Test device and test method for simulating liquid water accelerated rock creep process

Abstract

The present disclosure relates to a test device and a test method for simulating liquid water accelerated rock creep process. The test device for simulating liquid water accelerated rock creep process comprises: an environmental box arranged on a test platform, a temperature and humidity control unit in communication with the environmental box; a monitoring assembly arranged inside the environmental box; a first loading unit and a second loading unit are both mounted on the test platform through a mounting frame, and the first loading unit and the second loading unit are both arranged inside the environmental box; the first loading unit is arranged opposite to the second loading unit on the side close to the two first loading rollers, and the first loading unit is arranged above the second loading unit; the input end of a water injection pump is connected with a water source, and the output end of the water injection pump is communicated with a water storage tank arranged on the rock sample through a pipeline; the water storage tank is arranged opposite to the two first loading rollers. The present scheme improves the effect of simulating natural environment in the process of rock mechanics experiment.

Description

Technical Field

[0001] This disclosure relates to the field of materials mechanics, and in particular to an experimental apparatus and method for simulating the accelerated creep process of rocks by liquid water. Background Technology

[0002] In related technologies, Type I cracks (tensional cracks) are one of the most typical crack forms in the rock failure process, characterized by the opening of the crack surface under normal tensile stress. Numerous engineering and geological disaster studies have shown that Type I cracks are a significant mode leading to rock mass instability, slope collapse, and stratum fracturing. Existing research has confirmed that the presence of liquid water has a significant impact on rock fracture behavior: on the one hand, water infiltration reduces the fracture toughness of the rock, allowing cracks to initiate at lower stress levels; on the other hand, the action of water molecules accelerates the crack propagation rate, especially in the subcritical propagation stage. This effect has important implications in practical engineering. For example, in slope and underground engineering, rainfall or groundwater infiltration weakens the tensile strength and toughness of the rock mass, increasing the risk of instability; in tectonic stress fields, water-bearing cracks can slowly propagate under low stress conditions, thus affecting the gestation and occurrence cycle of earthquakes.

[0003] Current research methods for Type I cracks in rocks mainly include direct tension, three-point bending, and four-point bending. Among these, three-point bending and four-point bending tests are widely used due to their ease of sample preparation, stable loading structure, and controllable stress concentration at the crack tip. However, existing test setups are mostly used under dry or simple immersion conditions, making it difficult to simulate the entire process of liquid water gradually seeping into the crack tip and acting on it, especially in the study of accelerated failure behavior under long-term loading (creep) conditions. Summary of the Invention

[0004] To overcome the problems existing in related technologies, this disclosure provides an experimental apparatus and method for simulating the process of liquid water accelerating rock creep.

[0005] According to a first aspect of the present disclosure, a test apparatus for simulating the process of liquid water accelerating rock creep is provided, comprising an environmental chamber, a test platform, a monitoring component, a multi-point bending fixture, a temperature and humidity control unit, and a water storage unit. The water storage unit includes a water injection pump. The multi-point bending fixture includes a first loading unit and a second loading unit. The first loading unit includes two first loading rollers, and the second loading unit includes at least one second loading roller, wherein: The environmental chamber is set on the test platform, and the temperature and humidity control unit is connected to the environmental chamber for regulating the temperature and humidity inside the environmental chamber. The monitoring components are installed inside the environmental chamber; Both the first loading unit and the second loading unit are mounted on the test platform via mounting brackets, and both the first loading unit and the second loading unit are located inside the environmental chamber; The first loading unit is positioned opposite the side of the two first loading rollers to the side of the second loading unit that is adjacent to the at least one second loading roller, and the first loading unit is positioned above the second loading unit. The input end of the water injection pump is connected to a water source, and the output end of the water injection pump is connected to a water storage tank opened on the rock sample through a pipeline; the water storage tank is arranged opposite to the two first loading rollers; the water storage tank is used to simulate water-bearing cracks in the rock.

[0006] In some embodiments of this disclosure, the monitoring component includes a crack opening displacement sensor disposed inside a water tank of the rock sample.

[0007] In some embodiments of this disclosure, the water storage unit further includes a water-blocking plate, the water storage tank is disposed between the two first loading rollers, one end of the water storage tank is connected to the outside, the water-blocking plate is fitted to the one end and used to block the one end; the water-blocking plate is provided with a water injection hole, and the water injection pump is connected to the water storage tank through a pipe passing through the water injection hole.

[0008] In some embodiments of this disclosure, the water-blocking plate further includes a water outlet hole, which is disposed above the water injection hole and is connected to the outside through a pipeline.

[0009] In some embodiments of this disclosure, a limiting member is also fixed to the top of the water-blocking plate. The limiting member includes a first baffle and a second baffle. One end of the first baffle and the second baffle are both fixedly connected to the water-blocking plate. The first baffle is horizontally arranged, and the second baffle is vertically arranged below the first baffle. The top of the second baffle is fixedly connected to the bottom of the first baffle. The first baffle is arranged at the top of the water storage tank, and the second baffle is arranged inside the water storage tank. Furthermore, both the first baffle and the second baffle are arranged above the water outlet hole.

[0010] In some embodiments of this disclosure, the water injection pump is a peristaltic pump.

[0011] In some embodiments of this disclosure, the monitoring component further includes a temperature and humidity sensor, a magnetic base, a first connecting rod, and a second connecting rod. One end of the first connecting rod is fixedly connected to the magnetic base, and one end of the second connecting rod is slidably connected to the first connecting rod via a first mounting ring. The temperature and humidity sensor is slidably connected to the end of the second connecting rod away from the first mounting ring via a second mounting ring.

[0012] According to a second aspect of the present disclosure, a test method is provided for a test apparatus for simulating the process of liquid water accelerating rock creep, employing the test apparatus for simulating the process of liquid water accelerating rock creep as described in any one of the first aspects, the test method comprising: The water storage tank is opened on the rock sample to be tested; The rock sample to be tested is placed between the first loading unit and the second loading unit of the multi-point bending fixture; wherein the water storage tank is located on the side close to the first loading unit; the multi-point bending fixture is controlled to apply initial pressure to the rock sample to be tested so that the multi-point bending fixture fixes the rock sample to be tested. The temperature and humidity control unit controls the temperature and humidity inside the environmental chamber to maintain the temperature at the target temperature and the humidity at the target humidity. The multi-point bending fixture is controlled to preload the rock sample to be tested until the rock sample is preloaded to a preset load value; the water pump is controlled to deliver water to the water storage tank. The monitoring component is used to collect target data of the rock sample to be tested until the rock sample breaks.

[0013] In some embodiments of this disclosure, the water storage unit further includes a water-blocking plate, the water storage tank is disposed between the two first loading rollers, one end of the water storage tank is connected to the outside, and the water-blocking plate is fitted to the one end to block the one end; the water-blocking plate is provided with a water injection hole, and the water injection pump is connected to the water storage tank through a pipe passing through the water injection hole; the water injection pump is a peristaltic pump; The control of the water injection pump to deliver water to the water storage tank includes: The peristaltic pump is controlled to deliver water through the water injection hole of the water-blocking plate to the water storage tank at a first rate; When water flows out of the outlet hole of the water-blocking plate, the peristaltic pump is controlled to deliver water to the water storage tank at a second rate; the second rate is less than the first rate, so that the water volume in the water storage tank is maintained at a preset water volume.

[0014] The technical solution provided by the embodiments of this disclosure can include the following beneficial effects: an environmental chamber is set on the test platform, and a temperature and humidity control unit is connected to the environmental chamber to regulate the temperature and humidity inside the environmental chamber; a monitoring component is set inside the environmental chamber; both the first loading unit and the second loading unit are mounted on the test platform via mounting brackets, and both the first loading unit and the second loading unit are set inside the environmental chamber; the side of the first loading unit near the two first loading rollers is arranged opposite to the side of the second loading unit near at least one second loading roller, and the first loading unit is set above the second loading unit; the input end of the water injection pump is connected to a water source, and the output end of the water injection pump is connected to a water storage tank opened on the rock sample via a pipeline; the water storage tank is arranged opposite to the two first loading rollers; the water storage tank is used to simulate water-bearing cracks in the rock. Thus, by using the water storage unit to simulate the natural environment of the rock, the influence of water on rock cracks is considered, thereby improving the effect of simulating the natural environment during the experiment and thus improving the accuracy of the experimental results.

[0015] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0017] Figure 1 This is a schematic diagram of a test apparatus for simulating the process of rock creep accelerated by liquid water, according to an exemplary embodiment.

[0018] Figure 2 This is a schematic diagram of the structure of a first loading unit and a second loading unit according to an exemplary embodiment.

[0019] Figure 3 This is a schematic diagram of the structure of a water storage tank according to an exemplary embodiment.

[0020] Figure 4 This is a schematic diagram of the structure of a temperature and humidity sensor according to an exemplary embodiment.

[0021] Figure 5 This is a schematic diagram of the slide rail structure according to another exemplary embodiment.

[0022] Figure 6 This is a schematic diagram of the structure of a water-blocking plate according to yet another exemplary embodiment.

[0023] Figure 7 This is a cross-sectional structural schematic diagram of a water-blocking plate according to yet another exemplary embodiment.

[0024] Figure 8 This is a flowchart illustrating a test method for a test apparatus used to simulate the process of rock creep accelerated by liquid water, according to an exemplary embodiment.

[0025] Figure 9 This is a schematic diagram of a four-point bending fixture according to an exemplary embodiment.

[0026] Figure Labels 1. Rock sample; 11. Water storage tank; 2. First loading unit; 21. First loading roller; 3. Second loading unit; 31. Second loading roller; 4. Test platform; 41. Slide rail; 42. Slider; 5. Environmental chamber; 6. Crack opening displacement sensor; 7. Water blocking plate; 71. Water injection hole; 72. Water outlet hole; 73. First baffle; 74. Second baffle; 8. Drainage outlet; 9. Display screen; 10. Mounting bracket; 20. Camera; 30. Liftable platform; 40. Pressure sensor; 50. Loading rod; 60. Heat dissipation subunit; 70. Compressor assembly; 80. Temperature and humidity sensor; 81. Magnetic base; 82. First connecting rod; 83. Second connecting rod; 84. First mounting ring; 85. Second mounting ring. Detailed Implementation

[0027] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0028] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. The singular forms “a” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0029] It should be understood that although the terms first, second, third, etc., may be used to describe various information in embodiments of this disclosure, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first information may also be referred to as second information without departing from the scope of embodiments of this disclosure, and similarly, second information may also be referred to as first information. Depending on the context, the words “if” and “suppose” as used herein may be interpreted as “when”, “when”, or “in response to a determination”.

[0030] Furthermore, various forms of processes shown in the embodiments of this disclosure can be used to reorder, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this disclosure can be achieved, and no limitation is imposed herein.

[0031] In rock fracturing technology, Type I cracks (tensional cracks) are one of the most typical crack forms in the rock failure process, characterized by the opening of the crack surface under normal tensile stress. Numerous engineering and geological disaster studies have shown that Type I cracks are a significant mode leading to rock mass instability, slope collapse, and stratum fracturing. Existing research has confirmed that the presence of liquid water has a significant impact on rock fracture behavior: on the one hand, water infiltration reduces the fracture toughness of the rock, allowing cracks to initiate at lower stress levels; on the other hand, the action of water molecules accelerates the crack propagation rate, especially in the subcritical propagation stage. This effect has important implications in practical engineering. For example, in slope and underground engineering, rainfall or groundwater infiltration weakens the tensile strength and toughness of the rock mass, increasing the risk of instability; in tectonic stress fields, water-bearing cracks can slowly propagate under low stress conditions, thus affecting the gestation and occurrence cycle of earthquakes.

[0032] Current research methods for Type I cracks in rocks mainly include direct tension, three-point bending, and four-point bending. Among these, three-point bending and four-point bending tests are widely used due to their ease of sample preparation, stable loading structure, and controllable stress concentration at the crack tip. However, existing test setups are mostly used under dry or simple immersion conditions, making it difficult to simulate the entire process of liquid water gradually seeping into the crack tip and acting on it, especially in the study of accelerated failure behavior under long-term loading (creep) conditions. To address the aforementioned problems, this disclosure provides an experimental apparatus and method for simulating the process of liquid water accelerating rock creep. An environmental chamber is installed on a test platform, and a temperature and humidity control unit is connected to the environmental chamber to regulate the temperature and humidity within it. A monitoring component is located inside the environmental chamber. Both a first loading unit and a second loading unit are mounted on the test platform via mounting brackets, and both are located inside the environmental chamber. The side of the first loading unit closest to the two first loading rollers is positioned opposite the side of the second loading unit closest to at least one second loading roller, with the first loading unit positioned above the second loading unit. The input end of a water injection pump is connected to a water source, and the output end of the pump is connected to a water storage tank on the rock sample via a pipeline. The water storage tank is positioned opposite to the two first loading rollers and is used to simulate water-bearing cracks in the rock. Thus, by using the water storage unit to simulate the natural environment in which the rock is situated, the influence of water on rock cracks is considered, thereby simulating the process of liquid water accelerating rock creep in rock mechanics experiments and improving the accuracy of the experimental results.

[0033] Figure 1 This is a structural diagram of an experimental apparatus for simulating the accelerated rock creep process by liquid water, according to an exemplary embodiment. Figure 1 As shown, it should be noted that the experimental apparatus for simulating the process of liquid water accelerating rock creep in this embodiment of the present disclosure is applied to the experimental apparatus method for simulating the process of liquid water accelerating rock creep. For example... Figure 1 As shown, the test apparatus for simulating the process of liquid water accelerating rock creep may include an environmental chamber 5, a test platform 4, a monitoring component, a multi-point bending fixture, a temperature and humidity control unit, and a water storage unit. The water storage unit includes a water injection pump, and the multi-point bending fixture includes a first loading unit 2 and a second loading unit 3. The first loading unit 2 includes two first loading rollers 21, and the second loading unit 3 includes at least one second loading roller 31.

[0034] Among them, the environmental chamber 5 is set on the test platform 4, and the temperature and humidity control unit is connected to the environmental chamber 5 to regulate the temperature and humidity inside the environmental chamber 5. The monitoring components are located inside environmental chamber 5; The first loading unit 2 and the second loading unit 3 are both mounted on the test platform 4 via the mounting bracket 10, and both the first loading unit 2 and the second loading unit 3 are located inside the environmental chamber 5; The first loading unit 2 is positioned opposite to the side of the two first loading rollers 21 and the side of the second loading unit 3 is positioned opposite to the side of the second loading unit 3 that is adjacent to at least one second loading roller 31. The first loading unit 2 is positioned above the second loading unit 3. The input end of the water injection pump is connected to a water source, and the output end of the water injection pump is connected to a water storage tank 11 opened on the rock sample 1 through a pipeline; the water storage tank 11 is arranged opposite to the two first loading rollers 21; the water storage tank 11 is used to simulate the water-bearing cracks in the rock.

[0035] In this embodiment of the present disclosure, the test apparatus for simulating the process of liquid water accelerating rock creep can be used to carry out water-induced crack accelerated propagation test under controlled environmental temperature and humidity conditions. In order to realize the water-induced crack accelerated propagation test, a water storage tank 11 is pre-opened on the rock sample 1 so that water can be stored in the water storage tank 11 during the test.

[0036] Furthermore, it should be emphasized that, such as Figure 2As shown, in order to conduct water-induced crack propagation experiments on rocks using the three-point bending test method, the multi-point bending fixture in this disclosure is inverted. That is, unlike the traditional multi-point bending fixture which places the loading unit with one loading roller on top and the loading unit with two loading rollers on the bottom, this disclosure places the first loading unit 2, which includes two first loading rollers 21, on top of the second loading unit 3, which includes at least one second loading roller 31, and places the water storage tank 11 of the rock sample 1 to be tested facing upwards so that water can be stored in the water storage tank 11.

[0037] It is understood that the multi-point bending fixture inverted installation method in this embodiment can avoid the individual loading rollers from contacting and affecting each other with the water storage tank 11.

[0038] In one embodiment, such as Figure 1 As shown, the temperature and humidity control unit may include a heat dissipation subunit 60, a compressor assembly 70, and a temperature and humidity control subunit. The temperature and humidity simulation during the test can be controlled and adjusted by the compressor assembly 70, which functions as cooling and dehumidification. The heat dissipation module provides cooling for the compressor. The temperature and humidity control subunit includes components such as a circuit board and a wireless network card. The desired temperature and humidity are set via a touch screen 9 to control the compressor's operation. The built-in wireless network card can transmit real-time temperature and humidity data to a mobile device, allowing for control and adjustment of the device from the mobile device. The system's temperature and humidity control program can be set to step-like or sinusoidal rise and fall patterns, and the rate of temperature and humidity rise or fall and the holding time for each stage can be set. For example, the temperature and humidity adjustment range is: temperature -20℃ to 65℃, accuracy ±1℃; humidity 20% to 90%, accuracy ±2%.

[0039] In this embodiment, the multi-point bending fixture can be hydraulically servo controlled, with a maximum loading force of 1000kN, and features both force-controlled and displacement-controlled loading modes. A phased loading process can be set, and parameter configuration can include loading rate, loading time, and sampling frequency.

[0040] like Figure 1 As shown, the mounting frame 10 (i.e., the loading frame) can adopt a high-rigidity four-column structure. The loading rod 50 is connected to the pressure sensor 40 through studs. The pressure sensor 40 is fixedly connected to the mounting frame 10 through mounting parts. The other end of the loading rod 50 is fixedly connected to the first loading unit 2 through a detachable fixing ring. The fixing ring is fixed by tightening bolts.

[0041] It should be noted that a multi-point bending fixture can be a three-point bending fixture or a four-point bending fixture.

[0042] In some embodiments of this disclosure, such as Figure 2As shown, when the multi-point clamp is a three-point bending clamp, the three-point bending clamp is installed upside down. That is, under normal circumstances, the two first loading rollers 21 are set below the rock sample 1 to be tested, and the second loading roller 31 is set above the rock sample 1 to be tested. However, in this application, the opposite is true. The two first loading rollers 21 are set below the rock sample 1 to be tested, and the second loading roller 31 is set above the rock sample 1 to be tested.

[0043] In some embodiments of this disclosure, such as Figure 9 As shown, in the case of a four-point bending clamp, the four-point bending clamp is installed upside down. That is, under normal circumstances, the two first loading rollers 21 (closely spaced) of the four-point bending clamp are placed below the rock sample 1 to be tested, and the two second loading rollers 31 (far apart) are placed above the rock sample 1 to be tested. However, in this application, the opposite is true. Since the water storage tank 11 used to simulate water storage cracks needs to extend from the top to the bottom, the two first loading rollers 21 (closely spaced) need to be placed below the rock sample 1 to be tested, and the two second loading rollers 31 (far apart) need to be placed above the rock sample 1 to be tested.

[0044] In one embodiment, the first loading unit 2 may include two sets of slidable loading rods (i.e., first loading rollers 21) to facilitate experiments on samples of different sizes. The lower half of the fixture is also fixed to the base by bolts.

[0045] In some embodiments of this disclosure, the monitoring component may integrate any one or more of the following: temperature and humidity sensor 80, crack opening displacement sensor 6, ultrasonic detection, strain measurement, and acoustic emission technology.

[0046] The device may also include a camera 20, which can be used to collect deformation data of the rock sample 1. The camera 20 can be mounted on the experimental platform described above via a liftable platform 30.

[0047] In some embodiments of this disclosure, such as Figure 5 As shown, the environmental chamber 5 and the test platform 4 are slidably connected via a sliding rail 41. A slider 42 is fixed at the bottom, and the slider 42 is slidably connected to the sliding rail 41 installed on the side of the test platform 4. The chamber and the loader can be separated and combined by pushing. A sliding base is provided to facilitate combination or separation with the environmental chamber 5 and the loader.

[0048] In some embodiments of this disclosure, the environmental chamber 5 is equipped with a front-heated glass panel for observation; the glass is heated to prevent fogging on its inner surface. The environmental chamber 5 also has wiring holes for connecting wires from outside the chamber to internal sensors. A drain outlet 8 drains water accumulated during high-humidity operation within the environmental chamber 5, as well as water drained from the water storage tank 11. The door of the environmental chamber 5 can be opened by rotating a handle with a lock to prevent accidental opening and subsequent temperature and humidity control within the chamber. Temperature and humidity data for a specific time period can be exported via a USB port.

[0049] In some embodiments of this disclosure, the monitoring component includes a crack opening displacement sensor 6, which is disposed inside the water storage tank 11 of the rock sample 1.

[0050] In one embodiment, the crack opening displacement sensor 6 can be used to capture the entire process of crack propagation in the rock sample 1 under test.

[0051] In some embodiments of this disclosure, such as Figure 3 As shown, the water storage unit also includes a water-blocking plate 7. The water storage tank 11 is disposed between the two first loading rollers 21. One end of the water storage tank 11 is connected to the outside. The water-blocking plate 7 is fitted to one end to block one end. The water-blocking plate 7 is provided with a water injection hole 71. The water injection pump is connected to the water storage tank 11 through a pipe passing through the water injection hole 71.

[0052] In this embodiment, the water in the water storage tank 11 is blocked by the water-blocking plate 7, and water is injected through the water injection hole 71, thereby enabling the water injection pump to inject water into the water storage tank 11 stably and improving the stability of the experimental process.

[0053] In one embodiment, one end of the water storage tank 11 is connected to the outside and a water storage plate is fixed thereon, while the other end is not connected to the outside.

[0054] In some embodiments of this disclosure, the water-blocking plate 7 further includes a water outlet hole 72, which is disposed above the water injection hole 71 and is connected to the outside through a pipeline.

[0055] In this embodiment, the water outlet hole 72 is located above the water inlet hole 71. The position of the water outlet hole 72 can be set according to the expected water storage capacity in the water storage tank 11. That is, the height of the water outlet hole 72 can be determined according to the water storage capacity and the size of the water storage tank 11. When the water level in the water storage tank 11 exceeds the height of the water outlet hole, water flows out through the water outlet hole, thereby maintaining the water volume in the water storage tank 11 at the expected water storage capacity.

[0056] In some embodiments of this disclosure, such as Figure 6 and Figure 7As shown, a limiting component is also fixed to the top of the water-blocking plate 7. The limiting component includes a first baffle 73 and a second baffle 74. One end of the first baffle 73 and the second baffle 74 are fixedly connected to the water-blocking plate 7. The first baffle 73 is horizontally arranged, and the second baffle 74 is vertically arranged below the first baffle 73. The top of the second baffle 74 is fixedly connected to the bottom of the first baffle 73. The first baffle 73 is arranged at the top of the water storage tank 11, and the second baffle 74 is arranged inside the water storage tank 11. Furthermore, both the first baffle 73 and the second baffle 74 are arranged above the water outlet hole 72.

[0057] In one embodiment, in order to ensure that the water-blocking plate 7 can be fixed at one end of the water storage tank 11, a limiting member can be provided on the water-blocking plate 7 to improve the stability of the water-blocking plate 7 without obstructing the water inlet.

[0058] In some embodiments of this disclosure, the water injection pump may be a peristaltic pump.

[0059] It is understandable that a peristaltic pump is a positive displacement pump. Its working principle mimics the peristaltic phenomenon of the biological digestive tract. Peristaltic pumps have low shear force and can gently propel fluid movement. Using a peristaltic pump as a water injection pump can precisely control the water volume in the water storage tank 11, with a minimum rate of 1µL / s.

[0060] In some embodiments of this disclosure, such as Figure 4 As shown, the monitoring assembly also includes a temperature and humidity sensor 80, a magnetic base 81, a first connecting rod 82, and a second connecting rod 83. One end of the first connecting rod 82 is fixedly connected to the magnetic base 81, and one end of the second connecting rod 83 is slidably connected to the first connecting rod 82 via a first mounting ring 84. The temperature and humidity sensor 80 is slidably connected to the end of the second connecting rod 83 away from the first mounting ring 84 via a second mounting ring 85. Furthermore, both the first mounting ring 84 and the second mounting ring 85 are equipped with locking screws for positioning.

[0061] The experimental apparatus for simulating the accelerated rock creep process by liquid water, according to an embodiment of this disclosure, comprises an environmental chamber mounted on a test platform. A temperature and humidity control unit is connected to the environmental chamber to regulate the temperature and humidity within it. A monitoring component is located inside the environmental chamber. Both a first loading unit and a second loading unit are mounted on the test platform via mounting brackets, and both are located inside the environmental chamber. The side of the first loading unit closest to the two first loading rollers is positioned opposite to the side of the second loading unit closest to at least one second loading roller, with the first loading unit positioned above the second loading unit. The input end of a water injection pump is connected to a water source, and the output end of the pump is connected to a water storage tank on the rock sample via a pipeline. The water storage tank is positioned opposite to the two first loading rollers and is used to simulate water-bearing cracks in the rock. Thus, by using the water storage unit to simulate the natural environment of the rock, the influence of water on rock cracks is considered, thereby improving the simulation of the natural environment during the experiment and ultimately enhancing the accuracy of the experimental results.

[0062] Figure 8 This is a flowchart illustrating a test method for an experimental apparatus used to simulate the accelerated rock creep process by liquid water, according to an exemplary embodiment. (Refer to...) Figure 8 The method includes: Step 801: Create a water storage tank on the rock sample to be tested.

[0063] Step 802: The rock sample to be tested is placed between the first loading unit and the second loading unit of the multi-point bending fixture; wherein, the water storage tank is placed on the side closer to the first loading unit.

[0064] Step 803: Control the multi-point bending fixture to apply initial pressure to the rock sample to be tested, so that the multi-point bending fixture can fix the rock sample to be tested.

[0065] For example, the loading rod can be controlled to apply a constant force of 0.1 kN to a multi-point bending fixture to fix the specimen.

[0066] Step 804: Control the temperature and humidity control unit to maintain the temperature and humidity inside the environmental chamber at the target temperature and humidity.

[0067] For example, close the environmental chamber door and start the environmental chamber. Set the temperature to 25℃ and the humidity to 50%, and debug the DIC camera. Perform environmental equilibration. Environmental equilibration should take more than 12 hours. Humidity fluctuations within ±2% should be less than 30 minutes, then proceed to loading preparation.

[0068] Step 805: Control the multi-point bending fixture to preload the rock sample under test until the rock sample under test is preloaded to the preset load value and maintained for the preset time.

[0069] In one embodiment, the preset load value can be approximately 75% of the peak pressure of the specimen. After applying the preset value to the specimen, the pressure is maintained for >3 days to ensure that creep failure does not occur during the maintenance phase, and then water is injected to accelerate creep failure. Step 806: Control the water injection pump to deliver water to the water storage tank.

[0070] Step 807: Use the monitoring component to collect target data of the rock sample to be tested until the rock sample breaks.

[0071] In some embodiments of this disclosure, a crack opening displacement sensor can be placed inside a water storage tank to monitor the crack opening process.

[0072] In some embodiments of this disclosure, the water storage unit further includes a water-blocking plate. A water storage tank is disposed between two first loading rollers, with one end of the water storage tank connected to the outside. The water-blocking plate is fitted to one end to seal it. The water-blocking plate has a water injection hole, and a water injection pump is connected to the water storage tank through a pipe passing through the water injection hole. The water injection pump is a peristaltic pump. Step 806 may specifically include: Control the peristaltic pump to deliver water through the water injection hole of the water-blocking plate to the water storage tank at the first rate; When water flows out of the outlet hole of the water-blocking plate, the peristaltic pump is controlled to deliver water to the water storage tank at a second rate; the second rate is less than the first rate so that the water volume in the water storage tank is maintained at a preset water volume.

[0073] In some embodiments of this disclosure, the water-blocking sheet can be glued to one end of the water storage tank, and an inlet pipe can be installed at the water injection hole.

[0074] In one embodiment, a peristaltic pump can be started to draw water at a rate of 10 µL / s. Once water flows out of the outlet of the water-blocking plate, the rate is switched to 1 µL / s to ensure a constant water volume in the storage tank. Changes in crack opening, pressure, and sample deformation monitored by the DIC camera are recorded in the rock sample as water is drawn, until the sample fractures.

[0075] In the embodiments of this disclosure, the relevant experimental data and results collected during the test by the test method proposed in this disclosure may include the crack aperture CMOD curve, the nonlinear acceleration law of the sample as the wetting crack opens, the crack propagation path diagram DIC, and the visualization of the crack tip movement path and bifurcation, etc.

[0076] In other embodiments of this disclosure, the water-blocking plate may also include a water outlet hole, which is disposed above the water injection hole. The water outlet hole is connected to the outside through a pipe, and a water outlet pipe can be installed in the water outlet hole. The water outlet pipe can be connected to the drain outlet of the device.

[0077] According to the experimental method proposed in this disclosure, a water storage tank is opened on the rock sample to be tested; the rock sample to be tested is placed between the first loading unit and the second loading unit of a multi-point bending fixture; wherein, the water storage tank is located on the side closer to the first loading unit; the multi-point bending fixture is controlled to apply initial pressure to the rock sample to fix it; the temperature and humidity control unit is controlled to maintain the temperature and humidity in the environmental chamber at the target temperature and humidity; the multi-point bending fixture is controlled to preload the rock sample to the target load value; a water pump is controlled to deliver water to the water storage tank; and a monitoring component is used to collect target data of the rock sample to the target load until the rock sample fractures. Thus, the water storage unit considers the influence of water on rock cracks during the simulation of the natural environment of the rock, thereby improving the simulation of the natural environment during the experiment and thus improving the accuracy of the experimental results.

[0078] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0079] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0080] In this disclosure, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0081] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.

[0082] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. An experimental apparatus for simulating the accelerated rock creep process by liquid water, characterized in that, The system includes an environmental chamber, a test platform, monitoring components, a multi-point bending fixture, a temperature and humidity control unit, and a water storage unit. The water storage unit includes a water injection pump. The multi-point bending fixture includes a first loading unit and a second loading unit. The first loading unit includes two first loading rollers, and the second loading unit includes at least one second loading roller. The environmental chamber is set on the test platform, and the temperature and humidity control unit is connected to the environmental chamber for regulating the temperature and humidity inside the environmental chamber. The monitoring components are installed inside the environmental chamber; Both the first loading unit and the second loading unit are mounted on the test platform via mounting brackets, and both the first loading unit and the second loading unit are located inside the environmental chamber; The first loading unit is positioned opposite the side of the two first loading rollers to the side of the second loading unit that is adjacent to the at least one second loading roller, and the first loading unit is positioned above the second loading unit. The input end of the water injection pump is connected to a water source, and the output end of the water injection pump is connected to a water storage tank opened on the rock sample through a pipeline; the water storage tank is arranged opposite to the two first loading rollers; the water storage tank is used to simulate water-bearing cracks in the rock. The water storage unit further includes a water-blocking plate. The water storage tank is disposed between the two first loading rollers. One end of the water storage tank is connected to the outside. The water-blocking plate is fitted to the one end and is used to block the one end. The water-blocking plate is provided with a water injection hole. The water injection pump is connected to the water storage tank through a pipe passing through the water injection hole. The water-blocking plate is characterized in that it further includes a water outlet hole, which is disposed above the water injection hole and is connected to the outside through a pipe. The top of the water-blocking plate is also fixed with a limiting component, which includes a first baffle and a second baffle. One end of the first baffle and the second baffle are both fixedly connected to the water-blocking plate. The first baffle is horizontally arranged, and the second baffle is vertically arranged below the first baffle. The top of the second baffle is fixedly connected to the bottom of the first baffle. The first baffle is arranged at the top of the water storage tank, and the second baffle is arranged inside the water storage tank. Furthermore, both the first baffle and the second baffle are arranged above the water outlet hole.

2. The experimental apparatus for simulating the accelerated rock creep process by liquid water according to claim 1, characterized in that, The monitoring component includes a crack opening displacement sensor, which is installed inside the water storage tank of the rock sample.

3. The experimental apparatus for simulating the accelerated rock creep process by liquid water according to claim 1, characterized in that, The water injection pump is a peristaltic pump.

4. The experimental apparatus for simulating the accelerated rock creep process by liquid water according to claim 1, characterized in that, The monitoring component also includes a temperature and humidity sensor, a magnetic base, a first connecting rod, and a second connecting rod. One end of the first connecting rod is fixedly connected to the magnetic base, and one end of the second connecting rod is slidably connected to the first connecting rod via a first mounting ring. The temperature and humidity sensor is slidably connected to the end of the second connecting rod away from the first mounting ring via a second mounting ring.

5. A test method for an experimental apparatus used to simulate the accelerated creep process of rocks by liquid water, characterized in that, The experimental apparatus for simulating the accelerated rock creep process by liquid water as described in any one of claims 1-4, wherein the experimental method comprises: The water storage tank is opened on the rock sample to be tested; The rock sample to be tested is placed between the first loading unit and the second loading unit of the multi-point bending fixture; wherein the water storage tank is located on the side close to the first loading unit; the multi-point bending fixture is controlled to apply initial pressure to the rock sample to be tested so that the multi-point bending fixture fixes the rock sample to be tested. The temperature and humidity control unit adjusts the temperature and humidity inside the environmental chamber to maintain the temperature inside the environmental chamber at the target temperature and the humidity inside the environmental chamber at the target humidity. The multi-point bending fixture is controlled to preload the rock sample to be tested until the rock sample is preloaded to a preset load value and held for a preset time; the water pump is controlled to deliver water to the water storage tank. The monitoring component is used to collect target data of the rock sample to be tested until the rock sample breaks.

6. The test method according to claim 5, characterized in that, The water storage unit also includes a water-blocking plate. The water storage tank is disposed between the two first loading rollers. One end of the water storage tank is connected to the outside. The water-blocking plate is fitted to one end to seal it. The water-blocking plate is provided with a water injection hole. The water injection pump is connected to the water storage tank through a pipe passing through the water injection hole. The water injection pump is a peristaltic pump. The control of the water injection pump to deliver water to the water storage tank includes: The peristaltic pump is controlled to deliver water through the water injection hole of the water-blocking plate to the water storage tank at a first rate; When water flows out of the outlet hole of the water-blocking plate, the peristaltic pump is controlled to deliver water to the water storage tank at a second rate; the second rate is less than the first rate, so that the water volume in the water storage tank is maintained at a preset water volume.

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