A device for water inrush and sand inrush simulation test

Abstract

The present disclosure provides a device for water inrush and sand collapse simulation test, comprising a test system, a bearing system, a control system and a collection system; the control system is used for controlling the output of the pressure liquid to apply multi-source pressure to the test system; the test system is used for simulating test on similar simulation material, comprising a test mold, an adjustable fracture mold and a three-stage variable-diameter pressure head; the three-stage variable-diameter pressure head is used for applying axial pressure and water pressure to the test mold; the test mold is used for accommodating the similar simulation material and providing a confining pressure loading space; the adjustable fracture mold is arranged at the bottom of the test mold and is used for adjusting the opening of the fracture passage; the bearing system is used for fixing and supporting the simulation test device; and the collection system is used for collecting test data in the test system. The present disclosure can truly simulate the whole process of water inrush and sand collapse under different ground stress, water pressure and fracture opening conditions by integrating multi-source pressure loading, fracture opening adjustment and test data collection.

Description

Technical Field

[0001] This disclosure relates to the field of mine water hazard prevention and similar material simulation testing technology, and in particular to a device for simulating water inrush and sand collapse tests. Background Technology

[0002] During the construction and operation of tunnels, mines, underground caverns, and deep underground engineering projects, the coupling effects of tectonic fracture zones, highly permeable rock masses, and groundwater can easily lead to water inrush and sand bursting disasters. These disasters typically manifest as groundwater, driven by a high hydraulic head difference, rapidly infiltrating the engineering space through fractured rock masses or fissure networks, carrying with it large amounts of sand or rock debris. This results in severe consequences such as surrounding rock instability, collapse, equipment flooding, and casualties, and has become one of the most significant disaster types restricting the safe construction of deep underground engineering projects. Especially under conditions of weakly cemented soft rock, the rock mass has low cementation strength and is prone to disintegration upon contact with water. The erosion, transport, and inrush processes of rock particles by water flow are highly nonlinear, exhibiting distinct spatiotemporal evolution characteristics. Therefore, conducting indoor physical simulation experiments is an important means of revealing the mechanism of water inrush and sand bursting.

[0003] Currently, the simulation test devices for water inrush and sand bursting in related technologies are difficult to integrate lateral confining pressure loading, axial pressure loading and water pressure loading in a systematic way. In addition, the crack width is fixed, the mix ratio of weakly cemented soft rock is not suitable, and the sealing pressure bearing capacity is insufficient, so they cannot truly simulate the water and sand bursting process of cracks with different openings under complex geostress environments.

[0004] It should be noted that the above description of the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of the present invention and facilitating understanding by those skilled in the art. It should not be assumed that the above technical solutions are known to those skilled in the art simply because they have been described in the background section of this invention. Summary of the Invention

[0005] In view of this, the purpose of one or more embodiments of this disclosure is to provide an apparatus for simulating water inrush and sand collapse tests, so as to solve or partially solve the problems raised in the background art.

[0006] To achieve the above objectives, this disclosure provides an apparatus for simulating water inrush and sand collapse tests, the apparatus comprising a test system, a load-bearing system, a control system, and a data acquisition system;

[0007] The control system is used to control the output of the pressurized liquid to apply multi-source pressure to the test system; The test system is used to conduct simulation tests on similar simulated materials, including a test mold, an adjustable crack mold, and a three-stage variable diameter indenter; the three-stage variable diameter indenter is used to apply axial pressure and water pressure to the test mold, the test mold is used to contain the similar simulated materials and provide confining pressure loading space, and the adjustable crack mold is set at the bottom of the test mold to adjust the opening of the crack channel; The load-bearing system is used to fix and support the simulation test device; The acquisition system is used to collect test data from the test system.

[0008] Furthermore, the control system includes a controller, a first hydraulic chamber, a second hydraulic chamber, and a third hydraulic chamber. The controller controls the first hydraulic chamber to output a first pressurized liquid through a first pipeline to apply axial pressure to the test system; controls the second hydraulic chamber to output a second pressurized liquid through a second pipeline to apply circumferential pressure to the test system; and controls the third hydraulic chamber to output a third pressurized liquid through a third pipeline to apply pressurized water flow to the test system.

[0009] Furthermore, the test mold includes a hydraulic loading cylinder, and the first hydraulic chamber injects a first pressurizing liquid into the hydraulic loading cylinder through the first pipeline to drive the three-stage variable diameter pressure head to apply axial pressure to the similar simulated material in the test mold.

[0010] Furthermore, the three-stage variable diameter pressure head includes a sealing cap, a rubber ring, and a pressure head. The sealing cap is disposed on the lower bottom surface of the hydraulic loading cylinder, and the rubber ring is disposed between the sealing cap and the pressure head. The three-stage variable diameter pressure head has an axially extending water inlet pipe. The bottom end of the pressure head has a mesh structure. The second hydraulic chamber injects a second pressurizing liquid into the pressure head through a second pipeline and the water inlet pipe. The second pressurizing liquid applies pressurized water flow to the similar simulation material in the test mold through the mesh structure.

[0011] Furthermore, the test mold also includes a test mold shell and an air bladder. The air bladder is disposed on the inner wall of the test mold shell and connected to the third pipeline. The third hydraulic chamber injects a third pressurized liquid into the air bladder through the third pipeline to apply circumferential pressure to the similar simulation material inside the test mold chamber.

[0012] Furthermore, the test mold also includes a test mold base, which has a water and sand inrush port and multiple sensor mounting slots. The upper surface of the test mold base is fixedly connected to the test mold shell and the bottom edge of the airbag. The water and sand inrush port is used to allow similar simulated materials inside the test mold to gush outwards. The sensor mounting slots are used to embed and install a second water pressure sensor, which is used to monitor the pressure, flow rate, and particle concentration data of the similar simulated materials inside the test mold chamber during the test.

[0013] Furthermore, the adjustable crack mold includes an adjusting nut, a crack plate, two movable support rods, and two movable sliders. Limiting holes are formed at the four corners of the crack plate. Bolts are inserted through these limiting holes to fix the adjustable crack mold to the lower surface of the test mold base. A through hole is formed along the axial direction of the crack plate, allowing the movable support rods to move axially within the crack plate. One end of each movable support rod is fixedly connected to the adjusting nut, and the other end is fixedly connected to the movable slider. Rotating the adjusting nut drives the movable support rod, thereby changing the distance between the two movable sliders and adjusting the opening of the crack channel. Multiple first water pressure sensors are provided on the opposing sides of the two movable sliders to monitor water pressure changes during the sudden sand inrush process.

[0014] Furthermore, the test mold also includes a test mold column, a base, a drain outlet, and a drain trough. The test mold column is used to support the test mold, with one end fixed to the lower surface of the test mold base and the other end inserted into the base. The base has the drain outlet, and the drain trough is embedded in the base and connected to the drain outlet, used to discharge the waste similar simulation material flowing out through the water and sand inrush outlet during the test.

[0015] Furthermore, the bearing system includes a simulation test device base, multiple support columns and a support plate. One end of each support column is fixed to the simulation test device base, and the other end is fixed to the support plate. The support plate is used to fix the hydraulic loading cylinder and provides reaction force support when the hydraulic loading cylinder applies axial pressure.

[0016] Furthermore, the acquisition system includes an acquisition computer, a data acquisition cable, and an acquisition instrument. The acquisition instrument acquires data from a first water pressure sensor and a second water pressure sensor installed in the sensor mounting slot, and transmits the acquired data to the acquisition computer via the data acquisition cable.

[0017] This disclosure provides an apparatus for simulating water inrush and sand bursting tests. A load-bearing system fixes and supports the simulation test device. A control system applies multi-source pressure to simultaneously apply confining pressure, axial pressure, and water pressure to similar simulated materials within the test mold. An adjustable fracture mold adjusts the fracture channel opening to control the migration and outflow of the similar simulated material. Simultaneously, a data acquisition system collects test data in real time during the test. This disclosure solves the technical problem that related devices cannot simultaneously achieve coordinated loading of confining pressure, axial pressure, and water pressure, and adjustable fracture width. It realizes coordinated loading of multiple stress fields and adjustable fracture opening, enabling realistic simulation of the entire process of water inrush and sand bursting under different in-situ stress, water pressure, and fracture opening conditions. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in one or more embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only one or more embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1a A schematic diagram of a device for simulating water inrush and sand collapse, provided in an embodiment of this disclosure; Figure 1b A top view of the load-bearing system provided in an embodiment of this disclosure; Figure 2a A schematic diagram showing the movable slider of the adjustable crack mold provided in an embodiment of this disclosure in the closed position; Figure 2b A schematic diagram showing the movable slider of the adjustable crack mold provided in an embodiment of this disclosure in the open position; Figure 2c This is a schematic diagram of the movable support rod, movable slider, and adjusting nut provided in an embodiment of this disclosure; Figure 3 A top view of a multi-stage pressure head provided in an embodiment of this disclosure; Figure 4 A top view of the test chamber and flexible airbag provided in an embodiment of this disclosure; Figure 5 This is a schematic diagram of the test chamber structure after loading, provided in an embodiment of this disclosure. Figure 6 A flowchart illustrating the method of using an apparatus for simulating water inrush and sand collapse, as provided in this embodiment of the disclosure.

[0020] Explanation of reference numerals in the attached diagram: 1. Controller; 2. First hydraulic chamber; 3. Second hydraulic chamber; 4. Third hydraulic chamber; 5. Support plate; 6. Hydraulic loading cylinder; 7. Sealing cover; 8. Rubber ring; 9. Pressure head; 10. Water inlet pipe; 11. Test mold chamber; 12. Test mold outer shell; 13. Airbag; 14. Mud and sand material; 15. Support column; 16. Sensor mounting slot; 17. Water and sand inrush outlet; 18. Adjusting nut; 19. First water pressure sensor; 20. Drain outlet; 21. Drain trough; 22. Simulation test device base; 23. Data acquisition instrument; 24. Data acquisition computer; 25. First pipeline; 26. Second pipeline; 27. Third pipeline; 28. Data acquisition line; 29. ​​Moving slider; 30. Test mold base; 31. Crack plate; 32. Moving support rod; 33. Limiting hole; 34. Test mold column; 35. Base platform. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0022] It should be noted that, unless otherwise defined, the technical or scientific terms used in one or more embodiments of this disclosure should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar words used in one or more embodiments of this disclosure 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 following 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 used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] As described in the background section, the water inrush and sand bursting simulation test device in the related technology is difficult to integrate the system of lateral confining pressure loading, axial pressure loading and water pressure loading. At the same time, it has problems such as the inability to adjust the fracture opening, insufficient sealing pressure bearing capacity and insufficient compatibility of weak cemented soft rock mix. It cannot truly simulate the whole process of water inrush and sand bursting under different in-situ stress, different water pressure and different fracture opening conditions.

[0024] Therefore, there is an urgent need to develop a technical solution for a device used in water inrush and sand collapse simulation tests to meet the requirements of multi-stress field synergistic loading, adjustable crack opening, controllable material parameters, and high-pressure sealing in water inrush and sand collapse simulation tests.

[0025] According to some implementations of this disclosure, a device for simulating water inrush and sand collapse tests is provided, featuring flexible airbag confining pressure loading with a three-stage variable-diameter pressure head and adjustable fracture channels. In this design, by integrating flexible airbag lateral confining pressure loading, integrated axial pressure and water pressure loading with a three-stage variable-diameter pressure head, and an adjustable fracture mold into the same testing device, synergistic loading of lateral confining pressure, axial pressure, and water pressure is achieved. The fracture opening can be adjusted to adapt to different fracture width conditions, and a multi-seal structure is employed to improve high-pressure sealing performance. Furthermore, it is applicable to granular materials of different particle sizes. Through the solution of this disclosure, a water inrush and sand collapse simulation test system integrating flexible lateral confining pressure, multi-stage variable-diameter axial pressurization, integrated water pressure, adjustable fractures, and multiple seals can be realized, applicable to granular materials of different particle sizes.

[0026] refer to Figure 1a This disclosure provides an apparatus for simulating water inrush and sand bursting tests, comprising a test system, a support system, a control system, and a data acquisition system. The control system controls the output of pressurized liquid to apply multi-source pressure to the test system; the test system is used to conduct water inrush and sand bursting simulation tests on similar simulated materials; the support system is used to fix and support the simulation test apparatus; and the data acquisition system is used to collect test data from the test system.

[0027] In some embodiments, the control system includes a controller 1, a first hydraulic chamber 2, a second hydraulic chamber 3, and a third hydraulic chamber 4. The controller 1 controls the first hydraulic chamber 2 to output a first pressurized liquid through a first pipeline 25 to apply axial pressure to the test system; controls the second hydraulic chamber 3 to output a second pressurized liquid through a second pipeline 26 to apply circumferential pressure to the test system; and controls the third hydraulic chamber 4 to output a third pressurized liquid through a third pipeline 27 to apply pressurized water flow to the test system.

[0028] In some embodiments, water pressure and flow sensors are installed inside the first hydraulic chamber 2, the second hydraulic chamber 3, and the third hydraulic chamber 4, and are controlled by the controller 1.

[0029] In some embodiments, the first pressurizing liquid stored in the first hydraulic chamber 2 can be hydraulic oil, which is pumped into the hydraulic loading cylinder 6 through the first pipeline 25 to drive the hydraulic loading cylinder 6 to apply axial pressure to the test system; the second pressurizing liquid stored in the second hydraulic chamber 3 can be water, which is pumped into the pressure head 9 through the second pipeline 26 and the water inlet pipe 10 to apply pressurized water to the similar simulated material in the test system; the third pressurizing liquid stored in the third hydraulic chamber 4 can be water, which is pumped into the airbag 13 through the third pipeline 27 to apply circumferential pressure to the similar simulated material in the test system.

[0030] In some embodiments, the testing system includes a test mold, an adjustable crack mold, and a multi-stage variable-diameter pressure head. The test mold is used to contain similar simulated materials and provide confining pressure loading space; the adjustable crack mold is disposed at the bottom of the test mold and is used to adjust the opening of the crack channel to control the migration and outflow of the similar simulated materials during the sand inrush process.

[0031] In some embodiments, the test mold includes a hydraulic loading cylinder 6, and the first hydraulic chamber 2 injects a first pressurizing liquid into the hydraulic loading cylinder 6 through the first pipeline 25 to drive the three-stage variable diameter pressure head to apply axial pressure to the similar simulated material in the test mold.

[0032] In some embodiments, reference Figure 3 The three-stage variable diameter pressure head includes a sealing cover 7, a rubber ring 8, and a pressure head 9. The sealing cover 7 is disposed on the lower bottom surface of the hydraulic loading cylinder 6, and the rubber ring 8 is disposed between the sealing cover 7 and the pressure head 9. The three-stage variable diameter pressure head has an axially extending water inlet pipe 10, and the bottom end of the pressure head 9 has a mesh structure. The second hydraulic chamber 3 injects a second pressurizing liquid into the pressure head 9 through the second pipeline 26 and the water inlet pipe 10. The second pressurizing liquid applies pressurized water flow to the similar simulation material in the test mold through the mesh structure.

[0033] In some embodiments, reference Figure 5 A silicone rubber sealing ring is provided at the lower edge of the sealing cover 7. During the loading process of the sand bursting test, the sealing cover 7 is pressed against the top end face of the outer wall 12 of the test mold by the silicone rubber sealing ring to seal the test mold chamber 11 and provide a sealed high water pressure environment; the rubber ring 8 is pressed against the top edge of the airbag 13 to prevent the high pressure water flow in the test mold chamber 11 from escaping; the lower surface of the pressure head 9 extends into the test mold chamber 11 and acts on the similar simulated material (i.e., mud and sand material 14), applying axial pressure and water pressure to it.

[0034] In some embodiments, the test mold further includes a test mold housing 12 and an airbag 13; the airbag 13 is a pressure-bearing flexible airbag. The airbag 13 is disposed on the inner wall of the test mold housing 12 and connected to the third pipeline 27. The third hydraulic chamber 4 injects a third pressurizing liquid into the airbag 13 through the third pipeline 27. Through the continuous pressure of the pressurizing liquid, a uniform flexible circumferential pressure is applied to the similar simulation material inside the test mold chamber 11. Both the test mold housing 12 and the airbag 13 are cylindrical.

[0035] In some embodiments, the test mold further includes a test mold base 30, which has a water and sand inrush outlet 17 and a plurality of sensor mounting slots 16. (Reference) Figure 4 The upper surface of the test mold base 30 is fixedly connected to the bottom edge of the test mold shell 12 and the airbag 13; the water and sand inrush port 17 is used to allow similar simulated materials inside the test mold to gush outward, so as to simulate the movement and outflow channel of the water and sand mixture during the sand inrush process; the sensor mounting slot 16 is used to embed and install a second water pressure sensor, which is used to monitor the pressure, flow rate and particle concentration data of the similar simulated materials inside the test mold chamber 11 during the test.

[0036] In some embodiments, the adjustable crack mold includes an adjusting nut 18, a crack plate 31, two movable support rods 32, and two movable sliders 29. (Reference) Figure 2a , 2b 2c, the crack plate 31 has limit holes 33 at its four corners, and the adjustable crack mold is fixed to the lower surface of the test mold base 30 by bolts passing through the limit holes 33; the crack plate 31 has through holes along the axial direction, so that the movable support rod 32 can move axially inside the crack plate 31; one end of the movable support rod 32 is fixedly connected to the adjusting nut 18, and the other end is fixedly connected to the movable slider 29; by rotating the adjusting nut 18, the movable support rod 32 is driven to change the distance between the two movable sliders 29, thereby adjusting the opening of the crack channel to simulate the size of the channel during sand inrush; multiple first water pressure sensors 19 are provided on the opposite sides of the two movable sliders 29 to monitor water pressure changes during sand inrush.

[0037] In some embodiments, the test mold further includes a test mold column 34, a base 35, a drain outlet 20, and a drain trough 21. (See reference) Figure 1a The four test mold columns 34 are used to support the test mold. One end of each column is fixed to the bottom surface of the test mold base 30, and the other end is inserted into the base platform 35. The base platform 35 has a drain outlet 20. The drain trough 21 is embedded in the base platform 35 and connected to the drain outlet 20, and is used to discharge the waste similar simulation material that flows out through the water and sand inrush outlet 17 during the test.

[0038] In some embodiments, the support system includes a simulation test device base 22, a plurality of support columns 15, and a support plate 5. (Reference) Figure 1a and 1bOne end of each of the four support columns 15 is fixed to the base 22 of the simulation test device, and the other end is fixed to the four corners of the support plate 5. The support plate 5 is used to fix the hydraulic loading cylinder 6 and to provide reaction force support when the hydraulic loading cylinder 6 applies axial pressure.

[0039] In some embodiments, the data acquisition system includes a data acquisition computer 24, a data acquisition cable 28, and a data acquisition instrument 23. (See reference) Figure 1a The data acquisition device 23 acquires data from the first water pressure sensor 19 and the second water pressure sensor installed in the sensor mounting slot 16, and transmits the acquired data to the acquisition computer 24 via the data acquisition line 28. The data includes water pressure data from the fracture channels acquired by the first water pressure sensor 19 and seepage pressure data acquired by the second water pressure sensor during the water inrush and sand collapse process. The second water pressure sensor is a pore water pressure sensor.

[0040] In some embodiments, the test system is the main body of the test device, used to simulate water inrush and sand bursting in weakly cemented soft rock under confining pressure, axial pressure, and water pressure. The bearing system supports the test system and fixes the multi-stage pressure head, providing reverse support force for applying axial pressure during the test. The control system is connected to the multi-stage pressure head and flexible airbag, providing axial pressure, confining pressure, and water pressure to the test chamber. The adjustable crack mold is located below the test mold chamber, used to simulate the changes in the water inrush and sand bursting channel. The acquisition system is connected to the water pressure sensor installed on the adjustable crack mold and the pore water pressure sensor inside the test mold chamber for data monitoring and analysis.

[0041] This disclosure integrates flexible airbag lateral confining pressure loading, three-stage variable diameter indenter axial pressure and water pressure integrated loading, and an adjustable fracture mold into a single experimental device, enabling realistic simulation of the entire process of water inrush and sand collapse in weakly cemented soft rock under different in-situ stresses, water pressures, and fracture openings. The design of the pressure-bearing flexible airbag achieves flexible lateral confining pressure loading on similar simulated materials, effectively mimicking the real in-situ stress environment. The sealing cap and rubber ring of the three-stage variable diameter indenter, in close fit with the flexible airbag, significantly improve high-pressure sealing performance. The adjustable fracture mold, working synergistically with the axial pressure, water pressure, and confining pressure system, closely reflects the dynamic changes in fracture channel width under actual in-situ stress and water pressure. This simulation experimental device overcomes the technical limitations of traditional equipment that cannot simultaneously achieve coordinated loading of confining pressure, axial pressure, and water pressure, as well as adjustable fracture width, on similar simulated materials of weakly cemented soft rock, thus better meeting actual engineering needs.

[0042] refer to Figure 6 This disclosure also provides a method for using the simulation test of sudden water inrush and sand runoff, including the following steps: Step S1: Check the simulation test device to ensure that all systems are operating normally. Check whether there are any residues inside the test mold chamber 11, whether the airbag 13 is intact and undamaged, whether the water and sand inlet 17 is blocked, and whether the rubber ring 8 and the silicone rubber seal are damaged; connect the control system and check whether the oil pressure and water pressure can be loaded normally; connect the acquisition system and check whether the sensor, data acquisition line 28 and acquisition instrument 23 can operate normally.

[0043] Step S2: Lay out similar simulation material, embed pore water pressure sensors, and adjust the crack mold to the preset test opening. Based on similar materials and similar simulation theory, the prepared rock stratum similar simulation material is filled into the test mold chamber 11 according to the preset thickness and height, and a pore water pressure sensor is embedded in the sensor installation slot 16 during the filling process; after filling is completed, an adjustable crack mold is installed, and the distance of the moving slider 29 is changed by driving the moving support rod 32 through the adjusting nut 18 to set the opening of the crack channel.

[0044] Step S3: Connect the data acquisition system to the sensor and set it to working status. Connect the data acquisition line 28 in the acquisition system to the first water pressure sensor 19 and the second water pressure sensor respectively, and connect the data acquisition line 28 to the acquisition computer 24 and debug it to the working state.

[0045] Step S4: Apply axial and circumferential pressures to the similar simulated material. The control system is activated, and according to the test settings, hydraulic oil is injected into the hydraulic loading cylinder 6 through the first hydraulic chamber 2 and the first pipeline 25, driving the three-stage variable diameter pressure head to move downward and contact the similar simulated material to apply axial pressure; at the same time, liquid is injected into the airbag 13 through the third hydraulic chamber 4 and the third pipeline 27 to apply circumferential pressure until the preset axial pressure and circumferential pressure values ​​are reached.

[0046] Step S5: Conduct water inrush and sand collapse tests on similar simulated materials. After the axial and circumferential pressures of the similar simulated material in the test chamber reach the preset values, the control system controls the second hydraulic chamber to inject water with a set pressure into the test mold chamber through the second pipeline. After the water pressure stabilizes, the water and sand inrush port 17 is opened, and the water pressure is gradually increased until the water and sand inrush phenomenon occurs. Then, the pressurization is stopped and the test is ended.

[0047] Step S6: Save all process data, unload the confining pressure and axial pressure, clean the test mold, and end the test. The system collects and records water pressure, pore water pressure, flow velocity and particle concentration data in real time during the test, which is convenient for subsequent analysis. After the test, the axial pressure and circumferential pressure are unloaded, the similar simulation material in the test mold chamber 11 is cleaned, the sensors and adjustable crack mold are removed, and the test device is tidied up.

[0048] This disclosure integrates flexible airbag lateral confining pressure loading, three-stage variable diameter indenter axial pressure and water pressure integrated loading, and adjustable crack mold into the same test device, realizing multi-stress field synergistic loading and adjustable crack opening. It can realistically simulate the entire process of water inrush and sand bursting in weakly cemented soft rock under different ground stress, water pressure and crack opening conditions. It breaks through the technical limitations of traditional equipment that cannot simultaneously achieve synergistic loading of confining pressure, axial pressure and water pressure and adjustable crack width, and provides a test platform that is closer to the actual engineering needs for the study of the mechanism of water inrush and sand bursting disasters in deep underground engineering.

[0049] It should be noted that the above description pertains to specific embodiments of this disclosure. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than those shown in the embodiments and may still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired results. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0050] Furthermore, although the operations of the methods of this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all of the operations shown must be performed to achieve the desired result. Rather, the steps depicted in the flowcharts may be executed in a different order. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0051] The use of the verbs "including" and "contains" and their inflections in the application documents does not preclude the existence of elements or steps other than those described in the application documents. The article "a" or "one" preceding an element does not preclude the existence of multiple such elements.

[0052] While the spirit and principles of this disclosure have been described with reference to several specific embodiments, it should be understood that this disclosure is not limited to the disclosed specific embodiments, and the division of aspects does not imply that features in these aspects cannot be combined for benefit; such division is merely for convenience of expression. This disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the appended claims is to be interpreted in the broadest sense, thereby encompassing all such modifications and equivalent structures and functions.

Claims

1. A device for simulating water inrush and sand collapse tests, characterized in that, The device includes a testing system, a load-bearing system, a control system, and a data acquisition system; The control system is used to control the output of the pressurized liquid to apply multi-source pressure to the test system; The test system is used to conduct simulation tests on similar simulated materials, including a test mold, an adjustable crack mold, and a three-stage variable diameter indenter; the three-stage variable diameter indenter is used to apply axial pressure and water pressure to the test mold, the test mold is used to contain the similar simulated materials and provide confining pressure loading space, and the adjustable crack mold is set at the bottom of the test mold to adjust the opening of the crack channel; The load-bearing system is used to fix and support the simulation test device; The acquisition system is used to collect test data from the test system.

2. The apparatus according to claim 1, characterized in that, The control system includes a controller, a first hydraulic chamber, a second hydraulic chamber, and a third hydraulic chamber. The controller controls the first hydraulic chamber to output a first pressurized liquid through a first pipeline to apply axial pressure to the test system; controls the second hydraulic chamber to output a second pressurized liquid through a second pipeline to apply circumferential pressure to the test system; and controls the third hydraulic chamber to output a third pressurized liquid through a third pipeline to apply pressurized water flow to the test system.

3. The apparatus according to claim 2, characterized in that, The test mold includes a hydraulic loading cylinder. The first hydraulic chamber injects a first pressurized liquid into the hydraulic loading cylinder through the first pipeline to drive the three-stage variable diameter pressure head to apply axial pressure to the similar simulated material in the test mold.

4. The apparatus according to claim 3, characterized in that, The three-stage variable diameter pressure head includes a sealing cover, a rubber ring, and a pressure head. The sealing cover is disposed on the bottom surface of the hydraulic loading cylinder, and the rubber ring is disposed between the sealing cover and the pressure head. The three-stage variable diameter pressure head has an axially extending water inlet pipe. The bottom end of the pressure head has a mesh structure. The second hydraulic chamber injects a second pressurizing liquid into the pressure head through a second pipeline and the water inlet pipe. The second pressurizing liquid applies pressurized water flow to the similar simulation material in the test mold through the mesh structure.

5. The apparatus according to claim 2, characterized in that, The test mold also includes a test mold shell and an air bladder. The air bladder is disposed on the inner wall of the test mold shell and connected to the third pipeline. The third hydraulic chamber injects a third pressurized liquid into the air bladder through the third pipeline to apply circumferential pressure to the similar simulation material inside the test mold chamber.

6. The apparatus according to claim 5, characterized in that, The test mold also includes a test mold base, which has a water and sand inrush port and multiple sensor mounting slots. The upper surface of the test mold base is fixedly connected to the test mold shell and the bottom edge of the airbag. The water and sand inrush port is used to allow similar simulated materials inside the test mold to gush outwards. The sensor mounting slots are used to embed and install a second water pressure sensor, which is used to monitor the pressure, flow rate, and particle concentration data of the similar simulated materials inside the test mold chamber during the test.

7. The apparatus according to claim 6, characterized in that, The adjustable crack mold includes an adjusting nut, a crack plate, two movable support rods, and two movable sliders. Limiting holes are formed at the four corners of the crack plate. Bolts are inserted through these limiting holes to fix the adjustable crack mold to the lower surface of the test mold base. A through hole is formed along the axial direction of the crack plate, allowing the movable support rods to move axially within the crack plate. One end of each movable support rod is fixedly connected to the adjusting nut, and the other end is fixedly connected to the movable slider. Rotating the adjusting nut drives the movable support rod, changing the distance between the two movable sliders and thus adjusting the opening of the crack channel. Multiple first water pressure sensors are provided on the opposing sides of the two movable sliders to monitor water pressure changes during the sudden sand inrush process.

8. The apparatus according to claim 6, characterized in that, The test mold also includes a test mold column, a base, a drain outlet, and a drain trough. The test mold column is used to support the test mold, with one end fixed to the lower surface of the test mold base and the other end inserted into the base. The base has the drain outlet, and the drain trough is embedded in the base and connected to the drain outlet, used to discharge the waste similar simulation material flowing out through the water and sand inrush outlet during the test.

9. The apparatus according to claim 3, characterized in that, The load-bearing system includes a base for a simulation test device, multiple support columns and a support plate. One end of each support column is fixed to the base for the simulation test device, and the other end is fixed to the support plate. The support plate is used to fix the hydraulic loading cylinder and provides reaction force support when the hydraulic loading cylinder applies axial pressure.

10. The apparatus according to claim 1, characterized in that, The data acquisition system includes a data acquisition computer, a data acquisition cable, and a data acquisition instrument. The data acquisition instrument acquires data from a first water pressure sensor and a second water pressure sensor installed in the sensor mounting slot, and transmits the acquired data to the data acquisition computer via the data acquisition cable.

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