A hydraulic coupling loading test system and method for a fractured rock mass model

Abstract

The application provides a hydraulic coupling loading test system and method for a fractured rock mass model, and the system comprises: a hydraulic loading module, which comprises a force transmission module, a transfer cavity is arranged in the force transmission module, the transfer cavity is used for placing a prefabricated fractured rock mass model, and the hydraulic loading module is configured to load stress on the fractured rock mass model; and a hydraulic loading module, which comprises a plurality of water injection pipes and water return pipes, the plurality of water injection pipes all extend into the fractured rock mass model after penetrating through the hydraulic loading module, the plurality of water return pipes are all connected with the fractured rock mass model, and the hydraulic loading module is configured to pass water into the fractured rock mass model to load hydraulic force on the fractured rock mass model. Through the cooperation of the hydraulic loading module and the hydraulic loading module, the hydraulic coupling loading test on the fractured rock mass model can be better and more finely performed.

Description

Technical Field

[0001] This application relates to the field of rock mass engineering technology, and in particular to a hydraulic coupling loading test system and method for fractured rock mass models. Background Technology

[0002] In deep rock engineering, buried caverns need to operate for extended periods in extreme environments characterized by high ground stress and high osmotic pressure. Under high ground stress, parts of the surrounding rock mass are at critical failure, leading to frequent disasters such as rock cracking, rock bursts, softening, and collapses. High osmotic pressure not only causes engineering disasters such as water inrush, damage to the surrounding rock and lining, but also exacerbates the rock softening process and reduces the rock mass strength. Under the combined effects of high ground stress, high osmotic pressure, and dynamic loads, the seepage stability and dynamic mechanical response of fractured surrounding rock are severely affected, threatening the safe operation of underground caverns. Summary of the Invention

[0003] In view of this, the purpose of this application is to propose a hydraulic coupling loading test system and method for fractured rock mass models.

[0004] To achieve the above objectives, this application provides a first aspect of a hydraulically coupled loading test system for a fractured rock mass model, comprising:

[0005] A hydraulic loading module includes a force transmission module, which has a transfer cavity for placing a prefabricated fractured rock mass model. The hydraulic loading module is configured to apply stress to the fractured rock mass model.

[0006] The hydraulic loading module includes multiple water injection pipes and return pipes. The multiple water injection pipes pass through the hydraulic loading module and extend into the fractured rock mass model. The multiple return pipes are connected to the fractured rock mass model. The hydraulic loading module is configured to pump water into the fractured rock mass model to apply hydraulic pressure to the fractured rock mass model.

[0007] Optionally, the force transmission module includes a first top plate at the top and a support platform at the bottom. A first side plate, a second side plate, a third side plate, and a reaction pad are sequentially connected between the first top plate and the support platform. The first side plate, the second side plate, the third side plate, and the reaction pad together form the transfer cavity.

[0008] Optionally, the first top plate, the first side plate, the second side plate, and the third side plate each include multiple force transmission and correction plates, and two adjacent force transmission and correction plates are movably connected.

[0009] Optionally, the first side plate, the second side plate, and the third side plate each include a plurality of force transmission and straightening plates that are movably connected from top to bottom. The stress applied by the hydraulic loading module to the force transmission and straightening plate on the side closer to the support platform is greater than the stress applied by the hydraulic loading module to the force transmission and straightening plate on the side farther from the support platform.

[0010] Optionally, each of the force transmission straightening plates is provided with a first pad and a second pad on the side away from the transfer cavity, and a support roller is rotatably provided on the second pad; in two adjacent force transmission straightening plates, the first pad of one force transmission straightening plate is used to support the support roller of the other force transmission straightening plate, and the support roller can move along the first pad to realize the movable connection between the two adjacent force transmission straightening plates.

[0011] Optionally, the first pad includes a plurality of first sub-pads spaced apart, the second pad includes a plurality of second sub-pads spaced apart, each force transmission correction plate has a plurality of correction sub-plates on the side away from the transfer cavity, each correction sub-plate has a first sub-pad and a second sub-pad spaced apart, a force transmission pad is provided between the first sub-pad and the second sub-pad, the side of the force transmission pad away from the force transmission correction plate is provided with a ball joint support, and the side of the ball joint support away from the force transmission correction plate is provided with a ball joint joint.

[0012] Optionally, the hydraulic loading module further includes a rigid reaction frame, the inner wall of which is provided with a plurality of hydraulic jacks, each of which is connected to a ball joint, and the hydraulic jacks are connected to an external high-pressure oil source. The hydraulic jacks are used to apply stress to the corresponding force transmission correction plate.

[0013] Optionally, the hydraulic loading module further includes multiple seepage pipes, all of which are connected to the water injection pipe. The multiple seepage pipes are respectively embedded in multiple rock fissures of the prefabricated fractured rock mass model, and the sidewalls of the seepage pipes have multiple seepage holes.

[0014] Optionally, the model also includes a monitoring module, which includes multiple piezometers, with multiple piezometers placed around each rock mass fracture in the prefabricated fractured rock mass model.

[0015] The second aspect of this application provides a method for using the hydraulically coupled loading test system for a fractured rock mass model as described in any of the first aspects above, comprising the following steps:

[0016] To create a fractured rock mass model, the model is printed to a predetermined height according to pre-set requirements, and then seepage pipes, piezometers, and sensors are installed.

[0017] The fractured rock mass model is cured to the predetermined age, the seepage pipe is connected to the water injection pipe of the hydraulic loading module, the return water pipe of the hydraulic loading module is connected to the fractured rock mass model, and the piezometer and sensor are connected to an external data acquisition instrument.

[0018] The fractured rock mass model is placed in the transfer chamber of the hydraulic loading module, and the hydraulic loading module is adjusted to fit the edge of the fractured rock mass model. A displacement meter is installed inside the fractured rock mass model and connected to the external data acquisition instrument.

[0019] According to the preset requirements, the hydraulic loading module is activated to apply stress to the fractured rock mass model, and the hydraulic loading module is activated to flow water into the fractured rock mass model to apply hydraulic force to the fractured rock mass model. At the same time, the external data acquisition instrument is activated to monitor the monitoring data of each piezometer, sensor and displacement gauge.

[0020] As can be seen from the above, the hydraulic coupling loading test system and method for fractured rock mass models provided in this application fully consider the discontinuity problem of fractured rock masses. The prefabricated fractured rock mass model is placed in the transfer chamber of the force transmission module, and the transfer chamber fits tightly with the fractured rock mass model, forming a horizontal stress loading surface for better loading effect. Simultaneously, stress is applied to the fractured rock mass model through the hydraulic loading module, enabling simulation tests of stress loading on the fractured rock mass model. The force transmission module can achieve non-uniform stress loading on the fractured rock mass model, making the entire simulation experiment more consistent with the actual environment. Furthermore, multiple water injection pipes pass through the hydraulic loading module and extend into the fractured rock mass model, allowing the hydraulic loading module to directly apply hydraulic loading to the rock mass fractures within the fractured rock mass model. The combined use of the hydraulic loading module and the water loading module allows for better and more precise hydraulic coupling loading tests on the fractured rock mass model. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the hydraulic coupling loading test system according to an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the force transmission module according to an embodiment of this application;

[0024] Figure 3 Appendix to this application specification Figure 2A magnified view of part of D;

[0025] Figure 4 This is a schematic diagram of the structure of a single correction subplate according to an embodiment of this application;

[0026] Figure 5 This is a schematic diagram of the first structure of the fractured rock mass model according to an embodiment of this application;

[0027] Figure 6 Appendix to this application specification Figure 5 A schematic diagram of the cross-section of surface AA;

[0028] Figure 7 This is a schematic diagram of the seepage pipe according to an embodiment of this application;

[0029] Figure 8 This is a schematic diagram of the hydraulic loading module according to an embodiment of this application;

[0030] Figure 9 This is a schematic diagram of the second structure of the fractured rock mass model according to an embodiment of this application;

[0031] Figure 10 Appendix to this application specification Figure 9 Schematic diagram of the installation of the piezometer at the BB surface section;

[0032] Figure 11 Appendix to this application specification Figure 9 Schematic diagram of the installation of the displacement gauge at the C-plane.

[0033] In the diagram, 1. Hydraulic loading module; 11. High-pressure active; 12. Rigid reaction frame; 13. Hydraulic jack; 14. Force transmission module; 141. First top plate; 142. Bearing platform; 143. First side plate; 144. Second side plate; 145. Third side plate; 146. Reaction pad; 147. Force transmission and correction plate; 1471. First pad block; 14711. First sub-pad block; 1472. Second pad block; 14721. Second sub-pad block; 1473. Support roller; 1474. Force transmission pad block; 1475. Ball joint 1. Head; 1476. Correction plate; 148. Transfer roller; 149. Transfer chamber; 2. Hydraulic loading module; 20. Mixer; 21. Water source interface; 22. Water storage tank; 23. High-pressure pump; 24. Return water pipe; 25. Return water inlet; 26. Flow meter; 27. Pressure gauge; 28. Water injection valve; 29. ​​Water injection pipe; 291. Seepage pipe; 2911. Seepage hole; 3. Fractured rock mass model; 31. Underground structure model; 32. Rock mass fracture; 4. Monitoring module; 41. Piezometer; 42. Strain gauge; 43. Displacement gauge. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0035] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0036] As described in the background section, under the influence of high ground stress, high osmotic pressure and dynamic loads, the seepage stability and dynamic mechanical response of fractured surrounding rock are severely affected, threatening the safe operation of underground caverns.

[0037] Traditional theoretical methods are insufficient for investigating the hydraulic coupling mechanism of fractured surrounding rock in deeply buried caverns under high stress and high permeability. Numerical simulation parameters are subject to significant randomness, and in-situ testing conditions are limited. In contrast, geomechanical model tests offer intuitive, controllable, and realistic advantages, making them a crucial tool for studying the hydraulic coupling characteristics of fractured surrounding rock in deeply buried caverns. Geomechanical model tests can supplement and validate numerical simulation studies, accurately simulating the hydraulic coupling failure process of fractured surrounding rock during long-term operation of deeply buried caverns. They play an irreplaceable role in discovering new phenomena, revealing new mechanisms, exploring new laws, and verifying new theories.

[0038] However, to conduct hydraulic coupling simulations of fractured rock mass models, a matching geomechanical model testing system is required. Currently, both domestic and international geomechanical model hydraulic coupling testing systems generally suffer from the following problems:

[0039] 1) The existing hydraulic coupling test system directly lays out the geological model, but does not take into account the discontinuity of the fractured rock mass when loading three-dimensional stress. The force transmission module does not have targeted designs such as model fitting, force transmission correction, and friction reduction. The non-uniform stress loading effect of the fractured rock mass geological model is not good.

[0040] 2) The existing hydraulic coupling test system geological model hydraulic loading method is mostly hydraulic pressure model surface loading, without the functional design to directly hydraulically load the fracture surface, and cannot carry out the study of hydraulic transmission and fracture contact mechanical softening characteristics in rock fracture space;

[0041] 3) Existing hydraulic coupling test systems do not provide specific seepage monitoring schemes for the differences in hydraulic conduction between the rock matrix and fractures, nor do they propose targeted monitoring methods for the internal stress state of intact rock masses.

[0042] Based on the above problems, this application proposes a hydraulic coupling loading test system and method for fractured rock mass models. By using the hydraulic loading module and the hydraulic loading module in combination, the hydraulic coupling loading test on the fractured rock mass model can be achieved better and more accurately.

[0043] See Figure 1 The first aspect of this application provides a hydraulically coupled loading test system for a fractured rock mass model, comprising:

[0044] The hydraulic loading module 1 includes a force transmission module 14, which has a transfer cavity 149 for placing a prefabricated fractured rock mass model 3. The hydraulic loading module 1 is configured to apply stress to the fractured rock mass model 3.

[0045] The hydraulic loading module 2 includes multiple water injection pipes 29 and return water pipes 24. The multiple water injection pipes 29 pass through the hydraulic loading module 1 and extend into the fractured rock mass model 3. The multiple return water pipes 24 are connected to the fractured rock mass model 3. The hydraulic loading module 2 is configured to flow water into the fractured rock mass model 3 to apply hydraulic pressure to the fractured rock mass model 3.

[0046] Specifically, the transfer cavity 149 is used to place the prefabricated fractured rock mass model 3. In actual use, the prefabricated fractured rock mass model 3 is placed in the transfer cavity 149 of the force transmission module 14. The transfer cavity 149 and the fractured rock mass model 3 are closely fitted, which can form a horizontal stress loading surface and achieve a better loading effect.

[0047] The prefabricated fractured rock mass model 3 is a prefabricated rock mass model with fractures, used to simulate the surrounding rock of deep-buried caverns in actual deep rock engineering. The prefabricated fractured rock mass model 3 also includes an underground structure model 31, which is used to simulate deep-buried caverns so that the entire hydraulic coupling loading test is more in line with the actual surrounding rock conditions of deep-buried caverns.

[0048] Specifically, the prefabricated fractured rock mass model 3 can be a large-scale cement-based 3D printed fractured rock mass model. This model is constructed using a dual-arm multi-material concrete 3D printing additive-subtractive molding system and molding method disclosed in related technologies, and multiple rock mass fractures 32 are cut within the model. After the prefabricated fractured rock mass model 3 is printed, it is cured to a specified age and then placed in the transfer cavity 149 within the force transmission module 14 for subsequent mechanical loading. By applying stress to the fractured rock mass model 3 through the hydraulic loading module 1, a simulation test of the stress loading on the fractured rock mass model 3 can be conducted. The force transmission module 14 can achieve non-uniform stress loading on the fractured rock mass model 3, making the entire simulation experiment more consistent with the actual environment.

[0049] The hydraulic loading module 2 includes multiple water injection pipes 29 and return pipes 24. The multiple water injection pipes 29 pass through the hydraulic loading module 1 and extend into the fractured rock mass model 3, so that the hydraulic loading module 2 can directly apply hydraulic loading to the rock mass fractures 32 in the fractured rock mass model 3, instead of only loading the surface of the fractured rock mass model 3. This can more realistically simulate the hydraulic loading situation in the actual rock mass fractures, and can further study the hydraulic transmission and fracture contact mechanical softening characteristics of each rock mass fracture 32 space in the fractured rock mass model 3.

[0050] In this application, based on actual needs, different stresses are applied to the fractured rock mass model 3 through the hydraulic loading module 1, and water at different pressures is introduced into the fractured rock mass model 3 through the hydraulic loading module 2, so as to apply different hydraulic forces (i.e., seepage pressures) to the fractured rock mass model 3. The combined use of the hydraulic loading module 1 and the hydraulic loading module 2 can better and more accurately simulate the hydraulic coupling failure process of fractured surrounding rock during long-term operation of deep buried caverns. It plays an irreplaceable and important role in discovering new phenomena, revealing new mechanisms, exploring new laws, and verifying new theories.

[0051] In some embodiments, the force transmission module 14 includes a first top plate 141 at the top and a support platform 142 at the bottom. A first side plate 143, a second side plate 144, a third side plate 145, and a reaction pad 146 are sequentially connected between the first top plate 141 and the support platform 142. The first side plate 143, the second side plate 144, the third side plate 145, and the reaction pad 146 together form the transfer cavity 149.

[0052] Specifically, the first side plate 143 is disposed opposite to the reaction pad 146. In practice, the hydraulic loading module 1 applies stress to the first top plate 141, the first side plate 143, the second side plate 144, and the third side plate 145. The stress is transmitted through the first top plate 141, the first side plate 143, the second side plate 144, and the third side plate 145 to the prefabricated fractured rock mass model 3 located in the transfer cavity 149, thereby applying stress to the fractured rock mass model 3. The hydraulic loading module 1 does not apply stress to the reaction pad 146 and the support platform 142; the reaction pad 146 and the support platform 142 exist as reaction surfaces.

[0053] In this application, the stress applied by the hydraulic loading module 1 is transmitted through the first top plate 141, the first side plate 143, the second side plate 144, and the third side plate 145 to the prefabricated fractured rock mass model 3 located in the transfer cavity 149, so as to apply stress to the fractured rock mass model 3. The stress applied to the fractured rock mass model 3 is transmitted through the first top plate 141, the first side plate 143, the second side plate 144, and the third side plate 145, so that the stress applied to the fractured rock mass model 3 is more uniform, avoiding excessive local stress on the fractured rock mass model 3, which may lead to test failure or inaccuracy, and improving the accuracy of the entire test.

[0054] In some embodiments, see continue to see Figure 2 The first top plate 141, the first side plate 143, the second side plate 144 and the third side plate 145 each include a plurality of force transmission and correction plates 147, and two adjacent force transmission and correction plates 147 are movably connected.

[0055] Specifically, adjacent force-transmitting correction plates 147 are movably connected, allowing them to move relative to each other. This enables the stresses applied to each force-transmitting correction plate 147 to be different. When the stresses applied to each force-transmitting correction plate 147 are different, each force-transmitting correction plate 147 can move different distances relative to its original position under the applied stress without interference between them. Thus, this experimental system allows the stresses applied to each force-transmitting correction plate 147 to be either the same or different, enriching the experimental conditions and scenarios that this system can simulate. It can better, more precisely, and more diversely simulate real-world environments, resulting in higher accuracy of the simulation results.

[0056] In some embodiments, see continue to see Figure 2The first side plate 143, the second side plate 144 and the third side plate 145 each include a plurality of force transmission and straightening plates 147 that are movably connected from top to bottom. The stress that the hydraulic loading module 1 applies to the force transmission and straightening plate 147 on the side closer to the support platform 142 is greater than the stress that the hydraulic loading module 1 applies to the force transmission and straightening plate 147 on the side farther away from the support platform 142.

[0057] Specifically, in actual deep rock engineering, the geostress and seepage pressure borne by the surrounding rock of deeply buried caverns are not strictly the same. In fact, the deeper the rock is from the surface, the greater the geostress it bears, and the shallower the rock is from the surface, the smaller the geostress it bears. Therefore, in this application, the stress applied by the hydraulic loading module 1 to the force transmission correction plate 147 (i.e., the force transmission correction plate 147 at a greater distance from the surface) closer to the support platform 142 is greater than the stress applied by the hydraulic loading module 1 to the force transmission correction plate 147 (i.e., the force transmission correction plate 147 at a smaller distance from the surface) further away from the support platform 142. This ensures that, in practical implementation, the stress applied to the lower part of the prefabricated fractured rock mass model 3 (i.e., the part at a greater distance from the surface) is greater than the stress applied to its upper part (i.e., the part at a smaller distance from the surface), thus better reflecting the actual environment and obtaining more accurate test results.

[0058] For example, assuming that the first side plate 143, the second side plate 144, and the third side plate 145 each include a first straightening plate, a second straightening plate, and a third straightening plate that are sequentially and movably connected from top to bottom, then the stress loaded on the first straightening plate can be 15 MPa, the stress loaded on the second straightening plate can be 12 MPa, and the stress loaded on the third straightening plate can be 10 MPa. Applying gradient stress to the first side plate 143, the second side plate 144, and the third side plate 145 in the vertical direction can avoid loading imbalance caused by local displacement deformation of the fractured rock mass model 3.

[0059] In some embodiments, see continue to see Figure 2 and Figure 3 Each of the force transmission and correction plates 147 is provided with a first pad 1471 and a second pad 1472 at intervals on the side away from the transfer cavity 149. A support roller 1473 is rotatably disposed on the second pad 1472. In two adjacent force transmission and correction plates 147, the first pad 1471 of one force transmission and correction plate 147 is used to support the support roller 1473 of the other force transmission and correction plate 147. The support roller 1473 can move along the first pad 1471 to realize the movable connection between the two adjacent force transmission and correction plates 147.

[0060] Specifically, the first pad 1471 is disposed on the upper part of the force transmission and correction plate 147, and the second pad 1472 is disposed on the lower part of the force transmission and correction plate 147. The second pad 1472 has a plurality of roller holes, and the support roller 1473 passes through the roller holes and can rotate in the roller holes. The support roller 1473 contacts the first pad 1471 located below it and can roll along the first pad 1471.

[0061] See also Figure 3 In two adjacent force transmission and correction plates 147, the first pad 1471 of one of the force transmission and correction plates 147 is used to support the support roller 1473 on the second pad 1472 of the other force transmission and correction plate 147. The support roller 1473 can move along the first pad 1471 under the action of external force to realize the movable connection between the two adjacent force transmission and correction plates 147. In practice, when the stress applied to two adjacent force-transmitting correction plates 147 is different, the distances that the two adjacent force-transmitting correction plates 147 move relative to their original positions are different. Therefore, the force-transmitting correction plate 147 with a larger applied stress will move a greater distance towards the prefabricated fractured rock mass model 3, while the force-transmitting correction plate 147 with a smaller applied stress will move a smaller distance towards the prefabricated fractured rock mass model 3. At this time, there will be a difference in the moving distance between the two adjacent force-transmitting correction plates 147. This difference in moving distance is achieved by the support roller 1473 moving along the first pad 1471, ensuring that when different stresses are applied, each force-transmitting correction plate 147 can still fit with the corresponding part of the prefabricated fractured rock mass model 3, and can transfer stress to the fractured rock mass model 3.

[0062] Meanwhile, the first pad 1471 of one of the force transmission correction plates 147 is used to support the support roller 1473 on the second pad 1472 of the other force transmission correction plate 147, ensuring that the movement of the support roller 1473 is always supported. During the test, the volume of the fractured rock mass model 3 shrinks, and the first top plate 141, the first side plate 143, the second side plate 144, and the third side plate 145 are subjected to lateral friction thrust. The constant support can ensure that each force transmission correction plate (jack) will not be deformed or damaged due to lateral displacement, thereby ensuring the safety and stability of the entire test system.

[0063] Furthermore, adjacent force transmission correction plates 147 are connected by the cooperation of support rollers 1473 and first pads 1471. Adjacent force transmission correction plates 147 are not fixedly locked together. When they move relative to each other, the movement of the support rollers 1473 reduces the frictional resistance between them, facilitating faster and more accurate testing. Simultaneously, the cooperation between the support rollers 1473 and the first pads 1471 can also resist the tangential force of the hydraulic jack 13.

[0064] In some embodiments, see Figure 4 The first pad 1471 includes a plurality of first sub-pads 14711 spaced apart, and the second pad 1472 includes a plurality of second sub-pads 14721 spaced apart. Each force transmission correction plate 147 has a plurality of correction sub-plates 1476 on the side away from the transfer cavity 149. Each correction sub-plate 1476 has a first sub-pad 14711 and a second sub-pad 14721 spaced apart. A force transmission pad 1474 is provided between the first sub-pad 14711 and the second sub-pad 14721. A ball joint support is provided on the side of the force transmission correction plate 1474 away from the force transmission correction plate 147, and a ball joint joint 1475 is provided on the side of the ball joint support away from the force transmission correction plate 147.

[0065] Specifically, a force transmission pad 1474 is provided between the first sub-pad 14711 and the second sub-pad 14721. The force transmission pad 1474 includes a central pad and multiple pads evenly distributed around the central pad. The central pad and the multiple pads form a structure similar to a "pentagon". This structure can make the stress loaded on the corresponding correction sub-plate 1476 through the force transmission pad 1474 more uniform. The stress can be evenly loaded onto each position of the correction sub-plate 1476, without causing excessive local loading stress, thus ensuring more accurate testing.

[0066] The force transmission pad 1474 is provided with a ball joint support on the side away from the force transmission correction plate 147, and the ball joint support is provided with a ball joint connector 1475 on the side away from the force transmission correction plate 147. The ball joint connector 1475 is used to connect with the hydraulic jack 13 in the hydraulic loading module 1.

[0067] In some embodiments, see continue to see Figure 1 The hydraulic loading module 1 also includes a rigid reaction frame 12. The inner wall of the rigid reaction frame 12 is provided with a plurality of hydraulic jacks 13. Each hydraulic jack 13 is connected to a ball joint 1475. The hydraulic jack 13 is connected to an external high-pressure oil source. The hydraulic jack 13 is used to apply stress to the corresponding force transmission correction plate 147.

[0068] Specifically, the hydraulic jack 13, through a ball joint 1475 connected to it, applies stress to the force transmission pad 1474 and the force transmission straightening plate 147 connected to the ball joint 1475, thereby transferring the stress to the prefabricated fractured rock mass model 3 that is in contact with the force transmission straightening plate 147. Simultaneously, when no stress needs to be applied, the hydraulic jack 13 can also limit and fix each force transmission straightening plate 147, preventing significant tilting or shaking of the plates.

[0069] In some embodiments, see Figure 5 , Figure 6 and Figure 7 The hydraulic loading module 2 also includes multiple seepage pipes 291, all of which are connected to the water injection pipe 29. The multiple seepage pipes 291 are respectively built into multiple rock mass fissures 32 of the prefabricated fractured rock mass model 3, and multiple seepage holes are opened on the side wall of the seepage pipe 291.

[0070] Specifically, when fabricating the prefabricated fractured rock mass model 3, multiple seepage pipes 291 can be embedded in multiple rock mass fractures 32 of the prefabricated fractured rock mass model 3. Specifically, at least one seepage pipe 291 can be embedded in each rock mass fracture 32. The outer diameter of the seepage pipe 291 is equivalent to the opening of the rock mass fracture 32, and the outer diameter of the seepage pipe 291 can be 3-5mm. The seepage pipe 291 embedded in the rock mass fracture 32 will not interfere with the prefabricated fractured rock mass model 3 and the actual surrounding rock structure. Moreover, the water in the seepage pipe 291 can be directly injected into the rock mass fracture 32, and the rock mass fracture 32 can be directly hydraulically loaded. This facilitates more accurate monitoring and research on the hydraulic transmission and fracture contact mechanical softening characteristics of each rock mass fracture 32 space.

[0071] In addition, when the seepage pipe 291 is installed in the rock mass fissure 32, the end of the seepage pipe 291 is 50-100mm away from the edge of the fissure rock mass model 3 to ensure effective sealing of the edge of the rock mass fissure 32. The side wall of the seepage pipe 291 has multiple seepage holes 2911.

[0072] Specifically, in practice, the hydraulic loading module 2 injects water into the seepage pipe 291 through the water injection pipe 29. The water in the seepage pipe 291 flows out from multiple seepage holes 2911 and flows to multiple rock fractures 32 in the prefabricated fractured rock mass model 3 and around the rock fractures 32, so as to more realistically simulate the hydraulic loading situation in the actual rock fractures 32. This allows for further research on the hydraulic transmission and fracture contact mechanical softening characteristics of each rock fracture 32 space in the fractured rock mass model 3.

[0073] In some embodiments, see continue to see Figure 1 and Figure 8The hydraulic loading module 2 also includes a water storage tank 22, with a water source interface 21 on one side for connecting to an external water source. Multiple water injection pipes 29 and multiple water return pipes 24 are connected to one side of the water storage tank 22 via a high-pressure pump 23. Each water injection pipe 29 is equipped with a water injection valve 28, a pressure gauge 27, and a flow meter 26 to adjust the water pressure injected into each pipe in real time. This allows for control of the water pressure applied to different parts of the prefabricated fractured rock mass model 3, enabling different water pressure loading on different fracture surfaces of the same fractured rock mass model 3, thus facilitating successful simulation tests under various experimental conditions.

[0074] Multiple return water pipes 24 are provided, and multiple return water pipes 24 can be connected to different parts of the prefabricated fractured rock mass model 3 or different rock mass fractures 32. Each return water pipe 24 is equipped with a return water valve, and each return water valve is independently controlled.

[0075] The return water pipe 24, the injection water pipe 29, and the seepage pipe 291 are all made of Teflon tubing, which is tougher and has a thicker wall, in order to improve the service life of the entire test system.

[0076] The top of the water storage tank 22 is also equipped with a stirrer 20, which pre-prepares the seepage water containing ink stored in the water storage tank 22 to facilitate the observation of the seepage test.

[0077] In some embodiments, see continue to see Figure 9 , Figure 10 and Figure 11 The test system also includes a monitoring module 4, which includes multiple piezometers 41. Multiple piezometers 41 are provided around each rock mass fissure 32 in the prefabricated fractured rock mass model 3.

[0078] Specifically, each rock mass fissure 32 in the prefabricated fissure rock mass model 3 is surrounded by multiple piezometers 41. The piezometers 41 are directly installed at the edge of the rock mass fissure 32, which can monitor the pore water pressure in the rock mass fissure 32 in real time, making the monitoring data more accurate. At the same time, according to research needs, pressure gauges and other sensors can also be installed at the edge of the rock mass fissure 32.

[0079] The monitoring module 4 also includes multiple strain bricks 42, which are evenly distributed in the prefabricated fractured rock mass model 3 to monitor the stress state inside the fractured rock mass model 3 under long-term high stress and high permeability conditions.

[0080] The monitoring module 4 also includes multiple displacement gauges 43, which are evenly distributed within the underground structure model 31 of the prefabricated fractured rock mass model 3. Contact displacement gauges 43 are used within the underground structure model 31 to monitor the deformation of the underground structure of the prefabricated fractured rock mass model 3 under hydraulic coupling loading conditions.

[0081] The monitoring module 4 also includes a data acquisition instrument. The piezometer 41, strain brick 42, and displacement meter 43 are all electrically connected to the data acquisition instrument to realize real-time monitoring and acquisition of various data.

[0082] This application also provides a method for using a hydraulically coupled loading test system for a fractured rock mass model, including the following steps:

[0083] S100. Make a fractured rock mass model 3. During the production process, after printing the model to the preset height according to the preset requirements, install the seepage pipe 291, piezometer 41 and sensor.

[0084] S200. Curing the fractured rock mass model 3 to the predetermined age, connecting the seepage pipe 291 to the water injection pipe 29 of the hydraulic loading module 2, connecting the return water pipe 24 of the hydraulic loading module 2 to the fractured rock mass model 3, and connecting the piezometer 41 and the sensor to the external data acquisition instrument.

[0085] S300. Place the fractured rock mass model 3 into the transfer cavity 149 of the hydraulic loading module 1, adjust the hydraulic loading module 1 to fit the edge of the fractured rock mass model 3, install the displacement gauge 43 inside the fractured rock mass model 3 and connect it to the external data acquisition instrument.

[0086] S400. According to the preset requirements, the hydraulic loading module 1 is started to apply stress to the fractured rock mass model 3, and the hydraulic loading module 2 is started to flow water into the fractured rock mass model 3 to apply hydraulic force to the fractured rock mass model 3. At the same time, the external data acquisition instrument is started to monitor the monitoring data of each piezometer 41, sensor and displacement gauge 43.

[0087] Specifically, in step S100, the fractured rock mass model 3 is printed using a dual-arm printer according to the preset rock mass and fracture model. During the production of the fractured rock mass model 3, a seepage pipe 291 is buried when the printing reaches a specified height according to the fracture hydraulic loading requirements. At the same time, a sensor is buried when the printing reaches a specified height according to the monitoring requirements.

[0088] In step S200, after the fractured rock mass model 3 is printed, it is wrapped with plastic film, and water is sprayed around the model regularly to keep it moist. Then the fractured rock mass model 3 is cured to the predetermined age, and the water injection pipe 29 and the return water pipe 24 are connected. At the same time, all sensors are connected to the data acquisition instrument and debugged for use.

[0089] In step S300, after the fractured rock mass model 3 is prepared, the fractured rock mass model 3 is hoisted into the rigid reaction frame 12, the transfer cavity 149 of the force transmission module is adjusted to fit the edge of the fractured rock mass model 3, the displacement gauge 43 is installed and connected to the data acquisition instrument, and then stress preloading is performed.

[0090] In step S400, the hydraulic loading module 2 is started to vent air through each pipeline one by one, and then the frequency of the high-pressure water pump is adjusted by frequency modulation to adjust the water injection pressure; the required stress and water pressure are determined according to the test purpose to carry out the test, and the data acquisition instrument is started to monitor the test data such as pressure and displacement.

[0091] The hydraulic coupling loading test system for fractured rock mass models described in this application can realize high-stress, high-permeability hydraulic coupling loading test research on geological models containing complex fractures and fracture networks.

[0092] It should be noted that the above description describes some embodiments of this disclosure. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0093] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this disclosure (including the claims) is limited to these examples; within the framework of this disclosure, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this disclosure as described above, which are not provided in detail for the sake of brevity.

[0094] This disclosure is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A hydraulically coupled loading test system for fractured rock mass models, characterized in that, include: A hydraulic loading module includes a force transmission module, which has a transfer cavity for placing a prefabricated fractured rock mass model. The hydraulic loading module is configured to apply stress to the fractured rock mass model. The hydraulic loading module includes multiple water injection pipes and return pipes. The multiple water injection pipes pass through the hydraulic loading module and extend into the fractured rock mass model. The multiple return pipes are connected to the fractured rock mass model. The hydraulic loading module is configured to pump water into the fractured rock mass model to apply hydraulic pressure to the fractured rock mass model. The force transmission module includes a first top plate at the top and a support platform at the bottom. A first side plate, a second side plate, a third side plate, and a reaction pad are sequentially connected between the first top plate and the support platform. The first side plate, the second side plate, the third side plate, and the reaction pad together form the transfer cavity. The first top plate, the first side plate, the second side plate, and the third side plate each include multiple force transmission and correction plates, and two adjacent force transmission and correction plates are movably connected; each force transmission and correction plate is provided with a first pad and a second pad at intervals on the side away from the transfer cavity, and a support roller is rotatably provided on the second pad; In two adjacent force transmission straightening plates, the first pad of one of the force transmission straightening plates is used to support the support roller of the other force transmission straightening plate. The support roller can move along the first pad to realize the movable connection between the two adjacent force transmission straightening plates. The first side plate, the second side plate, and the third side plate each include a plurality of force transmission and straightening plates that are movably connected from top to bottom. The stress applied by the hydraulic loading module to the force transmission and straightening plate on the side closer to the support platform is greater than the stress applied by the hydraulic loading module to the force transmission and straightening plate on the side farther from the support platform. The first pad includes a plurality of first sub-pads spaced apart, and the second pad includes a plurality of second sub-pads spaced apart. Each force transmission and correction plate has a plurality of correction sub-plates on the side away from the transfer cavity. Each correction sub-plate has a first sub-pad and a second sub-pad spaced apart. A force transmission pad is provided between the first sub-pad and the second sub-pad. A ball joint support is provided on the side of the force transmission pad away from the force transmission and correction plate, and a ball joint joint is provided on the side of the ball joint support away from the force transmission and correction plate.

2. The hydraulic coupling loading test system according to claim 1, characterized in that, The hydraulic loading module also includes a rigid reaction frame, the inner wall of which is provided with multiple hydraulic jacks. Each hydraulic jack is connected to a ball joint. The hydraulic jacks are connected to an external high-pressure oil source and are used to apply stress to the corresponding force transmission correction plate.

3. The hydraulic coupling loading test system according to claim 1, characterized in that, The hydraulic loading module also includes multiple seepage pipes, all of which are connected to the water injection pipe. The multiple seepage pipes are respectively embedded in multiple rock fissures of the prefabricated fractured rock mass model, and the sidewalls of the seepage pipes have multiple seepage holes.

4. The hydraulic coupling loading test system according to claim 1, characterized in that, It also includes a monitoring module, which includes multiple piezometers, with multiple piezometers placed around each rock mass fracture in the prefabricated fractured rock mass model.

5. A method of using the hydraulically coupled loading test system for a fractured rock mass model according to any one of claims 1 to 4, characterized in that, Includes the following steps: To create a fractured rock mass model, the model is printed to a predetermined height according to pre-set requirements, and then seepage pipes, piezometers, and sensors are installed. The fractured rock mass model is cured to the predetermined age, the seepage pipe is connected to the water injection pipe of the hydraulic loading module, the return water pipe of the hydraulic loading module is connected to the fractured rock mass model, and the piezometer and sensor are connected to an external data acquisition instrument. The fractured rock mass model is placed in the transfer chamber of the hydraulic loading module, and the hydraulic loading module is adjusted to fit the edge of the fractured rock mass model. A displacement meter is installed inside the fractured rock mass model and connected to the external data acquisition instrument. According to the preset requirements, the hydraulic loading module is activated to apply stress to the fractured rock mass model, and the hydraulic loading module is activated to flow water into the fractured rock mass model to apply hydraulic force to the fractured rock mass model. At the same time, the external data acquisition instrument is activated to monitor the monitoring data of each piezometer, sensor and displacement gauge.

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