used to collect the acceleration responses of the box at different elevations.

[0035] The strain gauge is attached to the tunnel and is used to collect the deformation of the tunnel during the earthquake.

[0036] The effects of the above settings are as follows: the accelerometers on the model box are arranged on the bottom plate and the side walls of the box at the same height as the accelerometers in the tunnel and surrounding rock. They are mainly used to verify the role of the shear model box in reducing boundary effects and to clarify the dynamic deformation law of the model box.

[0037] Preferably, the accelerometers are vertically spaced apart in the surrounding rock and the fault fracture zone at a vertical spacing of 250 mm.

[0038] The strain gauges are respectively pasted on the vault, the invert, the left arch waist and the right arch waist in each tunnel segment, and one strain gauge is pasted at each position along the tunnel axis and perpendicular to the tunnel axis.

[0039] In a second aspect, the present invention provides a test method for a shaking table test device for earthquake dynamic response of a cross-fault mountain tunnel, based on the test device described in the first aspect, comprising the following steps:

[0040] S1: Design the test, determine the test similarity ratio, make the shear model box and tunnel model, prepare similar materials of surrounding rock and fault fracture zone, and formulate the test loading system and monitoring and measurement plan;

[0041] S2: Fix the laminated shear model box on the table of the earthquake simulation shaking table, and stick the sponge and rubber film on the inner wall of the model box in sequence;

[0042] S3: According to the test plan, the surrounding rock and fault fracture zone materials are filled layer by layer in the model box and the tunnel model is buried;

[0043] S4: Install and connect the monitoring and measurement system to ensure that the monitoring and measurement system can work normally;

[0044] S5: Conduct white noise frequency sweep test to obtain the dynamic characteristics of the installed test device;

[0045] S6: Conduct a shaking table test on the earthquake dynamic response of a cross-fault mountain tunnel. Select earthquake waves with different spectral characteristics according to the test loading system. The shaking table applies earthquake loads by inputting acceleration amplitudes from small to large. At the same time, according to the monitoring and measurement plan, collect data on the surrounding rock, fault fracture zone and tunnel model through the monitoring and measurement system.

[0046] The advantages and technical effects of the present invention are:

[0047] 1) The laminated shear model box in the test device of the present invention is a flexible model box, which can effectively overcome the boundary effect of the traditional rigid model box, realize the simulation of the vibration shear deformation of the rock and soil body, and meet the requirements of the infinite domain of the site.

[0048] 2) The test device and test method of the present invention can simulate the relative displacement of the surrounding rocks on both sides of the fault fracture zone under the action of an earthquake, and can consider the influence of the terrain, shock-absorbing measures, etc. on the seismic response of the tunnel.

[0049] 3) The tunnel model, surrounding rock, and fault fracture zone in the test device of the present invention are designed and manufactured in a similar ratio according to actual structural characteristics, size specifications, and performance parameters, and can objectively reflect the seismic response characteristics of a cross-fault mountain tunnel.

[0050] 4) The test device and test method of the present invention can obtain the acceleration, strain and other data of the tunnel under different earthquake spectrum characteristics and amplitude conditions. By analyzing the data, the time evolution and spatial distribution characteristics of the tunnel seismic response can be clarified, the influence of faults, terrain and seismic wave characteristics on the tunnel seismic response can be revealed, the shock-absorbing effect of the shock-absorbing layer on the cross-fault tunnel can be evaluated, and a reference can be provided for the seismic design and shock-absorbing control of the coupling system. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic diagram of the connection of the components in the test device of the present invention;

[0052] Figure 2 It is a schematic diagram of the tunnel model in the present invention;

[0053] Figure 3 It is a schematic diagram of the plane layout of the monitoring section in the present invention;

[0054] Figure 4 It is a schematic diagram of the arrangement of monitoring points in the monitoring section of a tunnel without a shock-absorbing layer in the present invention;

[0055] Figure 5 It is a schematic diagram of the arrangement of monitoring points in the monitoring section of the tunnel with a shock-absorbing layer in the present invention;

[0056] Marked in the figure: 1-earthquake simulation shaking table, 2-laminated shear model box, 21-bolts, 22-sponge and rubber membrane, 3-surrounding rock, 31-hanging wall surrounding rock, 32-footwall surrounding rock, 4-fault fracture zone, 5-tunnel model, 51-tunnel without shock-absorbing layer, 52-tunnel with shock-absorbing layer, 521-shock-absorbing layer, 6-sensor, 61-accelerometer, 62-strain gauge, 7-data acquisition equipment, 8-computer. DETAILED DESCRIPTION

[0057] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0058] Embodiment 1:

[0059] like Figure 1 , Figure 2 As shown, this embodiment provides a vibration table test device for earthquake dynamic response of a cross-fault mountain tunnel, including an earthquake simulation vibration table 1, a laminated shear model box 2, surrounding rock 3, a fault fracture zone 4, a tunnel model 5, a sensor 6, a data acquisition device 7, and a computer 8.

[0060] The earthquake simulation vibration table 1 is used to input earthquake waves and provide earthquake power. The loading direction is consistent with the direction of the fault fracture zone 4 and perpendicular to the direction of the tunnel model 5.

[0061] The laminated shear model box 2 has an opening at the top, and its bottom is fixed to the surface of the earthquake simulation vibration table 1 by bolts 21 , and a sponge and a rubber film 22 are sequentially pasted on the inner wall of the box.

[0062] The surrounding rock 3 and the fault fracture zone 4 are the constraint materials of the tunnel model 5 and the propagation medium of the seismic wave. The selection and preparation method of the similar materials are determined according to the properties and similarity ratio of the prototype materials. After preparation, they are loaded into the model box. The inclination angle of the fault fracture zone 4 is 90°, and the surface elevations of the upper wall surrounding rock 31 and the lower wall surrounding rock 32 on the left and right sides of the fault fracture zone 4 are inconsistent.

[0063] The tunnel model 5 includes a tunnel without a shock-absorbing layer 51 and a tunnel with a shock-absorbing layer 52, which are arranged in parallel, and each tunnel is assembled by bonding a plurality of segments.

[0064] The tunnel model 5 is a scaled model, the model size and material are determined according to the prototype tunnel and the similarity ratio, and a plurality of tunnel segments are provided. The manufactured tunnel model 5 is buried in the surrounding rock 3 inside the model box and intersects the fault fracture zone 4 vertically.

[0065] The monitoring and measuring system includes a sensor 6, a data acquisition device 7 and a computer 8, wherein the sensor 6 is connected to the data acquisition device 7, the data acquisition device 7 is connected to the computer 8, and the computer 8 is equipped with a control system for data acquisition, classification, aggregation and management. The control system can use conventional test data automatic recording management software on the market.

[0066] The sensor 6 includes an accelerometer 61 and a strain gauge 62. The accelerometer 61 is arranged on the invert in each tunnel segment, arranged vertically at intervals in the surrounding rock 3 and the fault fracture zone 4, and arranged vertically at intervals on the side wall parallel to the vibration direction on the model box 2. The strain gauge 62 is respectively pasted on the vault, the invert, the left arch waist and the right arch waist in each tunnel segment, and one strain gauge is pasted at each position along the tunnel axis and perpendicular to the tunnel axis.

[0067] The test device can simulate the dynamic response process of a cross-fault mountain tunnel under the action of an earthquake, clarify the temporal evolution and spatial distribution characteristics of the tunnel's seismic response, reveal the influence of faults, topography, and seismic wave characteristics on the tunnel's seismic response, evaluate the shock-absorbing effect of the shock-absorbing layer on the cross-fault tunnel, and provide a reference for the seismic design and shock-absorbing control of mountain tunnels.

[0068] Specific test parameters:

[0069] like Figure 1 As shown in the figure, the size of the earthquake simulation shaking table used in the test is 6.0m×4.0m, and a unidirectional loading method is adopted. The loading direction is consistent with the fault direction and perpendicular to the tunnel direction.

[0070] like Figure 1 As shown in the figure, according to the size of the vibration table surface, the outer dimensions of the model box are designed to be 2.9m×2m×1.9m (length×width×height), and the inner net dimensions of the box are designed to be 2.7m×1.8m×1.9m. It is assembled by 16 layers of steel pipe frames, and each layer of the frame is welded from square steel pipes with a side length of 10cm.

[0071] Table 1 shows the experimental similarity relationship and similarity ratio. Taking length l, density ρ and elastic modulus E as the basic unknowns, considering the bearing capacity of the vibration table and the size of the model box, the similarity ratio of the experimental geometric dimensions is λ l =1 / 40, density similarity ratio is λ ρ =1 / 1.5, elastic modulus similarity ratio is λ E =1 / 1.5, other physical quantities are determined by these three quantities.

[0072] Table 1 Similarity relations and similarity ratios of various physical quantities

[0073]

[0074] In actual engineering, tunnel model 5 mainly passes through the IV grade surrounding rock area, and the surrounding rock density ρ=2.47g / cm 3 , internal friction angle φ = 53°, uniaxial compressive strength R c =9.5MPa. According to the similarity relationship in Table 1, the target parameters of the surrounding rock similar material must meet the following requirements: density ρ = 2.47g / cm 3 , internal friction angle φ = 53°, uniaxial compressive strength R c =0.24MPa. After investigation, the mixture of fly ash, river sand and engine oil was selected as the similar material of surrounding rock.

[0075] In actual engineering, the width of the fault fracture zone 4 is 20m. According to the size similarity ratio λ in Table 1 l=1 / 40, the width of the fault model is 0.5m, and the fault-similar material is loose gravel with a particle size of 1.0~1.5cm.

[0076] In actual engineering, the cross section of tunnel model 5 is a tricentric circle, the maximum width of the tunnel is about 15m, the maximum height is about 12.2m, the lining thickness is 0.8m, C40 concrete is used, the longitudinal length of the tunnel is 60m, deformation joints are set, the deformation joint spacing is 10m, and the joint width is 2cm. According to the size similarity ratio λ in Table 1 l =1 / 40, the tunnel model 5 is 375 mm wide, 305 mm high, 20 mm thick, and 1500 mm long in the longitudinal direction. It is made in 6 sections, each 250 mm long. The tunnel shock-absorbing layer is simulated by sponge and rubber film 22 with a thickness of 5 cm, which is wrapped around the outer wall of the tunnel model 5. Figure 2 shown.

[0077] like Figure 3 As shown, the tunnel 51 without a shock-absorbing layer is connected into a whole by epoxy resin anchoring glue, and a monitoring section (numbered I~VI) is set in the center of each segment, among which sections III and IV are located within the range of the fault fracture zone 4, sections I and II are located within the range of the surrounding rock 3 with higher terrain, sections V and VI are located within the range of the surrounding rock 3 with lower terrain, and monitoring section AA is set in the surrounding rock just above the tunnel axis. The tunnel with a shock-absorbing layer is connected into a whole by epoxy resin anchoring glue, and a monitoring section (numbered VII~XII) is set in the center of each segment, among which sections IX and X are located within the range of the fault, sections VII and VIII are located within the range of the surrounding rock with higher terrain, sections XI and XII are located within the range of the surrounding rock with lower terrain, and monitoring section BB is set in the surrounding rock just above the tunnel axis.

[0078] like Figure 4 As shown, in the tunnel 51 without a shock-absorbing layer, an accelerometer 61 (numbered A1 to A6) is provided at the invert in each segment, for a total of 6;

[0079] The resistance strain gauges 62 are respectively affixed to four positions of the outer arch crown, left arch waist, inverted arch and right arch waist of each segment. One strain gauge 62 (numbered Sijk, i=I~VI, j=1~4, k=1~2) is affixed to each position along the tunnel axis and perpendicular to the tunnel axis, for a total of 48 strain gauges.

[0080] In section AA, four accelerometers 61 (numbered A13 to A16) and three accelerometers 61 (numbered A17 to A19) are respectively set in the surrounding rock above the tunnel on the left and right sides of the fault, and three accelerometers 61 (numbered A27 to A29) are set from bottom to top in the fault above the tunnel, with a spacing of 250 mm between the accelerometers.

[0081] like Figure 5 As shown, in the tunnel 52 with a shock-absorbing layer, one accelerometer 61 (numbered A7~A12) is set at the invert in each segment, for a total of 6; resistance strain gauges 62 are respectively attached to the outer arch crown, left arch waist, invert, and right arch waist of each segment, and one strain gauge 62 (numbered Sijk, i=VII~XII, j=1~4, k=1~2) is attached to each position along the tunnel axis and perpendicular to the tunnel axis, for a total of 48. In the BB section, 4 accelerometers 61 (numbered A20~A23) and 3 accelerometers 61 (numbered A24~A26) are respectively set in the surrounding rock above the tunnel on the left and right sides of the fault, and 3 accelerometers 61 (numbered A30~A32) are set from bottom to top in the fault above the tunnel, and the spacing between the accelerometers 61 is 250 mm.

[0082] After the laminated shear model box 2, the tunnel model 5, the surrounding rock 3 and the similar materials of the fault fracture zone 4 are prepared, the model system is installed.

[0083] First, the laminated shear model box 2 is fixed to the surface of the earthquake simulation vibration table 1 by bolts 21, and sponges and rubber films 22 are sequentially pasted on the inner wall of the model box to reduce the boundary effect and prevent water and soil leakage.

[0084] Secondly, the stacked shear model box 2 is filled with 30cm thick surrounding rock 3 and fault fracture zone 4 materials to the tunnel bottom elevation, and then the tunnel without shock-absorbing layer 51 and the tunnel with shock-absorbing layer 52 are hoisted to the predetermined position respectively, and then the surrounding rock 3 and fault fracture zone 4 are filled in layers to the predetermined elevation. Figure 4 , Figure 5 In the monitoring scheme shown, an accelerometer 61 and a strain gauge 62 are set in the tunnel model, and an accelerometer 61 is set in the surrounding rock 3 and the fault fracture zone 4.

[0085] Then, the sensor 6, the data acquisition device 7 and the computer 8 are connected, and the performance of each sensor 6 and the control system is checked to ensure that they can all work normally.

[0086] Conduct white noise frequency sweep test, i.e. use white noise frequency sweep with amplitude less than or equal to 0.05g to obtain dynamic characteristics such as natural frequency and damping ratio of the installed model system;

[0087] A shaking table test of the earthquake dynamic response of a cross-fault mountain tunnel was carried out. According to the loading system listed in Table 2, the loading waveforms include two types, namely white noise and seismic waves. The seismic waves are low-frequency waves - Kobe waves, medium-frequency waves - ElCentro waves, and high-frequency waves - Taft waves. The time step of the acceleration time history of the three prototype seismic waves is 0.02s. According to the time similarity ratio λ in Table 1 t=1⁄√40, adjust the time step to 0.0032s, since the acceleration similarity ratio is λ a =1, so the acceleration peak remains unchanged after amplitude modulation.

[0088] As listed in Table 2, the loading process is divided into 7 levels according to the order of the peak value of the loading waveform from small to large. In levels L1~L6, each level contains 4 loading waveforms, namely 1 white noise and 3 seismic waves, and the seismic waves in the same level use the same acceleration peak; L7 loading only contains white noise. The first working condition of each level of loading is white noise, with an acceleration peak of 0.05g; in the early stage of the test, in levels L1~L4, the difference in the peak value of the seismic wave acceleration is 0.1g, and the maximum load is 0.4g; in the later stage of the test, in levels L5~L6, the difference in the peak value of the seismic wave acceleration is 0.2g, and the maximum load is 0.8g.

[0089] Table 2 Loading conditions of shaking table model test

[0090]

[0091] Note: WN stands for white noise; KB stands for Kobe wave; EL stands for El-Centro wave; TF stands for Taft wave.

[0092] During the seismic wave loading process, the acceleration and strain of the tunnel, the acceleration response of the surrounding rock 3, the fault fracture zone 4 and the laminated shear model box 2 are measured by the sensor 6, and the collected signals are transmitted to the data acquisition device 7 and then to the computer 8 to obtain the dynamic response data of the test system.

[0093] By analyzing the data obtained from monitoring, we can clarify the time evolution and spatial distribution of the seismic response of cross-fault mountain tunnels, reveal the influence of faults, terrain, and seismic wave characteristics on the seismic response of tunnels, and evaluate the shock-absorbing effect of shock-absorbing layers on cross-fault tunnels.

[0094] Embodiment 2:

[0095] This embodiment provides a test method for a shaking table test device for earthquake dynamic response of a cross-fault mountain tunnel, based on the test device described in Embodiment 1, comprising the following steps:

[0096] S1: Design the test, determine the test similarity ratio, make the laminated shear model box 2 and the tunnel model 5, prepare similar materials of the surrounding rock 3 and the fault fracture zone 4, formulate the test loading system and the monitoring and measurement plan; the test similarity ratio design follows the similarity principle, with length l, density ρ and elastic modulus E as basic unknown quantities, and other physical quantities are determined by these three quantities. Detailed description is given in Example 1.

[0097] S2: fix the laminated shear model box 2 to the surface of the earthquake simulation vibration table 1, and sequentially adhere the sponge and rubber film 22 to the inner wall of the model box;

[0098] S3: According to the test plan, the surrounding rock 3 and the fault fracture zone 4 materials are filled layer by layer in the model box, the tunnel model 5 is buried, and the sensors 6 are installed at the predetermined positions of the tunnel model 5, the surrounding rock 3, the fault fracture zone 4 and the laminated shear model box 2;

[0099] S4: Connect the sensors 6, data acquisition equipment 7 and computer 8 to ensure that the equipment and control system can work normally;

[0100] S5: Conduct a white noise frequency sweep test, i.e., use a white noise frequency sweep with an amplitude of less than or equal to 0.05g to obtain the dynamic characteristics of the installed test system, such as the natural frequency and damping ratio;

[0101] S6: Conduct a shaking table test on the earthquake dynamic response of a cross-fault mountain tunnel, i.e. select earthquake waves with different spectral characteristics, and use the shaking table to input the acceleration amplitude step by step from small to large to apply earthquake loads.

[0102] During the process, the dynamic responses of the tunnel model 5, surrounding rock 3, fault fracture zone 4 and laminated shear model box 2 are measured by sensors 6, and the collected signals are transmitted to data acquisition equipment 7, and then to computer 8. Specifically, the tunnel model 5 collects acceleration and strain, the surrounding rock 3 and fault fracture zone 4 collect acceleration, and the laminated shear model box 2 mainly collects acceleration. The data of the tunnel with shock-absorbing layer 52 and the tunnel without shock-absorbing layer 51 are collected synchronously.

[0103] S7: Analyze the test data obtained in S6. Through comparison and analysis, we can clarify the time evolution and spatial distribution characteristics of the seismic dynamic response of the cross-fault mountain tunnel, reveal the influence of faults, terrain, and seismic wave characteristics on the seismic response of the tunnel, and evaluate the seismic effect of the shock-absorbing layer on the cross-fault tunnel.

[0104] By analyzing the test results of the accelerometer 61 and the strain gauge 62 in the tunnel model 5, the spatial distribution characteristics and time evolution laws of the tunnel acceleration and strain, as well as the influence of the fault and the shock-absorbing layer on the tunnel seismic response can be clarified.

[0105] By analyzing the test results of accelerometer 61 in the surrounding rock 3 and the fault fracture zone 4, it is possible to clarify the law of upward propagation of seismic waves and the influence of topography and shock-absorbing layers on the law of earthquake propagation.

[0106] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features, and in the description of the present invention, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0107] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0108] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0109] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0110] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A shaking table test device for earthquake dynamic response of a cross-fault mountain tunnel, characterized in that: It includes earthquake simulation shaking table, laminated shear model box, surrounding rock, fault fracture zone, tunnel model and monitoring and measurement system; The laminated shear model box is fixedly mounted on the earthquake simulation vibration table; the earthquake simulation vibration table is used to input earthquake waves to drive the laminated shear model box to vibrate; The surrounding rock and the fault fracture zone are filled in the laminated shear model box, and the tunnel model is buried in the surrounding rock and intersects with the fault fracture zone; The monitoring and measuring system is used to collect data of the surrounding rock, fault fracture zone and tunnel model; The laminated shear model box has an opening at the top, and its bottom is fixed on an earthquake simulation vibration table. Sponges and rubber films are sequentially pasted on the inner wall of the box.

2. The shaking table test device for earthquake dynamic response of a cross-fault mountain tunnel according to claim 1 is characterized in that: The surrounding rock and fault fracture zone are the restraining materials of the tunnel and also the propagation medium of seismic waves. The selection and preparation method of similar materials are determined according to the properties and similarity ratio of the prototype material, and are loaded into the model box after preparation; The surrounding rock comprises an upper plate surrounding rock and a lower plate surrounding rock respectively arranged on both sides of the laminated shear model box; the fault fracture zone is arranged through and between the upper plate surrounding rock and the lower plate surrounding rock.

3. The shaking table test device for earthquake dynamic response of a cross-fault mountain tunnel according to claim 1 is characterized in that: The fault fracture zone has a fault dip angle of 90°; The surface elevations of the upper wall surrounding rock and the lower wall surrounding rock on both sides of the fault fracture zone are inconsistent.

4. The shaking table test device for earthquake dynamic response of a cross-fault mountain tunnel according to claim 1 is characterized in that: The earthquake simulation vibration table is used to input earthquake waves and provide earthquake power. The loading direction is consistent with the direction of the fault fracture zone and perpendicular to the direction of the tunnel.

5. The shaking table test device for earthquake dynamic response of a cross-fault mountain tunnel according to claim 1 is characterized in that: The tunnel model comprises two tunnels, one without a shock-absorbing layer and the other with a shock-absorbing layer, which are arranged in parallel, and each tunnel is assembled by bonding a plurality of segments.

6. The shaking table test device for earthquake dynamic response of a cross-fault mountain tunnel according to claim 1 is characterized in that: The tunnel model is a scaled model, and the model size and material are determined according to the prototype tunnel and the similarity ratio. The manufactured tunnel is buried in the surrounding rock inside the model box and intersects the fault fracture zone vertically.

7. The shaking table test device for earthquake dynamic response of a cross-fault mountain tunnel according to claim 1 is characterized in that: The monitoring and measuring system includes a sensor, a data acquisition device and a computer, wherein the sensor is connected to the data acquisition device, the data acquisition device is connected to the computer, and the computer is loaded with a control system for data acquisition, analysis and management.

8. The shaking table test device for earthquake dynamic response of a cross-fault mountain tunnel according to claim 7 is characterized in that: The sensor includes an accelerometer and a strain gauge; The accelerometers are arranged on the invert in each tunnel segment, arranged vertically at intervals in the surrounding rock and fault fracture zone, and arranged vertically at intervals on the side wall of the model box parallel to the vibration direction; The accelerometers installed in the tunnel are used to collect the acceleration response of the tunnel during the earthquake motion; The accelerometers installed in the surrounding rock and fault fracture zone are used to collect the acceleration response at different depths in the surrounding rock and fault fracture zone to study the propagation law of seismic waves; The accelerometers installed on the side walls of the model box are used to collect the acceleration responses of the box at different elevations; The strain gauge is attached to the tunnel and is used to collect the deformation of the tunnel during the earthquake.

9. The shaking table test device for earthquake dynamic response of a cross-fault mountain tunnel according to claim 8, characterized in that: The vertical spacing of the accelerometers arranged vertically in the surrounding rock and fault fracture zone is 250 mm; The strain gauges are respectively pasted on the vault, the invert, the left arch waist and the right arch waist in each tunnel segment, and one strain gauge is pasted at each position along the tunnel axis and perpendicular to the tunnel axis.

10. A test method for a shaking table test device for earthquake dynamic response of a cross-fault mountain tunnel, characterized in that: The test device according to claim 1 comprises the following steps: S1: Design the test, determine the test similarity ratio, make the shear model box and tunnel model, prepare similar materials of surrounding rock and fault fracture zone, and formulate the test loading system and monitoring and measurement plan; S2: Fix the laminated shear model box on the table of the earthquake simulation shaking table, and stick the sponge and rubber film on the inner wall of the model box in sequence; S3: According to the test plan, the surrounding rock and fault fracture zone materials are filled layer by layer in the model box and the tunnel model is buried; S4: Install and connect the monitoring and measurement system to ensure that the monitoring and measurement system can work normally; S5: Conduct white noise frequency sweep test to obtain the dynamic characteristics of the installed test device; S6: Conduct a shaking table test on the earthquake dynamic response of a cross-fault mountain tunnel. Select earthquake waves with different spectral characteristics according to the test loading system. The shaking table applies earthquake loads by inputting acceleration amplitudes from small to large. At the same time, according to the monitoring and measurement plan, collect data on the surrounding rock, fault fracture zone and tunnel model through the monitoring and measurement system.

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