Indoor simulation device for natural stress and water flow environment of fractured rock mass

Abstract

The application provides a fissure rock mass natural stress and water flow environment indoor simulation device, and relates to the technical field of fluid-structure coupling test.The simulation device uses the fissure rock mass sample to be placed in a stress and water flow environment simulation tank, injects hydraulic oil into the test cabin, transmits the hydraulic oil through the flexible shell and the confining pressure head, applies the specified confining pressure to the fissure rock mass sample, drives the shaft pressure rod to apply the specified axial pressure to the fissure rock mass sample through the shaft pressure head, simulates the specified water flow environment to the fissure rock mass sample through the water inlet and the water outlet, and makes the simulation device apply the three-dimensional natural stress to the fissure rock mass sample and apply the water flow environment to the lateral side of the sample, so that the water can flow into the fissure rock mass sample and flow out of the sample.Based on the simulation device, the important tests such as the triaxial compression test and the borehole water pressure test under the coupling condition of the fissure rock mass stress and the water flow can be carried out, and the simulation device has the characteristics of simple operation, various functions and wide application range.

Description

Technical Field

[0001] This invention relates to the field of fluid-structure interaction testing technology, specifically to an indoor simulation device for natural stress and water flow environment in fractured rock masses. Background Technology

[0002] Fractured rock masses are mostly found in complex geological environments, especially those in water-rich areas. Groundwater flows intricately through the interconnected fractures, resulting in significant heterogeneity and anisotropy in the engineering properties of these masses. Current in-situ testing techniques struggle to accurately obtain the physical, mechanical, and hydraulic properties of fractured rock masses due to the complexity and difficulty in probing their initial geological environment. Therefore, laboratory testing remains the primary method for acquiring these properties. Laboratory testing plays an irreplaceable role in solving engineering problems related to fractured rock masses and in understanding their scientific principles.

[0003] However, both triaxial compression tests and other mechanical property tests of fractured rock masses, as well as borehole water pressure tests and other hydraulic property tests, require simulating the natural stress and water flow environment of the fractured rock mass under laboratory test conditions. Otherwise, the obtained test data cannot accurately reflect the actual field conditions. Currently, while existing indoor permeability testing devices can simulate groundwater seepage in fractured rock masses, they can only test the seepage characteristics of cubic or cylindrical rock samples in a specific direction. That is, a water pressure difference is applied to both ends of the cylindrical sample during the test, but no water flow environment is created around the sample. In actual geological environments, groundwater often enters the rock mass fractures from all sides and flows through the interconnected fractures; groundwater should also be able to flow out from the periphery of the fractured rock mass. Furthermore, current indoor rock mass testing devices, after applying three-dimensional stress to the rock mass sample, find it difficult to simulate a dynamic or static water flow environment around it. In summary, it is difficult to simultaneously simulate the natural stress and water flow environment of fractured rock masses using current indoor testing equipment. This makes it impossible to accurately reflect the natural stress and water flow environment conditions of fractured rock masses. Consequently, our understanding of the physical and mechanical properties and their variation laws of fractured rock masses under natural stress and water flow environments is not deep enough. We also cannot accurately predict the changes in the hydraulic properties of different fractured rock masses under different geological environmental conditions, which is detrimental to the development of rock mechanics and the safe and efficient construction of rock engineering.

[0004] Therefore, there is an urgent need for an indoor testing device that can simulate the natural stress and water flow environment of fractured rock masses. This device can be used to conduct important tests such as triaxial compression tests and borehole water pressure tests under the coupled conditions of stress and water flow in fractured rock masses. This will enable us to better study the evolution of the relevant mechanical and hydraulic properties of fractured rock masses and improve the accuracy and practicality of indoor tests. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides an indoor simulation device for natural stress and water flow environment in fractured rock masses, which solves the problem that indoor simulation devices for natural stress and water flow environment in fractured rock masses cannot simultaneously simulate natural stress and water flow environment.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] An indoor simulation device for natural stress and water flow environment in fractured rock mass, the simulation device comprising: an environmental simulation tank, a test chamber, and an axial compression rod;

[0010] The environmental simulation tank is installed inside the test chamber, which is equipped with an oil passage.

[0011] The environmental simulation tank includes: a base, a flexible outer shell, a top cover, and a confined water flow isolation inner shell;

[0012] The confining water flow isolation inner shell is set inside the flexible outer shell;

[0013] Both ends of the flexible outer shell and both ends of the inner shell of the confining water flow isolation are sealed to the base and the top cover.

[0014] The inner wall of the flexible shell is provided with a number of confining pressure heads. The confining water flow is isolated from the shell wall of the inner shell and a through hole corresponding to each confining pressure head is opened. The confining pressure head is dynamically sealed and inserted into the corresponding through hole.

[0015] The environmental simulation tank is provided with an inlet and an outlet at its lower and upper parts, respectively, and both the inlet and outlet are connected to the interior of the confining water flow isolation shell.

[0016] The environmental simulation tank is equipped with an axial pressure head, and the axial pressure rod is dynamically sealed through the test chamber and the top cover and connected to the axial pressure head.

[0017] Preferably, the top of the flexible shell is provided with a lower cover, the top of the lower cover is provided with an annular groove, and a sealing ring is provided in the annular groove;

[0018] The bottom of the top cover is provided with a ring buckle and a sealing ring. The ring buckle fits tightly with the ring groove, and the sealing ring seals the gap between the ring buckle and the ring groove, thereby achieving a sealed connection between the flexible shell and the top cover.

[0019] The sealing ring contacts and covers the top of the inner shell of the confined water flow isolation, achieving a sealed connection between the inner shell of the confined water flow isolation and the top cover.

[0020] Preferably, the top cover is a cylindrical cover made of steel with an inner diameter of 215mm, an outer diameter of 240mm, and a height of 50mm;

[0021] The lower cover has an inner diameter of 215mm, an outer diameter of 240mm, and a height of 10mm.

[0022] The sealing ring has a diameter of 215mm and a height of 30mm;

[0023] The diameter of the axial pressure head is 200mm and the height is 60mm;

[0024] The ring is a circular ring with an outer diameter of 225mm, a thickness of 2mm, and a height of 5mm;

[0025] The flexible outer shell is a cylindrical shell with an outer diameter of 215mm and a thickness of 1mm, and the inner shell of the confining water flow barrier is a rigid cylindrical shell with a thickness of 3mm.

[0026] The thickness of the confining pressure head is 15mm;

[0027] The annular groove is a circular groove with an outer diameter of 225 mm, a thickness of 2 mm, and a depth of 7 mm.

[0028] The sealing ring is a ring-shaped elastic rubber with an inner diameter of 223 mm, an outer diameter of 225 mm, and a thickness of 2.3 mm.

[0029] Preferably, the confining pressure head is a hexagonal prism with good elasticity.

[0030] Preferably, an axial pressure sensor is provided at the bottom of the axial pressure head, and a confining pressure sensor is provided at the head end of the confining pressure head.

[0031] (III) Beneficial Effects

[0032] This invention provides an indoor simulation device for the natural stress and water flow environment of fractured rock masses. Compared with the prior art, it has the following advantages:

[0033] In this invention, during the use of the simulation device, a fractured rock mass sample is placed in a stress and water flow environment simulation tank. Hydraulic oil is injected into the test chamber, and the hydraulic oil applies a specified confining pressure to the fractured rock mass sample through the flexible outer shell and the confining pressure head. A specified axial pressure is applied to the fractured rock mass sample through the axial pressure head, driven by a axial pressure rod. A specified water flow environment is simulated on the fractured rock mass sample through the inlet and outlet. This allows the simulation device to apply three-dimensional natural stress to the fractured rock mass sample and also to apply a water flow environment laterally, allowing water to both flow into and out of the sample. Based on this simulation device, important tests such as triaxial compression tests and borehole water pressure tests under the coupled conditions of fractured rock mass stress and water flow can be carried out. It features simple operation, diverse functions, and wide applicability. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0035] Figure 1 This is a schematic diagram of the lower half of the environmental simulation tank in an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the top cover structure in an embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of the structure of the environmental simulation tank in an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the structure of the confining water flow isolation inner shell in an embodiment of the present invention;

[0039] Figure 5 This is a top view of the assembly of the flexible outer shell, the confining water flow isolation inner shell, and the confining pressure head in an embodiment of the present invention;

[0040] Figure 6 This is a schematic diagram of the internal structure of the simulation device in an embodiment of the present invention;

[0041] The attached diagram is labeled as follows: 1. Test chamber; 2. Oil passage hole; 3. Base; 4. Flexible outer shell; 5. Top cover; 6. Confining water flow isolation inner shell; 7. Confining pressure head; 8. Through hole; 9. Water inlet; 10. Water outlet; 11. Axial pressure rod; 12. Axial pressure head; 13. Fractured rock mass sample; 14. Rock mass sample fissure; 15. Lower cover; 16. Ring groove; 17. Sealing ring; 18. Ring buckle; 19. Sealing rubber ring. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0043] This application provides an indoor simulation device for natural stress and water flow environment in fractured rock masses, which solves the problem that indoor simulation devices for natural stress and water flow environment in fractured rock masses are difficult to simultaneously simulate natural stress and water flow environment.

[0044] The technical solution in this application is to solve the above-mentioned technical problems, and the general idea is as follows:

[0045] In this embodiment of the invention, during the use of the simulation device, a fractured rock mass sample is placed in a stress and water flow environment simulation tank. Hydraulic oil is injected into the test chamber, and the hydraulic oil applies a specified confining pressure to the fractured rock mass sample through the flexible outer shell and the confining pressure head. The driving axial pressure rod applies a specified axial pressure to the fractured rock mass sample through the axial pressure head. A specified water flow environment is simulated on the fractured rock mass sample through the inlet and outlet. This allows the simulation device to apply three-dimensional natural stress to the fractured rock mass sample and also to apply a water flow environment laterally, allowing water to flow into and out of the sample. Based on this simulation device, important tests such as triaxial compression tests and borehole water pressure tests under the coupled conditions of fractured rock mass stress and water flow can be carried out. It features simple operation, diverse functions, and wide applicability.

[0046] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0047] Example:

[0048] like Figures 1-6 As shown, the present invention provides an indoor simulation device for natural stress and water flow environment in fractured rock mass. The simulation device includes: an environmental simulation tank, a test chamber 1, and an axial compression rod 11.

[0049] The environmental simulation tank is installed in the test chamber 1, and the test chamber 1 is provided with an oil passage 2, which provides a path for hydraulic oil to enter and flow out of the test chamber 1.

[0050] The environmental simulation tank includes: a base 3, a flexible outer shell 4, a top cover 5, and a confined water flow isolation inner shell 6;

[0051] The confining water flow isolation inner shell 6 is disposed inside the flexible outer shell 4;

[0052] Both ends of the flexible outer shell 4 and both ends of the confining water flow isolation inner shell 6 are sealed to the base 3 and the top cover 5.

[0053] The inner wall of the flexible outer shell 4 is provided with a plurality of confining pressure heads 7, and the inner shell wall of the confining water flow isolation shell 6 is provided with through holes 8 corresponding to the confining pressure heads 7 one by one. The confining pressure heads 7 are dynamically sealed and inserted into the corresponding through holes 8.

[0054] The lower and upper parts of the environmental simulation tank are respectively provided with an inlet 9 and an outlet 10, and both the inlet 9 and the outlet 10 are connected to the interior of the confining water flow isolation shell 6.

[0055] The environmental simulation tank is equipped with an axial pressure head 12, and the axial pressure rod 11 is dynamically sealed through the test chamber 1 and the top cover 5 and then connected to the axial pressure head 12.

[0056] During the use of the simulation device, the fractured rock mass sample 13 is placed in the environmental simulation tank, and hydraulic oil is injected into the test chamber 1. The hydraulic oil is transmitted through the flexible shell 4 and the confining pressure head 7 to apply a specified confining pressure to the fractured rock mass sample 13. The driving axial pressure rod 11 applies a specified axial pressure to the fractured rock mass sample 13 through the axial pressure head 12. The specified water flow environment is simulated to the fractured rock mass sample 13 through the water inlet 9 and the water outlet 10. This allows the simulation device to simulate the natural stress and water flow environment for the fractured rock mass sample 13.

[0057] The simulation device can apply three-dimensional natural stress to fractured rock mass samples and also create a water flow environment laterally, allowing water to flow into and out of the samples. Based on this simulation device, important tests such as triaxial compression tests and borehole water pressure tests under the coupled conditions of fractured rock mass stress and water flow can be carried out. It features simple operation, diverse functions, and wide applicability.

[0058] like Figures 1-3 As shown, the top of the flexible shell 4 is provided with a lower cover 15, the top of the lower cover 15 is provided with an annular groove 16, and a sealing ring 17 is provided in the annular groove 16;

[0059] The bottom of the top cover 5 is provided with a ring buckle 18 and a sealing ring 19. The ring buckle 18 fits tightly with the ring groove 16, and the ring buckle 18 squeezes the sealing ring 17 inside the ring groove 16. The sealing ring 17 deforms and seals the gap between the ring buckle 18 and the ring groove 16, thereby achieving a sealed connection between the flexible shell 4 and the top cover 5.

[0060] The sealing ring 19 contacts and covers the top of the confining pressure water flow isolation inner shell 6, realizing a sealed connection between the confining pressure water flow isolation inner shell 6 and the top cover 5; thus, the water flow environment is sealed in the confining pressure water flow isolation inner shell 6, isolating the water flow environment from the confining pressure and preventing the two from affecting each other.

[0061] like Figures 1-5 As shown, the top cover 5 is a cylindrical cover made of steel with an inner diameter of 215mm, an outer diameter of 240mm, and a height of 50mm;

[0062] The lower cover 15 has an inner diameter of 215mm, an outer diameter of 240mm, and a height of 10mm.

[0063] The sealing ring 19 has a diameter of 215 mm and a height of 30 mm;

[0064] The diameter of the axial pressure head 12 is 200mm and the height is 60mm;

[0065] The ring buckle 18 is a circular ring with an outer diameter of 225 mm, a thickness of 2 mm, and a height of 5 mm;

[0066] The flexible outer shell 4 is a cylindrical outer shell with an outer diameter of 215mm and a thickness of 1mm, and the confining water flow isolation inner shell 6 is a rigid cylindrical material with a thickness of 3mm.

[0067] The confining pressure head 7 is 15mm thick;

[0068] The annular groove 16 is a circular groove with an outer diameter of 225 mm, a thickness of 2 mm, and a depth of 7 mm.

[0069] The sealing ring 17 is a ring-shaped elastic rubber with an inner diameter of 223 mm, an outer diameter of 225 mm, and a thickness of 2.3 mm.

[0070] The test chamber 1 can be a conventional triaxial stress test chamber, providing a sealed space for the device of the invention. The tester can also equip it with relevant test devices according to the test requirements.

[0071] like Figure 2 As shown, the confining pressure head 7 is a hexagonal prism with good elasticity and good force conduction. It can not only satisfy the requirement of applying pressure to the internal fractured rock mass sample 13 when the confining pressure head 7 is subjected to external hydraulic oil, but also allow the confining pressure heads 7 to deform freely without affecting each other, preventing the confining pressure head 7 on one side from deforming too much due to the protrusion of the fractured rock mass sample 13, thus affecting the other side.

[0072] After the fractured rock mass sample 13 is placed inside the device, the flexible outer shell 4 will contract inward under external oil pressure, generating a corresponding force on the confining pressure head 7. The confining pressure head 7 undergoes small deformation, squeezing the fractured rock mass sample and applying confining pressure. Simultaneously, the confining pressure on the part of the flexible outer shell 4 that is not in contact with the confining pressure head 7 is blocked by the confining pressure water flow isolation inner shell 6. After the confining pressure water flow isolation inner shell 6 is filled with water, it can flow in the water-conducting gap formed by the confining pressure head 7 and the confining pressure water flow isolation inner shell 6, applying a water flow environment to the fractured rock mass sample 13. The force exerted on the sample by the confining pressure water flow isolation inner shell 6 and the confining pressure head 7 is similar to the force exerted on the fractured rock mass by the surrounding rock mass, and the water flow in the water-conducting gap is similar to the groundwater environment around the fractured rock mass. This device can simulate the natural stress and water flow environment of the fractured rock mass.

[0073] An axial pressure sensor is provided at the bottom of the axial pressure head 12, and a confining pressure sensor is provided at the head of the confining pressure head 7. The axial pressure sensor and the confining pressure sensor transmit monitoring signals to the controller, which calculates and displays the magnitude of the load on the test piece based on the received signals.

[0074] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0075] In this embodiment of the invention, during the use of the simulation device, a fractured rock mass sample is placed in a stress and water flow environment simulation tank. Hydraulic oil is injected into the test chamber, and the hydraulic oil applies a specified confining pressure to the fractured rock mass sample through the flexible outer shell and the confining pressure head. The driving axial pressure rod applies a specified axial pressure to the fractured rock mass sample through the axial pressure head. A specified water flow environment is simulated on the fractured rock mass sample through the inlet and outlet. This allows the simulation device to apply three-dimensional natural stress to the fractured rock mass sample and also to apply a water flow environment laterally, allowing water to flow into and out of the sample. Based on this simulation device, important tests such as triaxial compression tests and borehole water pressure tests under the coupled conditions of fractured rock mass stress and water flow can be carried out. It features simple operation, diverse functions, and wide applicability.

[0076] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0077] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for laboratory simulation of natural stresses in fractured rock mass and water flow environment, characterized in that, The simulation device comprises an environment simulation tank, a test cabin (1) and a shaft pressure rod (11); The environment simulation tank is installed in the test cabin (1), and the test cabin (1) is provided with an oil passage hole (2); The environment simulation tank comprises a base (3), a flexible shell (4), a top cover (5) and a confining pressure water flow isolation inner shell (6); The confining pressure water flow isolation inner shell (6) is arranged in the flexible shell (4); Both ends of the flexible shell (4) and the confining pressure water flow isolation inner shell (6) are in sealing connection with the base (3) and the top cover (5); The inner wall of the flexible shell (4) is provided with a plurality of confining pressure heads (7), and the shell wall of the confining pressure water flow isolation inner shell (6) is provided with through holes (8) corresponding to the confining pressure heads (7) one by one, and the confining pressure heads (7) are in dynamic sealing insertion with the corresponding through holes (8); The lower part and the upper part of the environment simulation tank are respectively provided with a water inlet (9) and a water outlet (10), and the water inlet (9) and the water outlet (10) are in communication with the inside of the confining pressure water flow isolation inner shell (6); after the confining pressure water flow isolation inner shell (6) is filled with water, the water can flow in the water guide gap formed by the confining pressure head (7) and the confining pressure water flow isolation inner shell (6) to apply a water flow environment to the fractured rock mass sample (13); The environment simulation tank is provided with a shaft pressure head (12), and the shaft pressure rod (11) is in dynamic sealing penetration through the test cabin (1) and the top cover (5) and is connected with the shaft pressure head (12).

2. The apparatus of claim 1, wherein the apparatus is configured to simulate the natural stress field of a fractured rock mass and the flow environment of water in the fractured rock mass. The top end of the flexible shell (4) is provided with a lower cover (15), and the lower cover (15) is provided with a ring groove (16) at the top, and the ring groove (16) is provided with a sealing ring (17); The bottom of the top cover (5) is provided with a ring buckle (18) and a sealing rubber ring (19), the ring buckle (18) is closely combined with the ring groove (16), the sealing ring (17) blocks the gap between the ring buckle (18) and the ring groove (16), and the sealing connection between the flexible shell (4) and the top cover (5) is realized; The sealing rubber ring (19) contacts and covers the top end of the confining pressure water flow isolation inner shell (6), and the sealing connection between the confining pressure water flow isolation inner shell (6) and the top cover (5) is realized.

3. The apparatus of claim 2, wherein the apparatus is configured to simulate the effect of a fracture in the rock mass on the water flow in the fracture. The top cover (5) is a cylindrical cover made of steel material with an inner diameter of 215 mm, an outer diameter of 240 mm and a height of 50 mm; The inner diameter of the lower cover (15) is 215 mm, the outer diameter is 240 mm, and the height is 10 mm; The diameter of the sealing rubber ring (19) is 215 mm, and the height is 30 mm; The diameter of the shaft pressure head (12) is 200 mm, and the height is 60 mm; The ring buckle (18) is a circular ring with an outer diameter of 225 mm, a thickness of 2 mm and a height of 5 mm; The flexible shell (4) is a cylindrical shell with an outer diameter of 215 mm and a thickness of 1 mm, and the confining pressure water flow isolation inner shell (6) is a rigid material cylinder with a thickness of 3 mm; The confining pressure head (7) is 15 mm thick; The ring groove (16) is a circular ring-shaped groove with an outer diameter of 225 mm, a thickness of 2 mm and a depth of 7 mm; The sealing ring (17) is a circular ring-shaped elastic rubber with an inner diameter of 223 mm, an outer diameter of 225 mm and a thickness of 2.3 mm.

4. The apparatus of claim 1, wherein the apparatus is configured to simulate the natural stress field of a fractured rock mass and the flow environment of water in the fractured rock mass. The confining pressure head (7) is a hexagonal prism with elasticity.

5. The apparatus of claim 1, wherein the apparatus is configured to simulate the natural stress field of a fractured rock mass and the flow environment of water in the fractured rock mass. The shaft pressure head (12) is provided with a shaft pressure sensor at the bottom, and the head end of the confining pressure head (7) is provided with a confining pressure sensor.

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