High-temperature tri-axial rock mass shear fracturing three-dimensional dynamic seepage heat exchange coupling test system

Abstract

The application discloses a high-temperature true triaxial rock mass shearing and fracturing three-direction dynamic percolation heat exchange coupling test system and relates to the field of hot dry rock mining. The application discloses a high-temperature true triaxial rock mass shearing and fracturing three-direction dynamic percolation heat exchange coupling test system and relates to the field of hot dry rock mining. The application discloses a high-temperature true triaxial rock mass shearing and fracturing three-direction dynamic percolation heat exchange coupling test system and relates to the field of hot dry rock mining. The application discloses a high-temperature true triaxial rock mass shearing and fracturing three-direction dynamic percolation heat exchange coupling test system and relates to the field of hot dry rock mining. The application discloses a high-temperature true triaxial rock mass shearing and fracturing three-direction dynamic percolation heat exchange coupling test system and relates to the field of hot dry rock mining. The application discloses a high-temperature true triaxial rock mass shearing and fracturing three-direction dynamic percolation heat exchange coupling test system and relates to the field of hot dry rock mining.

Description

Technical Field

[0001] This invention relates to the field of hot dry rock mining, and in particular to a high-temperature true triaxial rock mass shear fracturing three-dimensional dynamic seepage heat transfer coupling test system. Background Technology

[0002] Hot dry rock, as a new type of geothermal energy, refers to high-temperature rock bodies buried deep in the earth, containing little or no fluid, and with a temperature above 150°C. Its matrix is ​​mainly composed of low-permeability metamorphic rocks, with dense crystallization characteristics, among which granite reservoirs are the most typical. Hot dry rock resources are mainly distributed in global plate tectonic activity zones. These areas have intense tectonic activity and local fault development characteristics, which makes hot dry rock reservoirs exhibit three typical characteristics: (1) Regional reservoir characteristics: deep reservoirs generally develop multi-scale primary natural fractures, but due to geostress, they are mostly closed, with extremely low permeability (10). -16 ~10 -17 m 2 (1) The natural fracture system is located in an anisotropic geostress field and is generally subjected to combined compressive and shear stress. (2) The regional geothermal characteristics are such that the reservoir temperature is between 150 and 300°C, forming a complex geological environment of "three highs" (high geostress, high geothermal temperature, and high pore pressure). Against this background, how to construct a network of interconnected fractures and establish an effective fluid circulation system has become the core technical challenge for the development of hot dry rock geothermal energy.

[0003] Hydraulic fracturing technology, widely used in traditional oil and gas reservoir development (creating tensile main fractures through high-volume, short-duration injection), faces significant limitations in hot dry rock reservoirs. Generating tensile fractures in high-tensile-strength crystalline rock masses requires extremely high injection energy, posing a risk of induced seismic activity. Furthermore, the resulting unidirectional fractures are insufficient to meet the demands of complex heat exchange networks, and fracture extension is uncontrollable, making communication between injection and production wells difficult. International engineering case studies demonstrate that, considering the pre-existing joint development characteristics of hot dry rock reservoirs, a "flexible reservoir creation" approach—inducing pressure / volume oscillations through cyclic / intermittent water injection to achieve low-disturbance shear stimulation (controlling injection pressure ≤ minimum principal stress)—can effectively induce shear slip in natural fractures, thereby improving permeability through the self-supporting effect of micro-protrusions on the rough fracture surface. Therefore, conducting experimental simulations of water injection shear-permeability enhancement in high-temperature rock masses is a pressing challenge in the field of hot dry rock extraction, crucial for achieving efficient thermal resource extraction and controlling the stability of the surrounding rock.

[0004] However, existing experimental systems suffer from the following key deficiencies: 1) Limitations in stress simulation: Conventional triaxial devices cannot achieve true triaxial independent stress loading, making it difficult to recreate the non-uniform stress state of deep formations, leading to distortion of fracture shear behavior; 2) Lack of multi-parameter monitoring: Key parameters such as fracture surface damage propagation, dynamic changes in permeability anisotropy, and triaxial fluid migration paths lack real-time synchronous monitoring methods during shearing; 3) Gap in heat transfer mechanism research: Existing equipment generally ignores the dynamic coupling effect of shear-seepage-heat transfer, making it impossible to quantify the impact of fracture shear on heat exchange efficiency, resulting in difficulty in scientifically evaluating the effects of hydraulic shearing modification; 4) Insufficient system integration: The modules for mechanical loading, fluid injection, multi-directional seepage monitoring, and temperature field control under high temperature and high pressure environments have poor coordination, and the experimental process is cumbersome and has a low degree of automation. It is evident that existing fracture shear seepage experiments cannot obtain some key parameters, thus failing to comprehensively characterize the seepage and heat transfer evolution characteristics of natural fracture surfaces during water injection shearing. Furthermore, existing experimental processes are complex to operate and have a low degree of automation. Summary of the Invention

[0005] To address the above technical problems, this invention provides a high-temperature true triaxial rock mass shear fracturing three-dimensional dynamic seepage heat transfer coupling test system, which can comprehensively characterize the seepage heat transfer evolution characteristics of natural fracture surfaces during water injection shearing, making the test process simpler and improving the degree of automation.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides a high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system, comprising a true triaxial rock direct shear testing machine, a true triaxial direct shear box, a normal force loading device, a lateral force loading device, a shear force loading device, a heating and temperature control device, a water injection device, an effluent collection device, a water temperature monitoring device, and a controller. The true triaxial direct shear box is fixed on the frame of the true triaxial rock direct shear testing machine, and the interior of the true triaxial direct shear box forms a chamber for accommodating the test rock sample. The normal force loading device extends into the true triaxial direct shear box and applies a preset normal force to the test rock sample under the action of the true triaxial rock direct shear testing machine. The lateral force loading device extends into the true triaxial direct shear box and applies a preset lateral force to the test rock sample under the action of the true triaxial rock direct shear testing machine. The shear force loading device extends into the true triaxial direct shear box and applies a preset shear force to the test rock sample under the action of the true triaxial rock direct shear testing machine; the heating and temperature control device heats the test rock sample to reach a first preset temperature; the water injection device injects water with a second preset temperature into the natural fracture surface of the test rock sample so that the injected water seeps in four directions inside the test rock sample; the water outflow collection device collects and measures the flow rate of water seeping out from the four directions of the test rock sample; the water temperature monitoring device monitors the inlet and outlet water temperatures; the true triaxial rock direct shear testing machine, the heating and temperature control device, the water injection device, the water outflow collection device, and the water temperature monitoring device are all connected to the controller.

[0007] The present invention achieves the following technical effects compared to the prior art: The high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system of the present invention includes a true triaxial rock direct shear testing machine, a true triaxial direct shear box, a normal force loading device, a lateral force loading device, a shear force loading device, a heating and temperature control device, a water injection device, an outflow water acquisition device, a water temperature monitoring device, and a controller. This system enables water injection shear fracturing seepage heat transfer tests on test rock samples under specific temperature, normal force, lateral force, and shear force conditions. It can also collect and calculate the flow rate of water seeping from the natural fracture surface of the test rock sample in real time. Based on this outflow water data, the real-time hydraulic aperture and real-time anisotropic permeability of the natural fracture surface can be further calculated. In other words, the test system provided by this invention can obtain key parameters characterizing the seepage heat transfer evolution characteristics of the natural fracture surface during the water injection shear process, thereby comprehensively characterizing the seepage heat transfer evolution characteristics of the natural fracture surface during the water injection shear process.

[0008] Furthermore, based on the aforementioned real-time hydraulic aperture and real-time anisotropic permeability, this invention can further obtain the hydraulic aperture variation curve, average hydraulic aperture, and anisotropic permeability variation curve of the natural fracture surface, and can further calculate the average convective heat transfer coefficient of the natural fracture surface based on the above data. Moreover, during the water injection shearing process, the experimental system of this invention monitors the operation of each device through a controller and processes the data collected by each device, thus automatically acquiring the aforementioned key parameters. This simplifies the experimental process and improves its automation level. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 The overall structural diagram of the high-temperature true triaxial rock mass shear fracturing three-dimensional dynamic seepage heat transfer coupling test system provided by the present invention; Figure 2 The external structural diagram of the high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system provided by the present invention is shown in the main view of the true triaxial rock direct shear test machine without the main view of the external structure. Figure 3 The high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system provided by the present invention is shown in the main view of the internal structure of the true triaxial rock direct shear test machine without the true triaxial rock direct shear test machine. Figure 4 The internal structure diagram of the high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system provided by the present invention is shown below, without the top view of the true triaxial rock direct shear test machine. Figure 5 A schematic diagram of the upper box structure of the high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system provided by the present invention; Figure 6 A schematic diagram of the upper shear box in the high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system provided by the present invention; Figure 7 A schematic diagram of the force-up block in the high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system provided by the present invention; Figure 8 A schematic diagram of the lateral loading component in the high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system provided by the present invention; Figure 9Internal structure diagram of the normal force loading device in the high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system provided by the present invention; Figure 10 Internal structure diagram of the lateral loading component in the high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system provided by the present invention; Figure 11 A schematic diagram of the load block and horizontal pressure bar in the high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system provided by the present invention; Figure 12 A schematic diagram of the structure of the force transmission block and tangential loading rod in the high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system provided by the present invention; Figure 13 A schematic diagram of the structure of the first strip-shaped sealing component in the high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system provided by the present invention; Figure 14 A schematic diagram of the structure of the second annular sealing component in the high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system provided by the present invention; Figure 15 A schematic diagram of the structure of the three-dimensional laser scanner in the high-temperature true triaxial rock mass shear fracturing three-dimensional dynamic seepage heat transfer coupling test system provided by the present invention.

[0011] Figure reference numerals: 100. High-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system; 1. True triaxial rock direct shear test machine; 101. Frame; 2. True triaxial direct shear box; 21. Upper box body; 22. Lower box body; 23. Upper shear box; 24. Lower shear box; 25. Rolling disc; 26. Limiting column; 27. Lower mounting groove; 28. Upper mounting groove; 29. ​​First through hole; 210. Second through hole; 211. Upper pad; 212. Second water injection channel; 213. Third grid groove; 214. Fifth grid groove; 215. Third water outlet channel; 216. Second annular sealing component; 217. Upper solid... Fixed mechanism; 2171, upper fixing bolt; 218, lower fixing mechanism; 2181, lower fixing bolt; 219, chamber; 220, lower pad; 3, normal force loading device; 31, normal loading rod; 32, normal loading block; 33, first hot oil circulation channel; 34, first oil inlet; 35, first oil outlet; 36, first water injection channel; 4, lateral force loading device; 41, lateral loading component; 411, lateral loading rod; 412, lateral loading block; 42, second hot oil circulation channel; 43, second oil inlet; 44, second oil outlet; 45, first mesh groove; 46, first water outlet channel; 47, first... 5. Annular sealing component; 5. Shear force loading device; 51. Tangential loading mechanism; 511. Lower force transmission block; 512. Tangential loading rod; 513. Second grid groove; 514. Second strip groove; 515. Second strip sealing component; 516. Third strip groove; 517. Third strip sealing component; 518. Second water outlet channel; 52. Horizontal positioning mechanism; 521. Upper force transmission block; 522. Horizontal pressure bar; 523. Fourth grid groove; 524. First strip groove; 525. First strip sealing component; 6. Heating and temperature control device; 61. Hot oil circulation device; 62. Rock sample temperature monitoring component; 63. Oil supply port; 64. Oil return port; 7. Water injection device; 71. Heating water tank; 72. Water injection pipe; 73. Water injection pump; 8. Water collection device; 81. Water collection mechanism; 811. Water collection pipe; 812. Beaker; 813. Electronic balance; 814. Back pressure valve; 9. Water temperature monitoring device; 91. Inlet water temperature monitoring component; 92. Outlet water temperature monitoring component; 10. Controller; 11. 3D laser scanner; 12. First temperature recorder; 13. Second temperature recorder; 200. Test rock sample; 201. Natural fracture surface; 202. Lower fracture block; 203. Upper fracture block; 204. Third water injection channel. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] The purpose of this invention is to provide a high-temperature true triaxial rock mass shear fracturing three-dimensional dynamic seepage heat transfer coupling test system, which can comprehensively characterize the seepage heat transfer evolution characteristics of natural fracture surfaces during water injection shearing, making the test process simpler and improving the degree of automation of the test process.

[0014] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] like Figures 1-15 As shown, this embodiment provides a high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system 100, including a true triaxial rock direct shear test machine 1, a true triaxial direct shear box 2, a normal force loading device 3, a lateral force loading device 4, a shear force loading device 5, a heating and temperature control device 6, a water injection device 7, an outlet water collection device 8, a water temperature monitoring device 9, and a controller 10. The true triaxial direct shear box 2 is fixed on the frame 101 of the true triaxial rock direct shear test machine 1, and a chamber 219 for accommodating the test rock sample 200 is formed inside the true triaxial direct shear box 2.

[0016] The normal force loading device 3 is used to extend into the true triaxial direct shear box 2 and apply a preset normal force to the test rock sample 200 under the action of the true triaxial rock direct shear testing machine 1; the lateral force loading device 4 is used to extend into the true triaxial direct shear box 2 and apply a preset lateral force to the test rock sample 200 under the action of the true triaxial rock direct shear testing machine 1; the shear force loading device 5 is used to extend into the true triaxial direct shear box 2 and apply a preset shear force to the test rock sample 200 under the action of the true triaxial rock direct shear testing machine 1.

[0017] The heating and temperature control device 6 is used to heat the test rock sample 200 and bring it to a first preset temperature. The water injection device 7 is used to inject water with a second preset temperature into the natural fracture surface 201 of the test rock sample 200, so that the injected water seeps in four directions inside the test rock sample 200. When the shear displacement changes significantly, the water pressure is kept constant. When a new mechanical equilibrium is reached, the water pressure is increased to induce a new shear slip. The water collection device 8 is used to collect and measure the flow rate of water seeping out of the test rock sample 200 from four directions. The water temperature monitoring device 9 is used to monitor the inlet and outlet water temperatures. The true triaxial rock direct shear testing machine 1, the heating and temperature control device 6, the water injection device 7, the water collection device 8, and the water temperature monitoring device 9 are all connected to the controller 10. The controller 10 is used to monitor the operation of each device and process the data collected by each device.

[0018] The experimental system in this embodiment enables water injection shear fracturing and heat transfer tests on test rock sample 200 under specific temperature, normal force, lateral force, and shear force conditions. It can also collect and calculate the flow rate of water seeping from the natural fracture surface 201 of the test rock sample 200 in real time. Based on this flow rate data, the real-time hydraulic aperture and real-time anisotropic permeability of the natural fracture surface 201 can be further calculated. In other words, the experimental system provided in this embodiment can obtain key parameters characterizing the evolution of heat transfer and permeability of the natural fracture surface 201 during water injection shearing, thereby comprehensively characterizing its evolution.

[0019] Furthermore, this embodiment can further obtain the hydraulic opening variation curve, average hydraulic opening, and anisotropic permeability variation curve of the natural fracture surface 201 based on the aforementioned real-time hydraulic opening and real-time anisotropic permeability. It can also further calculate the average convective heat transfer coefficient of the natural fracture surface 201 based on the aforementioned data. Moreover, during the water injection shearing process, the experimental system of this embodiment monitors the actions of each device through the controller 10 and processes the data collected by each device, thus automatically acquiring the aforementioned key parameters. This simplifies the experimental process and improves its automation level.

[0020] As can be seen, this embodiment provides a highly integrated experimental system capable of simulating the fully coupled process of true triaxial stress field-rock shear-triaxial dynamic seepage-heat transfer, providing key technical support for revealing the evolution mechanism of high-temperature fractured rock masses under the action of multiple physical fields, and promoting the safe and efficient development of hot dry rock resources.

[0021] Specifically, the true triaxial direct shear box 2 includes an upper box body 21, a lower box body 22, an upper shear box 23, a lower shear box 24, a rolling disk 25, and four limiting posts 26. The lower box body 22 is fixed on the frame 101 of the true triaxial rock direct shear testing machine 1, the rolling disk 25 is fixed in the lower box body 22, and the lower shear box 24 is placed on the upper part of the rolling disk 25.

[0022] In this embodiment, the rolling disk 25 includes a frame and multiple rollers. The frame is fixed in the lower box 22. The front and rear ends of each roller are rotatably mounted on the frame. The multiple rollers are arranged in parallel in sequence, and the axial direction of each roller is perpendicular to the shearing direction. The lower shearing box 24 is placed on the multiple rollers, thereby reducing the friction during the shearing process and improving the test accuracy.

[0023] The lower shear box 24 is provided with a lower mounting groove 27 at its upper part. The lower mounting groove 27 runs through the front and rear sides of the lower shear box 24. The lower fracture block 202 of the test rock sample 200 is placed in the lower mounting groove 27. The shear force loading device 5 includes a tangential loading mechanism 51 and a horizontal positioning mechanism 52. The tangential loading mechanism 51 includes a lower force transmission block 511 and a tangential loading rod 512 fixed to one end of the lower force transmission block 511. The lower force transmission block 511 is set in the lower mounting groove 27 and is located on the right side of the lower fracture block 202. The tangential loading rod 512 passes through the right side of the lower shear box 24 and extends to the outside to connect with the true triaxial rock direct shear testing machine 1.

[0024] The upper shear box 23 is located above the lower shear box 24. The lower part of the upper shear box 23 is provided with an upper mounting groove 28, which runs through the front and rear sides of the upper shear box 23. The upper fracture block 203 of the test rock sample 200 is placed in the upper mounting groove 28. The horizontal positioning mechanism 52 includes an uploading force block 521 and a horizontal pressure bar 522 fixed to one end of the uploading force block 521. The uploading force block 521 is located on the left side of the upper fracture block 203. The horizontal pressure bar 522 passes through the left side of the upper shear box 23 and extends to the outside to connect with the true triaxial rock direct shear testing machine 1. The true triaxial rock direct shear testing machine 1 can constrain the horizontal pressure bar 522. The tangential loading rod 512 can apply a preset shear force to the test rock sample 200 under the action of the true triaxial rock direct shear testing machine 1.

[0025] The upper box 21 is fixed to the upper shear box 23. The upper part of the upper box 21 is provided with a first through hole 29, and the upper part of the upper shear box 23 is provided with a second through hole 210 corresponding to the position of the first through hole 29. The normal force loading device 3 can pass through the first through hole 29 and the second through hole 210 and apply a preset normal force to the test rock sample 200 under the action of the true triaxial rock direct shear test machine 1.

[0026] In this specific embodiment, the true triaxial shear box 2 also includes a connecting mechanism, which includes multiple connecting bolts. The upper part of the upper box body 21 is provided with multiple connecting through holes, and the upper part of the upper shear box 23 is provided with multiple threaded holes corresponding to the connecting through holes. Each connecting bolt passes through a connecting through hole and is installed in a threaded hole, and the head of the connecting bolt abuts against the upper surface of the upper box body 21, thereby realizing the fixed connection between the upper shear box 23 and the upper box body 21.

[0027] Each of the upper shear box 23 and the lower shear box 24 has a limiting post 26 on the left and right sides of its front part, and a limiting post 26 on the left and right sides of its rear part. The four limiting posts 26 are used to limit the front and rear sides of the upper shear box 23 and the lower shear box 24. The lateral force loading device 4 includes two lateral loading members 41 respectively located on the front and rear sides of the test rock sample 200. Both lateral loading members 41 are connected to the true triaxial rock direct shear testing machine 1. Under the action of the true triaxial rock direct shear testing machine 1, the two lateral loading members 41 can apply a preset lateral force to the front and rear sides of the test rock sample 200. The two limiting posts 26 located on the front side are used to limit the left and right sides of the front lateral loading member 41. The left and right sides of the front lateral loading member 41 are respectively in contact with the two limiting posts 26 on the front side. The two limiting posts 26 located on the rear side are used to limit the left and right sides of the rear lateral loading member 41, and the left and right sides of the rear lateral loading member 41 are respectively in contact with the two limiting posts 26 on the rear side. The front lateral loading member 41 is in contact with the front side of the upper crack block 203 and the lower crack block 202, and the rear lateral loading member 41 is in contact with the rear side of the upper crack block 203 and the lower crack block 202.

[0028] This embodiment also includes an upper pad 211, which is disposed in the second through hole 210 and contacts the upper surface of the test rock sample 200; the normal force loading device 3 includes a normal loading rod 31 and a normal loading block 32 fixed to the lower end of the normal loading rod 31. The normal loading rod 31 is connected to the true triaxial rock shear test machine 1. The normal loading rod 31 can apply a preset normal force to the test rock sample 200 under the action of the true triaxial rock shear test machine 1. The normal loading block 32 is disposed in the first through hole 29 and contacts the upper surface of the upper pad 211.

[0029] This embodiment also includes a lower pad 220. A positioning groove is provided on the bottom surface of the lower mounting groove 27. The lower pad 220 is disposed in the positioning groove. The upper part of the lower pad 220 is used to place the test rock sample 200. Specifically, the lower fracture block 202 is used to place the test rock sample 200.

[0030] The normal loading block 32 is provided with a first hot oil circulation channel 33, which has a first oil inlet 34 and a first oil outlet 35, both of which are located on the upper part of the normal loading block 32. Each lateral loading member 41 is provided with a second hot oil circulation channel 42, which has a second oil inlet 43 and a second oil outlet 44. The second oil inlet 43 and the second oil outlet 44 of the front lateral loading member 41 are both located on the front side of the lateral loading member 41, and the second oil inlet 43 and the second oil outlet 44 of the rear lateral loading member 41 are both located on the rear side of the lateral loading member 41.

[0031] The heating and temperature control device 6 includes a hot oil circulation device 61 and a rock sample temperature monitoring component 62. The first oil inlet 34 and the second oil inlet 43 are both connected to the oil supply port 63 of the hot oil circulation device 61, and the first oil outlet 35 and the second oil outlet 44 are both connected to the oil return port 64 of the hot oil circulation device 61. The rock sample temperature monitoring component 62 is used to monitor the temperature of the test rock sample 200. Both the hot oil circulation device 61 and the rock sample temperature monitoring component 62 are connected to a controller 10, which can control the temperature of the hot oil supplied by the hot oil circulation device 61. During operation, the rock sample temperature monitoring component 62 monitors the temperature of the test rock sample 200, and the controller 10, by controlling the temperature of the hot oil supplied by the hot oil circulation device 61, enables the temperature of the test rock sample 200 to reach a first preset temperature.

[0032] Specifically, the controller 10 works in conjunction with the heating element and temperature sensing element in the hot oil circulation device 61 to control the temperature of the hot oil supplied by the hot oil circulation device 61.

[0033] The water injection device 7 includes a heating water tank 71, a water injection pipe 72, and a water injection pump 73. A first water injection channel 36 is provided on the normal loading rod 31 and the normal loading block 32. A second water injection channel 212 connected to the first water injection channel 36 is provided on the upper pad block 211. A third water injection channel 204 penetrating both ends of the upper fracture block 203 is provided. The upper end of the third water injection channel 204 is connected to the second water injection channel 212, and the lower end is connected to the natural fracture surface 201. The rock sample temperature monitoring component 62 is fixed in the third water injection channel 204.

[0034] The second water injection channel 212 passes through both the upper and lower ends of the upper pad 211. The upper part of the upper pad 211 is provided with a first annular groove, which is fitted over the upper end of the second water injection channel 212 with a gap between them. A first sealing ring is installed in the first annular groove. The lower part of the upper pad 211 is provided with a second annular groove, which is fitted over the lower end of the second water injection channel 212 with a gap between them. A second sealing ring is installed in the second annular groove. By providing the first and second sealing rings, the sealing performance of the water injection structure formed by the connection of the first water injection channel 36, the second water injection channel 212, and the third water injection channel 204 is enhanced.

[0035] The two ends of the water injection pipe 72 are connected to the first water injection channel 36 and the heating water tank 71, respectively. The water injection pump 73 is installed on the water injection pipe 72. The heating water tank 71 and the water injection pump 73 are both connected to the controller 10. The controller 10 can control the temperature of the water in the heating water tank 71 so that the temperature of the water in the heating water tank 71 is maintained at the second preset temperature, thereby enabling the injection of water with the second preset temperature.

[0036] Specifically, the controller 10 works in conjunction with the heating element and temperature sensing element in the heating water tank 71 to control the temperature of the water in the heating water tank 71.

[0037] In this embodiment, the test rock sample 200 is a geothermal reservoir rock sample with a natural fracture surface 201. The natural fracture surface 201 is a single fracture surface, horizontally distributed, and located in the middle of the vertical direction of the test rock sample 200. The natural fracture surface 201 divides the test rock sample 200 into an upper fracture block 203 and a lower fracture block 202. The test rock sample 200 is cubic in shape, with a side length of 100 mm. A third water injection channel 204 with a diameter of 3 mm is drilled at the center of the top of the upper fracture block 203 as a water injection hole. The third water injection channel 204 is perpendicularly connected to the natural fracture surface 201.

[0038] In this specific embodiment, the natural fracture surface 201 is either a naturally cemented and filled fracture surface or an unfilled fracture surface.

[0039] The lateral loading member 41 has a first grid groove 45 on the side that contacts the test rock sample 200. A first water outlet channel 46 is provided in the lateral loading member 41, with both ends connected to the first grid groove 45 and the water collection device 8, respectively. Water seeping from the natural fracture surface 201 of the test rock sample 200 flows through the first grid groove 45 on the lateral loading member 41 to the first water outlet channel 46 and enters the water collection device 8 connected thereto. Water seeping from the natural fracture surface 201 of the test rock sample 200 flows through the first grid groove 45 on the lateral loading member 41 to the rear side and enters the first water outlet channel 46 and enters the water collection device 8 connected thereto.

[0040] The lateral loading component 41 includes a lateral loading block 412 and a lateral loading rod 411 fixed to the outer end of the lateral loading block 412. Both lateral loading rods 411 are connected to the true triaxial rock direct shear testing machine 1. The front lateral loading block 412 contacts the front sides of the upper fracture block 203 and the lower fracture block 202, and the rear lateral loading block 412 contacts the rear sides of the upper fracture block 203 and the lower fracture block 202. A first grid groove 45 is provided on the side of the lateral loading block 412 that contacts the test rock sample 200. A first water outlet channel 46 is provided in the lateral loading block 412 and the lateral loading rod 411, and a second hot oil circulation channel 42 is provided in the lateral loading block 412.

[0041] The lower force transmission block 511 has a second grid groove 513 on the side that contacts the right side of the test rock sample 200, and the inner wall of the upper shear box 23 has a third grid groove 213 on the side that contacts the right side of the test rock sample 200. The second grid groove 513 and the third grid groove 213 are connected. A second water outlet channel 518 is provided in the lower force transmission block 511, and the two ends of the second water outlet channel 518 are connected to the second grid groove 513 and the water collection device 8, respectively. Water seeping from the natural fracture surface 201 of the test rock sample 200 to the right side flows into the second water outlet channel 518 through the second grid groove 513 on the lower force transmission block 511 and the third grid groove 213 on the upper shear box 23, and then enters the water collection device 8 connected to it.

[0042] The uploading force block 521 has a fourth grid groove 523 on the side that contacts the left side of the test rock sample 200, and the inner wall of the lower shear box 24 has a fifth grid groove 214 on the side that contacts the left side of the test rock sample 200. The fourth grid groove 523 and the fifth grid groove 214 are connected. A third water outlet channel 215 is provided in the lower shear box 24, and the two ends of the third water outlet channel 215 are connected to the fifth grid groove 214 and the water collection device 8, respectively. Water seeping from the natural fracture surface 201 of the test rock sample 200 to the left side flows into the third water outlet channel 215 through the fourth grid groove 523 on the uploading force block 521 and the fifth grid groove 214 on the lower shear box 24, and then enters the water collection device 8 connected to it.

[0043] The water collection device 8 includes four water collection mechanisms 81. The outlet ends of the second water outlet channel 518, the third water outlet channel 215, and the two first water outlet channels 46 are all connected to one water collection mechanism 81. The water collection mechanism 81 includes a water collection pipe 811, a beaker 812, and an electronic balance 813. The beaker 812 is placed on the electronic balance 813. A back pressure valve 814 is installed on the water collection pipe 811. The back pressure valve 814 and the electronic balance 813 are both connected to the controller 10. The outlet ends of the second water outlet channel 518, the third water outlet channel 215, and the two first water outlet channels 46 are all connected to one end of a water collection pipe 811. The other end of each water collection pipe 811 extends into a beaker 812.

[0044] During the experiment, water injected into the test rock sample 200 through the third water injection channel 204 radiates to the four sides of the natural fracture surface 201. The water flowing into the four sides flows out through the second water outlet channel 518, the third water outlet channel 215 and the two first water outlet channels 46 respectively. Due to the pressure limitation of the back pressure valve 814, the outflowing water remains in a liquid state. The transient water output can then be measured by the electronic balance 813.

[0045] The water temperature monitoring device 9 includes an inlet water temperature monitoring component 91 and four outlet water temperature monitoring components 92. The inlet water temperature monitoring component 91 and the four outlet water temperature monitoring components 92 are all connected to the controller 10. The inlet water temperature monitoring component 91 is fixed in the first water injection channel 36, and an outlet water temperature monitoring component 92 is fixed in the second water outlet channel 518, the third water outlet channel 215 and the two first water outlet channels 46.

[0046] This embodiment also includes a first temperature recorder 12 and four second temperature recorders 13. The inlet water temperature monitoring component 91 is connected to the first temperature recorder 12, and each outlet water temperature monitoring component 92 is connected to a second temperature recorder 13.

[0047] In this specific embodiment, the rock sample temperature monitoring component 62, the inlet water temperature monitoring component 91, and the outlet water temperature monitoring component 92 are all thermocouples.

[0048] The lower part of the uploading force block 521 has a first strip groove 524 extending through its front and rear ends, and a first strip sealing component 525 is installed in the first strip groove 524. The upper part of the downloading force block 511 has a second strip groove 514 extending through its front and rear ends, and a second strip sealing component 515 is installed in the second strip groove 514. The lower part of the downloading force block 511 has a third strip groove 516 extending through its front and rear ends, and a third strip sealing component 517 is installed in the third strip groove 516.

[0049] This embodiment also includes two first annular sealing components 47. Each lateral loading member 41 has a first annular sealing component 47 fixedly fitted onto the outer side of the end closest to the test rock sample 200. The dimension of the side of the lateral loading member 41 that contacts the test rock sample 200 is smaller than the dimensions of the front and rear sides of the test rock sample 200, and the lateral loading member 41 contacts the middle of the test rock sample 200. The dimension of the outer edge of the first annular sealing component 47 is larger than the dimensions of the front and rear sides of the test rock sample 200. The two front limiting posts 26 are used to compress and fix the front first annular sealing component 47, and the two rear limiting posts 26 are used to compress and fix the rear first annular sealing component 47. Specifically, the rear of the two front limiting posts 26 is provided with a notch matching the structure of the first annular sealing component 47, and the front of the two rear limiting posts 26 is provided with a notch matching the structure of the first annular sealing component 47.

[0050] Specifically, a first annular sealing component 47 is fixedly fitted on the outside of the end of each lateral loading block 412 near the test rock sample 200.

[0051] A second annular sealing component 216 is fixedly sleeved on the outer side of the lower part of the upper pad block 211. The left and right sides of the second annular sealing component 216 contact the inner walls of the upper force block 521 and the upper shear box 23, respectively, and the front and rear sides of the second annular sealing component 216 contact the two first annular sealing components 47, respectively. In this embodiment, a positioning protrusion is provided in the middle of the bottom end of the upper pad block 211, and the second annular sealing component 216 is fixedly sleeved on the positioning protrusion.

[0052] In this embodiment, the sealing of all sides of the test rock sample 200 is achieved by setting the first strip sealing component 525, the second strip sealing component 515, the third strip sealing component 517, the first annular sealing component 47, and the second annular sealing component 216, thereby improving the accuracy of the test.

[0053] In this specific embodiment, the first strip sealing component 525, the second strip sealing component 515 and the third strip sealing component 517 are all graphite strips, the first annular sealing component 47 is a graphite packing, and the second annular sealing component 216 is a rectangular sealing ring.

[0054] The true three-axis straight shear box 2 also includes four upper fixing mechanisms 217 and four lower fixing mechanisms 218. Each upper fixing mechanism 217 is used to fix the upper part of a limiting post 26. Each upper fixing mechanism 217 includes two mutually perpendicular upper fixing bolts 2171. Each upper fixing bolt 2171 is threadedly installed on the side of the upper box body 21, extends into the upper box body 21 and abuts against the upper part of one side of the limiting post 26. The two upper fixing bolts 2171 abut against the upper parts of two mutually perpendicular sides of the limiting post 26. Each lower fixing mechanism 218 is used to fix the lower part of a limiting post 26. Each lower fixing mechanism 218 includes two mutually perpendicular lower fixing bolts 2181. Each lower fixing bolt 2181 is threadedly installed on the side of the lower box body 22, extends into the lower box body 22 and abuts against the lower part of one side of the limiting post 26. The two lower fixing bolts 2181 abut against the lower parts of two mutually perpendicular sides of the limiting post 26. Each limiting post 26 is fixed by the corresponding upper fixing mechanism 217 and lower fixing mechanism 218.

[0055] This embodiment also includes a three-dimensional laser scanner 11, which is used to scan the morphological features of the natural fracture surface 201 of the test rock sample 200 to obtain the roughness of the natural fracture surface 201, thereby conducting a comprehensive study on the mechanical deformation, seepage phenomenon, and evolution of fracture convection heat transfer characteristics of the fracture surface during shearing.

[0056] This embodiment uses a square granite specimen with a size of 100×100×100mm and a naturally cemented fracture surface as an example, and selects pure water as the permeation medium. Then, this test system is used to illustrate the test steps of the natural fracture water injection shear-seepage-heat transfer test at a high temperature of 300 degrees Celsius. The specific implementation steps are as follows: Step 1: Sample Preparation: Select a large rock block from an outcrop in a geothermal reservoir containing a naturally cemented fracture surface. Transport the block indoors and process it into a square test rock sample 200 with dimensions of 100 x 100 x 100 mm, ensuring that the unevenness of each side does not exceed 0.01 mm. The horizontal position of the naturally cemented fracture surface is located at the center of the vertical direction of the test rock sample 200. Drill a third water injection channel 204 with a diameter of 3 mm in the center of the fractured block 203 of the test rock sample 200 as a water injection hole. The third water injection channel 204 is connected to the naturally cemented fracture surface. Step 2, Sample Loading: The lower shear box 24 is placed on the rolling disk 25. A lower pad block 220 is set in the positioning groove of the lower shear box 24, so that the lower crack block 202 and the lower force transmission block 511 are respectively set on the left and right sides of the lower shear box 24. An upper shear box 23 is set on the upper part of the lower shear box 24, so that the upper force transmission block 521 and the upper crack block 203 are respectively set on the left and right sides of the upper shear box 23. During the installation of the upper force transmission block 521 and the lower force transmission block 511, the first strip sealing component 525, the second strip sealing component 515, and the third strip sealing component 517 are installed simultaneously; so that the two lateral loading components 41 are respectively set The first annular sealing component 47 is placed on the front and rear sides of the test rock sample 200, and the installation of the two first annular sealing components 47 is completed simultaneously. Then, the lower parts of the four limiting posts 26 are fixed by the four lower fixing mechanisms 218 respectively. The upper pad 211 is placed in the second through hole 210 of the upper shear box 23 so that it contacts the upper part of the upper fracture block 203, and the second annular sealing component 216 is installed simultaneously. Then, the upper box 21 is fixed to the upper shear box 23, and the upper parts of the four limiting posts 26 are fixed by the four upper fixing mechanisms 217 respectively, so that the normal loading block 32 is located in the first through hole 29 of the upper box 21 and contacts the upper pad 211. During the test, the first strip sealing component 525, the second strip sealing component 515, the third strip sealing component 517, the first annular sealing component 47 and the second annular sealing component 216 achieve sealing of all sides of the test rock sample 200.

[0057] Step 3: Heating the test rock sample 200: Hot oil is introduced into the normal loading block 32 and the lateral loading member 41 through the first hot oil circulation channel 33 and the second hot oil circulation channel 42, respectively, to achieve heating. The test rock sample 200 is then heated through heat transfer. The rock sample temperature monitoring component 62 monitors the temperature of the test rock sample 200 and feeds it back to the controller 10. The controller 10 controls the temperature of the hot oil supplied by the hot oil circulation device 61 so that the temperature of the test rock sample 200 reaches the first preset temperature. Specifically, the temperature of the test rock sample 200 reaches 300 degrees and is kept constant.

[0058] Step 4: Apply normal force: Fix the lower box 22 onto the frame 101 of the true triaxial rock direct shear testing machine 1. Apply a preset normal force to the normal loading rod 31 through servo control of the true triaxial rock direct shear testing machine 1. Apply the normal force to 20 MPa at a constant loading rate of 0.02 MPa / s and maintain it stably for 4 hours to allow the test rock sample 200 to be fully heated in a high-temperature environment.

[0059] Step 5: Apply lateral force: Apply a preset lateral force to the lateral loading member 41 by servo-controlled true triaxial rock shear testing machine 1. Apply the lateral force to 20MPa at a constant loading rate of 0.02MPa / s and maintain it stably for 4 hours to allow the test rock sample 200 to be fully heated in a high-temperature environment.

[0060] Step 6: Apply shear force: Apply a preset shear force to the tangential loading rod 512 using a servo-controlled true triaxial rock direct shear testing machine 1 at a constant loading rate of 0.02 MPa / s. Simultaneously, fix the constraint horizontal pressure rod 522 and the uploading force block 521, and observe the shear stress-shear displacement curve in real time. When the curve reaches the plastic zone, maintain a constant shear stress.

[0061] Step 7: Fracture Water Injection: The water temperature in the heating tank 71 is controlled by controller 10 to reach 60 degrees Celsius. Then, the water pump is turned on and water is injected into the naturally cemented fracture surface of the test rock sample 200 at a constant loading rate of 0.01 MPa / s through the inlet end of the first injection channel. The shear displacement change of the naturally cemented fracture surface is observed simultaneously as the water pressure increases. When a significant change in shear displacement occurs, the water pressure is kept constant. When the naturally cemented fracture surface reaches a new mechanical equilibrium, the water pressure is increased at a constant loading rate of 0.01 MPa / s to induce new shear slip. This process is repeated.

[0062] Step 8: Permeability Calculation: The back pressure valve 814 is set to 9 MPa, and the temperature of the test rock sample 200 is 300 degrees Celsius. Based on the saturated vapor pressure of water at different temperatures, water at 300 degrees Celsius and 9 MPa pressure will not vaporize; therefore, the water remains liquid. The water radiates outwards from the center of the naturally cemented fracture surface, collecting in the grid grooves on the side of the test rock sample 200. The water then flows out through the outlet channel. The volume of the outflowing water is then collected by the electronic balance 813. Based on the volume of water collected from each side, the anisotropy of the permeability of the test rock sample 200 during the shearing process can be calculated.

[0063] Step 9, Temperature Monitoring: The inlet water temperature monitoring component 91 can monitor and record the inlet water temperature through the first temperature recorder 12, and the outlet water temperature monitoring component 92 can monitor and record the outlet water temperature through the second temperature recorder 13. The temperature rise inside the test rock sample 200 can be obtained by the difference between the inlet water temperature and the outlet water temperature.

[0064] Step 10: Surface damage characterization of test rock sample 200: Turn off the water injection pump 73, unload the shear force, normal force, and lateral force to 0 MPa, and then turn off the hot oil circulation device 61 to allow the true triaxial shear box 2 to cool to room temperature. Remove the upper shear box 23 and take out the test rock sample 200 as a whole. Gently clean and collect the minerals on the fracture surface worn by the shear surface using a brush, and use a laser particle size analyzer to statistically analyze the particle size distribution of the wear material. Then, use a three-dimensional laser scanner 11 to scan the roughness characteristics of the fracture surface and analyze the surface wear characteristics of the naturally cemented fracture surface.

[0065] The experiment is now complete.

[0066] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A high-temperature true triaxial rock mass shear fracturing three-dimensional dynamic seepage heat transfer coupling test system, characterized in that, Including a true triaxial rock direct shear testing machine; A true triaxial direct shear box, which is fixed on the frame of the true triaxial rock direct shear testing machine, and the interior of the true triaxial direct shear box forms a chamber for accommodating the test rock sample; A normal force loading device is used to extend into the true triaxial direct shear box and apply a preset normal force to the test rock sample under the action of the true triaxial rock direct shear testing machine; A lateral force loading device is used to extend into the true triaxial direct shear box and apply a preset lateral force to the test rock sample under the action of the true triaxial rock direct shear testing machine; A shear force loading device is used to extend into the true triaxial direct shear box and apply a preset shear force to the test rock sample under the action of the true triaxial rock direct shear testing machine. A heating and temperature control device is used to heat the test rock sample and bring the test rock sample to a first preset temperature; The water injection device is used to inject water with a second preset temperature into the natural fracture surface of the test rock sample so that the injected water seeps in four directions inside the test rock sample. A water collection device is used to collect and measure the flow rate of water seeping out from the four directions of the test rock sample. A water temperature monitoring device, wherein the water temperature monitoring device is used to monitor the inlet water temperature and the outlet water temperature; The controller, the true triaxial rock direct shear testing machine, the heating and temperature control device, the water injection device, the water collection device and the water temperature monitoring device are all connected to the controller; The true triaxial direct shear box includes an upper box body, a lower box body, an upper shear box, a lower shear box, a rolling disk, and four limiting posts. The lower box body is fixed on the frame of the true triaxial rock direct shear testing machine, the rolling disk is fixed in the lower box body, and the lower shear box is placed on top of the rolling disk. The lower shear box has a lower mounting groove at its upper part, which extends through the front and rear sides of the lower shear box. The lower fracture block of the test rock sample is placed in the lower mounting groove. The shear force loading device includes a tangential loading mechanism and a horizontal positioning mechanism. The tangential loading mechanism includes a lower force transmission block and a tangential loading rod fixed to one end of the lower force transmission block. The lower force transmission block is located in the lower mounting groove and is situated on the right side of the lower fracture block. The tangential loading rod extends through the right side of the lower shear box to the outside and connects to the true triaxial rock direct shear testing machine. The upper shear box is disposed above the lower shear box. The lower part of the upper shear box has an upper mounting groove that extends through both the front and rear sides of the upper shear box. The upper fracture block of the test rock sample is placed in the upper mounting groove. The horizontal positioning mechanism includes an upper force block and a horizontal pressure rod fixed to one end of the upper force block. The upper force block is disposed on the left side of the upper fracture block. The horizontal pressure rod extends through the left side of the upper shear box to the outside and connects to the true triaxial rock direct shear testing machine. The upper box body is fixed to the upper part of the upper shear box. The upper part of the upper box body has a first through hole, and the upper part of the upper shear box has a second through hole corresponding to the position of the first through hole. The normal force loading device can pass through the first through hole and the second through hole and apply a preset normal force to the test rock sample under the action of the true triaxial rock direct shear testing machine. Each of the upper and lower shear boxes has a limiting post on its left and right sides at the front, and each of the upper and lower shear boxes has a limiting post on its left and right sides at the rear. The four limiting posts are used to limit the front and rear sides of the upper and lower shear boxes. The lateral force loading device includes two lateral loading members respectively located on the front and rear sides of the test rock sample. Both lateral loading members are connected to the true triaxial rock direct shear testing machine. The two limiting posts on the front side limit the left and right sides of the lateral loading member on the front side, and the two limiting posts on the rear side limit the left and right sides of the lateral loading member on the rear side. The lateral loading member on the front side contacts the front side of the upper and lower fractured blocks, and the lateral loading member on the rear side contacts the rear side of the upper and lower fractured blocks. The normal force loading device includes a normal loading rod and a normal loading block fixed to the lower end of the normal loading rod. The normal loading block is provided with a first hot oil circulation channel, which has a first oil inlet and a first oil outlet. Each of the lateral loading members is provided with a second hot oil circulation channel, which has a second oil inlet and a second oil outlet. The heating and temperature control device includes a hot oil circulation device and a rock sample temperature monitoring component. The first oil inlet and the second oil inlet are both connected to the oil supply port of the hot oil circulation device, and the first oil outlet and the second oil outlet are both connected to the oil return port of the hot oil circulation device. The rock sample temperature monitoring component is used to monitor the temperature of the test rock sample. Both the hot oil circulation device and the rock sample temperature monitoring component are connected to the controller, which can control the temperature of the hot oil supplied by the hot oil circulation device.

2. The high-temperature true triaxial rock mass shear fracturing three-dimensional dynamic seepage heat transfer coupling test system according to claim 1, characterized in that, It also includes an upper pad block, which is disposed in the second through hole and contacts the upper surface of the test rock sample; the normal loading rod is connected to the true triaxial rock shear test machine, and the normal loading block is disposed in the first through hole and contacts the upper surface of the upper pad block.

3. The high-temperature true triaxial rock mass shear fracturing three-dimensional dynamic seepage heat transfer coupling test system according to claim 2, characterized in that, The water injection device includes a heating water tank, a water injection pipe, and a water injection pump. A first water injection channel is provided on the normal loading rod and the normal loading block. A second water injection channel, connected to the first water injection channel, is provided on the upper pad block. A third water injection channel, penetrating both ends of the upper fracture block, is provided on the upper fracture block. The upper end of the third water injection channel communicates with the second water injection channel, and the lower end communicates with the natural fracture surface. The rock sample temperature monitoring component is fixed in the third water injection channel. Both ends of the water injection pipe are connected to the first water injection channel and the heating water tank, respectively. The water injection pump is mounted on the water injection pipe. Both the heating water tank and the water injection pump are connected to the controller, which can control the temperature of the water in the heating water tank.

4. The high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system according to claim 3, characterized in that, The lateral loading member has a first grid groove on the side that contacts the test rock sample, and a first water outlet channel is provided in the lateral loading member. The two ends of the first water outlet channel are respectively connected to the first grid groove and the water collection device. The lower force transmission block has a second grid groove on the side that contacts the right side of the test rock sample, and the inner wall of the upper shear box has a third grid groove on the side that contacts the right side of the test rock sample. The second grid groove is connected to the third grid groove. The lower force transmission block has a second water outlet channel, and the two ends of the second water outlet channel are respectively connected to the second grid groove and the water collection device. The uploading force block has a fourth grid groove on the side that contacts the left side of the test rock sample, and the inner wall of the lower shear box has a fifth grid groove on the side that contacts the left side of the test rock sample. The fourth grid groove and the fifth grid groove are connected. The lower shear box has a third water outlet channel, and the two ends of the third water outlet channel are connected to the fifth grid groove and the water collection device, respectively. The water collection device includes four water collection mechanisms, each including a water collection pipe, a beaker, and an electronic balance. The beaker is placed on the electronic balance, and a back pressure valve is installed on the water collection pipe. The back pressure valve and the electronic balance are both connected to the controller. The outlet ends of the second water outlet channel, the third water outlet channel, and the two first water outlet channels are all connected to one end of the water collection pipe, and the other end of each water collection pipe extends into a beaker.

5. The high-temperature true triaxial rock mass shear fracturing triaxial dynamic seepage heat transfer coupling test system according to claim 4, characterized in that, The water temperature monitoring device includes an inlet water temperature monitoring component and four outlet water temperature monitoring components. The inlet water temperature monitoring component and the four outlet water temperature monitoring components are all connected to the controller. The inlet water temperature monitoring component is fixed in the first water injection channel, and one outlet water temperature monitoring component is fixed in each of the second water outlet channel, the third water outlet channel, and the two first water outlet channels.

6. The high-temperature true triaxial rock mass shear fracturing three-dimensional dynamic seepage heat transfer coupling test system according to claim 2, characterized in that, The lower part of the transmitting force block has a first strip-shaped groove penetrating its front and rear ends, and a first strip-shaped sealing component is installed in the first strip-shaped groove; the upper part of the transmitting force block has a second strip-shaped groove penetrating its front and rear ends, and a second strip-shaped sealing component is installed in the second strip-shaped groove; the lower part of the transmitting force block has a third strip-shaped groove penetrating its front and rear ends, and a third strip-shaped sealing component is installed in the third strip-shaped groove; it also includes two first annular sealing components, and each of the lateral loading components has a first annular sealing component fixedly fitted on the outer side of the end near the test rock sample, the dimension of the side of the lateral loading component that contacts the test rock sample is smaller than that of the test rock sample. The dimensions of the front and rear sides are such that the lateral loading member contacts the middle of the test rock sample. The outer edge of the first annular sealing member is larger than the dimensions of the front and rear sides of the test rock sample. The two limiting posts on the front side are used to squeeze and fix the first annular sealing member on the front side, and the two limiting posts on the rear side are used to squeeze and fix the first annular sealing member on the rear side. The outer side of the lower part of the upper pad is fixedly fitted with a second annular sealing member. The left and right sides of the second annular sealing member are in contact with the inner wall of the upper force block and the upper shear box, respectively. The front and rear sides of the second annular sealing member are in contact with the two first annular sealing members, respectively.

7. The high-temperature true triaxial rock mass shear fracturing three-dimensional dynamic seepage heat transfer coupling test system according to claim 1, characterized in that, The true triaxial shear box further includes four upper fixing mechanisms and four lower fixing mechanisms. Each upper fixing mechanism is used to fix the upper part of one of the limiting posts. Each upper fixing mechanism includes two mutually perpendicular upper fixing bolts. Each upper fixing bolt is threaded onto the side of the upper box body, extends into the upper box body, and abuts against the upper part of one side of the limiting post. The two upper fixing bolts abut against the upper parts of two mutually perpendicular sides of the limiting post. Each lower fixing mechanism is used to fix the lower part of one of the limiting posts. Each lower fixing mechanism includes two mutually perpendicular lower fixing bolts. Each lower fixing bolt is threaded onto the side of the lower box body, extends into the lower box body, and abuts against the lower part of one side of the limiting post. The two lower fixing bolts abut against the lower parts of two mutually perpendicular sides of the limiting post.

8. The high-temperature true triaxial rock mass shear fracturing three-dimensional dynamic seepage heat transfer coupling test system according to claim 1, characterized in that, It also includes a three-dimensional laser scanner, which is used to scan the morphological features of the natural fracture surface of the test rock sample to obtain the roughness of the natural fracture surface.

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