Soil coupling test device and test method for studying full-scale strength of soil

Abstract

Provided are a soil coupling test device and a test method for studying the full-scale strength of soil. The soil coupling test device comprises a soil test machine (1), a rail (2), a box (3) and an environment simulation assembly, wherein the soil test machine (1) comprises a test platform (10) and a loading assembly (20), and is configured to perform one or more of a tensile test, a compression-shear test and a tensile-shear test on a soil sample (40), so as to test the physical properties of the soil sample (40). The box (3) is movably arranged on the rail (2), and the box (3) is provided with a test cavity configured to accommodate the soil sample (40) and at least part of the loading assembly (20). When the test cavity is adjusted to a suitable temperature and humidity by means of the environment simulation assembly, the physical properties and mechanical laws of the soil sample (40) in different environments such as high temperature, heavy fog and rainy days can be simulated.

Description

Soil coupling test apparatus and test method for studying soil strength at all scales

[0001] This patent application claims priority to Chinese Patent Application No. CN202411749179.0, filed on December 2, 2024, entitled "Soil Coupling Test Apparatus and Test Method for Studying the Full-Scale Strength of Soil". The disclosure of the earlier application is incorporated herein by reference in its entirety. Technical Field

[0002] This application belongs to the field of soil coupling test technology, specifically relating to a soil coupling test device and a test method for studying the full-scale strength of soil. Background Technology

[0003] The failure of engineering soil is not only related to factors such as changes in groundwater levels, increased external loads, and earthquakes, but also closely related to its environmental conditions. For example, in hot weather, due to high ambient temperature and low relative humidity, moisture in the soil evaporates, leading to a decrease in water content. In cold weather, water in the soil freezes and expands. In foggy and rainy weather, the relative humidity of the air is high, and as the temperature drops, water in the air liquefies into droplets and enters the soil, increasing its water content. Under different environmental conditions, the properties of the soil change, and its corresponding mechanical properties also differ.

[0004] In existing technologies, tensile and shear coupling tests on soil are conducted in laboratory environments, which differ from the actual environment in which the soil exists. Therefore, the results of soil coupling tests conducted in the laboratory will deviate from actual conditions. Thus, studying the influence of different environmental conditions on the mechanical properties of soil is crucial for guiding engineering practice and improving engineering quality. Technical issues

[0005] This application provides a soil coupling test device and a test method for studying the full-scale strength of soil, aiming to solve the problem that the existing soil coupling tests are all carried out in a laboratory environment, and the test results deviate from the actual results. Technical solutions

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0007] In a first aspect, this application provides a soil coupling test apparatus, comprising:

[0008] A soil testing machine, including a test bench and a loading assembly disposed on the test bench;

[0009] The track is horizontally positioned on one side of the soil testing machine;

[0010] A housing, slidably mounted on the track, has a test chamber with an inlet / outlet on the side facing the soil testing machine, and a door movably connected to the inlet / outlet; the housing has a test position and an idle position; when in the test position, the loading component is at least partially housed within the test chamber; when in the idle position, the loading component is disengaged from the test chamber; and

[0011] An environmental simulation component includes a temperature control module and a humidity control module, which are respectively located in the chamber. The temperature control module is used to adjust the temperature of the test chamber, and the humidity control module is used to adjust the humidity of the test chamber.

[0012] In one possible implementation, the sidewall of the test chamber is provided with heat exchange holes, which are connected to air ducts. The output terminals of the temperature control module and the humidity control module are respectively connected to the air ducts.

[0013] In one possible implementation, the soil coupling test device further includes a reaction frame, which is disposed on the test bench and used to enclose a test area with the test bench surface. The test area is functionally divided into a tension-shear zone, a tensile zone, and a compression-shear zone. The loading component includes a first shear test mechanism disposed in the tension-shear zone, a tensile test mechanism disposed in the tensile zone, and a second shear test mechanism disposed in the compression-shear zone.

[0014] In one possible implementation, the reaction frame includes:

[0015] A top plate, located above the test bench; and

[0016] Two side plates are arranged opposite each other and are connected between the top plate and the test platform. The top plate, the side plates and the upper surface of the test platform together enclose the test area. The tensile shear area is arranged adjacent to one of the side plates and the compression shear area is arranged adjacent to the other side plate.

[0017] In one possible implementation, the first shear test mechanism includes:

[0018] The first slide rail is horizontally positioned on the test bench and located in the corresponding tension-shear zone;

[0019] The first soil-making device is slidably fitted onto the first slide rail;

[0020] A first shear loading unit is disposed on the reaction frame and has a first telescopic end capable of extending and retracting along the length direction of the first slide rail; the first telescopic end is provided with a first shear block; and

[0021] The first shear top block is disposed on the test platform. The first shear top block and the first shear block are disposed opposite each other on both sides of the first soil maker and are staggered in the vertical direction.

[0022] In one possible implementation, the first shear test mechanism, the tensile test mechanism, and the second shear test mechanism are arranged in a straight line. The reaction frame has an adjustment groove above the first shear test mechanism, the tensile test mechanism, and the second shear test mechanism. The loading assembly also includes a tension-compression loading mechanism slidably disposed in the adjustment groove. The tension-compression loading mechanism has a lifting end that can move vertically.

[0023] In one possible implementation, the first soil maker includes:

[0024] The first connecting block is slidably fitted onto the first slide rail;

[0025] A first constraint cylinder is disposed above the first connecting block and is detachably connected to the first connecting block;

[0026] A second constraint cylinder is disposed above the first constraint cylinder and is detachably connected to the first constraint cylinder; and

[0027] The second connecting block is located above the second constraint cylinder and is detachably connected to the second constraint cylinder. The upper part of the second connecting block is detachably connected to the lifting end. The first connecting block, the first constraint cylinder, the second constraint cylinder and the second connecting block together constitute the forming cavity of the soil sample. The radial cross-section of the forming cavity is circular, and the radial cross-section diameter of the forming cavity gradually shrinks from both ends to the middle.

[0028] In one possible implementation, a temperature monitoring element and a humidity monitoring element are provided on one side of the first connecting block forming the molding cavity and / or on one side of the second connecting block forming the molding cavity. The temperature monitoring element is used to monitor the temperature of the soil sample, and the humidity monitoring element is used to monitor the humidity of the soil sample.

[0029] In a second aspect, this application provides a test method for studying the full-scale strength of soil, employing the soil coupling test apparatus described in any of the above implementations, comprising the following steps:

[0030] Determine the required temperature and humidity for the experiment;

[0031] The prepared soil sample is fixed on the loading assembly, and the box is pushed to move it from the idle position to the test position, so that the soil sample is placed in the test chamber.

[0032] Close the cabinet door and set the temperature parameters of the temperature control module and the humidity parameters of the humidity control module according to the temperature and humidity requirements.

[0033] Wait until the temperature and humidity of the soil sample stabilize, then control the loading component to conduct a soil coupling test on the soil sample, and save the test results as images and data.

[0034] After the test, the temperature control module was adjusted to the cooling state to freeze the soil sample and preserve its damaged state.

[0035] In one possible implementation, multiple soil samples are provided, and a loading assembly is used to perform tensile tests, tensile-shear tests, and compression-shear tests on the multiple soil samples respectively. After the test, the strength envelope of the soil sample is plotted based on the test results. Beneficial effects

[0036] Compared with the prior art, the beneficial effects of the soil coupling test device provided in this application are:

[0037] The soil coupling testing device provided in this application includes a soil testing machine, a track, a housing, and an environmental simulation component. The soil testing machine includes a test bench and a loading component, used to perform one or more of tensile, compression-shear, and tension-shear tests on soil samples to test the soil's properties. The housing is movably mounted on the track and has a test chamber for accommodating the soil sample and at least partially accommodating the loading component. The environmental simulation component adjusts the sample chamber to suitable temperature and humidity, simulating the physical properties and mechanical laws of the soil sample under different environments such as high temperature, heavy fog, and rain, thus better guiding engineering practice.

[0038] In this application, the test chamber is designed to be movable, moving only to the test position during testing. Before testing, the soil sample can be placed inside the test chamber to gradually reach the required temperature and humidity. Then, the chamber is moved to the test position, and the soil sample is mounted on the loading assembly for testing. This design helps reduce the time the loading assembly spends inside the test chamber, thus preventing damage to components on the loading assembly from the temperature or humidity of the test chamber, and improving the service life of the loading assembly.

[0039] In this application, the temperature control module can regulate the temperature in the test chamber. After the test, the temperature control module can be used to cool the test chamber and freeze the soil sample to preserve its damaged state. This allows for further study of the soil's micro-deformation and microstructure using methods such as CT scanning, SEM scanning, XRD analysis, and transmission electron microscopy, facilitating subsequent research.

[0040] The test method for studying the full-scale strength of soil provided in this application is implemented using the soil coupling test device described in any of the above implementation methods, and has the same technical effect, which will not be repeated here. Attached Figure Description

[0041] Figure 1 is a schematic diagram of the soil coupling test device provided in one embodiment of this application;

[0042] Figure 2 is a partial enlarged view of part A in Figure 1;

[0043] Figure 3 is a schematic diagram of the soil testing machine in another embodiment of this application;

[0044] Figure 4 is a schematic diagram of the structure of the first soil-making device in another embodiment of this application;

[0045] Figure 5 is a schematic diagram of the structure of the second soil-making device in another embodiment of this application;

[0046] Figure 6 shows the strength envelope of soil plotted using the test method provided in this application for studying the full-scale strength of soil.

[0047] Explanation of reference numerals in the attached figures:

[0048] 1. Soil testing machine; 2. Track; 3. Box body; 4. Box door; 10. Test bench; 20. Loading assembly; 21. First shear testing mechanism; 211. First slide rail; 212. First soil mold; 2121. First connecting block; 2122. First constraint cylinder; 2123. Second constraint cylinder; 2124. Second connecting block; 2125. Temperature monitoring element; 2126. Humidity monitoring element; 213. First shear loading unit; 214. First shear top 22. Tensile testing mechanism; 23. Second shear testing mechanism; 231. Second slide rail; 232. Second soil mold; 2321. Third connecting block; 2322. Fourth connecting block; 2323. Third constraint cylinder; 2324. Fourth constraint cylinder; 2325. Fifth constraint cylinder; 233. Second shear loading unit; 234. Second shear top block; 24. Tension and compression loading mechanism; 30. Reaction frame; 31. Top plate; 32. Side plate; 40. Soil sample. Embodiments of the present invention

[0049] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0050] Please refer to Figures 1 to 6 together. The following describes the soil coupling test device and the test method for studying the full-scale strength of soil provided in the embodiments of this application.

[0051] Referring to Figure 1, in a first aspect, this application provides a soil coupling testing device, including a soil testing machine 1, a track 2, a housing 3, and an environmental simulation component. The soil testing machine 1 includes a test bench 10 and a loading component 20 disposed on the test bench 10; the track 2 is disposed horizontally on one side of the soil testing machine 1; the housing 3 is slidably disposed on the track 2, and the housing 3 has a test chamber, with an inlet and outlet on the side of the test chamber facing the soil testing machine 1, and a door 4 is movably connected to the inlet and outlet; the housing 3 has a test position and an idle position. When in the test position, the loading component 20 is housed in the test chamber, and when in the idle position, the loading component 20 is disengaged from the test chamber; the environmental simulation component includes a temperature control module and a humidity control module, which are respectively disposed in the housing 3. The temperature control module is used to adjust the temperature of the test chamber, and the humidity control module is used to adjust the humidity of the test chamber.

[0052] Compared with the prior art, the beneficial effects of the soil coupling test device provided in this application are:

[0053] The soil coupling testing device provided in this application includes a soil testing machine 1, a track 2, a housing 3, and an environmental simulation component. The soil testing machine 1 includes a test bench 10 and a loading component 20, used to perform one or more of tensile, compression-shear, and tension-shear tests on a soil sample 40, thereby testing the physical properties of the soil. The housing 3 is movably mounted on the track 2 and has a test chamber for accommodating the soil sample 40 and at least partially accommodating the loading component 20. The environmental simulation component adjusts the sample chamber to suitable temperature and humidity, simulating the physical characteristics and mechanical properties of the soil sample 40 under different environments such as high temperature, heavy fog, and rain, thus better guiding engineering practice and improving engineering quality.

[0054] In this embodiment, the housing 3 is designed to be movable, moving only to the test position during testing. Before testing, the soil sample 40 can be placed inside the test chamber to gradually reach the required temperature and humidity. Then, the housing 3 is moved to the test position, and the soil sample 40 is mounted on the loading assembly 20 for testing. This arrangement helps reduce the time the loading assembly 20 remains inside the test chamber, thereby preventing damage to components on the loading assembly 20 (such as force sensors and clamps) from the temperature or humidity of the test chamber, and improving the service life of the loading assembly 20.

[0055] In this embodiment, the temperature control module can regulate the temperature in the test chamber. After the test, the temperature control module can cool the test chamber to freeze the soil sample 40 and preserve its damaged state. This allows for further research on the microstructure and microdeformation of the soil using methods such as CT (Computed Tomography), SEM (Scanning Electron Microscope), XRD (X-ray Diffraction), and transmission electron microscopy, facilitating subsequent research.

[0056] The soil testing machine 1 is a multi-functional soil testing device. Different models and specifications of testing equipment can be selected as needed to perform tests such as tensile tests, tensile-shear tests, and compression-shear tests on soil samples 40. The soil testing machine 1 includes a test bench 10 and a loading assembly 20. The loading assembly 20 is mounted on the test bench 10 and can specifically include a tensile loading mechanism, a compression-shear loading mechanism, and a tensile-shear loading mechanism. The loading assembly 20 can include all three loading mechanisms simultaneously, or only one or two loading mechanisms. Different loading forms can be achieved by changing components or selectively using components; there are no specific limitations on this. For example, the loading assembly 20 shown in Figure 1 can perform tensile tests, tensile-shear tests, and compression-shear tests. However, it should be noted that this structure has only one soil mold, therefore, only a single test can be performed at a time. As another example, the loading assembly 20 shown in Figure 3 can also perform tensile tests, tensile-shear tests, and compression-shear tests. However, it should be noted that this structure has three soil molds, therefore, tests can be performed sequentially.

[0057] Track 2 is positioned on one side of the test bench 10. Track 2 is horizontal and can be circular, square, or other shaped guide rails, as long as it allows the housing 3 to move smoothly. The housing 3 is movably mounted on track 2 and can be driven manually or by hydraulic push rods or other driving components. The housing 3 has a test cavity for accommodating the soil sample 40 and the loading assembly 20. When the loading assembly 20 is only partially accommodated in the test cavity as shown in Figure 1, clearance holes or clearance grooves should be provided on the side wall of the test cavity to allow corresponding parts of the loading assembly 20 to pass through.

[0058] The door 4 is located at the entrance / exit. The door 4 can be installed and fixed to the housing 3 using methods such as screw connection, plug-in connection, or hinge rotation connection. To facilitate operator observation of the interior, an observation window with a transparent glass panel can be provided on the door 4.

[0059] Understandably, before conducting the test, the soil sample 40 needs to be placed in the test chamber for a period of time to allow the temperature, humidity, and other parameters of the soil sample 40 to meet the environmental simulation requirements. Optionally, the soil sample 40 can be first installed on the loading component 20, and then the box 3 can be moved to the test position. At this time, both the soil sample 40 and the loading component 20 are in the temperature and humidity environment simulated by the test chamber. Alternatively, the soil sample 40 can also be placed in the test chamber first, and after the temperature and humidity of the soil sample 40 meet the requirements, the box 3 can be moved to the test position, and the soil sample 40 can be installed on the loading component 20 for coupling testing. In this method, the loading component 20 stays in the test chamber for a shorter time, and the related components are less affected by factors such as temperature and humidity.

[0060] The environmental simulation components include a temperature control module and a humidity control module. The temperature control module specifically includes a refrigeration unit and a heating unit, while the humidity control module includes a humidifier. The refrigeration unit can use a compressor, and the heating unit can be a heat pump or an electric heater. Airflow is achieved through a circulating fan and air inlets / outlets within the test chamber, ensuring uniform temperature and humidity. The humidifier is equipped with a water tank and a water level indicator; operators should promptly add water to the tank when the humidifier is low on water.

[0061] The environmental simulation components can be controlled via an LCD touchscreen display. The humidity adjustment range is 15% to 95%RH (Relative Humidity), and the temperature adjustment range is -30℃ to 60℃.

[0062] Please refer to Figure 1. In some possible embodiments, the housing 3 also includes an equipment housing cavity. The temperature control module and the humidity control module are respectively located in the equipment housing cavity. The side wall of the test cavity is provided with heat exchange holes, which are connected to air ducts. The air inlet of the air duct is located in the equipment housing cavity. The output ends of the temperature control module and the humidity control module are respectively connected to the air ducts. A circulating fan is provided in the air ducts. After the airflow is mixed in the air ducts, it enters the test cavity through the heat exchange holes.

[0063] Referring to Figures 1 and 3, in some possible embodiments, the soil coupling test apparatus further includes a reaction frame 30, which is disposed on the test bench 10 and used to enclose the test area with the test bench 10 to form a test area. The test area is functionally divided into a tension-shear zone, a tensile zone, and a compression-shear zone. The loading assembly 20 includes a first shear testing mechanism 21 disposed in the tension-shear zone, a tensile testing mechanism 22 disposed in the tensile zone, and a second shear testing mechanism 23 disposed in the compression-shear zone. As shown in Figure 3, the first shear testing mechanism 21, the tensile testing mechanism 22, and the second shear testing mechanism 23 can share a single translational tension-compression loading mechanism 24, or they can each be configured with a separate tension-compression loading mechanism 24; there is no limitation on this.

[0064] In this embodiment, the test area is functionally divided into a tensile-shear zone, a tension zone, and a compression-shear zone, which are used to conduct tensile-shear, tension, and compression-shear tests on the soil sample 40, respectively. This allows for uniaxial tensile, tension-shear, and compression-shear mechanical property experiments on the soil sample 40. Specifically, during uniaxial tensile and tension-shear tests, the soil sample 40 is shaped with wider ends and a narrower middle section. Its radial cross-section is circular, while the middle section is cylindrical. The overall height of the soil sample 40 is 120 mm, with the middle cylindrical section being 20 mm high and 39 mm in diameter. Since the soil sample 40 is not subjected to tensile force during the compression-shear test, the soil sample for compression-shear can be designed with the same dimensions as the aforementioned middle cylindrical section, i.e., a cylinder with a height of 20 mm and a diameter of 39 mm.

[0065] The three tests described above—tensile, tensile-shear, and compression-shear—can be performed simultaneously or sequentially. Since the middle section of the soil sample 40 used in these three tests has the same shape and size, the loading assembly 20 can achieve experimental measurement of the complete strength envelope of the soil, as shown in Figure 6, providing a theoretical basis for engineering practice. The loading assembly 20 can be driven by a servo motor controlled by a controller, offering high control precision, good stability, and saving time and effort. It is also equipped with data recording and processing software, enabling real-time data recording and processing.

[0066] It should be noted that when conducting tensile and tensile-shear tests, the soil specimen 40 is shaped to be thicker at both ends and thinner in the middle. The purpose is to partially accommodate both ends of the soil specimen 40 in the upper and lower clamps, so that the tensile state of the soil specimen 40 can be realistically simulated during tensile testing, thereby ensuring the accuracy of the test results.

[0067] Referring to Figures 1 and 3, in some possible embodiments, the reaction frame 30 includes a top plate 31 and two side plates 32. The top plate 31 is located above the test bench 10, and the two side plates 32 are arranged opposite to each other. The side plates 32 are connected between the top plate 31 and the test bench 10. The top plate 31, the side plates 32 and the upper surface of the test bench 10 together enclose a test area. The tensile shear zone is located adjacent to one of the side plates 32, the compressive shear zone is located adjacent to the other side plate 32, and the tension zone is located between the tensile shear zone and the compressive shear zone.

[0068] Referring to Figures 3 and 4, in some possible embodiments, the first shear testing mechanism 21 includes a first slide rail 211, a first soil mold 212, a first shear loading unit 213, and a first shear top block 214. The first slide rail 211 is arranged horizontally on the test bench 10 and located in the corresponding tension-shear zone. The first soil mold 212 is used to make soil samples 40 and is slidably fitted to the first slide rail 211. The first shear loading unit 213 is arranged on the reaction frame 30 and has a first telescopic end that can extend and retract along the length direction of the first slide rail 211. The first telescopic end is provided with a first shear block. The first shear top block 214 is arranged on the test bench 10 and is arranged opposite to the first shear block on both sides of the first soil mold 212 and is offset from each other in the vertical direction.

[0069] In this embodiment, the first shear testing mechanism 21 includes a first slide rail 211, a first soil-making device 212, a first shear loading unit 213, and a first shear top block 214. The first shear loading unit 213 and the first shear top block 214 are arranged opposite to the first soil-making device 212 and can move along their respective length directions to apply shear force to the soil sample 40. The movement of the first shear loading unit 213 and the first shear top block 214 can be automatically controlled by power equipment such as servo motors and hydraulic cylinders, or manually adjusted by structures such as lead screws and handwheels. A pressure sensor is provided between the first telescopic end and the first shear block to measure the pressure applied by the first shear block to the soil sample 40.

[0070] The first soil preparation device 212 is used to prepare a soil sample 40 of a specific shape. The lower end of the first soil preparation device 212 is slidably mounted on the first slide rail 211, and the upper end of the first soil preparation device 212 is used to connect with the tension and compression loading mechanism 24. The tension and compression loading mechanism 24 can be driven by a servo motor or hydraulic cylinder, etc., and contains a displacement sensor and a tension sensor to apply a tension or compression force to the soil sample 40 in the vertical direction.

[0071] It should be noted that the first soil-making device 212 has a soil-making state and a testing state. When in the soil-making state, it can form a closed molding cavity to form a soil sample 40 of a specific shape. When testing is required, the arc-shaped plate or sleeve used to enclose the molding cavity of the first soil-making device 212 can be removed as needed, putting the first soil-making device 212 into the testing state. During the test, a shear ring is added to the outer periphery of the soil sample 40, and the first shear loading unit 213 applies shear force to the soil sample 40 through the shear ring. Of course, if the arc-shaped plate does not affect the normal test, it can also be left in place; the operator can choose according to the actual situation.

[0072] Referring to Figure 3, in some possible embodiments, the first shear test mechanism 21, the tensile test mechanism 22, and the second shear test mechanism 23 are arranged in a straight line. The reaction frame 30 has an adjustment groove above the first shear test mechanism 21, the tensile test mechanism 22, and the second shear test mechanism 23. The loading assembly 20 also includes a tension / compression loading mechanism 24 slidably disposed in the adjustment groove. The tension / compression loading mechanism 24 has a lifting end capable of vertical movement. In this embodiment, the first shear test mechanism 21, the tensile test mechanism 22, and the second shear test mechanism 23 share a single tension / compression loading mechanism 24.

[0073] In this embodiment, the tension-compression loading mechanism 24 can move along the adjustment groove, thereby switching between the tension-shear zone, the tensile zone, and the compression-shear zone, and can perform tension-shear tests, tensile tests, and compression-shear tests respectively. On the one hand, it simplifies the device structure and saves the device manufacturing cost. On the other hand, using the same tension-compression loading mechanism 24 to perform three tests can eliminate test errors caused by different instruments, which helps to improve the test accuracy and the accuracy of the results.

[0074] Referring to Figures 3 and 4, in some possible embodiments, the first soil mold 212 includes a first connecting block 2121, a first constraint cylinder 2122, a second constraint cylinder 2123, and a second connecting block 2124. The first connecting block 2121 is slidably fitted to the first slide rail 211; the first constraint cylinder 2122 is disposed above the first connecting block 2121 and is detachably connected to the first connecting block 2121; the second constraint cylinder 2123 is disposed above the first constraint cylinder 2122 and is detachably connected to the first constraint cylinder 2122; the second connecting block 2124 is disposed above the second constraint cylinder 2123 and is detachably connected to the second constraint cylinder 2123. The upper part of the second connecting block 2124 is detachably connected to the lifting end of the tension-compression loading mechanism 24. The first connecting block 2121, the first constraint cylinder 2122, the second constraint cylinder 2123, and the second connecting block 2124 together constitute the forming cavity of the soil sample 40. The radial cross-section of the forming cavity is circular, and the radial cross-section diameter of the forming cavity gradually shrinks from both ends to the middle.

[0075] In this embodiment, the first soil-making device 212 can also be used to prepare the soil sample 40 for tensile testing. The tension-compression loading mechanism 24 is connected to the top of the first soil-making device 212 (i.e., the second connecting block 2124) and can apply a certain tension to it for tensile or shear testing. It is understood that when the first slide rail 211 and the first shear loading unit 213 in the first shear testing mechanism 21 are not functioning, the first soil-making device 212 and the tension-compression loading mechanism 24 can be used for tensile testing. Of course, considering that the first slide rail 211 may cause instability, the tensile testing mechanism 22, which is in the middle position, is usually used for tensile testing. This tensile testing mechanism 22 includes a soil-making device with the same structure as the first soil-making device 212, and this soil-making device is immovable. Of course, when the tension-compression loading mechanism 24 is not functioning, the first slide rail 211, the first shear loading unit 213, and the first shear top block 214 can also be used for shear testing.

[0076] In this embodiment, the first connecting block 2121 and the first constraint cylinder 2122, and the second constraint cylinder 2123 and the second connecting block 2124, can be connected by threads. The first constraint cylinder 2122 and the second constraint cylinder 2123 are arranged opposite to each other and are detachably connected between their mating surfaces by screws. During testing, the screws between the first constraint cylinder 2122 and the second constraint cylinder 2123 are removed. The first constraint cylinder 2122 and the second constraint cylinder 2123 can be a single cylindrical body or an assembly formed by multiple arc-shaped plates, with adjacent arc-shaped plates being detachably connected by snap-fit, screw connection, etc. When the soil sample 40 is prepared and installed on the loading assembly 20, the first constraint cylinder 2122 and the second constraint cylinder 2123 can be removed, and then a shear ring can be added to the outer periphery of the soil sample 40. Of course, the first constraint cylinder 2122 and the second constraint cylinder 2123 may not be removed if it does not affect the normal test.

[0077] As shown in Figure 4, the first constraint cylinder 2122 and the second constraint cylinder 2123 have the same structure. The structure of the first constraint cylinder 2122 is described in detail below: Specifically, the first constraint cylinder 2122 includes a first forming inner cavity and a second forming inner cavity. The first forming inner cavity and the second forming inner cavity are connected to each other and extend through the first constraint cylinder 2122 axially. The first forming inner cavity is a conical inner cavity. The large-diameter end of the first forming inner cavity is connected to the first connecting block 2121, and the small-diameter end of the first forming inner cavity is connected to the second forming inner cavity. The second forming inner cavity is a cylindrical inner cavity with an inner diameter of 39 mm and a height of 10 mm.

[0078] During the tensile-shear test, the soil sample 40 is fixed on the first slide rail 211 below, which can effectively reduce friction and make the first shear block and the first shear top block 214 fit tightly against the soil sample 40. The first connecting block 2121 is set on the slider, and the slider slides in cooperation with the first slide rail 211, so that the slider and the soil sample 40 can move synchronously when sheared.

[0079] Please refer to Figure 4. In some possible embodiments, a temperature monitoring element 2125 and a humidity monitoring element 2126 are provided on one side of the molding cavity formed by the first connecting block 2121 and / or the other side of the molding cavity formed by the second connecting block 2124. The temperature monitoring element 2125 is used to monitor the temperature of the soil sample 40, and the humidity monitoring element 2126 is used to monitor the humidity of the soil sample 40.

[0080] In this embodiment, by installing a temperature monitoring element 2125 and a humidity monitoring element 2126 on at least one of the first connecting block 2121 or the second connecting block 2124, it is possible to monitor in real time whether the temperature and humidity of the soil sample 40 are consistent with the ambient temperature and humidity inside the test chamber, and whether the temperature and humidity state of the soil sample 40 has remained stable. When the state of the soil sample 40 is stable, the corresponding coupling test can be carried out, making the operation more convenient.

[0081] Referring to Figures 3 and 5, in some possible embodiments, the structure and working principle of the second shear testing mechanism 23 are similar to those of the first shear testing mechanism 21. Specifically, the second shear mechanism includes a second slide rail 231, a second soil-making device 232, a second shear loading unit 233, and a second shear top block 234. The second shear loading unit 233 and the second shear top block 234 are arranged opposite to the soil sample 40. The second soil-making device 232 is used to prepare the soil sample 40. Specifically, the second soil-making device 232 includes a third connecting block 2321, a fourth connecting block 2322, a third constraint cylinder 2323, a fourth constraint cylinder 2324, and a fifth constraint cylinder 2325, forming a cylindrical forming cavity to prepare the soil sample 40. The tension / compression loading mechanism 24 is connected to either the third connecting block 2321 or the fourth connecting block 2322; that is, the second soil-making device 232 can be reversed to apply a certain pressure for compression-shear testing. Similar to the first shear testing mechanism 21, tensile and shear tests can also be performed independently.

[0082] In a second aspect, embodiments of this application also provide a test method for studying the full-scale strength of soil, implemented using the soil coupling test device provided in any of the above embodiments, comprising the following steps: determining the required temperature and humidity for the test; fixing the prepared soil sample 40 on the loading component 20, pushing the chamber 3 to move it from an idle position to the test position, so that the soil sample 40 is placed inside the test chamber; closing the chamber door 4, setting the temperature parameters of the temperature control module and the humidity parameters of the humidity control module according to the temperature and humidity requirements; waiting until the temperature and humidity of the soil sample 40 tend to stabilize, controlling the loading component 20 to perform a soil coupling test on the soil sample 40, and saving the test results as images and data; after the test, adjusting the temperature control module to a cooling state to freeze the soil sample 40 and preserve its failure state.

[0083] In some possible embodiments, multiple soil samples 40 are provided, and the loading assembly 20 is used to perform tensile tests, tensile-shear tests and compression-shear tests on the multiple soil samples 40 respectively. After the test, the strength envelope of the soil sample 40 is plotted based on the test results.

[0084] The test method for studying the full-scale strength of soil provided in this application can perform tensile-shear, tensile, and compressive-shear tests on soil specimen 40. The uniaxial tensile and tensile-shear specimens of soil 40 are both of a thicker shape at both ends and thinner in the middle, with a height of 120 mm and a cylindrical middle section of 20 mm in height and 39 mm in diameter. The compressive-shear soil specimen 40 is a cylinder with a height of 20 mm and a diameter of 39 mm. This ensures that tensile force is applied to the soil specimen 40 during uniaxial tensile and tensile-shear tests, and that the normal stress is better transferred to the shear surface during compressive-shear tests. It also ensures the uniformity of the size and shape of the soil specimen 40 near the failure surface, thereby accurately measuring the complete strength envelope of the soil.

[0085] The loading component 20 can use a servo motor for loading, which has high loading accuracy and can achieve various test force application methods such as constant stress, constant displacement, constant deformation, and load holding. It can also set certain cyclic steps as needed, and can achieve shock-free switching between multiple control modes to realize fully automatic closed-loop control.

[0086] The loading component 20 is controlled by a controller, which can have built-in measurement and control software that can measure and display various signals such as test force, peak value, displacement, and deformation in real time. It can also realize real-time screen display of various experimental curves such as stress-strain and stress-displacement.

[0087] It is understood that the parts in the above embodiments can be freely combined or deleted to form different combined embodiments. The specific contents of each combined embodiment will not be repeated here. After this description, it can be considered that the present application specification has recorded each combined embodiment and can support different combined embodiments.

[0088] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A soil coupling test device, characterized in that, include: A soil testing machine, including a test bench and a loading assembly disposed on the test bench; The track is horizontally positioned on one side of the soil testing machine; A housing, slidably mounted on the track, has a test chamber with an inlet / outlet on the side facing the soil testing machine, and a door movably connected to the inlet / outlet; the housing has a test position and an idle position; when in the test position, the loading component is at least partially housed within the test chamber; when in the idle position, the loading component is disengaged from the test chamber; and An environmental simulation component includes a temperature control module and a humidity control module, which are respectively located in the chamber. The temperature control module is used to adjust the temperature of the test chamber, and the humidity control module is used to adjust the humidity of the test chamber.

2. The soil coupling test device according to claim 1, characterized in that, The test chamber has heat exchange holes on its side wall, which are connected to air ducts. The output terminals of the temperature control module and the humidity control module are respectively connected to the air ducts.

3. The soil coupling test device according to claim 1, characterized in that, The soil coupling test device also includes a reaction frame, which is disposed on the test bench and is used to enclose the test area with the test bench surface to form a test area. The test area is functionally divided into a tension-shear zone, a tensile zone, and a compression-shear zone. The loading component includes a first shear test mechanism disposed in the tension-shear zone, a tensile test mechanism disposed in the tensile zone, and a second shear test mechanism disposed in the compression-shear zone.

4. The soil coupling test device according to claim 3, characterized in that, The reaction frame includes: A top plate, located above the test bench; and Two side plates are arranged opposite each other and are connected between the top plate and the test platform. The top plate, the side plates and the upper surface of the test platform together enclose the test area. The tensile shear area is arranged adjacent to one of the side plates and the compression shear area is arranged adjacent to the other side plate.

5. The soil coupling test device according to claim 3, characterized in that, The first shear test mechanism includes: The first slide rail is horizontally positioned on the test bench and located in the corresponding tension-shear zone; The first soil-making device is slidably fitted onto the first slide rail; A first shear loading unit is disposed on the reaction frame and has a first telescopic end capable of extending and retracting along the length direction of the first slide rail; the first telescopic end is provided with a first shear block; and The first shear top block is disposed on the test platform. The first shear top block and the first shear block are disposed opposite each other on both sides of the first soil maker and are staggered in the vertical direction.

6. The soil coupling test device according to claim 5, characterized in that, The first shear test mechanism, the tensile test mechanism, and the second shear test mechanism are arranged in a straight line. The reaction frame has an adjustment groove above the first shear test mechanism, the tensile test mechanism, and the second shear test mechanism. The loading assembly also includes a tension-compression loading mechanism that is slidably disposed in the adjustment groove. The tension-compression loading mechanism has a lifting end that can move vertically.

7. The soil coupling test apparatus according to claim 6, characterized in that, The first soil-making device includes: The first connecting block is slidably fitted onto the first slide rail; A first constraint cylinder is disposed above the first connecting block and is detachably connected to the first connecting block; A second constraint cylinder is disposed above the first constraint cylinder and is detachably connected to the first constraint cylinder; and The second connecting block is located above the second constraint cylinder and is detachably connected to the second constraint cylinder. The upper part of the second connecting block is detachably connected to the lifting end. The first connecting block, the first constraint cylinder, the second constraint cylinder and the second connecting block together constitute the forming cavity of the soil sample. The radial cross-section of the forming cavity is circular, and the radial cross-section diameter of the forming cavity gradually shrinks from both ends to the middle.

8. The soil coupling test apparatus according to claim 7, characterized in that, A temperature monitoring element and a humidity monitoring element are provided on one side of the first connecting block forming the molding cavity and / or on one side of the second connecting block forming the molding cavity. The temperature monitoring element is used to monitor the temperature of the soil sample, and the humidity monitoring element is used to monitor the humidity of the soil sample.

9. A test method for studying the full-scale strength of soil, characterized in that, The soil coupling test apparatus according to any one of claims 1-8 includes the following steps: Determine the required temperature and humidity for the experiment; The prepared soil sample is fixed on the loading assembly, and the box is pushed to move it from the idle position to the test position, so that the soil sample is placed in the test chamber. Close the cabinet door and set the temperature parameters of the temperature control module and the humidity parameters of the humidity control module according to the temperature and humidity requirements. Wait until the temperature and humidity of the soil sample stabilize, then control the loading component to conduct a soil coupling test on the soil sample, and save the test results as images and data. After the test, the temperature control module was adjusted to the cooling state to freeze the soil sample and preserve its damaged state.

10. The test method for studying the full-scale strength of soil according to claim 9, characterized in that, The soil sample is provided in multiple ways. The loading component is used to perform tensile tests, tensile-shear tests and compression-shear tests on the multiple soil samples respectively. After the test, the strength envelope of the soil sample is drawn according to the test results.

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