A pressure-applied passive fault displacement simulation test device and method

Abstract

This invention proposes a pressure-applied passive fault displacement simulation test device and method for active faults, belonging to the technical field. It includes a shaking table, on which a movable base and a fixed base are fixedly mounted. A movable segment is mounted on the movable base, and a fixed segment is mounted on the fixed base. The fixed and movable segments are adjacent, top-open shell structures, with the contacting side of the fixed and movable segments being open. Side beams are respectively mounted on the movable and fixed bases, contacting the front and rear sides of the movable or fixed segments. A top beam is mounted on the top of the side beams, and a vertical loading device is mounted on the top beam. A surrounding rock model is set inside the shell structure. An upper frame is slidably mounted on the top of the movable and fixed segments. The vertical loading device is used to apply vertical loads to the upper frame and the surrounding rock model. This invention considers the geostress state and can conduct passive fault displacement tests on active faults under seismic loads, achieving visualization of passive fault displacement.

Description

Technical Field

[0001] This invention belongs to the field of active fault simulation testing, and particularly relates to a device and method for simulating passive displacement of active faults under pressure. Background Technology

[0002] In recent years, the demand for tunnel and underground engineering construction has been increasing in high-intensity earthquake zones and areas with densely developed active faults, especially for the Sichuan-Tibet Railway, which traverses areas prone to moderate to strong earthquakes and more than 10 deep and large active fault zones. Tunnels crossing active fault zones are highly susceptible to engineering disasters such as lining cracking, spalling, collapse, and misalignment under earthquake action, seriously threatening the structural safety of the tunnels and affecting construction quality and costs.

[0003] Active faults are faults that have been active since the Late Quaternary period and may continue to be active in the future. The damage caused by active faults to tunnels mainly falls into three categories: seismic damage, coseismic stick-slip faulting, and creep faulting.

[0004] (1) Shaking damage is tunnel damage caused purely by seismic waves. After an earthquake is induced by the movement of an active fault, the tunnel structure is damaged as the surrounding rock deforms during the propagation of seismic waves and under the action of seismic inertial force. Since the structural damage caused by seismic inertial force is relatively minor, it can usually be repaired after the earthquake.

[0005] (2) Co-seismic stick-slip faulting refers to the damage to the tunnel structure caused by the earthquake induced by the movement of the active fault, which also accelerates the relative displacement of the two sides of the fault. The fault displacement drives the tunnel through the fault to move together. When the magnitude is large, the significant relative displacement of the rock mass on both sides of the fault often causes irreparable or even catastrophic damage to the tunnel project.

[0006] (3) Creep slip failure is equivalent to a quasi-static loading process, in which the displacement accumulated over the years is gradually applied to the lining. Tunnel failure is mainly characterized by lining cracking, which occurs gradually with the creep slip of the fault. Coseismic stick-slip slip of active faults causes more severe damage to the tunnel structure. It is particularly important to explore the rupture mechanism of the strata under coseismic stick-slip slip of active faults and the characteristics of tunnel deformation and failure.

[0007] Currently, the main methods for simulating active fault displacement are quasi-static fault dislocation simulation and seismic wave excitation.

[0008] (1) Quasi-static fault dislocation simulation is an active displacement for active faults. The active displacement of the movable disk is achieved by setting jacks at the bottom of the movable disk model box, mainly to simulate the creep displacement failure of the tunnel.

[0009] (2) Seismic wave excitation is a passive displacement. By placing the model box on the vibration table, the passive displacement of the moving plate is realized, which mainly simulates the coseismic stick-slip displacement failure of the tunnel.

[0010] Coseismic stick-slip displacement of active faults can be simulated using a passive displacement simulation test device; however, this device currently has the following shortcomings:

[0011] (1) Passive fault simulation test devices are mostly designed as integral model boxes. The rigid boundary of the model box restricts the relative fault displacement of the upper and lower plates under vibration load, resulting in a small fault displacement or even no fault displacement.

[0012] (2) The passive fault simulation test device lacks the function of vertical active loading and cannot simulate the coseismic stick-slip fault under real ground stress.

[0013] (3) The integral model box is mostly made of opaque steel, and it is impossible to directly observe its deformation and crack propagation at the fault.

[0014] (4) Most passive fault simulation test devices only focus on realizing the horizontal fault displacement, while ignoring the vertical fault displacement. Summary of the Invention

[0015] To overcome the shortcomings of the prior art, the present invention provides a pressure-capable passive fault displacement simulation test device and method, which takes into account the ground stress state, can conduct passive fault displacement tests on active faults under seismic loads, realize the visualization of passive displacement, and solve the problems in the prior art.

[0016] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0017] The first aspect of the present invention provides a pressure-capable passive fault displacement simulation test device for active faults.

[0018] A pressure-controlled passive fault displacement simulation test device includes a vibration table. A movable base and a fixed base are fixedly mounted on the vibration table. A movable segment is mounted on the movable base, and a fixed segment is mounted on the fixed base. The fixed and movable segments are adjacent, top-open shell structures with their contact surfaces open. Side beams are mounted on both the movable and fixed bases, contacting the front and rear sides of the movable or fixed segments. A top beam is mounted on the top of each side beam, and a vertical loading device is mounted on the top beam. A surrounding rock model is housed inside the shell structure. An upper frame is slidably mounted on top of the movable and fixed segments. The vertical loading device is used to apply vertical loads to the upper frame and the surrounding rock model.

[0019] Optionally, the movable frame includes a front frame, a side frame, a rear frame, and a bottom plate. The front frame, side frame, and rear frame form a first C-shaped structure. The bottom plate is located at the bottom of the first C-shaped structure. An upper frame is slidably mounted on the top of the first C-shaped structure. A top plate is located at the bottom of the upper frame.

[0020] The fixed frame includes a front frame, a side frame, a rear frame, and a base plate. The front frame, side frame, and rear frame form a second C-shaped structure. The base plate is located at the bottom of the second C-shaped structure. An upper frame is slidably mounted on the top of the second C-shaped structure. A top plate is located at the bottom of the upper frame.

[0021] Optionally, the movable front frame and the movable rear frame are respectively provided with movable front side plates and movable rear side plates near the opening, and the fixed front frame and the fixed rear frame are respectively provided with fixed front side plates and fixed rear side plates near the opening. The movable front side plates and the fixed front side plates are adapted to each other, and the movable rear side plates and the fixed rear side plates are adapted to each other. Multiple positioning rods are provided between the movable front side plates and the fixed front side plates, the movable rear side plates and the fixed rear side plates. The movable front side plates and the movable rear side plates, the fixed front side plates and the fixed rear side plates, the movable top plate and the fixed top plate are all made of transparent material.

[0022] Optionally, a first movable connecting device is provided between the vibration table and the fixed base. The first movable connecting device includes a first limiting device, a first top plate, and a ball bearing assembly. The first limiting device has a groove, and the ball bearing assembly is disposed within the groove. The ball bearing assembly includes an upper clamping plate and a lower clamping plate, which are fixed together by bolts. Holes are provided at corresponding positions on the upper and lower clamping plates, and balls are disposed in the corresponding holes, with a rolling connection between the balls and the holes. The area of ​​the groove is larger than the area of ​​the upper and lower clamping plates. The lower surface of the first top plate is in contact with the balls, the upper surface of the first top plate is connected to the fixed base, and the first limiting device is connected to the vibration table.

[0023] Optionally, the diameter of the hole is smaller than the diameter of the ball, and the distance between the upper clamping plate and the lower clamping plate is smaller than the diameter of the ball.

[0024] Optionally, the side beam includes two side beam bottom plates, two side beam columns, a side beam top plate, and two side beam flanges. The side beam top plate is disposed on the two side beam columns, and the bottom of the two side beam columns is respectively connected to the side beam bottom plates. The two side beam bottom plates are respectively connected to the upper part of the movable frame base or the fixed frame base. The two side beam flanges are respectively disposed on both sides of the side beam top plate. The two side beam columns are in contact with the movable front frame and the movable rear frame, or the fixed front frame and the fixed rear frame, respectively.

[0025] Optionally, the vertical loading device includes a hydraulic power source, a cylinder, a guide rod, and hydraulic lines. The cylinder is embedded inside the top beam and connected to the hydraulic power source via the hydraulic lines. A guide rod is connected to the extended end of the cylinder and is positioned on the top beam. A sensor connection plate is connected to the extended end of the cylinder, and a force sensor is connected to the bottom of the sensor connection plate. A ball head is connected to the bottom of the force sensor, and a ball seat is connected to the bottom of the ball head. The extended end of the cylinder drives the ball seat to contact the upper frame, applying a load to the upper frame.

[0026] Optionally, a first positioning block and a second positioning block are respectively provided at corresponding positions of the movable side frame and the fixed side frame. A first ring beam channel steel and a second ring beam channel steel are respectively provided above the first positioning block and the second positioning block. A ring beam tie rod is provided between the first ring beam channel steel and the second ring beam channel steel. The ring beam tie rod is in contact with the side beam column. A pre-tension spring is provided on the outside of the first ring beam channel steel and is sleeved on the outside of the ring beam tie rod. A force sensor is provided on the outside of the second ring beam channel steel. Locking nuts are provided at both ends of the ring beam tie rod.

[0027] Optionally, a second movable connecting device is provided between the No. 1 ring beam channel steel and the movable side frame. The second movable connecting device includes a second limiting device, a second top plate and a ball bearing row. The second limiting device is connected to the ring beam channel steel, and the second top plate is connected to the movable side frame.

[0028] A positioning longitudinal plate is connected between the movable frame base and the fixed frame base, and a positioning transverse plate is connected between the movable frame base plate and the fixed frame base plate. The positioning transverse plate is connected to the positioning longitudinal plate.

[0029] The second aspect of the present invention provides a method for simulating passive fault displacement under pressure.

[0030] A method for simulating passive fault displacement under pressure includes the following steps:

[0031] The surrounding rock model is laid in layers in the fixed and movable frames to the specified height. During the laying, the sensors are pre-embedded in the design position in the surrounding rock model. After the tunnel model is prefabricated and the sensors are deployed, the tunnel model is placed in the design position in the surrounding rock model. The sensor wires in the surrounding rock model and the tunnel model are connected to the data acquisition device to build a pressure-pressurized passive fault simulation test device.

[0032] The extended end of the control cylinder moves downward, causing the ball seat to contact the fixed upper frame and the movable upper frame respectively;

[0033] Remove the positioning rod;

[0034] The surrounding rock model is subjected to graded loading. The next loading stage can only be carried out after each loading stage reaches the design value and remains stable. When the surrounding rock model reaches the final design value and remains stable, the loading is stopped, and the ball seat is kept stable at the position where the final loading ends.

[0035] During the graded loading process, if the lateral stress in the surrounding rock model is greater than the axial force of the ring beam tie rod, causing a crack between the fixed and movable frames, tighten the preload nuts of the No. 1 ring beam channel steel; if the lateral stress in the surrounding rock model is less than the axial force of the ring beam tie rod, causing the fixed and movable frames to be spliced ​​too tightly, loosen the preload nuts of the No. 1 ring beam channel steel.

[0036] A dynamic load is input to the vibration table surface, and the axial compression loading device remains stable during the vibration process. Data output from sensors in the surrounding rock model and tunnel model are collected and recorded in real time during the passive displacement process.

[0037] The above one or more technical solutions have the following beneficial effects:

[0038] (1) It has the function of vertical active loading. During vertical loading, the boundary of the model box can provide support reaction force to simulate the ground stress state at different burial depths of the fault, and it can also be vertically stable during the dynamic load process. After the stress in the stratum model reaches the design value and remains stable, if the axial pressure is removed, a tension fault can be simulated; if the axial pressure is not removed, a compression-torsion fault can be simulated.

[0039] (2) It has a horizontal passive displacement function. The model box of the simulation test device consists of a movable frame and a fixed frame. The bottom of the movable frame is bolted to the vibration table, and the movable frame can move indiscriminately with the vibration table. A ball bearing structure is set between the bottom of the fixed frame and the vibration table. This structure can minimize the friction between the fixed frame and the vibration table, so that the fixed frame is stationary relative to the vibration table (i.e., the movable frame). The fixed frame and the movable frame are in contact in the thickness plane of the front and rear side plates, the top plate and the bottom plate. When the horizontal dynamic load output by the vibration table exceeds the frictional resistance of the fault model, horizontal relative displacement can occur, and the maximum horizontal displacement is the thickness of the side plates.

[0040] (3) It has a vertical passive displacement function. When the vibration table outputs a vertical dynamic load, the movable frame can move vertically without difference with the vibration table. A ball bearing structure is set between the fixed frame and the vibration table. When the vertical dynamic load on the vibration table is transferred to the fixed frame above, it will be relatively reduced. The vibration amplitude of the fixed frame is less than the vibration amplitude of the movable frame that is directly bolted to the vibration table. Vertical relative displacement occurs between the fixed frame and the movable frame, and the maximum vertical displacement is the thickness of the top and bottom plates.

[0041] (4) A ball bearing structure is provided on one side of the movable frame. The movable frame is directly bolted to the vibration table and vibrates indiscriminately with the vibration table. The vibration of the movable frame may be transmitted to the fixed frame. In order to reduce the transmission of the vibration of the movable frame to the fixed frame, a ball bearing structure is provided on one side of the movable frame to make the vibration difference between the two as large as possible.

[0042] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0043] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0044] Figure 1 This is a three-dimensional schematic diagram of the overall structure of Embodiment 1 of the present invention.

[0045] Figure 2 This is a front view schematic diagram of the overall structure of Embodiment 1 of the present invention.

[0046] Figure 3 This is a side view of the overall structure of Embodiment 1 of the present invention.

[0047] Figure 4 This is a top view of the overall structure of Embodiment 1 of the present invention.

[0048] Figure 5 This is a front view schematic diagram of the first active connecting device according to Embodiment 1 of the present invention.

[0049] Figure 6 This is a front view schematic diagram of the second active connecting device according to Embodiment 1 of the present invention.

[0050] Figure 7 This is a schematic diagram of the contact between the ball bearing and the clamping plate in the first movable connecting device according to Embodiment 1 of the present invention.

[0051] The attached diagram lists the components represented by each number as follows:

[0052] 1-Guide rod, 2-Hydraulic cylinder, 3-Top beam, 4-Side beam top plate, 5-Front flange, 6-Side beam flange, 7-Side beam column, 8-Modible frame front frame, 9-First top plate, 10-Ball bearing, 11-First limit device, 12-Locking nut, 13-Preload spring, 1401-First ring beam channel steel, 1402-Second ring beam channel steel, 1501-First positioning block, 1502-Second positioning block, 16-Modible frame bottom plate, 17-Modible frame base, 18-Side beam bottom plate, 19-Positioning longitudinal plate, 20-Positioning transverse plate, 21-Fixed frame base, 22-Fixed frame bottom plate, 23-Ring beam tie rod, 24- Force sensor, 25-fixed front frame, 26-movable front side plate, 27-fixed front side plate, 28-positioning rod, 29-sensor connecting plate, 30-ball head, 31-ball seat, 32-movable side frame, 33-movable rear frame, 34-lower clamping plate, 35-movable rear side plate, 36-movable upper frame, 37-fixed side frame, 38-fixed upper frame, 39-fixed rear side plate, 40-fixed rear frame, 41-movable top plate, 42-fixed top plate; 43-upper clamping plate, 44-bolt, 45-groove, 46-second limiting device, 47-second top plate. Detailed Implementation

[0053] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0054] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0055] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0056] The overall concept proposed in this invention is as follows:

[0057] This invention proposes a simulation test device and method for passively displaced active faults under pressure. The model box in the device adopts a segmented design, consisting of a fixed frame and a movable frame. The two model boxes can be spliced ​​at a certain angle, and this angle can be automatically adjusted according to the dip angle of the simulated fault. When used in conjunction with a shaking table, the two model boxes can undergo horizontal and vertical displacement separately or simultaneously under vibration load. The maximum horizontal and vertical displacement does not exceed the thickness of the front and rear side plates and the top and bottom plates of the two model boxes, respectively, and the maximum displacement can be automatically adjusted according to the coseismic stick-slip displacement of the simulated fault.

[0058] The top of each of the two model boxes is equipped with an axial compression loading device, which can load the surrounding rock model in the two model boxes in stages before the vibration load is applied, so that the stress in the surrounding rock model reaches the design value and simulates the in-situ stress state of the surrounding rock at the depth of the tunnel. In addition, during the vibration load, the axial compression loading device can also stabilize the stress in the surrounding rock model at the design value level, without being disturbed by dynamic loads and horizontal and vertical displacement.

[0059] Example 1

[0060] This embodiment discloses a pressure-capable passive fault displacement simulation test device for active faults.

[0061] like Figure 1 As shown, a pressure-applied passive fault displacement simulation test device for active faults includes a vibration table. A movable base 17 and a fixed base 21 are fixedly mounted on the vibration table. A movable component is mounted on the movable base 17, and a fixed component is mounted on the fixed base 21. The fixed and movable components are adjacent, top-open shell structures, with the contacting side of the fixed and movable components being open. Side beams are respectively mounted on the movable base 17 and the fixed base 21, contacting the front and rear sides of the movable or fixed components. A top beam 3 is mounted on the top of the side beams, and a vertical loading device is mounted on the top beam 3. A surrounding rock model is installed inside the shell structure. An upper frame is slidably mounted on the top of the movable and fixed components. The vertical loading device is used to apply vertical loads to the upper frame and the surrounding rock model.

[0062] Furthermore, the movable frame includes a front frame 8, a side frame 32, a rear frame 33, and a bottom plate 16. The front frame 8, side frame 32, and rear frame 33 form a first C-shaped structure. The bottom plate 16 is located at the bottom of the first C-shaped structure. An upper frame 36 is slidably mounted on the top of the first C-shaped structure. A top plate 41 is mounted on the lower part of the upper frame 36.

[0063] The fixing frame includes a front fixing frame 25, a side fixing frame 37, a rear fixing frame 40, and a base fixing frame 22. The front fixing frame 25, the side fixing frame 37, and the rear fixing frame 40 form a second C-shaped structure. The base fixing frame 22 is located at the bottom of the second C-shaped structure. An upper fixing frame 38 is slidably mounted on the top of the second C-shaped structure. A top fixing frame 42 is located at the bottom of the upper fixing frame 38.

[0064] The movable front frame 8 and movable rear frame 33 are respectively provided with movable front side plates 26 and movable rear side plates 35 near the opening. The fixed front frame 25 and fixed rear frame 40 are respectively provided with fixed front side plates 27 and fixed rear side plates 39 near the opening. The movable front side plates 26 and fixed front side plates 27 are adapted to each other. Plate 35 and fixed rear side plate 39 are adapted to each other; multiple positioning rods 28 are provided between the movable front side plate 26 and the fixed front side plate 27, the movable rear side plate 35 and the fixed rear side plate 39; the movable front side plate 26 and the movable rear side plate 35, the fixed front side plate 27 and the fixed rear side plate 39, the movable top plate 41 and the fixed top plate 42 are all made of transparent material.

[0065] The simulation test device for passive displacement of active faults under pressure in this embodiment includes a model box, an axial compression loading device, a top beam 3, side beams, a base, a ring beam, and a 10-row ball bearing structure.

[0066] The model box mainly consists of two parts: a movable frame and a fixed frame. Both the fixed frame and the movable frame are composed of a front frame, a rear frame, side frames, a front side plate, a rear side plate, an upper frame, a top plate, and a bottom plate.

[0067] (1) The front frame, rear frame and side frame adopt a grid structure, which is welded from steel plates and steel grids;

[0068] (2) The front side plate, rear side plate and top plate are made of high-strength, transparent and durable materials. When a fault model is set at the splice of two pieces with horizontal and vertical misalignment, the horizontal and vertical passive misalignment and deformation and damage of the fault model can be captured by means of high-speed photography.

[0069] (3) The front and rear frame steel plates are respectively provided with front side plates and rear side plates. The front frame, front side plates and rear frame, rear side plates are respectively bolted 44. The frame and side plates together bear the transverse stress generated by Poisson effect under vertical load on the surrounding rock model.

[0070] (4) The inner side of the side frame steel plate is in direct contact with the surrounding rock model and can withstand the lateral stress generated by the surrounding rock model;

[0071] (5) The upper frame is a steel grid structure with no inner steel plate. It is in direct contact with the top plate below. The upper frame directly bears the vertical load applied by the axial compression loading device and transmits the vertical load to the top plate and surrounding rock model below in sequence.

[0072] (6) Sensor wire holes are reserved on the top plate to facilitate connecting the sensor wires in the surrounding rock model box to the data acquisition device;

[0073] (7) The base plate is made of steel and can withstand the gravity and vertical load of the surrounding rock model and tunnel model above.

[0074] The front frame, rear frame, and side frame are connected by bolts 44 to form a C-shaped structure, while the upper frame, to accommodate the vertical loading stroke of the hydraulic cylinder 2, is not connected to the aforementioned three frame bolts 44. The lateral stress generated by the surrounding rock model can easily cause relative displacement of the C-shaped structure formed by the aforementioned three frame bolts 44 at the opening; therefore, a crossbeam must be installed at this opening to prevent the front and rear frames from overturning. The aforementioned grating and steel grating design reduces their weight while ensuring the rigidity of the two model boxes.

[0075] To achieve a movable connection between the vibration table and the fixed base 21, and to allow asynchronous movement between the movable base 17 and the fixed base 21, facilitating misalignment between the fixed and movable bases connected thereto, a first movable connection device is provided between the vibration table and the fixed base 21. This first movable connection device includes a first limiting device 11, a first top plate 9, and a row of 10 balls. The first limiting device 11 has a groove 45, and the row of 10 balls is disposed within the groove 45. The row of 10 balls includes an upper clamping plate 43 and a lower clamping plate 34, which are fixed together by bolts 44. Holes are provided at corresponding positions on both the upper and lower clamping plates 43 and 34, and a ball 10 is disposed within each hole. The ball 10 is in a rolling connection with the hole.

[0076] The area of ​​the groove 45 is larger than the area of ​​the upper clamping plate 43 and the lower clamping plate 34; the lower surface of the first top plate 9 is in contact with the ball 10, the upper surface of the first top plate 9 is connected to the fixed base 21, and the first limiting device 11 is connected to the vibration table.

[0077] The diameter of the hole is smaller than the diameter of the ball 10, and the distance between the upper clamping plate 43 and the lower clamping plate 34 is smaller than the diameter of the ball 10.

[0078] The 10-row ball bearing structure mainly includes a 10-row ball bearing top plate, 10 balls, and a limiting device. This structure is arranged below the fixed frame base 21 and inside the channel steel of the movable frame ring beam. The 10-row ball bearing top plate is bolted 44 to the fixed frame base 21 and the movable frame side frame 32, respectively. The 10-row ball bearing top plate is in direct contact with the 10 balls. The 10 balls are held by two clamping plates of the same area, with the distance between the clamping plates being less than the diameter of the 10 balls. The two clamping plates are connected by bolts 44. The 10 balls and the clamping plates only have four points of contact. The 10 balls can easily overcome the frictional force at the point of contact and roll. When the 10 balls roll, they can maintain their initial distribution density and spacing.

[0079] The limiting device is connected to the vibration table and the ring beam channel steel bolt 44 at the movable frame. The height of the groove in the limiting device is level with the far surface of the clamping plate closest to the groove, and the area of ​​the groove is larger than the area of ​​the clamping plate. The clamping plate can only move as far as the groove, so the ball 10 can only roll within the area of ​​the groove. When the movement of the clamping plate is restricted by the groove, the ball 10 can still overcome the friction between itself and the clamping plate and roll.

[0080] The loads borne by the ball bearings 10 must be considered when arranging them. Since the top plate of the ball bearing 10 row is connected to the fixed base 21 by bolts 44, and the top plate of the ball bearing 10 row is in direct contact with the ball bearings 10, the ball bearings 10 must bear the force above the fixed base 21. Similarly, the limiting device is connected to the ring beam channel steel at the movable frame by bolts 44, and the limiting device is in direct contact with the ball bearings 10, so the ball bearings 10 must bear the axial force of the ring beam tie rod 23. Based on the loads that the ball bearings 10 at the fixed base 21 and the ring beam channel steel at the movable frame, and the ultimate bearing capacity of the ball bearings 10, the required number of ball bearings 10 is calculated. Following the principle of uniform force distribution on the ball bearings 10, the ball bearings 10 are evenly distributed with the midpoint of the groove surface as the center. The distance between the ball bearing 10 clamping plate and the groove is reserved according to the coseismic stick-slip horizontal displacement of the simulated fault.

[0081] The side beam includes two side beam base plates 18, two side beam columns 7, a side beam top plate 4, and two side beam flanges 6. The side beam top plate 4 is disposed on the two side beam columns 7. The bottom of the two side beam columns 7 is respectively connected to the side beam base plates 18. The two side beam base plates 18 are respectively connected to the upper part of the movable frame base 17 or the fixed frame base 21. The two side beam flanges 6 are respectively disposed on both sides of the side beam top plate 4. The two side beam columns 7 are in contact with the movable frame front frame 8 and the movable frame rear frame 33, or the fixed frame front frame 25 and the fixed frame rear frame 40.

[0082] The top beam 3, side beams, and base are all made of structural steel. The hydraulic cylinder 2 of the vertical loading device is mounted on the lower surface of the top beam 3 using a front flange. The main body of the cylinder 2 is embedded within the top beam 3, reducing the overall height of the device and preventing it from tilting under vibration loads due to excessive height. The side beam is welded from four parts: a top plate, columns, wing plates, and a bottom plate. The side beam columns 7 are in direct contact with the front and rear frames of the two model boxes, assisting the front and rear frames and their side plates in jointly bearing the lateral stress generated by the surrounding rock model. The base is bolted to the bottom plate of the model box (44), jointly bearing the weight and vertical load of the model box and the surrounding rock model. The top beam 3 and the base are connected to the side beam bolts (44) to form a closed-loop force distribution, providing reliable reaction force for the axial compression loading device and reliable support for the model box.

[0083] The vertical loading device includes a hydraulic power source, a cylinder 2, a guide rod 1, and hydraulic lines. The cylinder 2 is embedded inside the top beam 3 and connected to the hydraulic power source through the hydraulic lines. The guide rod 1 is connected to the extended end of the cylinder 2 and is positioned on the top beam 3. A sensor connection plate 29 is connected to the extended end of the cylinder 2. A force sensor 24 is connected to the bottom of the sensor connection plate 29. A ball head 30 is connected to the bottom of the force sensor 24. A ball seat 31 is connected to the bottom of the ball head 30. The extended end of the cylinder 2 drives the ball seat 31 to contact the upper frame, applying a load to the upper frame.

[0084] The vertical loading device in this embodiment mainly includes a hydraulic power source, a hydraulic cylinder 2, a guide rod 1 for the hydraulic cylinder 2, hydraulic pipelines, a servo motor valve group, a servo control system, and a control cabinet, etc.

[0085] (1) The hydraulic power source is the power source of the axial pressure loading device. It should have sufficient power to make the stress of the surrounding rock model in the two model boxes reach the design value.

[0086] (2) The hydraulic cylinder 2 is the terminal of the axial compression loading device to apply vertical load to the surrounding rock model, and has two loading control modes: constant displacement and constant force.

[0087] (3) During the vertical loading process, when the ball seat 31 of the hydraulic cylinder 2 contacts the surface of the upper frame at a certain angle, the ball head 30 can automatically correct the deviation to prevent the hydraulic cylinder 2 from deviating during the loading stroke; the guide rod 1 of the hydraulic cylinder 2 can prevent the hydraulic cylinder 2 from rotating during vertical displacement, thus avoiding torque on the contact surface between the hydraulic cylinder 2 and the upper frame.

[0088] (4) The hydraulic pipeline is controlled by the servo motor valve group to control the oil inlet and outlet of the oil cylinder 2. It can smoothly connect the control cabinet and the oil cylinder 2. The fixed frame and the movable frame are respectively equipped with hydraulic pipelines to prevent the top plates of the two frames from being misaligned during the staged loading process.

[0089] (5) The servo motor valve group can receive computer commands to control the output of fluid power sources such as air pressure, flow rate and hydraulic pressure, so as to achieve precise control of the oil inlet and outlet of the hydraulic pipeline;

[0090] (6) The servo control system can control the servo motor valve group to work. Its operating software has an industrial screen display function and is integrated on the surface of the control cabinet. It also has a computer synchronous display function. The loading parameters can be adjusted on the industrial screen or computer according to the actual situation.

[0091] (7) The hydraulic power source, servo motor valve group and servo control system are integrated in the control cabinet. The hydraulic pipeline is connected from the hydraulic power source in the control cabinet to the oil cylinder 2. The control cabinet adopts a mobile design to facilitate movement and transportation.

[0092] The movable side frame 32 and the fixed side frame 37 are respectively provided with a first positioning block 1501 and a second positioning block 1502 at corresponding positions. A first ring beam channel steel 1401 and a second ring beam channel steel 1402 are respectively provided above the first positioning block 1501 and the second positioning block 1502. A ring beam tie rod 23 is provided between the first ring beam channel steel 1401 and the second ring beam channel steel 1402. The ring beam tie rod 23 is in contact with the side beam column 7. A pre-tension spring 13 is provided on the outside of the first ring beam channel steel 1401. The pre-tension spring 13 is sleeved on the outside of the ring beam tie rod 23. A force sensor 24 is provided on the outside of the second ring beam channel steel 1402. Locking nuts 12 are provided at both ends of the ring beam tie rod 23.

[0093] A second movable connecting device is provided between the No. 1 ring beam channel steel and the movable side frame 32. The second movable connecting device includes a second limiting device 46, a second top plate 47 and 10 rows of ball bearings. The second limiting device 46 is connected to the ring beam channel steel, and the second top plate 47 is connected to the movable side frame 32.

[0094] The ring beam consists of a ring beam channel steel, a ring beam tie rod 23, a preload nut, a preload spring 13, and a force sensor 24. The ring beam channel steel is placed on the positioning block of the side frame of the model box and is connected by the tie rod, the preload spring 13, and the preload nut to form a closed force loop.

[0095] During the vertical load grading process, when the lateral stress gradually increases and a gap appears between the two models, the preload nut can be rotated to force the preload spring 13 to contract, so that the two model boxes can re-contact. In order to prevent the two model boxes from contacting too tightly and failing to produce horizontal and vertical displacement under vibration load, force sensors 24 are installed to monitor the axial force of the tie rod in real time, and earth pressure cells are installed in the surrounding rock model to monitor its lateral stress in real time. By rotating the preload nut, the preload spring 13 is forced to compress or stretch to adjust the axial force of the tie rod so that it is equal to the lateral stress of the surrounding rock model.

[0096] A positioning longitudinal plate 19 is connected between the movable base 17 and the fixed base 21, and a positioning transverse plate 20 is connected between the movable base plate 16 and the fixed base plate 22. The positioning transverse plate 20 is connected to the positioning longitudinal plate 19.

[0097] This device is used in conjunction with a shaking table. The fundamental frequency of the device must be far removed from the fundamental frequencies of both the device and the surrounding rock model to avoid resonance. Furthermore, the damping of the device must be lower than that of both the device and the surrounding rock model, with the damping of the device and the surrounding rock model taking precedence. The damping of the device will not significantly affect the vibration of the device and the surrounding rock model. The total weight of the device and the surrounding rock model must be lower than the maximum load of the shaking table, and the horizontal displacement between the two frames must be lower than the maximum horizontal displacement of the shaking table.

[0098] Example 2

[0099] This embodiment discloses a method for simulating passive displacement of active faults under pressure.

[0100] A method for simulating passive fault displacement under pressure includes the following steps:

[0101] The surrounding rock model is laid in layers in the fixed and movable frames to the specified height. During the laying, the sensors are pre-embedded in the design position in the surrounding rock model. After the tunnel model is prefabricated and the sensors are deployed, the tunnel model is placed in the design position in the surrounding rock model. The sensor wires in the surrounding rock model and the tunnel model are connected to the data acquisition device to build a pressure-pressurized passive fault simulation test device.

[0102] The extended end of the control cylinder 2 is moved downward, so that the ball seat 31 contacts the fixed frame 38 and the movable frame 36 respectively;

[0103] Remove positioning rod 28;

[0104] The surrounding rock model is subjected to graded loading. The next level of loading can only be applied after each level of loading reaches the design value and remains stable. When the graded loading of the surrounding rock model reaches the final design value and remains stable, the loading is stopped, and the ball seat 31 is kept stable at the position where the final loading ends.

[0105] During the graded loading process, if the lateral stress in the surrounding rock model is greater than the axial force of the ring beam tie rod 23, causing a crack between the fixed and movable frames, tighten the preload nut of the No. 1 ring beam channel steel 1401; if the lateral stress in the surrounding rock model is less than the axial force of the ring beam tie rod 23, causing the fixed and movable frames to be spliced ​​too tightly, loosen the preload nut of the No. 1 ring beam channel steel 1401.

[0106] A dynamic load is input to the vibration table surface, and the axial compression loading device remains stable during the vibration process. Data output from sensors in the surrounding rock model and tunnel model are collected and recorded in real time during the passive displacement process.

[0107] More specifically, including:

[0108] Step 1: Connect the movable base 17, the limiting device under the fixed base to the vibration table bolt 44, place the ball bearings 10 and the top plate of the ball bearings 10 in the groove of the limiting device in sequence, and connect the top plate of the ball bearings 10 to the fixed base 21 bolt 44.

[0109] Step 2: Connect the positioning plate 19 to the movable frame and the fixed frame base 21 with bolts 44 to ensure that the upper surfaces of the two bases are at the same height;

[0110] Step 3: Connect the two base plates to their base bolts 44. The positioning horizontal plate 20 is connected to the positioning vertical plate 19 with bolts 44 below the contact point of the two base plates to ensure that the upper surfaces of the two base plates are at the same height.

[0111] Step 4: After leveling the two base plates, connect the base plates, front frame, rear frame and side frame with bolts 44, and connect the front side plates and rear side plates to the front frame and rear frame with bolts 44 respectively. After splicing the two front side plates and the rear side plates at the same angle, insert the positioning rod 28 and fix it with bolts 44 at both ends to ensure that the two front side plates and the rear side plates are on the same side.

[0112] Step 5: Connect the four side beams to the two front and rear frames respectively, and connect them to the base bolts 44 respectively;

[0113] Step 6: Connect the front flange 5 of the cylinder 2 of the axial pressure loading device to the bolts 44 on the lower surface of the top beam 3, and at the same time pass the positioning rod 28 through the reserved hole provided for it in the top beam 3;

[0114] Step 7: Connect the top beam 3 to the side beam bolts 44 after installing the hydraulic cylinder 2 and positioning rod 28, and connect the hydraulic pipeline between the hydraulic cylinder 2 and the control cabinet. Debug the axial pressure loading device.

[0115] Step 8: Connect the positioning block to the two side frame bolts 44, and place the two ring beam channel steels on one side of the fixed frame on the positioning block;

[0116] Step 9: Connect the two ring beam channel steels on one side of the movable frame to the limiting device bolts 44, and connect the ball bearing 10-row top plate to the movable frame side frame 32 bolts 44;

[0117] Step 10: Place the ring beam channel steel of the bolt 44 connecting the limiting device on the positioning block, and clamp the ball 10 in the limiting device and the top plate of the ball 10 row;

[0118] Step 11: Pass the ring beam tie rod 23 through the reserved holes of the two ring beam channel steels. Install the force sensor 24 on the outside of the ring beam channel steel on the fixed side of the ring beam tie rod 23 and lock it with the preload nut. Install the preload spring 13 on the outside of the ring beam channel steel on the movable side of the ring beam tie rod 23 and lock it with the preload nut.

[0119] Step 12: Lay the surrounding rock model in layers inside the two model boxes, and embed various sensors in the design position in the surrounding rock model during the laying process. After prefabricating the tunnel model and installing the sensors, place it in the design position in the surrounding rock model.

[0120] Step 13: After laying the surrounding rock model to the specified height, lay the top plates of the two model boxes on the surrounding rock model, and connect the sensor wires in the surrounding rock model and tunnel model through the reserved holes on the top plates to the data acquisition device.

[0121] Step 14: Lay the upper frame on the top plate and control the hydraulic cylinder 2 to move downward so that the ball seat 31 contacts the upper frame;

[0122] Step 15: Remove positioning rod 28 and positioning plate;

[0123] Step 16: Apply graded loading to the surrounding rock model. The next grade of loading can only be applied after each loading reaches the design value and remains stable. When the graded loading of the surrounding rock model reaches the final design value and remains stable, stop loading and keep the ball seat 31 stable at the position where the final loading ends.

[0124] Step 17: During the graded loading process, if the lateral stress in the surrounding rock model is greater than the axial force of the ring beam tie rod 23, causing a crack between the two model boxes, tighten the preload nut on one side of the ring beam of the movable box; if the lateral stress in the surrounding rock model is less than the axial force of the ring beam tie rod 23, causing the two model boxes to be spliced ​​too tightly, loosen the preload nut on one side of the ring beam of the movable box.

[0125] Step 18: Input dynamic load to the vibration table surface. The axial compression loading device remains stable during vibration. Collect and record the data output by the sensors in the surrounding rock model and tunnel model in real time during the passive displacement process.

[0126] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0127] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A pressure-activated passive fault displacement simulation test device, characterized in that, The device includes a vibration table, on which a movable base and a fixed base are fixedly mounted. A movable component is mounted on the movable base, and a fixed component is mounted on the fixed base. The fixed and movable components are adjacent, top-open shell structures with the contacting surfaces of the fixed and movable components being open. Side beams are mounted on both the movable and fixed bases, contacting the front and rear sides of the movable or fixed component. A top beam is mounted on the top of each side beam, and a vertical loading device is mounted on the top beam. A surrounding rock model is housed inside the shell structure. An upper frame is slidably mounted on the top of the movable and fixed components. The vertical loading device is used to apply vertical loads to the upper frame and the surrounding rock model. A first movable connecting device is provided between the vibration table and the fixed base. The first movable connecting device includes a first limiting device, a first top plate, and a ball bearing assembly. The first limiting device has a groove, and the ball bearing assembly is disposed within the groove. The ball bearing assembly includes an upper clamping plate and a lower clamping plate, which are fixed together by bolts. Holes are provided at corresponding positions on the upper and lower clamping plates, and balls are disposed in the corresponding holes, with a rolling connection between the balls and the holes. The area of ​​the groove is larger than the area of ​​the upper and lower clamping plates. The lower surface of the first top plate is in contact with the balls, and the upper surface of the first top plate is connected to the fixed base. The first limiting device is connected to the vibration table. The movable frame includes a front frame, side frames, rear frames, and a base plate; the fixed frame includes a front frame, side frames, rear frames, and a base plate; a first positioning block and a second positioning block are respectively installed at corresponding positions on the movable and fixed side frames; a first ring beam channel steel and a second ring beam channel steel are respectively installed above the first and second positioning blocks; a ring beam tie rod is installed between the first and second ring beam channel steels; the ring beam tie rod is connected to... The side beams and columns are in contact. A pre-tensioning spring is provided on the outside of the first ring beam channel steel, and the pre-tensioning spring is sleeved on the outside of the ring beam tie rod. A force sensor is provided on the outside of the second ring beam channel steel. Locking nuts are provided at both ends of the ring beam tie rod. A second movable connecting device is provided between the first ring beam channel steel and the movable side frame. The second movable connecting device includes a second limiting device, a second top plate and a ball bearing row. The second limiting device is connected to the ring beam channel steel, and the second top plate is connected to the movable side frame.

2. The active fault pressure-capable passive displacement simulation test device as described in claim 1, characterized in that, The movable front frame, movable side frame, and movable rear frame form a first C-shaped structure. The movable bottom plate is located at the bottom of the first C-shaped structure. The movable upper frame is slidably mounted on the top of the first C-shaped structure. The movable top plate is located at the lower part of the movable upper frame. The fixed front frame, fixed side frame, and fixed rear frame form a second C-shaped structure. The fixed bottom plate is located at the bottom of the second C-shaped structure. The fixed upper frame is slidably mounted on the top of the second C-shaped structure. The fixed top plate is located at the bottom of the fixed upper frame.

3. The active fault pressure-capable passive displacement simulation test device as described in claim 2, characterized in that, The movable front frame and movable rear frame are respectively provided with movable front side plates and movable rear side plates near the opening. The fixed front frame and fixed rear frame are respectively provided with fixed front side plates and fixed rear side plates near the opening. The movable front side plates and fixed front side plates are adapted to each other, and the movable rear side plates and fixed rear side plates are adapted to each other. Multiple positioning rods are provided between the movable front side plates and fixed front side plates, the movable rear side plates and fixed rear side plates. The movable front side plates and movable rear side plates, the fixed front side plates and fixed rear side plates, the movable top plate and the fixed top plate are all made of transparent material.

4. The active fault pressure-capable passive displacement simulation test device as described in claim 1, characterized in that, The diameter of the hole is smaller than the diameter of the ball, and the distance between the upper clamping plate and the lower clamping plate is smaller than the diameter of the ball.

5. The active fault pressure-capable passive displacement simulation test device as described in claim 1, characterized in that, The side beam includes two side beam bottom plates, two side beam columns, a side beam top plate, and two side beam flanges. The side beam top plate is disposed on the two side beam columns. The bottom of the two side beam columns is respectively connected to the side beam bottom plates. The two side beam bottom plates are respectively connected to the upper part of the movable frame base or the fixed frame base. The two side beam flanges are respectively disposed on both sides of the side beam top plate. The two side beam columns are in contact with the movable front frame and the movable rear frame, or the fixed front frame and the fixed rear frame, respectively.

6. The active fault pressure-capable passive displacement simulation test device as described in claim 3, characterized in that, The vertical loading device includes a hydraulic power source, a cylinder, a guide rod, and hydraulic lines. The cylinder is embedded inside the top beam and connected to the hydraulic power source via the hydraulic lines. A guide rod is connected to the extended end of the cylinder and is positioned on the top beam. A sensor connection plate is connected to the extended end of the cylinder, and a force sensor is connected to the bottom of the sensor connection plate. A ball head is connected to the bottom of the force sensor, and a ball seat is connected to the bottom of the ball head. The extended end of the cylinder drives the ball seat to contact the upper frame, applying a load to the upper frame.

7. The active fault pressure-capable passive displacement simulation test device as described in claim 6, characterized in that, A positioning longitudinal plate is connected between the movable frame base and the fixed frame base, and a positioning transverse plate is connected between the movable frame base plate and the fixed frame base plate. The positioning transverse plate is connected to the positioning longitudinal plate.

8. A simulation test method for a pressure-applied passive fault displacement simulation test device as described in claim 6, characterized in that, Includes the following steps: The surrounding rock model is laid in layers in the fixed and movable frames to the specified height. During the laying, the sensors are pre-embedded in the design position in the surrounding rock model. After the tunnel model is prefabricated and the sensors are deployed, the tunnel model is placed in the design position in the surrounding rock model. The sensor wires in the surrounding rock model and the tunnel model are connected to the data acquisition device to build a pressure-pressurized passive fault simulation test device. The extended end of the control cylinder moves downward, causing the ball seat to contact the fixed upper frame and the movable upper frame respectively; Remove the positioning rod; The surrounding rock model is subjected to graded loading. The next loading stage can only be carried out after each loading stage reaches the design value and remains stable. When the surrounding rock model reaches the final design value and remains stable, the loading is stopped, and the ball seat is kept stable at the position where the final loading ends. During the graded loading process, if the lateral stress in the surrounding rock model is greater than the axial force of the ring beam tie rod, causing cracks between the fixed and movable frames, tighten the locking nut of the No. 1 ring beam channel steel. If the lateral stress in the surrounding rock model is less than the axial force of the ring beam tie rod, causing the fixed and movable frames to be spliced ​​too tightly, then loosen the locking nut of the No. 1 ring beam channel steel. A dynamic load is input to the vibration table surface, and the vertical loading device remains stable during the vibration process. Data output from sensors in the surrounding rock model and tunnel model are collected and recorded in real time during the passive displacement process.

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