A thermal-hydraulic-mechanical coupling test equipment

Abstract

The present invention relates to the technical field of rock mechanics experimental devices, and in particular, to a thermal-hydraulic-mechanical coupling test device, including a biaxial testing machine and a saturated water heating device; the biaxial testing machine can respectively clamp the two ends of a vertically arranged thin plate sample in the vertical direction and the horizontal direction, and can apply a force toward the center of the thin plate sample to the thin plate sample; the saturated water heating device includes a saturated water component and a heating component arranged in the saturated water component, the saturated water component includes a saturated water cylinder symmetrically arranged on both sides of the thin plate sample, a saturated water cavity with an opening is arranged in the saturated water cylinder, the opening is sealed and fitted on both sides of the thin plate sample, the saturated water cavity can be filled with liquid, and a heating component for heating the thin plate sample is arranged in the saturated water cavity. In this way, the problem that the prior art cannot conduct continuous thermal-mechanical and hydraulic-mechanical coupling tests on samples under loading in a single device is solved.

Description

Technical Field

[0001] The invention relates to the technical field of rock mechanics experimental devices, in particular to a thermal-hydraulic-mechanical coupling experimental device. Background Art

[0002] In recent years, with the widespread development of underground projects such as carbon dioxide geological storage, geothermal energy development, and oil and gas resource drilling, researchers generally recognize that rock mass, as a porous medium for fluid and heat conduction, has an important impact on the normal construction of underground projects. In addition, during the mining of mineral resources and the development of underground space, the temperature, pore pressure and stress conditions of the rock mass are very complex. Underground rock mass is often in a complex environment of high temperature, high pressure, and high stress, undergoing a thermal-hydraulic-mechanical coupling process. Therefore, understanding the multi-physics coupling in rocks is crucial for the development of mineral resources, oil and gas, geothermal resources, and other energy fields.

[0003] Nowadays, most studies focus on studying the mechanical response of rocks under loading conditions by applying a single load to rocks and measuring the changes in relevant parameters such as stress, strain, and strength, while ignoring the effects of temperature and pore water pressure on the mechanical properties of rocks. Some researchers also put the samples into a specific device for saturation before loading. Although this takes into account the influence of pore water on the mechanical properties of the samples, it ignores the influence of the in-situ stress field on the changes in its pore pressure, and few people study the mechanical response of rocks under thermal-hydraulic-mechanical coupling conditions. The existing saturation methods mainly use natural saturation, vacuum saturation, heating saturation and other methods to saturate rocks. These methods mainly place the sample in a specific container and apply corresponding pressure or temperature conditions for saturation. Rocks are mostly heated by direct baking or heat treatment through a servo electric furnace, mainly by directly baking and heating the rock at a heat source or placing it in an electric furnace and heating the sample by setting a predetermined temperature. The three major operation steps of saturating, heating and loading the rock samples are carried out in different devices, which not only consumes financial and material resources, but also consumes manpower and time. Moreover, each part of the operation is carried out separately, which is inconsistent with the actual state of the rock in situ and greatly reduces the efficiency and accuracy of the experiment. Summary of the invention

[0004] In order to solve the problem that the prior art cannot continuously perform thermal-mechanical and water-mechanical coupling tests on samples under loading in a single device, the present invention provides a thermal-hydraulic-mechanical coupling test device, including: a biaxial testing machine and a saturated water heating device; the biaxial testing machine can respectively clamp the two ends of a vertically arranged thin plate sample in the vertical direction and the horizontal direction, and can apply a force toward the center of the thin plate sample to the thin plate sample; the saturated water heating device includes a saturated water component and a heating component arranged in the saturated water component, the saturated water component includes a saturated water cylinder symmetrically arranged on both sides of the thin plate sample, a saturated water cavity with an opening is arranged in the saturated water cylinder, the opening is sealed and fitted on both sides of the thin plate sample, the saturated water cavity can be filled with liquid, and a heating component for heating the thin plate sample is arranged in the saturated water cavity.

[0005] In some embodiments, the saturated water heating device also includes a water delivery component, the water delivery component includes a water delivery cylinder and a water delivery pipe, the water delivery cylinder includes a water delivery chamber for carrying liquid, a piston is provided in the water delivery chamber and moves along the length direction of the water delivery chamber, the water delivery cylinder is provided with a water outlet on one side along the length direction of the water delivery cylinder, one end of the water delivery pipe is connected to the water delivery chamber through the water outlet, and the other end of the water delivery pipe is connected to the saturated water chamber, and the piston can press the liquid in the water delivery cylinder into the saturated water chamber through the water delivery pipe.

[0006] In some embodiments, the piston can separate the water delivery chamber into a water delivery part and a pressurizing part, the water outlet is arranged in the water delivery part, the pressurizing part is connected with the pressurizing component, the pressurizing component can introduce pressurized gas into the pressurizing part, and the piston is pushed to move with a first driving pressure to fill the saturated water chamber with liquid, and a water level detector for detecting the water level in the water delivery chamber is arranged on the side wall of the water delivery cylinder.

[0007] In some embodiments, the pressurizing assembly can also push the piston with a second driving pressure until the thin plate sample reaches a saturated state, and the second driving pressure is:

[0008]

[0009] Wherein, P2 is the second driving pressure, P1 is the first driving pressure, ρ w is the density of the liquid in the saturated cavity, g is the acceleration due to gravity, V w is the volume of liquid required for the thin plate sample in the saturated chamber to reach the saturated state, S is the cross-sectional area of ​​the piston; V w =knV s , k is the correction factor, the value range is 1.1-1.3, n is the porosity of the thin plate sample, V s is the volume of the thin plate specimen within the water-saturated cavity.

[0010] In some embodiments, the thermal-hydraulic-mechanical coupling test equipment also includes a vacuum device, which includes a vacuum pump and a first connecting pipe. The vacuum pump is connected to the water-saturated chamber through the first connecting pipe. The vacuum pump extracts the gas in the water-saturated chamber to reduce the pressure in the water-saturated chamber to a predetermined air pressure.

[0011] In some embodiments, the vacuum pump operates at rated power and for a preset time, where the preset time is:

[0012]

[0013] Where, t is the preset time; V a is the volume of the vacuum part in the saturated water chamber; P3 is the initial pressure before the vacuum pump is operated; P4 is the pressure value of the predetermined air pressure; Q is the volume of gas extracted by the vacuum pump per unit time at rated power.

[0014] In some embodiments, the predetermined pressure is 1×10 -4 Up to 1×10 -8 Torr.

[0015] In some embodiments, the thermal-hydraulic-mechanical coupling test equipment further includes a water collecting cylinder, in which a water collecting chamber is provided, and the water collecting chamber is connected to the top of the saturated water chamber.

[0016] In some embodiments, the heating assembly includes a radiation heating layer arranged on the side of the water-saturated chamber away from the thin plate sample, a temperature sensor, and a temperature controller electrically connected to the radiation heating layer and the temperature sensor; the radiation heating layer can emit heat radiation toward the thin plate sample, the temperature sensor is attached to the thin plate sample and can detect the temperature of the thin plate sample, and the temperature controller can display the temperature data detected by the temperature sensor and adjust the power of the radiation heating layer according to the temperature data.

[0017] In some embodiments, mounting surfaces inclined relative to the edge of the thin plate specimen are respectively provided at the four corners of the thin plate specimen; the saturated water heating device includes a plurality of fixed card assemblies, which are symmetrically arranged in pairs, and the fixed card assemblies include a U-shaped card and a telescopic structure. The bottom of the U-shaped card can abut against the mounting surface, and the two ends of the U-shaped card are respectively provided with telescopic structures, and the telescopic structure can be telescoped along the extension direction of the end of the U-shaped card. A connecting ring is provided at one end of the telescopic structure away from the U-shaped card, and a connecting structure matching the connecting ring is provided on the side of the saturated water cylinder; the two symmetrically arranged fixed card assemblies can shorten the length of the telescopic structure, thereby applying a force away from the center of the saturated water cylinder along the radial direction of the saturated water cylinder.

[0018] In order to solve the problem that the prior art cannot continuously test the specimen under the conditions of thermal-mechanical and water-mechanical coupling in a single device under loading, the present invention has the following advantages:

[0019] The biaxial testing machine can be used to fix the thin plate sample in a vertical state, and can continuously apply force to the thin plate sample according to the experimental requirements to simulate the stress state in the actual situation. At the same time, the saturated cylinders symmetrically arranged on both sides of the thin plate sample in the saturated heating device can be used to make the central part of the thin plate sample be in a liquid-filled environment, so as to be saturated with water. After the saturation, the heating component can also be used to heat the thin plate sample, so as to more accurately simulate the stress changes of the rock under the thermal-mechanical and water-mechanical coupling conditions. In particular, the device can perform saturation and heating operations for multiple times without removing the thin plate sample from the biaxial testing machine, which can solve the problem that the sample is damaged and cannot be installed again due to continuous experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of a thermal-hydraulic-mechanical coupling test device according to an embodiment is shown;

[0021] Figure 2 A side view of a thermal-hydraulic-mechanical coupling test apparatus according to an embodiment is shown;

[0022] Figure 3 A partial structural schematic diagram of a saturated water heating device according to an embodiment is shown;

[0023] Figure 4 Shows Figure 1 A partial enlarged structural diagram of the middle A part;

[0024] Figure 5 A schematic structural diagram of a water delivery assembly according to an embodiment is shown;

[0025] Figure 6 A schematic structural diagram of a pressurizing assembly according to an embodiment is shown;

[0026] Figure 7 A schematic structural diagram of a vacuum device according to an embodiment is shown;

[0027] Figure 8 A schematic structural diagram of a water collecting cylinder according to an embodiment is shown;

[0028] Fig. 9 A schematic structural diagram of a heating assembly according to an embodiment is shown;

[0029] Fig.10 A structural schematic diagram of a fixed card assembly according to an embodiment is shown;

[0030] Fig.11 A schematic structural diagram of a sealing member according to an embodiment is shown.

[0031] Reference numerals: 10-thin plate specimen; 11-central through hole; 12-mounting surface; 20-biaxial testing machine pressure head; 30-water-saturated heating device; 31-water-saturated assembly; 311-water-saturated cylinder; 3111-water-saturated cavity; 32-heating assembly; 321-radiant heating layer; 322-temperature sensor; 323-temperature controller; 33-water delivery assembly; 331-water delivery cylinder; 3311-water delivery cavity; 33111 -water delivery part; 33112-pressurizing part; 3312-water outlet; 332-piston; 333-water delivery pipe; 334-pressure gauge; 34-pressurizing assembly; 341-air pump; 35-fixing card assembly; 351-U-shaped card; 352-telescopic structure; 3521-connecting ring; 40-vacuum device; 41-vacuum pump; 42-first connecting pipe; 50-water collecting cylinder; 51-water collecting chamber; 60-sealing member. DETAILED DESCRIPTION

[0032] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, rather than implying any limitation on the scope of the present disclosure.

[0033] As used herein, the term "including" and its variants are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "based at least in part on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal" and the like is based on the orientation or position relationship shown in the accompanying drawings. These terms are mainly for better describing the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to being used to indicate an orientation or position relationship, some of the above terms may also be used to indicate other meanings, such as the term "upper" may also be used to indicate a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to the specific circumstances. In addition, the terms "install", "set", "provided with", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0034] This embodiment discloses a thermal-hydraulic-mechanical coupling test device, such as Figures 1 to 4 As shown, it may include: a biaxial testing machine and a saturated water heating device 30; the biaxial testing machine can clamp the two ends of the vertically arranged thin plate sample 10 in the vertical direction and the horizontal direction respectively, and can apply a force toward the center of the thin plate sample 10 to the thin plate sample 10; the saturated water heating device 30 includes a saturated water component 31 and a heating component 32 arranged in the saturated water component 31, the saturated water component 31 includes a saturated water cylinder 311 symmetrically arranged on both sides of the thin plate sample 10, and a saturated water cavity 3111 with an opening is arranged in the saturated water cylinder 311, and the opening is sealed and fitted on both sides of the thin plate sample 10, the saturated water cavity 3111 can be filled with liquid, and the saturated water cavity 3111 is provided with a heating component 32 for heating the thin plate sample 10.

[0035] It should be noted that the thin plate sample 10 is usually a standard rock sample for experiment, which can be a square thin plate-shaped stone plate, wherein the two relatively large surfaces are the front side and the rear side, respectively, and the side along the thickness direction is used to abut against the loading plate of the biaxial testing machine, and the biaxial testing machine can use the biaxial testing machine pressure head 20 to apply force to the thin plate sample 10 in the horizontal direction and the vertical direction respectively. The center position of the thin plate sample 10 can be provided with a central through hole 11 that penetrates the thin plate sample 10 in the thickness direction, and the through hole can be used to simulate the tunnel in the actual project. The liquid used in the saturation process is usually water.

[0036] In the above technical solution, if Figure 1 , Figure 2 As shown, the biaxial testing machine can be used to fix the thin plate sample 10 in a vertical state, and can continuously apply force to the thin plate sample 10 according to the experimental requirements to simulate the stress state in the actual situation. At the same time, the saturated cylinders 311 symmetrically arranged on both sides of the thin plate sample 10 in the saturated heating device 30 can be used to make the central part of the thin plate sample 10 be in a liquid-filled environment, so as to be saturated with water. After the saturation, the heating component 32 can also be used to heat the thin plate sample 10, so as to more accurately simulate the stress changes of the rock under the thermal-mechanical and water-mechanical coupling conditions. In particular, the device can perform saturation and heating operations continuously for multiple times without removing the thin plate sample 10 from the biaxial testing machine, which can solve the problem that the sample is damaged and cannot be installed again due to continuous experiments.

[0037] Among them, Figure 3 As shown, the saturated water cylinder 311 may be a thin-walled structure with an appropriate shape, wherein the saturated water chamber 3111 may have a similar shape to the saturated water cylinder 311, such as a cylindrical, truncated cone, square, etc., and in order to form a test area with a uniform distance relative to the geometric center of the thin plate sample 10, the opening of the saturated water chamber 3111 is preferably set to a circular shape, so that the saturated part of the thin plate sample 10 forms a circular part centered at its geometric center. In addition, in order to enable the saturated water chamber 3111 to be filled with liquid, the saturated water chamber 3111 may be provided with a water inlet for water intake. The setting mode of the water inlet for different rock thin plate specimens 10 can be changed accordingly. For the thin plate specimen 10 with a central through hole 11 in the center, the central through hole 11 can connect the saturated water chambers 3111 on both sides, so that it can be connected into a whole. At this time, it is possible to choose to set the water inlet only on one of the saturated water cylinders 311. For the thin plate specimen 10 without a central through hole 11 in the center, the saturated water chambers 3111 on both sides are not actually connected, so it is necessary to set water inlets separately. Furthermore, the water inlet can also be used as a drain. In order to facilitate drainage and fully discharge the water in the saturated water chamber 3111, the water inlet can be selected to be set at the lowest point of the saturated water chamber 3111 when it is installed on the thin plate specimen 10.

[0038] In order to make the connection between the saturated water tank 311 and the thin plate sample 10 fully sealed, Figure 4 , Fig.11 As shown, a sealing member 60 may be sleeved on the outer periphery of the saturated water cylinder 311. The sealing member 60 may be a sealing ring made of a flexible material, such as Figure 4 As shown, its inner circumference is in contact with the outer circumference of the water-saturated cylinder 311, and the side facing the thin plate sample 10 is in contact with the thin plate sample 10. Specifically, the sealing ring can be set as an oily sealing ring. By utilizing the incompatibility of oil and water, grease is filled in the tiny pores between the sealing ring and the water-saturated cylinder 311 and the thin plate sample 10 to prevent water from flowing out.

[0039] The heating component 32 can heat the part of the thin plate sample 10 that has been saturated with water, so as to simulate the influence of temperature on the mechanical properties of rock. The heating component 32 can select an appropriate implementation method. In order to allow the liquid in the saturated cavity 3111 to fully contact the sample, the heating component 32 can be set at a position in the saturated cavity 3111 that is a certain distance away from the opening. Therefore, the heating component 32 is preferably able to heat the thin plate sample 10 by non-contact heating.

[0040] In some embodiments, Figure 5 As shown, the saturated water heating device 30 also includes a water delivery component 33, which includes a water delivery cylinder 331 and a water delivery pipe 333. The water delivery cylinder 331 includes a water delivery chamber 3311 for carrying liquid. A piston 332 is provided in the water delivery chamber 3311 and moves along the length direction of the water delivery chamber 3311. The water delivery cylinder 331 is provided with a water outlet 3312 on one side along the length direction of the water delivery cylinder 331. One end of the water delivery pipe 333 is connected to the water delivery chamber 3311 through the water outlet 3312, and the other end of the water delivery pipe 333 is connected to the saturated water chamber 3111. The piston 332 can press the liquid in the water delivery cylinder 331 into the saturated water chamber 3111 through the water delivery pipe 333.

[0041] In this embodiment, the water delivery component 33 is used to deliver liquid for saturation into the saturated water chamber 3111. As an optional embodiment, the water delivery cylinder 331 can be used as a storage tank for storing liquid. Therefore, the total amount of liquid in the water delivery cylinder 331 should be greater than the volume of the saturated water chamber 3111, so that the liquid delivered to the saturated water chamber 3111 can completely fill the saturated water chamber 3111. The liquid can be delivered by directly pumping it into the saturated water chamber 3111 using a water pump or other mechanism, or the water delivery cylinder 331 can be set above the saturated water chamber 311 to use gravity to allow the liquid to naturally flow into the saturated water chamber 3111. In order to ensure that the saturated water chamber 3111 can be effectively filled with liquid, an exhaust port for exhaust can be set at the top of the saturated water chamber 3111. When the liquid flows into the saturated water chamber 3111, the liquid gradually fills the saturated water chamber 3111 from bottom to top, and at the same time, the gas is discharged through the exhaust port to avoid the formation of bubbles. The water outlet 3312 can be set at the lower part of the water delivery chamber 3311, specifically, it can be set on the side wall of the lower part of the water delivery cylinder 331, or it can be directly set at the bottom of the water delivery cylinder 331, so that the liquid flows out from the lower part of the water delivery cylinder 331, which can avoid the generation of bubbles and improve the water delivery efficiency. A valve for controlling the on-off of the pipeline can be set between the water delivery chamber 3311 and the saturated water chamber 3111.

[0042] In some embodiments, Figure 5 As shown, the piston 332 can separate the water delivery chamber 3311 into a water delivery portion 33111 and a pressurizing portion 33112, the water outlet 3312 is arranged in the water delivery portion 33111, the pressurizing portion 33112 is communicated with the pressurizing component 34, the pressurizing component 34 can introduce pressurized gas into the pressurizing portion 33112, and use the first driving pressure to push the piston 332 to move and fill the saturated water chamber 3111 with liquid, and a water level detector for detecting the water level in the water delivery chamber 3311 is arranged on the side wall of the water delivery cylinder 331.

[0043] In this embodiment, in order to promote the progress of saturation, during the water delivery process, the piston 332 can be driven to apply pressure to the liquid in the water delivery cylinder 331. In addition, by adjusting the force applied to the piston 332, the liquid pressure during the water delivery process and the saturation process can be easily adjusted, and the liquid can be kept at a preset pressure. Under the premise of preventing the excessive liquid pressure from causing unplanned damage to the thin plate sample 10, the saturation process is promoted. The first driving pressure only needs to be able to deliver the liquid to the saturation chamber 3111. The method of pushing the piston 332 may include a variety of appropriate implementations, such as using a mechanical structure to connect with the piston 332 and drive it, or by passing a fluid with a certain pressure into the pressurizing part 33112, thereby driving the movement of the piston 332. Preferably, an air pump 341 is selected. For a thin plate sample 10 with a perforation in the center, only one water delivery component 33 can be set, while for a thin plate sample 10 without a central perforation, two water delivery components 33 need to be set respectively corresponding to the two saturation cylinders 311 on both sides.

[0044] In addition, in order to monitor the pressure in the pressurizing section 33112 , a pressure gauge 334 may be provided in the pressurizing section 33112 .

[0045] In some embodiments, the pressurizing assembly 34 can also push the piston 332 with a second driving pressure until the thin plate sample 10 reaches a saturated state, and the second driving pressure is:

[0046]

[0047] Wherein, P2 is the second driving pressure, P1 is the first driving pressure, ρ w is the density of the liquid in the saturated cavity 3111, g is the acceleration due to gravity, V w is the volume of liquid required for the thin plate sample 10 in the saturated chamber 3111 to reach the saturated state, S is the cross-sectional area of ​​the piston; V w =knV s , k is the correction factor, the value range is 1.1-1.3, n is the porosity of the thin plate sample 10, V s is the volume of the thin plate sample 10 within the water-saturated cavity 3111.

[0048] In this embodiment, since the water in the rock mainly enters the pores of the rock during the saturation process, but due to human factors or differences in the properties of different samples themselves, it is necessary to correct the pore volume of the rock thin plate sample 10 within the range of the saturated heating component 32. Preferably, the correction coefficient k can be taken as 1.2.

[0049] n is the porosity of the thin plate sample 10, and the porosity n is usually measured by the saturation method. First, a standard-sized porosity sample is taken from the same parent rock as the rock thin plate sample 10. The size of the porosity sample can be set to 25mm×100mm×100mm, and then it is placed in a servo electric furnace and dried at a temperature of 105° for 24 hours. After drying, the dry mass m of the test sample is measured. d Next, put the test sample into a saturated bucket (a closed environment that can be filled with water), first evacuate the saturated bucket and the test sample for 24 hours to fully expel the air inside; then pass pure water to saturate it, and check the water level in the saturated bucket regularly. When the water level in the saturated bucket remains unchanged for a period of time (for example, the water level is consistently measured by multiple regular checks), it indicates that the test sample has been saturated with water. Take out the test sample and weigh the mass of the saturated test sample m s The saturation process generally lasts for 24 hours, and then the porosity of the rock thin plate sample 10 can be calculated according to the following formula:

[0050]

[0051] In the formula, m s is the mass of the test sample after saturation; m d is the mass of the test sample after drying; w is the density of water, which is numerically equal to 1g / cm 3 ; V r The volume of the test sample.

[0052] Since the internal pores of the rock thin plate sample 10 are actually filled with air under normal circumstances, if the saturation process is directly carried out, the air inside is difficult to be discharged, which will lead to the problem that the thin plate sample 10 is not fully saturated with water and the saturation time is too long. In order to solve this problem, Figure 1 as well as Figure 7 As shown, the thermal-hydraulic-mechanical coupling test equipment also includes a vacuum device 40, which includes a vacuum pump 41 and a first connecting pipe 42. The vacuum pump 41 is connected to the water-saturated chamber 3111 through the first connecting pipe 42. The vacuum pump 41 extracts the gas in the water-saturated chamber 3111 to reduce the pressure in the water-saturated chamber 3111 to a predetermined air pressure.

[0053] In this embodiment, by setting up the vacuum device 40, the air in the closed space enclosed by the saturation cylinder 311 and the thin plate sample 10 can be fully discharged before saturation with water, so that the liquid can more easily enter the pores of the rock, thereby making the rock thin plate sample 10 fully saturated with water, and the saturation time can be shortened to improve the experimental efficiency.

[0054] The vacuum pump 41 operates at rated power and for a preset time, and the preset time is:

[0055]

[0056] Where, t is the preset time; V a is the volume of the vacuum part in the saturated water chamber 3111; P3 is the initial pressure before the vacuum pump 41 is operated; P4 is the pressure value of the predetermined air pressure; Q is the volume of gas extracted by the vacuum pump 41 per unit time at rated power.

[0057] Specifically, for the thin plate sample 10 without a hole in the center for simulating a tunnel, V a =V1+V2, V1 is the sum of the volumes of the two saturated cavities 3111, and V2 is the pore volume of the thin plate sample 10 surrounded by the saturated cavities 3111; for the thin plate sample 10 with a hole in the center for simulating a tunnel, V a =V1+V2+V3, V3 is the volume of the hole at the center of the thin plate sample 10 used to simulate the tunnel.

[0058] In some embodiments, the predetermined pressure is 1×10 -4 Up to 1×10 -8 Torr.

[0059] In some embodiments, Figure 1 as well as Figure 8 As shown, the thermal-hydraulic-mechanical coupling test equipment further includes a water collecting cylinder 50 , in which a water collecting chamber 51 is provided, and the water collecting chamber 51 is connected to the top of the saturated water chamber 3111 .

[0060] When the saturated water cylinder 311 is filled with liquid, the liquid can flow from the top of the saturated water cylinder 311 into the water collecting chamber 51. Therefore, the setting of the water collecting chamber 50 can be used to detect whether the saturated water cylinder 311 is full of liquid. When liquid flows into the water collecting chamber 50, it can be considered that the saturated water chamber 3111 is full of liquid. At the same time, the water collecting chamber 50 is also used to collect and calculate the volume of liquid overflowing from the saturated water chamber 3111 during the stage of filling the saturated water chamber 3111. When liquid is observed to flow into the water collecting chamber 50, the connection between the saturated water cylinder 311 and the water collecting chamber 50 can be cut off.

[0061] During the experiment on the rock thin plate sample 10, it is necessary to calculate the liquid level in the saturated chamber 3111 to calculate the volume of the liquid entering the pores of the thin plate sample 10. However, the saturated chamber 3111 is closed and the liquid level is difficult to observe. As an implementation method, the volume of the liquid entering the pores of the thin plate sample 10 can be further calculated by observing the liquid level change of the water delivery cylinder 331 (for example, in the implementation method using the piston 332 as the pressure component, the position of the piston 332 can also be observed). When the volume value reaches V w At this time, the thin plate sample 10 can be considered to have reached the saturated state.

[0062] As an optional implementation, Figure 1 as well as Fig. 9 As shown, the heating assembly 32 includes a radiation heating layer 321, a temperature sensor 322, and a temperature controller 323 electrically connected to the radiation heating layer 321 and the temperature sensor 322, which are arranged on the side of the saturated chamber 3111 away from the thin plate sample 10; the radiation heating layer 321 can emit heat radiation toward the thin plate sample 10, the temperature sensor 322 is attached to the thin plate sample 10 and can detect the temperature of the thin plate sample 10, and the temperature controller 323 can display the temperature data detected by the temperature sensor 322 and adjust the power of the radiation heating layer 321 according to the temperature data.

[0063] Specifically, the radiation heating layer 321 can be a device capable of emitting electromagnetic waves, and can use light waves or microwaves to achieve the heating effect. For example, the radiation heating layer 321 can be a lamp capable of emitting infrared light waves; it can also be a device capable of emitting microwaves. Since there is a certain amount of water in the saturated thin plate sample 10, microwaves can be used in a manner similar to a microwave oven to make the water molecules in the thin plate sample 10 vibrate, thereby generating heat and achieving the purpose of heating. It is preferred to adopt an implementation method that can uniformly heat the thin plate sample 10 to avoid damage to it. The temperature sensor 322 can be set in the saturated water chamber 3111. In order to protect the temperature sensor 322 and facilitate its setting, it can also be selected to be set at a position where the thin plate sample 10 is close to the saturated water cylinder 311. The temperature controller 323 can be a computer, server, industrial computer, or other equipment with the ability to calculate and execute control programs.

[0064] like Figure 2 As shown, the coverage of the saturated cavity 3111 is actually smaller than the thin plate sample 10, and needs to be vertically fixed on both sides of the thin plate sample 10. If it is fixed by a support frame or other device, it is inevitably cumbersome, and the device is relatively large, which is not conducive to adjustment and transportation. Figure 2 as well as Fig.10As shown, mounting surfaces 12 inclined relative to the edge of the thin plate specimen 10 are respectively provided at the four corners of the thin plate specimen 10; the saturated water heating device 30 includes a plurality of fixing card assemblies 35, and the fixing card assemblies 35 are symmetrically arranged in pairs. The fixing card assemblies 35 include a U-shaped card 351 and a telescopic structure 352. The bottom of the U-shaped card 351 can abut against the mounting surface 12, and the two ends of the U-shaped card 351 are respectively provided with telescopic structures 352. The telescopic structure 352 can be telescoped along the extension direction of the end of the U-shaped card 351, and a connecting ring 3521 is provided at one end of the telescopic structure 352 away from the U-shaped card 351, and a connecting structure matching the connecting ring 3521 is provided on the side of the saturated water cylinder 311; the two symmetrically arranged fixing card assemblies 35 can shorten the length of the telescopic structure 352, thereby applying a force away from the center of the saturated water cylinder 311 along the radial direction of the saturated water cylinder 311.

[0065] In this embodiment, the U-shaped card 351 and the telescopic structure 352 can be integrally arranged or separately arranged, and the telescopic structure 352 can be a telescopic rod, a threaded rod, a spring or other structures. Preferably, the telescopic structure 352 includes internal threaded holes at both ends of the U-shaped card 351, and the telescopic structure 352 also includes a screw matched with the internal threaded hole. By adjusting the length of the matching part of the screw and the internal threaded hole, the length of the telescopic structure 352 can be adjusted. After the U-shaped card 351 is connected to the saturated water cylinder 311 through the connecting ring 3521 and the connecting structure, the length of each telescopic structure 352 can be adjusted by rotating the screw. On the one hand, the saturated water cylinder 311 can be accurately adjusted to the position corresponding to the geometric center of the thin plate sample 10. On the other hand, the adjusting screw can also adjust the force applied to the saturated water cylinder 311 so that it can be stably fixed at the geometric center of the thin plate sample 10.

[0066] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in actual applications, various changes may be made thereto in form and detail without departing from the scope of the present disclosure.

Claims

1. A thermal-hydraulic-mechanical coupling test equipment, characterized in that: The thermal-hydraulic-mechanical coupling test equipment comprises: Biaxial testing machine and saturated water heating device; The biaxial testing machine can clamp the two ends of a vertically arranged thin plate sample in the vertical direction and the horizontal direction respectively, and can apply a force toward the center of the thin plate sample to the thin plate sample; The saturated water heating device comprises a saturated water component and a heating component arranged in the saturated water component, wherein the saturated water component comprises a saturated water cylinder symmetrically arranged on both sides of the thin plate sample, wherein a saturated water cavity with an opening is arranged in the saturated water cylinder, wherein the opening is sealed and attached to both sides of the thin plate sample, wherein the saturated water cavity can be filled with liquid, and wherein a heating component for heating the thin plate sample is arranged in the saturated water cavity; The four corners of the thin plate sample are respectively provided with mounting surfaces inclined relative to the edge of the thin plate sample; The saturated water heating device comprises a plurality of fixed card assemblies, which are symmetrically arranged in pairs, and the fixed card assemblies comprise a U-shaped card and a telescopic structure, the bottom of the U-shaped card can abut against the mounting surface, and the two ends of the U-shaped card are respectively provided with telescopic structures, and the telescopic structures can be telescoped along the extension direction of the end of the U-shaped card, and a connecting ring is provided at one end of the telescopic structure away from the U-shaped card, and a connecting structure matching the connecting ring is provided at the side of the saturated water cylinder; The two symmetrically arranged fixing card assemblies can shorten the length of the telescopic structure, thereby applying a force away from the center of the saturated water cylinder to the saturated water cylinder along the radial direction of the saturated water cylinder.

2. A thermal-hydraulic-mechanical coupling test equipment according to claim 1, characterized in that: The saturated water heating device also includes a water delivery component, which includes a water delivery cylinder and a water delivery pipe. The water delivery cylinder includes a water delivery cavity for carrying liquid. A piston that moves along the length direction of the water delivery cavity is provided in the water delivery cavity. The water delivery cylinder is provided with a water outlet on one side along the length direction thereof. One end of the water delivery pipe is connected to the water delivery cavity through the water outlet, and the other end of the water delivery pipe is connected to the saturated water cavity. The piston can press the liquid in the water delivery cylinder into the saturated water cavity through the water delivery pipe.

3. A thermal-hydraulic-mechanical coupling test equipment according to claim 2, characterized in that: The piston can separate the water delivery chamber into a water delivery part and a pressurizing part. The water outlet is arranged in the water delivery part. The pressurizing part is connected with a pressurizing component. The pressurizing component can introduce pressurized gas into the pressurizing part to push the piston to move with a first driving pressure and fill the saturated water chamber with liquid. A water level detector for detecting the water level in the water delivery chamber is arranged on the side wall of the water delivery cylinder.

4. A thermal-hydraulic-mechanical coupling test equipment according to claim 3, characterized in that: The pressurizing assembly can also push the piston with a second driving pressure until the thin plate sample reaches a saturated state, and the second driving pressure is: Wherein, P2 is the second driving pressure, P1 is the first driving pressure, and ρ w is the density of the liquid in the saturated cavity, g is the acceleration due to gravity, V w is the volume of liquid required for the thin plate sample within the water-saturated chamber to reach a saturated state, and S is the cross-sectional area of ​​the piston; V w =knV s , k is the correction coefficient, the value range is 1.1-1.3, n is the porosity of the thin plate sample, V s is the volume of the thin plate sample within the water-saturated cavity.

5. The thermal-hydraulic-mechanical coupling test equipment according to claim 1, characterized in that: The thermal-hydraulic-mechanical coupling test equipment also includes a vacuum device, which includes a vacuum pump and a first connecting pipe. The vacuum pump is connected to the water-saturated chamber through the first connecting pipe. The vacuum pump extracts the gas in the water-saturated chamber to reduce the pressure in the water-saturated chamber to a predetermined air pressure.

6. A thermal-hydraulic-mechanical coupling test equipment according to claim 5, characterized in that: The vacuum pump operates at rated power and for a preset time, and the preset time is: Wherein, t is the preset time; V a is the volume of the vacuum part in the saturated water chamber; P3 is the initial pressure before the vacuum pump is operated; P4 is the pressure value of the predetermined air pressure; Q is the volume of gas extracted by the vacuum pump per unit time at rated power.

7. The thermal-hydraulic-mechanical coupling test equipment according to claim 6, characterized in that: The predetermined gas pressure is 1×10 -4 Up to 1×10 -8 Torr.

8. The thermal-hydraulic-mechanical coupling test equipment according to claim 1, characterized in that: The thermal-hydraulic-mechanical coupling test equipment further comprises a water collecting cylinder, in which a water collecting cavity is arranged, and the water collecting cavity is communicated with the top of the saturated water cavity.

9. The thermal-hydraulic-mechanical coupling test equipment according to claim 1, characterized in that: The heating assembly comprises a radiation heating layer disposed on a side of the saturated water chamber away from the thin plate sample, a temperature sensor, and a temperature controller electrically connected to the radiation heating layer and the temperature sensor; The radiation heating layer can emit heat radiation toward the thin plate sample, the temperature sensor is attached to the thin plate sample and can detect the temperature of the thin plate sample, the temperature controller can display the temperature data detected by the temperature sensor and adjust the power of the radiation heating layer according to the temperature data.

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