Simulation and prediction system for cascade fracture of rock-like mass model based on double sliding modes

Abstract

The invention belongs to the technical field of geological engineering and seismic dynamics, and particularly relates to a rock-like model cascade fracture simulation and prediction system based on a double-sliding mode, and the system comprises a model, the bottom of the model is in contact with the top of a bottom roller row, and the bottom of the bottom roller row is in sliding fit with the ground; the frame is fixed to the ground, and the model is installed in the frame; the fixed end of the axial compression system is fixedly connected with the frame, the movable end of the axial compression system is in contact with one end of the model, and the force application direction of the axial compression system is collinear with the axis of the model; the fixed end of the side pressure compression system is fixedly connected with the frame, the movable end of the side pressure compression system is in contact with the front side of the model, and the force application direction of the side pressure compression system is perpendicular to the axis space of the model; the axial compression system is in transmission connection with the lateral compression system; and the detection mechanism is mounted in the frame and is used for acquiring experimental data. The device has axial and lateral slip modes, and can reveal a stress transfer mechanism of a strike-slip fracture multi-section structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of geological engineering and earthquake dynamics, and in particular relates to a simulation and prediction system for cascading fracture of a rock-like model based on a dual-sliding mode. Background Art

[0002] Strike-slip faults are the main carriers of global seismic activity, and their cascading ruptures can trigger strong earthquakes and even supershear ruptures.

[0003] In fact, earthquake activity is often accompanied by stress adjustments and changes. During cascading ruptures, the dynamic evolution of the local stress field within the fault is the key driving force that triggers the instability of adjacent segments. Therefore, elucidating the distribution and adjustment of local stress within the fault is of great significance for understanding the dynamic processes of the Earth's surface and assessing seismic hazard.

[0004] Existing fault simulation methods are primarily categorized into physical simulation experiments and numerical simulation analysis. However, current experimental setups often focus on loading in a single sliding mode, which limits our understanding of the mechanical behavior of fault zones.

[0005] Therefore, there is an urgent need for a test system that can dynamically simulate the entire process of strike-slip fault cascade rupture, so as to reveal the stress transfer mechanism of the multi-section structure of strike-slip fault, effectively monitor the instability precursor signals of cascade rupture, and provide technical support for emergency management decisions of major projects. Summary of the Invention

[0006] The purpose of the present invention is to provide a simulation and prediction system for cascading fracture of a rock-like model based on a dual sliding mode to solve the above problems.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A simulation and prediction system for cascading fracture of a rock-like model based on dual sliding modes, comprising:

[0009] a model, wherein the bottom of the model contacts the top of the bottom roller row, and the bottom of the bottom roller row is in sliding engagement with the ground;

[0010] a frame fixed to the ground, wherein the model is installed in the frame;

[0011] an axial compression system, wherein a fixed end is fixedly connected to the frame, a movable end of the axial compression system contacts one end of the model, and a force application direction of the axial compression system is collinear with an axis of the model;

[0012] A lateral pressure compression system, wherein a fixed end is fixedly connected to the frame, a movable end of the lateral pressure compression system contacts the front side of the model, and a force application direction of the lateral pressure compression system is arranged perpendicular to the axis space of the model;

[0013] The axial compression system is in transmission connection with the lateral compression system;

[0014] A detection mechanism is installed in the frame, and is used to obtain experimental data such as stress and strain, acoustic emission characteristic parameters, relative displacement and sliding rate.

[0015] Optionally, the framework includes:

[0016] Axis pressure plate, fixed on the experimental platform;

[0017] An axial reaction plate, located on one side of the axial pressure plate;

[0018] Four reaction force brackets are circumferentially arranged between the axial pressure plate and the axial reaction force plate, and both ends of the reaction force brackets are fixed to the axial pressure plate / the axial reaction force plate by reaction force bracket bolts respectively;

[0019] The inside of the frame area formed by the axial reaction plate, the axial pressure plate and the four reaction brackets is used to place the model.

[0020] Optionally, the axial compression system includes:

[0021] An axial press, the fixed end of which is fixedly connected to the axial pressure plate via a flange, and the movable end of the axial press is arranged coaxially with the model;

[0022] An axial roller row, one end of which is axially connected to the movable end of the axial press, the other end of which is in contact with one end of the mold, and the other end of which is in contact with the axial reaction plate;

[0023] The oil circuit of the axial press is communicated with the oil circuit of the side pressure compression system through a side pressure transmission pipe.

[0024] Optionally, the side pressure compression system includes:

[0025] A side pressure plate is provided on the front side of the frame, and the side pressure plate is fixed to the reaction force bracket on the corresponding side through a side pressure plate fixer;

[0026] A side pressure jack, a fixed end of which is fixedly connected to the side pressure plate, and a movable end of which is vertically arranged in the axis space of the model;

[0027] The side pressure jack is connected to a side pressure press, and the oil circuit of the side pressure press is connected to the axial press through the side pressure transmission pipe;

[0028] A side-pressure double-row roller row, one end of which is fixedly connected to the movable end of the side-pressure jack, and the other end of which is in contact with the front side wall of the mold;

[0029] The reaction force support portion is fixedly connected to the reaction force bracket on the side of the frame away from the side pressure plate, and the reaction force support portion is arranged in contact with the side of the model away from the side pressure double-row roller row.

[0030] Optionally, the reaction force support portion includes two symmetrically arranged side pressure reaction force rods, the two ends of the side pressure reaction force rods are respectively fixed to the two reaction force brackets on the corresponding sides, the two side pressure reaction force rods are fixed to the two ends of the same side pressure reaction force plate, and the side pressure reaction force plate is arranged in contact with the back side of the model;

[0031] One end of the lateral pressure reaction device is fixedly connected to the end of the lateral pressure reaction rod, and the other end of the lateral pressure reaction device is fixed to the lateral pressure reaction plate.

[0032] Optionally, the model is made of natural fault rock.

[0033] Optionally, the model is made of river sand: gypsum: cement: barite powder: water in a mass ratio of 54.64:8.2:5.5:13.66:18;

[0034] During molding, 0.016% of the total mass of the model is added to the retarder.

[0035] Optionally, the model has a size of 2 meters in length, 0.8 meters in width, and 0.6 meters in height.

[0036] Optionally, optical fiber cables and strain bricks are pre-embedded inside the model, and the optical fiber cables are arranged obliquely inside the model, and are pre-embedded on both sides of the locking section and the creeping section inside the model.

[0037] Optionally, the detection mechanism includes:

[0038] an optical fiber displacement sensor, the optical fiber displacement sensor being slidably connected to the optical fiber cable, the optical fiber displacement sensor being fixed to the reaction force bracket, and the optical fiber displacement sensor being used to detect the relative displacement between the optical fiber cable and the optical fiber displacement sensor;

[0039] The acoustic emission probe is embedded in the middle of the locking section on the surface of the model, the middle of the top surface of the model, and the middle of the bottom surface of the model.

[0040] Compared with the prior art, the present invention has the following advantages and technical effects:

[0041] When in use, the model is installed on the inside of the frame and connected to the axial compression system and the lateral pressure compression system. The axial compression system is connected to the lateral pressure compression system in a transmission manner, and axial pressure and lateral pressure are applied to the model in a coordinated manner to cause axial and lateral slip inside the model. The experimental data of the internal changes of the model can be obtained and analyzed through the detection mechanism. Compared with traditional devices, this device has both axial and lateral slip mode loading, which is convenient for revealing the stress transfer mechanism of multi-section structures of strike-slip faults, effectively monitoring the instability precursor signals of cascade fractures, and providing technical support for emergency management decisions of major projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work.

[0043] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0044] Figure 2 This is a schematic diagram of the interior of the double-row roller arrangement without a model and without side pressure according to the present invention;

[0045] Figure 3 This is a schematic diagram of the biaxial compression structure of the present invention;

[0046] Figure 4 This is a schematic diagram of the side pressure system of the present invention;

[0047] Figure 5 Schematic diagram of the model and monitoring equipment of the present invention;

[0048] Figure 6 For the present invention Figure 5 Schematic diagram of the cross-section structure at AA in the middle;

[0049] Figure 7 For the present invention Figure 5 Schematic diagram of the cross-section structure at the middle BB;

[0050] Figure 8 For the present invention Figure 5 Schematic diagram of the cross-section structure at CC;

[0051] Figure 9 This is a schematic diagram of axial compression of the present invention;

[0052] Figure 10 This is the main view of the structure of the present invention;

[0053] Figure 11 For the present invention Figure 10Schematic diagram of the cross-section structure at DD in the middle;

[0054] Among them, 1. Fiber optic cable; 2. Fiber optic displacement sensor; 3. Reaction bracket bolt; 4. Axial pressure plate; 5. Axial press; 5-1. Flange; 6. Axial roller row; 7. Lateral pressure transmission pipe; 8. Lateral pressure press; 9. Lateral pressure plate holder; 10. Lateral pressure plate; 11. Lateral pressure jack; 12. Lateral pressure double-row roller row; 13. Axial reaction plate; 14. Lateral pressure reaction plate; 15. Lateral pressure reaction rod; 16. Reaction bracket; 17. Bottom roller row; 18. Lateral pressure reaction device; 19. Strain brick; 20. Acoustic emission probe. DETAILED DESCRIPTION

[0055] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0056] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0057] Reference Figures 1 to 11 The present invention discloses a simulation and prediction system for cascading fracture of a rock-like model based on a dual sliding mode, comprising:

[0058] The bottom of the model contacts the top of the bottom roller row 17, and the bottom of the bottom roller row 17 is in sliding engagement with the ground;

[0059] A frame is fixed to the ground, and the model is installed in the frame;

[0060] An axial compression system, wherein the fixed end is fixedly connected to the frame, the movable end of the axial compression system contacts one end of the model, and the force direction of the axial compression system is collinear with the axis of the model;

[0061] A lateral pressure compression system, wherein the fixed end is fixedly connected to the frame, the movable end of the lateral pressure compression system contacts the front side of the model, and the force direction of the lateral pressure compression system is set perpendicular to the axis space of the model;

[0062] The axial compression system is transmission-connected to the lateral compression system;

[0063] The detection mechanism is installed in the frame and is used to obtain experimental data such as stress and strain, acoustic emission characteristic parameters, relative displacement and sliding rate.

[0064] When in use, the model is installed on the inside of the frame and connected to the axial compression system and the lateral pressure compression system. The axial compression system is connected to the lateral pressure compression system in a transmission manner, and axial pressure and lateral pressure are applied to the model in a coordinated manner to cause axial and lateral slip inside the model. The experimental data of the internal changes of the model can be obtained and analyzed through the detection mechanism. Compared with traditional devices, this device has both axial and lateral slip mode loading, which is convenient for revealing the stress transfer mechanism of multi-section structures of strike-slip faults, effectively monitoring the instability precursor signals of cascade fractures, and providing technical support for emergency management decisions of major projects.

[0065] As an optional implementation, the framework includes:

[0066] Axial pressure plate 4, fixed on the experimental platform;

[0067] An axial reaction plate 13 is located on one side of the axial pressure plate 4;

[0068] Four reaction force brackets 16 are circumferentially arranged between the axial pressure plate 4 and the axial reaction force plate 13, and the two ends of the reaction force bracket 16 are fixed to the axial pressure plate 4 / axial reaction force plate 13 respectively through the reaction force bracket bolts 3;

[0069] The inside of the frame area formed by the axial reaction plate 13, the axial pressure plate 4 and the four reaction brackets 16 is used to place the model.

[0070] As an optional embodiment, the axial compression system includes:

[0071] The fixed end of the axial press 5 is fixedly connected to the axial pressure plate 4 through the flange 5-1, and the movable end of the axial press 5 is arranged coaxially with the model;

[0072] An axial roller row 6 has one end axially connected to the movable end of the axial press 5, and the other end of the axial roller row 6 contacts one end of the mold, and the other end of the mold contacts the axial reaction plate 13;

[0073] The oil circuit of the axial press 5 is connected to the oil circuit of the side pressure compression system through the side pressure transmission pipe 7 .

[0074] As an optional embodiment, the side pressure compression system includes:

[0075] The side pressure plate 10 is arranged on the front side of the frame, and the side pressure plate 10 is fixed to the reaction force bracket 16 on the corresponding side through the side pressure plate fixer 9;

[0076] The side pressure jack 11 has a fixed end fixedly connected to the side pressure plate 10, and a movable end of the side pressure jack 11 is vertically arranged in the axis space of the model;

[0077] The lateral pressure jack 11 is connected to the lateral pressure press 8, and the oil circuit of the lateral pressure press 8 is connected to the axial press 5 through the lateral pressure transmission pipe 7;

[0078] The side pressure double-row roller row 12 has one end fixedly connected to the movable end of the side pressure jack 11, and the other end of the side pressure double-row roller row 12 contacts the front side wall of the model;

[0079] The reaction force support portion is fixedly connected to the reaction force bracket 16 on the side of the frame away from the side pressure plate 10 , and the reaction force support portion is arranged in contact with the side of the model away from the side pressure double-row roller row 12 .

[0080] As an optional embodiment, the reaction force support portion includes two symmetrically arranged side pressure reaction rods 15, the two ends of the side pressure reaction rods 15 are respectively fixed to the two reaction force brackets 16 on the corresponding sides, and the two side pressure reaction rods 15 are fixed to the two ends of the same side pressure reaction plate 14, and the side pressure reaction plate 14 is arranged in contact with the back side of the model;

[0081] One end of the lateral pressure reaction force device 18 is fixedly connected to the end of the lateral pressure reaction force rod 15 , and the other end of the lateral pressure reaction force device 18 is fixed to the lateral pressure reaction force plate 14 .

[0082] As an optional embodiment, the model is made from natural fault rock.

[0083] As an optional embodiment, the model is made of river sand: gypsum: cement: barite powder: water in a mass ratio of 54.64:8.2:5.5:13.66:18;

[0084] When making the mold, add 0.016% of the total mass of the model as retarder.

[0085] As an optional embodiment, the model size is 2 meters in length, 0.8 meters in width, and 0.6 meters in height.

[0086] As an optional embodiment, optical fiber cable 1 and strain bricks 19 are pre-buried inside the model. The optical fiber cable 1 is tilted in the model, and the strain bricks 19 are pre-buried on both sides of the locking section and creeping section inside the model.

[0087] As an optional implementation, the detection mechanism includes:

[0088] Fiber optic displacement sensor 2, which is slidably connected to the optical fiber cable 1 and fixed to the reaction force bracket 16, and is used to detect the relative displacement between the optical fiber cable 1 and the optical fiber displacement sensor 2;

[0089] The acoustic emission probe 20 is embedded in the middle of the locking section on the surface of the model, the middle of the top surface of the model, and the middle of the bottom surface of the model.

[0090] The relative displacement sliding system of the device consists of an optical fiber cable 1 and an optical fiber displacement sensor 2. The optical fiber cable 1 is pre-buried inside the model and is connected to the optical fiber displacement sensor 2 on the outside.

[0091] The axial compression system includes a reaction support 16, an axial press 5, an axial pressure plate 4, an axial roller row 6, and an axial reaction plate 13; the reaction support 16 is connected to the axial reaction plate 13, the axial press 5 is placed on the outside of the axial reaction plate 13, and the axial pressure plate 4 is placed on the inside, and the axial pressure plate 4 is connected to the axial roller row 6.

[0092] The side pressure compression system includes a side pressure transmission pipe 7, a side pressure press 8, a side pressure plate holder 9, a side pressure plate 10, a side pressure jack 11, a side pressure double-row roller row 12, and a side pressure reaction plate 14; the side pressure press 8 transmits pressure to the side pressure jack 11 through the side pressure transmission pipe 7 and finally transmits the pressure to the side pressure jack 11, the side pressure jack 11 is connected to the side pressure plate 10, the side pressure plate 10 is fixed to the reaction bracket 16 through the side pressure plate holder 9, the reaction bracket 16 and the side pressure plate holder 9 fix the side pressure double-row roller row 12 to the side of the model, the side pressure double-row roller row 12 is connected separately by two rows of rollers, and the side pressure reaction plate 14 is connected to the side pressure reaction rod 15 by the side pressure reaction device 18.

[0093] The bottom roller row 17 is placed at the bottom of the model to reduce the friction between the bottom of the model and the ground to achieve a sliding effect.

[0094] Strain bricks 19 are embedded on both sides of the locking section and creep section inside the model to monitor the mechanical evolution behavior of the model when it breaks.

[0095] The acoustic emission probe 20 is installed in the middle of the locking section on the surface of the model and in the middle of both sides of the model, and can be used to monitor the degree of model rupture and invert the Benioff strain.

[0096] The optical fiber cable 1 is pre-buried inside the model at both sides of the locking section and creep end and is connected to the external optical fiber displacement sensor 2. The relative slip velocity of the model cascade rupture can be obtained through the optical fiber data.

[0097] The axial pressure plate 4 is secured by a reaction bracket 16 and reaction bracket bolts 3. The reaction bracket bolts 3 securely connect the axial pressure plate 4 and the axial reaction plate 13 at either end of the reaction bracket 16, achieving stability. The axial pressure plate 4 is equipped with an axial press 5, which passes through the axial pressure plate 4 and is secured by a flange 5-1. The other end of the flange 5-1 is an axial roller row 6, which reduces friction at the axial end and moves in response to the application of lateral pressure.

[0098] The lateral pressure transmission pipe 7 is connected to the right side of the axial press 5, and the oil pressure can be transmitted to the lateral pressure press 8 through the lateral pressure transmission pipe 7, and then transmitted to the two lateral pressure jacks 11 located on the side to form lateral pressure.

[0099] The side pressure jack 11 is overlapped on the side pressure plate 10, and the side pressure plate 10 is fixed by four side pressure plate holders 9. The side pressure plate holder 9 is installed on the reaction force bracket 16 to apply side pressure to the side pressure double-row roller row 12. The side pressure double-row roller row 12 consists of two rows of rollers, the upper and lower rows, and the arc rectangular hole in the middle can be used to place equipment such as the acoustic emission probe 20 on the model surface.

[0100] In order to form a stable and reliable lateral pressure, a lateral pressure reaction device 18 is provided on the lateral pressure reaction rod 15 opposite the model to fix the lateral pressure reaction plate 14.

[0101] The bottom roller row 17 consists of 12 small roller rows of the same size placed at the bottom of the model, and the direction can be adjusted according to the direction of the strike-slip fault.

[0102] Acoustic emission probes 20 were installed in the middle of the locking section on the surface of the model and in the middle of both sides of the model to collect characteristic parameters of acoustic emission during rupture, which were used to invert the Benioff strain.

[0103] The assembly of this device includes the following steps:

[0104] Step 1: Frame assembly and arrangement of axial compression system;

[0105] Install the axial compression system and reaction support.

[0106] Place the axial pressure plate 4 and the axial reaction plate 13 at the reference point. Insert the reaction bracket 16 through the bolt holes in the axial pressure plate 4 and the axial reaction plate 13 and secure it to the experimental platform, ensuring it is firmly connected to the ground. Install the reaction bracket bolts 3 at both ends of the reaction bracket 16 to secure the axial pressure plate 4 and the axial reaction plate 13. Secure the axial press 5 to the outside of the axial pressure plate 4 via the flange 5-1, ensuring that the press axis is aligned with the center of the model. Connect the axial roller array 6 to the axial press 5 via the flange 5-1 and secure it to the inside of the axial pressure plate 4. Ensure that the roller array surface is flat and can be calibrated with a spirit level.

[0107] Step 2: Arrange the side pressure compression system;

[0108] Connect the lateral pressure transmission pipe 7 of the axial press 5 and check whether the oil pressure transmission is sealed and leak-free. Connect it to the reaction bracket 16 through the lateral pressure plate holder 9; install the lateral pressure jack 11 on the lateral pressure plate 10 and connect it to the lateral pressure press 8 through the lateral pressure transmission pipe 7. After connection, add oil pressure to the axial press 5 and transmit it to the lateral pressure press 8 through the lateral pressure transmission pipe 7. When applying pressure, the axial press 5 applies axial pressure at the same time through oil pressure, and the lateral pressure press 8 applies lateral pressure through the oil pressure of the lateral pressure transmission pipe 7. The oil pressures of the two are connected through the lateral pressure transmission pipe 7, but the power source comes from two presses. Then fix the lateral pressure double-row roller row on the lateral pressure jack, and then install the lateral pressure reaction rod 15 on the opposite lateral reaction bracket 16, and install the lateral pressure reaction device on the lateral pressure reaction rod 15 to fix the lateral pressure reaction plate 14. Finally, ensure that they are on the same horizontal plane and aligned.

[0109] Step 3: Install the bottom roller row 17 at the bottom of the model and adjust the roller direction to be consistent with the strike-slip fault simulation direction to reduce friction interference.

[0110] Step 4: Set up a testing organization;

[0111] Install the fiber optic displacement sensor and acoustic emission probe.

[0112] After securing them, connect the fiber optic displacement sensor 2 to the fiber optic cable 1. Place acoustic emission probes 20 on the surface and sides of the model, with a minimal spacing between them. Place them evenly between the locking and creeping sections of the model surface. Connect the power and data cables to collect data.

[0113] Step 5: Connect the transmission pipelines of the axial compression system and the lateral compression system;

[0114] Hydraulic line connections.

[0115] Connect one end of the lateral pressure transmission pipe 7 to the oil pressure output port of the axial press 5, and the other end to the lateral pressure press 8; check the hydraulic pipeline of the lateral pressure jack 11 to ensure that there are no bubbles and leakage.

[0116] Step 6: Connect the detection mechanism to the data acquisition unit;

[0117] Connect the signal lines of the optical fiber displacement sensor 2 and the acoustic emission probe 20 to the data acquisition unit; set the data sampling frequency.

[0118] Step 7: System calibration;

[0119] Start the axial press 5 and the lateral press 8, gradually increasing pressure to 20 MPa. Observe the pressure gauge readings for stability. Check that the rollers are moving smoothly and without any binding. Perform a zero-point calibration on the dynamic stress sensor to ensure data accuracy. Test the acoustic emission probe 20 by tapping the model surface to verify signal response time and positioning accuracy.

[0120] The preparation and installation of the model includes the following steps:

[0121] Step 1: Model preparation and installation

[0122] The model is made of natural fault rock or similar materials such as river sand: gypsum: cement: barite powder: water = 54.64%: 8.2%: 5.5%: 13.66%: 18%. To prevent the model from hardening, a retarder of 0.016% of the total mass of the model is added during molding to prepare a multi-section fracture model. The recommended model size is 2m × 0.8m × 0.6m in length × width × height to ensure compatibility with the experimental system.

[0123] Step 2: Lay out the fiber optic cables

[0124] An optical fiber cable 1 is pre-buried inside the model, and a dynamic stress sensor is embedded. The sensor wire is led out along the side of the model to avoid interfering with the movement of the roller row; the sensor mounting hole is sealed with glue to ensure consistency with the mechanical properties of the model.

[0125] Step 3: Fix the model

[0126] Place the model steadily on the bottom roller row 17, and adjust the position so that its center coincides with the axis of the axial press 5; clamp the model with the axial reaction plate 13 and the side pressure plate 10, and tighten the reaction bracket bolts 3 to ensure that the model is firmly fixed; check the contact between the side pressure double-row roller row 12 and the side of the model to ensure that there is no local stress concentration.

[0127] Precautions

[0128] During the installation process, avoid scratching the model surface to prevent rupture observation; regularly check the sealing of the hydraulic pipeline to prevent oil pressure leakage; perform at least three no-load test runs before the experiment to ensure system stability.

[0129] The specific implementation steps of this experiment are as follows:

[0130] Step 1: Select appropriate rock-like materials and prepare samples according to the proportions to simulate the mechanical properties of natural fault rocks. For example, river sand: gypsum: cement: barite powder: water = 54.64%: 8.2%: 5.5%: 13.66%: 18% is selected. To prevent the model from hardening too quickly, a retarder of 0.016% of the total mass of the model is added during molding.

[0131] Before casting the model, prefabricate locking and creeping sections using 10mm-thick cracked steel plates on the model's diagonal lines. For example, adopting a three-locking and four-creeping approach creates a weak link. A low-strength binder, such as gypsum powder, is then added with a mass ratio of 1:0.6 to water. When the model is halfway cast, 30mm cubic strain relief bricks (19) are placed on either side of the junction between the locking and creeping sections. This layer is then shaved. When the filler is almost at the top surface, optical fiber cables are placed on both sides of the locking and creeping sections. Casting is then continued to the top layer.

[0132] Step 2: After pouring, perform curing at a temperature of 25±2°C and a humidity of 50%±5% for 48 hours until the standard strength is reached. After that, demould and polish the surface of the model to ensure that there are no burrs on the contact surface with the roller row. Then proceed to the next test.

[0133] Step 3: Assemble and debug the system during the model maintenance process, and install the axial compression system. When installing the axial compression system, first fix the axial pressure plate 4 and the axial reaction plate 13 on the reference point, then pass the reaction bracket 16 through the reserved holes at the diagonal angles of the axial pressure plate 4 and the axial reaction plate 13 and tighten the reaction bracket bolts 3. Then, perform the same operation on the reaction bracket 16 at the other diagonal angle. After ensuring that the reaction bracket 16 is stable, position the axial press 5 and fix the axial press 5 to the outside of the axial pressure plate 4 through the flange 5-1. Ensure that the deviation between the axis of the axial press and the center of the model is less than 1mm.

[0134] Step 4: Install the lateral pressure compression system. First, fix the lateral pressure plate 10 to one side of the reaction bracket 16 through the lateral pressure plate fixture 9. Ensure the accuracy of the position of the lateral pressure plate 10 during installation. Then install the lateral pressure jack 11 at the fixed position of the lateral pressure plate 10. Then install the lateral pressure transmission pipe 7 between the axial press 7 and the lateral pressure press 8, so that the oil pressure in the axial press 5 can smoothly reach the lateral pressure press 8, and the lateral pressure press 8 can provide stable and effective lateral pressure for the lateral pressure jack 11. Finally, install the lateral pressure reaction rod 15 on the other side reaction bracket 16 of the lateral pressure plate 10, tighten the lateral pressure reaction device 18 on the lateral pressure reaction rod 15 and fix it. Then fix the lateral pressure reaction plate 14 through the lateral pressure reaction device 18, and ensure that the position of the lateral pressure reaction plate 14 is on the same horizontal line as the lateral pressure plate 10.

[0135] Step 5: Install the bottom roller array and optimize the roller array layout. The bottom roller array 17 uses 12 sets of rollers arranged in a 3×4 matrix with 10 cm spacing between the rollers to ensure uniform load distribution on the model. Test the rollers for integrity and measure sliding friction under no-load conditions.

[0136] Step 6: Install the axial and lateral pressure roller rows, use a laser level to adjust the flatness of the axial roller row 6 and the lateral pressure double-row roller row 12 and calibrate them, with an allowable error of ≤0.1mm / m.

[0137] Step 7: Place the prepared and cured model in the appropriate location, taking care to avoid bumps and bumps. Then, install the acoustic emission probes 20. After securing the model, install the probes 20 in the center holes of the locking and creeping sections of the double-row lateral pressure rollers 12 and the lateral pressure reaction plate 14. Arrange three probes 20 on the model surface, spaced 25 cm apart in a grid pattern, to cover all weak links. Place four probes 20 on each side of the model. Apply vaseline coupling agent to the contact surface between the probes and the model to ensure efficient sound wave transmission.

[0138] Step 8: Connect the strain sensor to the strain brick 19 to measure the mechanical evolution of the cascading failure during compression. Embed the fiber optic displacement sensor 2 to ensure the sensor's range and accuracy. The sensor wires are enclosed in a metal shielding tube to prevent electromagnetic interference and are routed through a reserved channel on the side of the model.

[0139] Step 9: Install the relative displacement sliding system; track the surface crack growth rate in real time during the compression process.

[0140] Step 10: The model was biaxially pressurized. First, the model was contacted using a lateral pressure hydraulic system. Then, axial pressure was applied and pressure was released at a rate of 0.01 mm / s to simulate the stress environment deep within the Earth's crust. Lateral pressure was released at a rate one-third the axial pressure. A low friction state of μ = 0.3 was maintained. Simultaneously, data was recorded to capture microfracture events. Initial fracture was detected by a sudden increase in acoustic emission events.

[0141] Step 11: During the experiment, converting the energy of the acoustic emission (AE) event into the equivalent Benioff strain (CBS) requires combining energy evolution theory with experimental parameter calibration. The relationship between AE event energy and elastic strain energy is shown in Equation 1, reflecting the relationship between the accumulation of elastic strain energy (Eelastic) and the presence of AE event energy (EAE).

[0142] The energy conversion model is:

[0143] E elastic =kE AE

[0144] Where k is the experimental calibration coefficient, which needs to be obtained by fitting the stress-strain curve and AE energy data measured simultaneously in the uniaxial loading test.

[0145] Calculation of Benioff strain, which is defined as the square root accumulation of elastic strain energy. Combined with AE data, the single-event Benioff strain can be obtained. The energy EAE of each AE event is square-root-converted to obtain the single-event equivalent Benioff strain. The cumulative Benioff strain CBS is shown in Equation 2.

[0146]

[0147] Where n is the total number of AE events, and the accumulation process needs to consider the division of time series or loading stages.

[0148] Experimental verification and parameter optimization involve dividing the energy evolution into stages and jointly verifying it with infrared radiation parameters. Based on the four stages of rock failure energy evolution—compaction, elasticity, elastoplasticity, and failure stage 1—the k value for each stage needs to be calibrated separately. For example, in the elastic stage, k ≈ 1, while in the elastoplastic stage, due to the increased dissipated energy, a correction factor is required. The reliability of the Benioff strain, such as the cubic polynomial relationship, is verified by combining the synchronous variation trends of the average cumulative radiant energy increment △ACRE and the CBS.

[0149] Using the above loading system, the axial pressure and confining pressure systems are first set to load synchronously to the set value. Then, the confining pressure is set to remain unchanged and the axial pressure loading path is set to load the model until it is destroyed. Then, the CBS data, local stress deflection angle, and relative movement rate of the two fracture plates after the elastic deformation stage and before the destruction stage are collected for Spearman correlation analysis to achieve cross-validation of each indicator, thereby establishing a three-indicator cascade fracture composite prediction system.

[0150] Step 12: Troubleshooting and System Maintenance Common Problems: Roller jam. Check the roller bearing lubrication and add high-temperature resistant grease regularly. Recalibrate the zero point of the sensor signal and check whether the wire shielding layer is damaged.

[0151] Compared with the prior art, the present invention has the following advantages and technical effects:

[0152] The patented invention provides a strike-slip fault cascade rupture simulation and prediction system based on a dual-slip mode. Through innovative dual-slip mode loading, multi-segment low-friction roller array design, and multi-source data fusion technology, it breaks through the technical bottleneck of existing systems in cascade rupture simulation and prediction, and achieves high-precision monitoring of the entire process of dynamic stress transfer, friction behavior switching, and rupture behavior prediction of multi-segment strike-slip fault structures, thereby constructing a composite criterion for simulation and prediction of cascade rupture based on the "movement rate of the two fault plates - local stress deflection angle - accumulated Benioff strain" model. Its technical effect not only promotes theoretical research in geomechanics, but also provides a new method for earthquake risk assessment and prediction of major projects, with significant scientific research and engineering application value.

[0153] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0154] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A simulation and prediction system for cascading fracture of rock-like models based on dual sliding modes, characterized by: include: A model, wherein the bottom of the model contacts the top of a bottom roller row (17), and the bottom of the bottom roller row (17) is in sliding engagement with the ground; a frame fixed to the ground, wherein the model is installed in the frame; an axial compression system, wherein a fixed end is fixedly connected to the frame, a movable end of the axial compression system contacts one end of the model, and a force application direction of the axial compression system is collinear with an axis of the model; A lateral pressure compression system, wherein a fixed end is fixedly connected to the frame, a movable end of the lateral pressure compression system contacts the front side of the model, and a force application direction of the lateral pressure compression system is arranged perpendicular to the axis space of the model; The axial compression system is in transmission connection with the lateral compression system; A detection mechanism is installed in the frame, and the detection mechanism is used to obtain experimental data.

2. The simulation and prediction system for cascading fracture of a rock-like model based on a dual sliding mode according to claim 1, characterized in that: The framework includes: Axis pressure plate (4), fixed on the experimental platform; An axial reaction plate (13) is located on one side of the axial pressure plate (4); Four reaction force brackets (16) are circumferentially arranged between the axial pressure plate (4) and the axial reaction force plate (13), and the two ends of the reaction force bracket (16) are respectively fixed to the axial pressure plate (4) / the axial reaction force plate (13) through reaction force bracket bolts (3); The inner side of the frame area formed by the axial reaction plate (13), the axial pressure plate (4) and the four reaction brackets (16) is used to place the model.

3. The simulation and prediction system for cascading fracture of a rock-like model based on dual sliding modes according to claim 2, characterized in that: The axial compression system comprises: An axial press (5), the fixed end of which is fixedly connected to the axial pressure plate (4) via a flange (5-1), and the movable end of the axial press (5) is arranged coaxially with the model; An axial roller row (6) has one end axially connected to the movable end of the axial press (5), the other end of the axial roller row (6) contacts one end of the mold, and the other end of the mold contacts the axial reaction plate (13); The oil circuit of the axial press (5) is connected to the oil circuit of the side pressure compression system through a side pressure transmission pipe (7).

4. The simulation and prediction system for cascading fracture of a rock-like model based on dual sliding modes according to claim 3 is characterized in that: The side pressure compression system includes: A side pressure plate (10) is arranged on the front side of the frame, and the side pressure plate (10) is fixed to the reaction force bracket (16) on the corresponding side through a side pressure plate fixer (9); A side pressure jack (11), the fixed end of which is fixedly connected to the side pressure plate (10), and the movable end of the side pressure jack (11) is vertically arranged in the axis space of the model; The side pressure jack (11) is connected to a side pressure press (8), and the oil circuit of the side pressure press (8) is connected to the axial press (5) through the side pressure transmission pipe (7); A side pressure double-row roller row (12), one end of which is fixedly connected to the movable end of the side pressure jack (11), and the other end of which is in contact with the front side wall of the model; The reaction force support portion is fixedly connected to the reaction force bracket (16) on the side of the frame away from the side pressure plate (10), and the reaction force support portion is arranged in contact with the side of the model away from the side pressure double-row roller row (12).

5. The simulation and prediction system for cascading fracture of a rock-like model based on dual sliding modes according to claim 4, characterized in that: The reaction force support portion includes two symmetrically arranged side pressure reaction force rods (15), the two ends of the side pressure reaction force rods (15) are respectively fixed to the two reaction force brackets (16) on the corresponding sides, and the two side pressure reaction force rods (15) are fixed to the two ends of the same side pressure reaction force plate (14), and the side pressure reaction force plate (14) is arranged in contact with the back side of the model; One end of the lateral pressure reaction force rod (15) is fixedly connected to one end of the lateral pressure reaction force device (18), and the other end of the lateral pressure reaction force device (18) is fixed to the lateral pressure reaction force plate (14).

6. The simulation and prediction system for cascading fracture of a rock-like model based on dual sliding modes according to claim 1, characterized in that: The model is made from natural fault rock.

7. The simulation and prediction system for cascading fracture of a rock-like model based on dual sliding modes according to claim 1, characterized in that: The model is made of river sand: gypsum: cement: barite powder: water in a mass ratio of 54.64:8.2:5.5:13.66:18; During molding, 0.016% of the total mass of the model is added to the retarder.

8. The simulation and prediction system for cascading fracture of a rock-like model based on dual sliding modes according to claim 1, characterized in that: The model dimensions are 2 meters in length, 0.8 meters in width, and 0.6 meters in height.

9. The simulation and prediction system for cascading fracture of a rock-like model based on dual sliding modes according to claim 2, characterized in that: Optical fiber cables (1) and strain bricks (19) are pre-buried inside the model; the optical fiber cables (1) are arranged obliquely inside the model; and the strain bricks (19) are pre-buried on both sides of the locking section and the creeping section inside the model.

10. The simulation and prediction system for cascading fracture of a rock-like model based on dual sliding modes according to claim 9, characterized in that: The detection mechanism includes: an optical fiber displacement sensor (2), the optical fiber displacement sensor (2) being slidably connected to the optical fiber cable (1), the optical fiber displacement sensor (2) being fixed on the reaction force bracket (16), and the optical fiber displacement sensor (2) being used to detect the relative displacement between the optical fiber cable (1) and the optical fiber displacement sensor (2); The acoustic emission probe (20) is embedded in the middle of the locking section on the surface of the model, the middle of the top surface of the model, and the middle of the bottom surface of the model.

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