Large-scale multifunctional experimental equipment and method for transparent simulation of multi-field coupled environment

Abstract

The present application relates to the fields of rock mechanics and underground engineering technology, and provides a large-scale multifunctional experimental device and method for transparent simulation of a multi-field coupled environment. The large-scale multifunctional experimental device for transparent simulation of a multi-field coupled environment comprises: a fixed frame, a three-axis power loading system, an environmental simulation chamber, a seepage system, and an information acquisition system; the three-axis power loading system is arranged on the fixed frame, the environmental simulation chamber is placed on the support platform of the fixed frame, and a rock sample is placed in the environmental simulation chamber; the seepage system is connected to the rock sample, and the information acquisition system is connected to the seepage system and the rock sample. By designing the fixed frame, the three-axis power loading system, the environmental simulation chamber, and the seepage system, precise control of the stress, temperature, and fluid of the rock sample is achieved, and the complex thermal-hydraulic-mechanical coupling environmental conditions deep underground can be simulated. The environmental simulation chamber can accommodate large-sized rock samples through a detachable upper and lower insulation boxes.

Description

Technical Field

[0001] The present application belongs to the field of rock mechanics and underground engineering technology, and more specifically, relates to a large-scale multifunctional experimental device and method for transparent simulation of a multi-field coupled environment. Background Art

[0002] With increasing demand for resources and the gradual depletion of shallow resources, mineral mining is advancing deeper. As a renewable, clean energy source with widespread reserves deep underground, geothermal energy offers new opportunities for innovation in deep mining models. The large-scale fracture networks created by techniques such as shaft excavation and drill-and-blast caving during mineral mining provide a sound structural foundation for geothermal mining, which in turn offers a cost-effective solution to mitigate the high-temperature heat damage associated with deep mining. The coordinated and integrated development and utilization of minerals and geothermal energy contributes to a win-win situation of enhanced economic efficiency and sustainable development, meeting the needs of energy transition and strategic resource development.

[0003] However, the deep underground environment is complex. Unconventional conditions such as high geostress, high ground temperature, and high osmotic pressure can significantly alter the physical and mechanical properties of rock masses. The mechanical behavior of rock masses under thermal-hydraulic-mechanical coupling is even more complex, especially near weak structures such as fault zones. Furthermore, engineering disturbances such as blasting, excavation, liquid injection heat extraction, and hydraulic fracturing can lead to a redistribution of the temperature-stress-fluid field, inducing new stress concentration areas and fracture networks. This increases the rock mass's high energy storage, increases the risk of fault slip, and triggers dynamic instability hazards. Therefore, to promote the active exploration and widespread application of deep mineral-thermal co-mining models and ensure their safety, it is particularly important to study the mechanisms of rock mass instability, especially fault instability, under multi-field coupling.

[0004] Due to the unconventional conditions required, existing rock experiment equipment involving multi-field coupling is typically limited to small specimen sizes (50x100mm cylinders) to ensure long-term stable operation. These instruments often utilize a heating method, whereby heat is transferred from a heated confining fluid to the rock. This method places high demands on the fluid's thermal stability, resulting in high costs. The equipment is typically housed in a highly enclosed space to ensure safety, making it difficult to visualize the experimental process. Furthermore, due to the small specimen size and highly sealed environment, monitoring instruments such as displacement sensors and acoustic emission sensors cannot directly contact the rock surface, making it difficult to accurately capture key signals during the experiment. This, in turn, hinders analysis of rock fracture propagation or the evolution of fault slip behavior. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the existing technologies, the purpose of the embodiments of the present application is to provide a large-scale multifunctional experimental equipment for transparent simulation of multi-field coupling environment, which has the advantages of transparency and visualization, large sample size, and direct contact of monitoring instruments.

[0006] To achieve the above objectives, the technical solution adopted in this application is to provide a large-scale multifunctional experimental device for multi-field coupled environmental transparency simulation, including: a fixed frame, a three-axis dynamic loading system, an environmental simulation chamber, a seepage system and an information acquisition system;

[0007] The triaxial dynamic loading system is arranged on a fixed frame, the environmental simulation chamber is placed on a supporting platform of the fixed frame, and a rock sample is placed in the environmental simulation chamber; the seepage system is connected to the rock sample, and the information acquisition system is connected to the seepage system and the rock sample;

[0008] The environmental simulation chamber includes: an upper insulation box, a lower insulation box, a transparent observation window, a movable pressure head and a heating component. The upper insulation box and the lower insulation box are sealed and docked and fixedly connected by a lock. The transparent observation window is arranged on one side of the upper insulation box and the lower insulation box; there are at least three movable pressure heads and they are movably arranged on the top side walls and left and right side walls of the upper insulation box and the lower insulation box and contact the rock samples placed inside. The three-axis power loading system is used to apply pressure to the movable pressure heads; a plurality of wiring holes are provided on the lower insulation box, and the pipes and wires of the seepage system and the information acquisition system are laid through the wiring holes. The heating component is arranged in the upper insulation box.

[0009] In one embodiment, the upper insulation box body and the lower insulation box body both adopt a three-layer structure, including a hard outer shell, a middle insulation layer and a hard inner shell, and the middle insulation layer is an aluminum silicate filling material.

[0010] In one embodiment, the butt joint surfaces of the upper heat-insulating box body and the lower heat-insulating box body are configured as a concave-convex splicing structure, and a high-temperature resistant fluororubber material layer is provided on the butt joint surfaces.

[0011] In one embodiment, the rock sample is a square rock sample, and a connecting plate is provided between the movable pressure heads on the left and right sides and the square rock sample. The connecting plate is detachably connected to the movable pressure head and contacts the side of the rock sample. The area of ​​the connecting plate is equal to the side area of ​​the square rock sample or half of the side area of ​​the square rock sample.

[0012] In one embodiment, the transparent observation window has a three-layer structure, including a mounting frame, and inner tempered glass, a vacuum layer, and outer tempered glass arranged in the mounting frame.

[0013] In one embodiment, the heating component includes an electric heating pipe, a heat circulation fan and a temperature sensor. The heating temperature range of the heating component is 0-300° C.; at least two temperature sensors are provided.

[0014] In one embodiment, the seepage system includes a seepage pump, a water pressure sensor, a water temperature sensor, an injection pipe, a water outlet pipe, a fluid container, a liquid collecting container and an electronic balance. The rock sample has a fault surface, and the rock sample is provided with a permeation hole and two monitoring holes, both of which are connected to the fault surface. The permeation hole is connected to the injection pipe, and the injection pipe is connected to the seepage pump and the fluid container; the two outlet pipes are respectively connected to the monitoring holes, and the outlet pipe is connected to the liquid collecting container. The liquid collecting container is placed on the electronic balance, and the injection pipe and the outlet pipe are both provided with the water pressure sensor and the water temperature sensor.

[0015] In one embodiment, the fixed frame includes at least: a base, a support platform, a guide rail and a lifting trolley, the base is arranged below the ground, the support platform is arranged on the base and is flush with the ground, the guide rail is arranged on the support platform, and the lifting trolley is movably arranged on the guide rail; the three-axis power loading system is arranged on the support platform, a load-bearing plate for placing the environmental simulation chamber is placed on the lifting trolley, and a laboratory table for placing the load-bearing plate is provided on the support platform; a plurality of hanging rings are provided on the environmental simulation chamber.

[0016] In one embodiment, the three-axis power loading system includes a left loading cylinder, a right loading cylinder and a top loading cylinder. The left loading cylinder and the right loading cylinder are fixedly connected by a crossbeam. The piston rods of the left loading cylinder and the right loading cylinder abut against the movable pressure heads on both sides through a sensor assembly and a fixed pressure head. The piston rod of the top loading cylinder abuts against the movable pressure head on the top through the sensor assembly and the fixed pressure head. The movable pressure head on the top abuts against the top of the rock sample through a roller row. The left loading cylinder and the right loading cylinder are driven to rise and fall by a lifting column, and the top loading cylinder is arranged on the top bracket.

[0017] Another object of the present application is to provide a large-scale multifunctional experimental method for transparent simulation of a multi-field coupled environment. Based on the large-scale multifunctional experimental device for transparent simulation of a multi-field coupled environment, the method comprises the following steps:

[0018] Step 1: Start the lifting column to raise the beam together with the left and right loading cylinders to the highest limit, control the lifting trolley to lift and extend the support platform along the guide rail;

[0019] Step 2: Use the lifting equipment's straps, hooks, and rings to place the lower insulation box on the load plate of the lifting trolley. Place the rock sample on the support seat inside the lower insulation box. Select a rock sample with a flat or oblique cut surface according to experimental requirements. Select a half-plate or full-plate connecting plate according to the rock sample type, and fix the connecting plate to the movable pressure heads on the left and right sides. Then, lift the movable pressure heads on the left and right sides into the lower insulation box and place them.

[0020] Step 3: According to the experimental plan, the acoustic emission sensor and displacement sensor are fixedly installed on the surface of the rock sample, the water injection pipe of the seepage system is connected to the penetration hole on the rock sample, and the water outlet pipe is connected to the monitoring hole. Then, all the leads of all pipes and sensors are led out through the wiring holes, and all wiring holes are blocked with high-temperature resistant soft pistons;

[0021] Step 4: Place the roller row and the top movable pressure head on the top of the rock sample in sequence, then use the lifting equipment to combine the upper insulation box with the lower insulation box through the concave-convex splicing structure to form a whole box, fasten the lock, lift the transparent observation window to the middle of the whole box, and fix it with screws;

[0022] Step 5: Control the lifting trolley to move the entire environmental simulation chamber along with the rock sample inside along the guide rail to the experimental table position of the support platform. Start the lifting column to lower the crossbeam together with the left and right loading cylinders to the lowest limit position and align them with the active pressure heads on the left and right sides.

[0023] Step 6: Start the experiment by turning on the heating component to heat the rock sample first. The computer inputs the preset heating and holding temperatures and starts heating according to the set program. At the same time, the anaerobic surface-mounted acoustic emission sensor and information collection system are turned on to monitor the rock acoustic emission signal throughout the experiment.

[0024] Step 7: When the rock reaches the target temperature, stress loading and fluid injection are carried out. The triaxial dynamic loading system and seepage system are started in sequence according to the experimental plan to make the axial stress, lateral stress and fluid pressure reach the target values, and the experiment is completed.

[0025] Step 8: After the experiment, remove the loading stress, start the lifting column to raise the crossbeam together with the left loading cylinder and the right loading cylinder to the highest limit, control the lifting trolley to move the entire environmental simulation chamber together with the internal rock sample along the guide rail and extend it out of the support platform, remove the transparent observation window, upper insulation box, top movable pressure head, roller row, right movable pressure head and left movable pressure head in turn, then remove the sensors and pipes connected to the surface of the rock sample, then take pictures of the rock sample status and record it before removing it for storage, and finally reset the environmental simulation chamber.

[0026] The beneficial effects of the large-scale multifunctional experimental equipment and method for transparent simulation of multi-field coupled environments provided by this application are:

[0027] 1. By designing a fixed frame, triaxial dynamic loading system, environmental simulation chamber, and seepage system, precise control of rock sample stress, temperature, and fluid flow is achieved, enabling simulation of the complex coupled thermal, hydraulic, and mechanical conditions deep underground. The introduction of an information acquisition system enables the simultaneous acquisition of parameters such as stress, temperature, fluid pressure, displacement, and acoustic emission, enabling simultaneous control and full-process monitoring of multiple environmental conditions—pressure, temperature, and fluid—during the experiment, improving the accuracy and reliability of the experimental data.

[0028] 2. The environmental simulation chamber, with its removable upper and lower insulation boxes, can accommodate large rock samples. Through the rational design of the box dimensions, rock samples can be as small as 400mm*400mm*400mm cubes. This overcomes the limitations of existing equipment for small sample sizes and can more realistically reflect the mechanical behavior of rock masses under actual engineering conditions. Furthermore, its open design facilitates the installation of monitoring instruments and signal acquisition, greatly improving experimental flexibility and ease of operation.

[0029] 3. By setting up a transparent perspective window, the state of the rock sample during the experiment can be monitored and recorded in real time, providing intuitive experimental data support for studying rock crack expansion and fault slip behavior.

[0030] Therefore, this application has important theoretical and practical value in studying the mechanism of rock instability disasters in multi-field coupling environments, and has promoted the theoretical construction and safe practice exploration of deep mining-thermal co-mining models. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 A schematic diagram of the positional relationship between the fixed frame, the three-axis dynamic loading system, and the environmental simulation chamber in the large-scale multifunctional experimental equipment for multi-field coupled environmental transparency simulation provided in an embodiment of the present application;

[0033] Figure 2 A schematic diagram of the front perspective structure of the environmental simulation chamber provided in an embodiment of the present application;

[0034] Figure 3A schematic diagram of the rear perspective structure of the environmental simulation chamber provided in an embodiment of the present application;

[0035] Figure 4 A schematic cross-sectional view of an environmental simulation chamber according to an embodiment of the present application;

[0036] Figure 5 A schematic diagram of the concave-convex joint structure of the butt joint surfaces of the upper insulation box and the lower insulation box in the environmental simulation chamber provided by an embodiment of the present application;

[0037] Figure 6 This is a schematic diagram of the three-dimensional structure of the environmental simulation chamber provided in an embodiment of the present application, omitting the upper insulation box;

[0038] Figure 7 A simplified structural diagram of an oblique-cut section rock sample installed in an environmental simulation chamber provided in an embodiment of the present application;

[0039] Figure 8 A simplified structural diagram of a flat-section rock sample installed in an environmental simulation chamber provided in an embodiment of the present application;

[0040] Figure 9 A simplified structural diagram of a horizontal section rock sample provided in an embodiment of the present application;

[0041] Figure 10 A simplified structural diagram of the seepage system provided in an embodiment of the present application;

[0042] Figure 11 A schematic diagram of a curve showing heating and heat preservation by a multi-stage program-controlled heating assembly according to an embodiment of the present application;

[0043] Figure 12 A schematic diagram of the workflow of the information collection system provided in an embodiment of the present application.

[0044] Among them, the reference numerals in the figures are:

[0045] 1. Fixed frame; 11. Base; 12. Support platform; 13. Guide rail; 14. Lifting trolley; 15. Loading plate; 16. Test bench; 2. Three-axis dynamic loading system; 21. Left loading cylinder; 22. Right loading cylinder; 23. Top loading cylinder; 24. Crossbeam; 25. Mounting seat; 26. Sensor assembly; 27. Fixed pressure head; 28. Roller row; 29. ​​Anti-rotation part; 201. Lifting column; 3. Environmental simulation chamber; 31. Upper insulation box; 32. Lower insulation box; 33. Transparent observation window; 34. Movable pressure head; 35. Heating component; 351. Electric heating tube; 352. Heat circulation fan; 353. Temperature sensor; 36. Locking buckle; 37. Wiring hole; 38. High-temperature resistant fluororubber material layer; 39. Connecting plate; 301. Lifting ring; 302. Water outlet; 4. Seepage system; 41. Seepage pump; 42. Water pressure sensor; 43. Water temperature sensor; 44. Water injection pipe; 45. Water outlet pipe; 46. Fluid container; 47. Liquid collecting container; 48. Electronic balance; 5. Rock sample; 51. Permeability hole; 52. Monitoring hole. DETAILED DESCRIPTION

[0046] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0047] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0048] It should be understood that the terms "length", "width", "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 this application and simplifying the description, and do not indicate or imply 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 this application.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0050] like Figures 1-12 As shown, a large-scale multifunctional experimental device for multi-field coupled environmental transparency simulation provided by an embodiment of the present application is now described. The large-scale multifunctional experimental device for multi-field coupled environmental transparency simulation includes: a fixed frame 1, a triaxial dynamic loading system 2, an environmental simulation chamber 3, a seepage system 4, and an information acquisition system.

[0051] Among them, such as Figure 1 As shown, the fixed frame 1 includes at least: a base 11, a support platform 12, guide rails 13, and a lifting trolley 14. The base 11 is located below the ground and can be a concrete column. The support platform 12 is located on the base 11 and is flush with the ground. The support platform 12 has a structure with a lower concrete platform and an upper steel plate. The guide rails 13 are located on the support platform 12, and the lifting trolley 14 is movably located on the guide rails 13. The three-axis dynamic loading system 2 is located on the support platform 12. The lifting trolley 14 is provided with a load plate 15 for placing the environmental simulation chamber 3. The top of the lifting trolley 14 is a U-shaped structure. The support platform 12 is provided with a test bench 16 for placing the load plate 15. The width of the load plate 15 is larger than the width of the test bench 16, and the width of the test bench 16 is smaller than the opening of the U-shaped structure. The environmental simulation chamber 3 is provided with several lifting rings 301. The corresponding support platform 12 is also equipped with a lifting device for lifting the environmental simulation chamber 3. The experimental table 16 is the loading position, and the lifting device is the lifting position. The guide rail 13 is used to transfer the lifting trolley 14 between the lifting and loading positions. The lifting trolley 14 is used to raise and lower the load plate 15 to transfer the environmental simulation chamber 3 from the lifting position to the experimental table 16 (loading position), or to transfer the environmental simulation chamber 3 from the loading position to the lifting position.

[0052] like Figure 1As shown, the three-axis dynamic loading system 2 includes a left loading cylinder 21, a right loading cylinder 22, and a top loading cylinder 23. A mounting bracket (not shown) is also provided on the support platform 12. The left loading cylinder 21 and the right loading cylinder 22 are respectively mounted on mounting bases 25. The two mounting bases 25 are fixedly connected by four crossbeams 24, allowing the left loading cylinder 21 and the right loading cylinder 22 to rise and fall synchronously and on the same horizontal axis. In this embodiment, the piston rods of the left loading cylinder 21 and the right loading cylinder 22 are in contact with the movable pressure heads 34 on the left and right sides of the environmental simulation chamber 3 through the sensor assembly 26 and the fixed pressure head 27. The sensor assembly 26 includes at least a force sensor and a displacement sensor. In this embodiment, the piston rod of the top loading cylinder 23 is in contact with the top movable pressure head 34 through the sensor assembly 26 and the fixed pressure head 27. The top movable pressure head 34 is in contact with the top of the rock sample 5 through the roller row 28. The purpose of the roller row 28 is to achieve rolling contact between the rock sample 5 and the top movable pressure head, thereby reducing the friction when the rock sample moves. Specifically, the piston rod of the top loading cylinder 23 is connected to the sensor assembly 26 and the fixed pressure head 27. The fixed pressure head 27 is pressed against the top movable pressure head 34. The top movable pressure head 34 is in rolling contact with the rock sample 5 through the roller row 28. Each sensor assembly 26 and each piston rod is fixed against rotation by an anti-rotation member 29 to ensure that the two are in a relatively static state; the anti-rotation member 29 includes an anti-rotation plate fixed on the piston rod and the sensor assembly 26 respectively, and the two anti-rotation plates are fixed by bolts.

[0053] In this embodiment, the left and right loading cylinders 21 and 22 are driven upward and downward by a lifting column 201, and the top loading cylinder 23 is mounted on the top bracket of the mounting bracket. The triaxial dynamic loading system 2 is used to apply horizontal and vertical stresses to the rock sample 5. During stress application, force sensors and displacement sensors detect changes in piston rod force and displacement, converting these signals into electrical signals that are output to a computer. Calibration curves are used to calculate the corresponding stress value and actual displacement of the piston rod.

[0054] In this embodiment, the triaxial dynamic loading system 2 is arranged on the fixed frame 1, the environmental simulation chamber 3 is placed on the support platform 12 of the fixed frame 1, and the rock sample 5 is placed in the environmental simulation chamber 3; the seepage system 4 is also arranged on the support platform 12 and is located next to the environmental simulation chamber 3. The seepage system 4 is connected to the rock sample 5 for injecting water pressure, and the information acquisition system is connected to the infiltration system and the rock sample 5 for collecting information from various sensors during the experiment.

[0055] In this embodiment, if Figure 2-Figure 9As shown, the environmental simulation chamber 3 includes: an upper insulation box 31, a lower insulation box 32, a transparent observation window 33, a movable pressure head 34 and a heating assembly 35. The upper insulation box 31 and the lower insulation box 32 are detachably connected, which facilitates the installation of large-sized rock samples 5. The upper insulation box 31 and the lower insulation box 32 are sealed and fixedly connected by a lock 36. The transparent observation window 33 is set on one side of the upper insulation box 31 and the lower insulation box 32. The transparent observation window 33 facilitates the camera and the experimenter to directly observe and record the changes in the rock sample 5. In this embodiment, there are at least three movable pressure heads 34 and they are movably set on the top side walls and left and right side walls of the upper insulation box 31 and the lower insulation box 32 and contact the rock sample 5 placed inside. The three-axis dynamic loading system 2 is used to apply pressure to each movable pressure head 34; the three movable pressure heads 34 are respectively an upper movable pressure head, a left movable pressure head and a right movable pressure head. A lower movable pressure head and a support seat can be provided in the lower heat-insulating box 32 for placing the rock sample 5 .

[0056] In this embodiment, the lower insulation box 32 is provided with several wiring holes 37, through which the pipes and wires associated with the seepage system 4 and the information collection system are routed. The wiring holes 37 are sealed with high-temperature-resistant soft pistons. A heating assembly 35 is located within the upper insulation box 31 and is used to heat the entire box to provide the required temperature conditions for the rock sample 5 experiments.

[0057] In this embodiment, both the upper and lower insulation boxes 31, 32 utilize a three-layer structure, comprising a rigid outer shell, an intermediate insulation layer filled with aluminum silicate, and a rigid inner shell. The intermediate insulation layer is filled with aluminum silicate. The mating surfaces of the upper and lower insulation boxes 31, 32 are configured as a concave-convex joint structure, and a layer of high-temperature-resistant fluororubber 38 is provided on the mating surfaces to ensure a tight seal between the upper and lower insulation boxes 31, 32. Once docked, they are locked securely in place using a number of latches 36.

[0058] Preferably, in this embodiment, the rock sample 5 is a square rock sample, and a connecting plate 39 is provided between the movable pressure heads 34 on the left and right sides and the square rock sample. The connecting plate 39 is detachably connected to the movable pressure head 34 and contacts the side of the rock sample 5. The area of ​​the connecting plate 39 is equal to the side area of ​​the square rock sample or half of the side area of ​​the square rock sample. Specifically, when the rock sample 5 is a flat cutting plane, the connecting plate 39 is a half plate, that is, the area of ​​the connecting plate 39 is half of the side area of ​​the rock sample 5; when the rock sample 5 is an oblique cutting plane, the connecting plate 39 is a full plate, that is, the area of ​​the connecting plate 39 is the side area of ​​the rock sample 5. The side of the connecting plate 39 is mounted on the side of the movable pressure head 34 by screws and the connecting plate 39.

[0059] Specifically, the transparent observation window 33 has a three-layer structure, including a mounting frame, inner tempered glass, a vacuum layer, and outer tempered glass within the mounting frame. To further enhance thermal insulation, the vacuum layer can be doubled, also including the middle tempered glass. The mounting frame of the transparent observation window 33 is fixed to the center of the entire box with screws and is removable. During experiments, a camera can be mounted outside the transparent observation window 33 to record the state of the rock sample 5 in real time.

[0060] In this embodiment, wiring holes 37 are used to route wires from various monitoring sensors located on the surface of the rock sample 5 within the chamber for connection to the information collection system. After the wires are routed out, the wiring holes are plugged with high-temperature-resistant soft pistons. Similarly, the infiltration system's water inlet pipe 44 and outlet pipe 45 are routed through wiring holes 37 and then plugged with high-temperature-resistant soft pistons. A water outlet 302 is provided at the bottom of the lower insulation chamber 32. A valve is installed on this outlet 302 to drain any water that overflows into the chamber during the test.

[0061] In this embodiment, the heating component 35 includes at least an electric heating pipe 351, a heat circulation fan 352 and a temperature sensor 353. The heating temperature range of the heating component 35 is 0-300°C. At least two temperature sensors 353 are provided, distributed at different positions in front and behind the upper insulation box 31, to ensure uniform temperature inside the box. Among them, there are multiple electric heating pipes 351 and multiple heat circulation fans 352. The heat circulation fan 352 includes a fan cover, a motor, a transmission shaft and fan blades. Figure 11As shown in the figure, according to the principle of heat transfer, a heating method to achieve a specific temperature is used by controlling the heating power P of the electric heating tube 351701. The formula is: P=C*M*(Ti-Tj) / 3600*t+P0, where P is the heating power W, C is the specific heat, J / kg, M is the weight, kg, Ti is the target temperature (°C), Tj is the initial temperature (°C), i≧j, when i>j, it is the heating stage, when i=j, it is the insulation stage, t is the time from the initial temperature to the target temperature, and P0 is the estimated heat loss of the system under constant temperature state. Temperature sensor 353 monitors the current internal temperature Tj (the average of measurements from multiple temperature sensors 353) in real time. The user enters a target temperature Ti and an estimated time t via the computer. Based on the calculated heating power P, the computer adjusts the power output of the heating tube 351 via a controller, initiating heating. Based on real-time temperature data, the power output of the heating tube 351 is adjusted to maintain the desired heating rate. When the temperature sensor 353 detects that the temperature has reached the target temperature Ti, the power output of the heating tube 351 is reduced to P0, entering the insulation phase. A heat circulation fan 352 is activated during operation of the heating assembly 35 to ensure uniform temperature distribution and prevent local overheating. The entire process utilizes PID feedback control. By continuously comparing the measured temperature with the set target temperature, the PID parameters are analyzed and adjusted to control the overall output, thereby adjusting the heating power of the heating tube 351 in real time. Controlling the heating rate prevents excessively rapid heating, which can lead to large temperature differences between the inside and outside of the rock and cause irreversible thermal damage to the structure.

[0062] In this embodiment, if Figure 9 and Figure 10 As shown, the seepage system 4 includes a seepage pump 41, a water pressure sensor 42, a water temperature sensor 43, an injection pipe 44, an outlet pipe 45, a fluid container 46, a liquid collection container 47, and an electronic balance 48. The rock sample 5 has a fault surface, and is provided with a permeation hole 51 and two monitoring holes 52, both of which are connected to the fault surface. The permeation hole 51 is connected to the injection pipe 44, which is connected to the seepage pump 41 and the fluid collection container 46. The two outlet pipes 45 are respectively connected to the monitoring holes 52, and the outlet pipe 45 is connected to the liquid collection container 47, which is placed on the electronic balance 48. The injection pipe 44 and the outlet pipe 45 are both equipped with a water pressure sensor 42 and a water temperature sensor 43. A seepage pump 41 provides seepage pressure, injecting liquid from a fluid container 46 into permeable pores 51 of the rock sample 5 along an injection pipe 44. The water flows along the rock's internal pores toward the fault plane, with some water potentially flowing out along an outlet pipe 45 and ultimately into a liquid collection container 47. Both the injection pipe 44 and the outlet pipe 45 are equipped with a water pressure sensor 42 and a water temperature sensor 43. An electronic balance 48 measures the weight of the fluid collected in the liquid collection container 47.

[0063] In this embodiment, if Figure 12As shown, the information acquisition system consists of sensors, signal conditioners, network optical fibers, and supporting software. Sensors include displacement sensors, temperature sensors 353, acoustic emission sensors, and force sensors. The standard current signals emitted by all sensors used in this equipment are converted into voltage signals via a signal conditioning terminal board. These signals are then synchronized and converted into digital signals via an A / D converter on a data acquisition card and transmitted to a computer. The corresponding system displacement, temperature, and force values ​​are determined based on the magnitude of changes in displacement, temperature, and force, and the linear relationship between the sensors. The supporting software enables simultaneous monitoring and visualization of multiple signals, including data processing, analysis, storage, and display.

[0064] In this embodiment, it can be understood that the three-axis power loading system 2 and the information acquisition system are existing technologies.

[0065] The present application also provides a large-scale multifunctional experimental method for multi-field coupled environment transparency simulation, based on the above-mentioned large-scale multifunctional experimental device for multi-field coupled environment transparency simulation, the experimental method comprises the following steps:

[0066] Step 1: Start the lifting column 201 to raise the beam 24 together with the left and right loading cylinders 22 to the upper limit position, and control the lifting trolley 14 to lift and extend it along the guide rail 13 to support the platform 12;

[0067] Step 2: Use the lifting straps, hooks, and lifting rings 301 of the lifting equipment to place the lower insulation box 32 on the load plate 15 of the lifting trolley 14, and place the rock sample 5 on the support seat in the lower insulation box 32. Select a rock sample 5 with a flat or oblique cut surface according to the experimental requirements. Select a half-plate or full-plate connecting plate 39 according to the type of rock sample 5, and fix the connecting plate 39 to the movable pressure heads 34 on the left and right sides. Then, lift the movable pressure heads 34 on the left and right sides into the lower insulation box 32 and place them.

[0068] Step 3: According to the experimental plan, the acoustic emission sensor and displacement sensor are fixedly installed on the surface of the rock sample 5. The water injection pipe 44 of the seepage system 4 is connected to the penetration hole 51 on the rock sample 5. The water outlet pipe 45 is connected to the monitoring hole 52. Then, all the leads of all pipes and sensors are led out through the wiring holes. All wiring holes are then blocked with high-temperature resistant soft pistons.

[0069] Step 4: Place the roller row 28 and the top movable pressure head 34 on the top of the rock sample 5 in sequence, then use the lifting equipment to combine the upper insulation box 31 with the lower insulation box 32 through the concave-convex splicing structure to form a whole box, fasten the lock 36, lift the transparent observation window 33 to the middle of the whole box, and fix it with screws;

[0070] Step 5: Control the lifting trolley 14 to move the entire environmental simulation chamber 3 together with the rock sample 5 inside along the guide rail 13 to the experimental table 16 position of the support platform 12, and start the lifting column 201 to lower the crossbeam 24 together with the left loading cylinder 21 and the right loading cylinder 22 to the lowest limit position to align with the movable pressure heads 34 on the left and right sides;

[0071] Step 6: Start the experiment by turning on the heating assembly 35 to heat the rock sample 5. The computer inputs the preset heating and holding temperatures and starts heating according to the set program. The acoustic emission sensor and information collection system attached to the surface of the rock sample are simultaneously turned on to monitor the rock acoustic emission signal throughout the experiment.

[0072] Step 7: When the rock reaches the target temperature, stress loading and fluid injection are performed. According to the experimental plan, the triaxial dynamic loading system 2 and the seepage system 4 are started in sequence to make the axial stress, lateral stress and fluid pressure reach the target values, and the experiment is completed.

[0073] Step 8: After the experiment, remove the loading stress, start the lifting column 201 to raise the beam 24 together with the left loading cylinder 21 and the right loading cylinder 22 to the highest limit, control the lifting trolley 14 to move the entire environmental simulation chamber 3 together with the internal rock sample 5 along the guide rail 13 and extend it out of the support platform 12, remove the transparent observation window 33, the upper insulation box 31, the top movable pressure head, the roller row 28, the right movable pressure head and the left movable pressure head in turn, then remove the sensors and pipes connected to the surface of the rock sample 5, then take a photo of the status of the rock sample 5 and remove it for storage, and finally reset the environmental simulation chamber 3.

[0074] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A large-scale multifunctional experimental device for transparent simulation of multi-field coupling environment, characterized by: include: Fixed frame (1), triaxial dynamic loading system (2), environmental simulation chamber (3), seepage system (4) and information acquisition system; The triaxial dynamic loading system (2) is arranged on a fixed frame (1), the environmental simulation chamber (3) is placed on a supporting platform (12) of the fixed frame (1), and a rock sample (5) is placed in the environmental simulation chamber (3); the seepage system (4) is connected to the rock sample (5), and the information acquisition system is connected to the seepage system (4) and the rock sample (5); The environmental simulation chamber (3) comprises: an upper heat-insulating box (31), a lower heat-insulating box (32), a transparent observation window (33), a movable pressure head (34) and a heating assembly (35); the upper heat-insulating box (31) and the lower heat-insulating box (32) are sealed and docked and fixedly connected by a lock (36); the transparent observation window (33) is arranged on one side of the upper heat-insulating box (31) and the lower heat-insulating box (32); the movable pressure heads (34) are at least three and are movably arranged on the upper heat-insulating box (31) and the lower heat-insulating box (32); The top side walls and left and right side walls of the upper insulation box (31) and the lower insulation box (32) are in contact with the rock sample (5) placed inside, and the three-axis power loading system (2) is used to apply pressure to the movable pressure head (34); the lower insulation box (32) is provided with a plurality of wiring holes (37), and the pipes and wires of the seepage system (4) and the information acquisition system are laid through the wiring holes (37), and the heating component (35) is arranged in the upper insulation box (31).

2. The large-scale multifunctional experimental device for multi-field coupled environment transparency simulation according to claim 1, characterized in that: The upper heat-insulating box body (31) and the lower heat-insulating box body (32) both adopt a three-layer structure, including a hard outer shell, an intermediate heat-insulating layer and a hard inner shell, and the intermediate heat-insulating layer is an aluminum silicate filling material.

3. The large-scale multifunctional experimental device for multi-field coupled environment transparency simulation according to claim 2, characterized in that: The butt joint surfaces of the upper heat-insulating box body (31) and the lower heat-insulating box body (32) are arranged in a concave-convex splicing structure, and a high-temperature resistant fluororubber material layer (38) is arranged on the butt joint surfaces.

4. The large-scale multifunctional experimental device for multi-field coupled environment transparency simulation according to claim 3, characterized in that: The rock sample (5) is a square rock sample. Connecting plates (39) are provided between the movable pressure heads (34) on the left and right sides and the square rock sample. The connecting plates (39) are detachably connected to the movable pressure heads (34) and are in contact with the side surfaces of the rock sample (5). The area of ​​the connecting plates (39) is equal to the side area of ​​the square rock sample or half of the side area of ​​the square rock sample.

5. The large-scale multifunctional experimental device for multi-field coupled environment transparency simulation according to claim 4, characterized in that: The transparent observation window (33) is a three-layer structure, comprising a mounting frame, and inner tempered glass, a vacuum layer and outer tempered glass arranged in the mounting frame.

6. The large-scale multifunctional experimental device for multi-field coupled environment transparency simulation according to claim 5, characterized in that: The heating component (35) comprises an electric heating pipe (351), a heat flow circulation fan (352) and a temperature sensor (353). The heating temperature range of the heating component (35) is 0-300° C.; at least two temperature sensors (353) are provided.

7. The large-scale multifunctional experimental device for multi-field coupled environment transparency simulation according to claim 6, characterized in that: The seepage system (4) comprises a seepage pump (41), a water pressure sensor (42), a water temperature sensor (43), a water injection pipe (44), a water outlet pipe (45), a fluid container (46), a liquid collecting container (47) and an electronic balance (48). The rock sample (5) has a fault surface. The rock sample (5) is provided with a permeation hole (51) and two monitoring holes (52) both of which are connected to the fault surface. The permeation hole (51) is connected to the water injection pipe (44), and the water injection pipe (44) is connected to the seepage pump (41) and the fluid container (46). The two water outlet pipes (45) are respectively connected to the monitoring holes (52). The water outlet pipe (45) is connected to the liquid collecting container (47). The liquid collecting container (47) is placed on the electronic balance (48). The water pressure sensor (42) and the water temperature sensor (43) are both provided on the water injection pipe (44) and the water outlet pipe (45).

8. The large-scale multifunctional experimental device for multi-field coupled environment transparency simulation according to claim 7, characterized in that: The fixed frame (1) comprises at least: a base (11), a support platform (12), a guide rail (13) and a lifting trolley (14); the base (11) is arranged below the ground; the support platform (12) is arranged on the base (11) and is flush with the ground; the guide rail (13) is arranged on the support platform (12); and the lifting trolley (14) is movably arranged on the guide rail (13); the three-axis power loading system (2) is arranged on the support platform (12); a bearing plate (15) for placing the environmental simulation chamber (3) is placed on the lifting trolley (14); and a test bench (16) for placing the bearing plate (15) is provided on the support platform (12); and a plurality of lifting rings (301) are provided on the environmental simulation chamber (3).

9. The large-scale multifunctional experimental device for transparent simulation of multi-field coupled environments according to claim 8, characterized in that: The three-axis power loading system (2) comprises a left loading cylinder (21), a right loading cylinder (22) and a top loading cylinder (23); the left loading cylinder (21) and the right loading cylinder (22) are fixedly connected via a crossbeam (24); the piston rods of the left loading cylinder (21) and the right loading cylinder (22) abut against the movable pressure heads (34) on both sides via a sensor assembly (26) and a fixed pressure head (27); the piston rod of the top loading cylinder (23) abuts against the movable pressure head (34) at the top via a sensor assembly (26) and a fixed pressure head (27); the movable pressure head (34) at the top abuts against the top of the rock sample via a roller row (28); the left loading cylinder (21) and the right loading cylinder (22) are driven to rise and fall via a lifting column (201); and the top loading cylinder (23) is arranged on a top bracket.

10. A large-scale multifunctional experimental method for multi-field coupled environment transparency simulation, based on the large-scale multifunctional experimental device for multi-field coupled environment transparency simulation according to claim 9, characterized in that: The method comprises the following steps: Step 1: Start the lifting column (201) to lift the crossbeam (24) together with the left and right loading cylinders (22) to the highest limit position, control the lifting trolley (14) to lift and extend the support platform (12) along the guide rail (13); Step 2: Use a lifting device to connect the lifting ring (301) to place the lower insulation box (32) on the bearing plate (15) of the lifting trolley (14), place the rock sample (5) on the support seat in the lower insulation box (32), select a rock sample (5) with a flat cutting surface or an oblique cutting surface according to experimental requirements, select a half-plate or full-plate connecting plate (39) according to the type of rock sample (5), and fix the connecting plate (39) to the movable pressure heads (34) on the left and right sides; then lift the movable pressure heads (34) on the left and right sides into the lower insulation box (32) and place them; Step 3: According to the experimental plan, the acoustic emission sensor and the displacement sensor are fixedly installed on the surface of the rock sample (5), the water injection pipe (44) of the seepage system (4) is connected to the permeation hole (51) on the rock sample (5), and the water outlet pipe (45) is connected to the monitoring hole (52). Then, all the leads of all pipes and sensors are led out through the wiring holes (37), and all wiring holes (37) are blocked with high-temperature resistant soft pistons; Step 4: Place the roller row (28) and the top movable pressure head (34) on the top of the rock sample (5) in sequence, and then use the lifting equipment to combine the upper insulation box (31) with the lower insulation box (32) through the concave-convex splicing structure to form a whole box, fasten the lock (36) to lock it, lift the transparent observation window (33) to the middle of the whole box, and fix it with screws; Step 5: Control the lifting trolley (14) to move the entire environmental simulation chamber (3) together with the rock sample (5) inside along the guide rail (13) to the experimental table (16) position of the support platform (12), and start the lifting column (201) to lower the crossbeam (24) together with the left loading cylinder (21) and the right loading cylinder (22) to the lowest limit position to align with the movable pressure heads (34) on the left and right sides; Step 6: Start the experiment, turn on the heating component (35) to heat the rock sample (5), input the preset heating and insulation temperatures into the computer, start heating according to the set program, and simultaneously turn on the acoustic emission sensor and information collection system attached to the surface of the rock sample to monitor the rock acoustic emission signal throughout the entire experiment; Step 7: When the rock reaches the target temperature, stress loading and fluid injection are performed. According to the experimental plan, the triaxial dynamic loading system (2) and the seepage system (4) are started in sequence to make the axial stress, lateral stress and fluid pressure reach the target values, and the experiment is completed; Step 8: After the experiment is completed, the loading stress is removed, and the lifting column (201) is started to lift the crossbeam (24) together with the left loading cylinder (21) and the right loading cylinder (22) to the highest limit. The lifting trolley (14) is controlled to move the entire environmental simulation chamber (3) together with the internal rock sample (5) along the guide rail (13) and extend out of the support platform (12). The transparent observation window (33), the upper insulation box (31), the top movable pressure head (34), the roller row (28), the right movable pressure head (34) and the left movable pressure head (34) are removed in turn. Then, the sensors and pipelines connected to the surface of the rock sample (5) are disassembled. Then, the state of the rock sample (5) is photographed and recorded, and then removed and stored. Finally, the environmental simulation chamber (3) is reset.

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