A device and method for simulating the expansion and contraction deformation of expansive soil during wet-dry cycles.

Abstract

The application relates to a device and a method for simulating the expansion and shrinkage deformation of an expansive soil in a dry-wet cycle process. The device comprises a soil sample dry-wet cycle device for containing a soil sample to be detected; a water supply pressure device arranged at the periphery of the soil sample dry-wet cycle device and used for giving a certain pressure to the soil sample in the soil sample dry-wet cycle device, controlling the expansion and shrinkage of the soil sample dry-wet cycle device along with the time deformation of the soil sample; a water supply and air supply device arranged at the periphery of the soil sample dry-wet cycle device and used for rapidly and sufficiently saturating and drying the soil sample in the soil sample dry-wet cycle device; and a weighing device arranged at the bottom of the soil sample dry-wet cycle device to bear the soil sample dry-wet cycle device and used for weighing the mass change of the overlying device. The application can realize the adjustment of the soil sample dry-wet cycle device along with the shrinkage and expansion deformation of the soil sample in the dry-wet cycle process of the expansive soil, and more accurately simulate the dynamic change process of the expansive soil under the dry-wet condition.

Description

Technical Field

[0001] This invention relates to the field of soil property testing equipment, specifically to a device and method for simulating the expansion and contraction deformation of expansive soil during wet-dry cycles. Background Technology

[0002] Expansive soil, also known as "swelling-shrinking soil," is a type of clayey soil that expands dramatically in volume when soaked in water and shrinks significantly in volume when dehydrated. Due to its high content of clay minerals such as montmorillonite and illite, it is highly hydrophilic. When the natural moisture content is high, the amount and force of expansion after soaking are relatively small, while the amount and force of shrinkage after dehydration are very large. A higher natural void ratio results in smaller expansion and expansion force, and larger shrinkage and shrinkage force.

[0003] Expansive soils often exhibit undesirable engineering characteristics such as multi-fissure and repeated expansion and contraction, leading to severe deterioration of their mechanical properties and triggering geological disasters such as slope instability. In particular, the structure and physical and mechanical properties of expansive soil slopes undergo significant changes under atmospheric forces (such as rainfall and evaporation). During dry seasons, large amounts of water evaporate, creating intricate drying and shrinkage fissures on the slope surface, damaging the slope's integrity and stability. After a period of rainfall, rainwater rapidly enters the slope through these fissures, further reducing the soil's strength. This cycle repeats, causing soil damage and weakening its strength, ultimately inducing landslides, collapses, and other disasters.

[0004] The development of fissures in expansive soil has a significant impact on its mechanical properties, and observing and measuring the development and evolution of fissures in expansive soil is a crucial step. Previous studies on fissure development in expansive soil under wet-dry cycles have all involved providing a fixed lateral confinement to the soil. The soil-containing device does not change with the expansion and contraction of the soil, leading to excessive fissure development after multiple wet-dry cycles. This approach fails to consider the expansion and closure process of fissures under repeated expansion and contraction conditions consistent with actual engineering boundary conditions, thus affecting the experimental study of the physical and mechanical properties of expansive soil. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the main objective of the present invention is to provide a device for simulating the expansion and contraction deformation of expansive soil during the wet-dry cycle, so as to solve the technical problem that the prior art cannot simulate the expansion and contraction process of expansive soil during the wet-dry cycle.

[0006] The technical solution of the present invention is as follows:

[0007] A device for simulating the expansion and contraction deformation of expansive soil during wet-dry cycles, comprising:

[0008] Soil sample dry-wet circulation device, used to hold soil samples to be tested;

[0009] A water supply pressure device is installed around the soil sample drying and wetting circulation device to apply a certain pressure to the soil sample in the soil sample drying and wetting circulation device and control the soil sample drying and wetting circulation device to deform in time with the expansion and contraction of the soil sample.

[0010] A water supply and air supply device is installed around the soil sample drying and wetting circulation device to quickly and fully saturate and dry the soil sample inside the soil sample drying and wetting circulation device.

[0011] A weighing device is installed at the bottom of the soil sample drying and wetting cycle device to support the soil sample drying and wetting cycle device, and is used to weigh the mass change of the overlying device.

[0012] Preferably, the soil sample wet-dry cycle device includes:

[0013] The base plate has water and air permeable holes in the middle.

[0014] A sliding rail is mounted on the base plate;

[0015] The sliding sidewalls are provided in multiple pieces, arranged in an enclosing shape on the base plate;

[0016] A pulley is installed at the bottom of the slidable sidewall, and the pulley is adapted to the sliding track to drive the slidable sidewall to slide along the sliding track;

[0017] An elastic stretchable membrane is disposed at the corner of two adjacent sliding sidewalls to connect the two adjacent sliding sidewalls.

[0018] Preferably, the sliding sidewall is made of acrylic sheet.

[0019] Preferably, the water supply pressure device includes:

[0020] A water storage tank with multiple drainage holes;

[0021] A water inlet pipe, with one end of each of the multiple water inlet pipes connected to one of the aforementioned drain holes;

[0022] A peristaltic pump, with each of the plurality of peristaltic pumps respectively installed on one of the water inlet pipes;

[0023] Movable pistons, each of a plurality of movable pistons being connected to the other end of one of the water inlet pipes; and

[0024] The movable piston is connected to the sliding sidewall of the soil sample drying and wetting circulation device, and is used to apply a certain pressure to the soil sample in the soil sample drying and wetting circulation device, so as to control the timely deformation of the soil sample drying and wetting circulation device as the soil sample expands and contracts.

[0025] Preferably, the water storage tank is a graduated water tank.

[0026] Preferably, the water supply and air supply device includes:

[0027] The leaching device is used to supply water to the soil sample in the soil sample wet-dry cycle device to achieve rapid and full saturation of the soil sample.

[0028] A recording device for real-time recording of surface crack development in soil samples;

[0029] An air supply device is used to dry soil samples after water supply, thereby accelerating the drying process of the soil samples.

[0030] Preferably, the water supply and air supply device further includes a bracket, on which the filtration device, imaging device and air supply device are all mounted and positioned directly above the soil sample wet-dry circulation device via the bracket.

[0031] Preferably, the filtration device includes a filter head, a water supply pipe, and a switch, wherein the filter head is connected to the water supply pipe, and the switch is coupled to the water supply pipe to control the water supply pipe to supply water to the filter head.

[0032] Preferably, the air supply device includes at least one fan, which is installed directly above the soil sample wet-dry circulation device.

[0033] A method for conducting tests using the aforementioned device for simulating the expansion and contraction deformation of expansive soil during wet-dry cycles includes the following steps:

[0034] S01: Prepare soil samples with a certain moisture content and density, compact them in layers, and fill them into a soil sample wet-dry cycle device;

[0035] S02: Perform one wet-dry cycle on the soil sample, specifically including:

[0036] S021: Turn on the peristaltic pump switch to allow the water flow to push the movable piston and apply a certain pressure to the soil sample wet-dry circulation device;

[0037] S022: Open the leaching device to start the first saturation of the soil sample, use the imaging device to record the development of surface cracks of the soil sample in real time, and transmit the data to the computer. Analyze the data using graphic processing software, and close the leaching device when the preset moisture content is reached by the weighing device.

[0038] S023: Turn on the air supply device to begin the first drying of the soil sample. Use the imaging device to record the development of surface cracks in the soil sample in real time, and transmit the data to the computer. Use the graphics processing software to analyze the data again. Use the weighing device to calculate again that the preset moisture content of the test is reached and then turn off the air supply device.

[0039] S03: Repeat step S02 according to the preset number of wet-dry cycles to complete multiple wet-dry cycle tests on the expansive soil sample.

[0040] The advantages of this invention over the prior art are:

[0041] This invention proposes a device to simulate the expansion and contraction deformation of expansive soil during wet-dry cycles. By using a soil sample wet-dry cycle device, a water supply pressure device, a water supply and air supply device, and a weighing device, the device simulates the repeated cycles of expansive soil under atmospheric forces such as rainfall and evaporation. This avoids excessive development of cracks in the soil after multiple wet-dry cycles and accurately obtains the development of cracks and the physical and mechanical properties of the expansive soil, which can provide a certain reference for the treatment of expansive soil slopes.

[0042] This invention provides a certain pressure to the soil sample in the soil sample drying and wetting cycle device through a water supply pressure device, allowing the device to deform in time with the expansion and contraction of the soil. This enables the adjustment of the outer wall of the device to expand and contract with the soil during the drying and wetting cycle of the expansive soil sample, ensuring the expansion and closure of cracks under repeated expansion and contraction conditions consistent with the actual engineering boundary adjustment, and ensuring the conduct of experiments on the physical and mechanical properties of expansive soil.

[0043] This invention uses a water supply and air supply device to supply water to the soil sample in the soil sample wet-dry cycle device to simulate the rainfall conditions of expansive soil in nature, and uses an air supply device to dry the soil sample in the soil sample wet-dry cycle device to simulate the evaporation conditions of expansive soil in nature, so as to more accurately simulate the dynamic change process of expansive soil under wet and dry conditions.

[0044] The weighing device of the present invention can weigh and record the total mass of soil samples after saturation and drying in a timely manner, so as to facilitate the calculation of the moisture content of the soil samples.

[0045] It should be understood that the implementation of any embodiment of the present invention does not mean that it will simultaneously possess or achieve multiple or all of the above-mentioned beneficial effects. Attached Figure Description

[0046] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0047] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0048] Figure 1 This is a schematic diagram of the overall structure of the device for simulating the expansion and contraction deformation of expansive soil during the wet-dry cycle according to some embodiments of the present invention.

[0049] Figure 2 This is a schematic diagram of the overall structure of the soil sample wet-dry cycle device according to some embodiments of the present invention;

[0050] Figure 3 This is a schematic diagram of the overall structure of the water supply pressure device according to some embodiments of the present invention;

[0051] Figure 4 This is a schematic diagram of the overall structure of the water supply and air supply device according to some embodiments of the present invention;

[0052] Figure 5 This is a schematic diagram of the overall structure of the weighing device according to some embodiments of the present invention.

[0053] Explanation of reference numerals in the attached figures:

[0054] 1-Soil sample wet-dry circulation device; 101-Base plate; 102-Sliding track; 103-Pulley; 104-Elastic stretchable membrane; 105-Sliding sidewall;

[0055] 2-Water supply pressure device; 201-Water storage tank; 202-Water inlet pipe; 203-Peristaltic pump; 204-Modible piston;

[0056] 3-Water supply and air supply device; 301-Filtering device; 302-Filming device; 303-Air supply device; 304-Support;

[0057] 4-Weighing device. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0059] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0060] It should be understood that the terms "comprising / including," "consisting of," or any other variations are intended to cover non-exclusive inclusion, such that a product, apparatus, process, or method that comprises a list of elements includes not only those elements but may also include, where necessary, other elements not expressly listed, or elements inherent to such a product, apparatus, process, or method. Without further limitation, an element defined by the phrases "comprising / including," "consisting of," does not exclude the presence of additional identical elements in the product, apparatus, process, or method that includes said element.

[0061] It should also be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device, component or structure referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation of the present invention.

[0062] In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0063] This invention provides a device for simulating the expansion and contraction deformation of expansive soil during the wet-dry cycle. It is used to simulate the wet-dry cycle process of expansive soil layers to study the crack development characteristics and physical and mechanical properties of the soil layer after the wet-dry cycle, so as to enable early treatment of expansive soil slopes and avoid disasters such as landslides and collapses.

[0064] The device will now be described in detail with reference to preferred embodiments and specific illustrations.

[0065] like Figures 1 to 5 As shown, the device for simulating the expansion and contraction deformation of expansive soil during the wet-dry cycle includes a soil sample wet-dry cycle device 1, a water supply pressure device 2, a water supply and air supply device 3, and a weighing device 4.

[0066] Specifically, the soil sample wet-dry cycle device 1 can simulate the expansion and contraction process of expansive soil during the wet-dry cycle. Specifically, it is a retractable pressure box used to hold the soil sample to be tested. The soil sample is placed in water circulation and air circulation through the retractable pressure box.

[0067] In some embodiments, see Figure 2 The soil sample dry-wet circulation device 1 includes a base plate 101, a sliding side wall 105, and an elastic stretchable membrane 104, which are connected to form a retractable pressure box.

[0068] The base plate 101 is a rectangular plate with four water-permeable and air-permeable holes (not shown in the figure) in the center, which can effectively prevent water from accumulating inside the expandable pressure box and facilitate water penetration into the soil and timely discharge.

[0069] The sliding sidewall 105 is provided in four pieces. The four sliding sidewalls 105 are arranged end to end and are slidably connected to the upper part of the base plate 101 in an enclosing shape. They can open and close along the center of the bottom edge 101 as the test soil expands and contracts, so that the sliding sidewall 105 can deform with the expansion and contraction of the soil.

[0070] An elastic stretchable membrane 104 is disposed at the corner of two adjacent sliding sidewalls 105, and the two adjacent sliding sidewalls 105 are connected at their corners.

[0071] The elastic stretchable membrane 104 surrounds and connects the four sliding sidewalls 105 at their corners, forming the outer wall of the retractable pressure box together with the sliding sidewalls 105. Due to the stretchability of the elastic stretchable membrane 104, the integrity of the overall outer wall of the retractable pressure box can be ensured when the mutually surrounding sliding sidewalls 105 open or close along the center of the bottom edge 101.

[0072] The elastic stretchable membrane 104 is arc-shaped, similar to the arc-shaped chamfers made at the corners of the rectangular frame formed by the four sliding sidewalls 105. The arc-shaped design can avoid friction with the soil.

[0073] The elastic stretchable membrane 104, as part of the outer wall of the stretchable pressure box, can stretch and deform when subjected to force to prevent soil samples from leaking out.

[0074] Furthermore, a sliding rail 102 is installed on the bottom edge 101, and a pulley 103 is installed on the bottom of the sliding sidewall 105. The pulley 103 works in conjunction with the sliding rail 102 to facilitate the sliding sidewall 105 to slide along the sliding rail 102.

[0075] Preferably, the sliding rails 102 are provided in four sets, which intersect at a point and are arranged perpendicularly to each other. Preferably, each set of sliding rails 102 is arranged along the middle of the bottom plate 101 perpendicular to the plate edge, and each set has two sliding rails 102.

[0076] In this invention, the length of the sliding track is determined according to the expansion and contraction of the expansive soil in actual engineering, and cannot be less than its maximum contraction value.

[0077] Preferably, the sliding sidewall 105 is positioned corresponding to the position of each set of sliding rails 102, and two pulleys 103 are set at the bottom of each sliding sidewall 105 corresponding to the positions of the two sliding rails 102, to ensure that the sliding sidewall 105 slides stably along the sliding rails 102, so as to realize the expansion and contraction deformation of the expandable pressure box with the expansion and contraction of the soil.

[0078] Preferably, both the bottom edge 101 and the sliding sidewall 105 are made of acrylic plates, which facilitates observation of soil changes inside the retractable pressure box.

[0079] Preferably, the elastic stretchable membrane 104 is a transparent PDMS dimethylsiloxane elastomer film with tensile properties. The advantage of this type of material is that it can be stretched and deformed and has hydrophobic properties. Wrapped around the four corners of the rectangle formed by the sliding sidewall 105, it helps to realize the expansion and contraction deformation of the stretchable pressure box with the soil and facilitates the observation of the internal soil sample.

[0080] The water supply pressure device 2 is set on the outside of the soil sample dry-wet circulation device 1. The water supply pressure device 2 is used to give a certain pressure to the soil sample in the soil sample dry-wet circulation device 1, so that the expandable pressure box can deform in time with the expansion and contraction of the soil. This realizes the adjustment of the soil sample dry-wet circulation device 1 with the expansion and contraction of the soil during the dry-wet circulation process of the expansive soil sample, and more accurately simulates the dynamic change process of expansive soil under dry and wet conditions.

[0081] In some embodiments, see Figure 3 The water supply pressure device 2 includes a water storage tank 201, a water inlet pipe 202, a peristaltic pump 203, and a movable piston 204. The water storage tank 201 has a drain hole at its bottom, which connects to one end of the water inlet pipe 202. The other end of the water inlet pipe 202 is connected to one end of the movable piston 204. The peristaltic pump 203 is connected to the middle of the water inlet pipe 202 and is used to apply pressure to the movable piston through the water inlet pipe 202. The other end of the movable piston 204 is connected to the outer wall of the retractable pressure box.

[0082] Preferably, the movable end of the movable piston 204 is perpendicularly attached to the surface of the sliding sidewall 105 of the soil sample wet-dry circulation device 1 to provide thrust to the sliding sidewall 105.

[0083] Preferably, the water storage tank 201 is placed on a table that is higher than the retractable pressure box. The peristaltic pump 203 can provide a certain water pressure to push the movable piston 204. The movable piston 204 can extend and deform. When there is water pressure, the piston pushes out and applies a certain pressure to the outer wall of the retractable pressure box.

[0084] In practice, the water in the water storage tank 201 is compressed by the peristaltic pump 203 through the water inlet pipe 202 to generate a certain pressure. The peristaltic pump 203 compresses the water with a certain pressure to the movable piston 204. The movable piston 204 applies a certain pressure to the outer wall of the retractable pressure box, thereby applying a certain pressure to the soil sample, so that the outer wall of the retractable pressure box can deform in time with the expansion and contraction of the soil.

[0085] Preferably, the bottom of the water storage tank 201 is provided with four drain holes, which are connected to one end of four water inlet pipes 202. The other end of the four water inlet pipes 202 is connected to four movable pistons 204. The four movable pistons 204 are respectively connected to four sliding sidewalls 105. Four peristaltic pumps 203 are provided, corresponding to each water inlet pipe 202, to ensure that each sliding sidewall 105 can generate a certain pressure.

[0086] Preferably, the water storage tank 201 is a graduated water tank, which makes it easy to calculate the water pressure based on the changes in the water volume inside the water storage tank 201.

[0087] This invention provides a certain pressure to the soil sample in the soil sample drying and wetting cycle device through a water supply pressure device, allowing the soil sample drying and wetting cycle device to deform in time with the expansion and contraction of the soil. This ensures the expansion and closure of cracks under repeated expansion and contraction conditions consistent with the actual engineering boundary adjustment, and ensures the conduct of experiments on the physical and mechanical properties of expansive soil.

[0088] The water supply and air supply device 3 is located above the soil sample wet-dry circulation device 1, see [reference]. Figure 4 The water supply and air supply device 3 includes a filtration device 301 and an air supply device 303. The filtration device 301 is used to supply water to the soil sample in the retractable pressure box to simulate the rainfall process and achieve rapid and full saturation of the soil sample. The air supply device 303 is used to dry the soil sample after water supply and accelerate the drying process of the soil sample.

[0089] Preferably, the filtration device 301 includes a square filtration head placed above the retractable pressure box, a water supply pipe, and a switch, wherein the square filtration head is connected to the water supply pipe, and the switch is coupled to the water supply pipe to control the water supply pipe to supply water to the filtration head.

[0090] During the simulation test, when water needs to be supplied to the soil sample in the retractable pressure box through the filtration device 301, the switch is closed, the water supply pipe is connected to the square shower head, and water is sprayed from the square shower head to the soil sample in the retractable pressure box until the soil sample is saturated. Then the switch is turned off, the water supply pipe is disconnected from the square shower head, and the square shower head stops discharging water.

[0091] Preferably, the air supply device 303 includes four small fans installed at the four corners of a rectangle directly above the soil sample wet-dry circulation device 1.

[0092] See also Figure 4 The water supply and air supply device 3 also includes a camera 302, which is set on the same horizontal plane as the filtration device 301 and the air supply device 303, making it convenient for later maintenance and installation, and is used to record the development of surface cracks on the soil sample in real time.

[0093] Preferably, the shooting device 302 can be a miniature camera.

[0094] In practical use, the imaging device 302 is connected to the computer signal. The imaging device 302 can transmit the data of the development of soil surface cracks recorded in real time during the test to the computer terminal, and use the image processing software in the computer to analyze it, so as to understand the development and evolution process of expansive soil cracks and obtain the accurate physical and mechanical properties of expansive soil, so as to be able to treat expansive soil slopes in advance.

[0095] In some embodiments, the water supply and air supply device 3 further includes a bracket 304, and the filtration device 301, the air supply device 303 and the imaging device 302 are all mounted on the bracket 304 and are all positioned directly above the soil sample wet-dry cycle device 1 via the bracket 304.

[0096] Preferably, the top of the support 304 is a rectangular frame, and the filtration device 301, the imaging device 302 and the air supply device 303 are all installed in the rectangular frame. Four columns are provided at the bottom of the four corners of the rectangular frame, and the rectangular frame is supported directly above the soil sample wet-dry cycle device 1 by the four columns.

[0097] Preferably, the bracket is made of 304 stainless steel.

[0098] When using the water supply and air supply device 3, first turn on the switch of the leaching device 301 to place the soil sample in the water channel to achieve rapid and uniform saturation of the soil sample; after saturation, switch the switch of the air supply device 303 to place the soil sample in the air channel to achieve rapid drying of the soil sample.

[0099] This invention uses a water supply and air supply device to supply water to the soil sample in the soil sample wet-dry cycle device to simulate the rainfall conditions of expansive soil in nature, and uses an air supply device to dry the soil sample in the soil sample wet-dry cycle device to simulate the evaporation conditions of expansive soil in nature, so as to more accurately simulate the dynamic change process of expansive soil under wet and dry conditions.

[0100] It should be explained that the terms "water channel" and "air channel" here refer to the passage of water or air through the soil sample.

[0101] See Figure 1 , Figure 5 Weighing device 4 is located at the bottom of soil sample wet-dry cycle device 1 to weigh the mass of the overlying device in a timely manner so as to calculate the moisture content of the soil sample.

[0102] The weighing device 4 is equipped with a display screen to facilitate real-time display of the mass of the covering device it is weighing.

[0103] As is easy to understand, the overlying device here refers to the soil sample wet-dry cycle device and the soil sample placed in the device for wet-dry cycle testing.

[0104] Weighing device 4 is used to record the total mass of the soil sample and the soil after each saturation and drying cycle, so as to weigh the total mass in a timely manner and calculate the moisture content of the soil sample.

[0105] Preferably, the weighing device 4 is an electronic weighing meter.

[0106] The device proposed in this invention simulates the expansion and contraction deformation of expansive soil during the wet-dry cycle. It simulates the repeated cycles of expansive soil under atmospheric forces such as rainfall and evaporation by using a soil sample wet-dry cycle device, a water supply pressure device, a water supply and air supply device, and a weighing device. This avoids the excessive development of cracks in the soil after multiple wet-dry cycles and accurately obtains the development of cracks and the physical and mechanical properties of the expansive soil.

[0107] This invention also proposes a method for conducting experiments using the aforementioned device to simulate the expansion and contraction deformation of expansive soil during wet-dry cycles. This method considers the expansion and closure process of cracks under repeated expansion and contraction conditions consistent with actual engineering boundary conditions, and can accurately simulate the dynamic changes of expansive soil under wet-dry conditions, ensuring the effective conduct of experiments on the physical and mechanical properties of expansive soil. Specifically, it includes the following steps:

[0108] S01: Prepare soil samples with a certain moisture content and density, compact them in layers, and fill them into a soil sample wet-dry cycle device;

[0109] S02: Perform one wet-dry cycle on the soil sample, specifically including:

[0110] S021: Turn on the peristaltic pump switch to allow the water flow to push the movable piston and apply pressure to the outer wall of the retractable pressure box.

[0111] S022: Turn on the leaching device to start the first saturation of the soil sample, use the imaging device to record the development of surface cracks of the soil sample in real time, transmit the data to the computer, use the graphics processing software in the computer for analysis, and use the weighing device to calculate that when the preset moisture content of the test is reached, turn off the leaching device.

[0112] S023: Turn on the air supply device to begin the first drying of the soil sample. Use the imaging device to record the development of surface cracks in the soil sample in real time. Transmit the data to the computer and use the graphics processing software on the computer to analyze it again. Then, use the weighing device to calculate again that the preset moisture content of the test is reached and turn off the air supply device.

[0113] S03: Repeat step S02 according to the preset number of dry and wet cycles to complete multiple dry and wet cycle tests.

[0114] It will be readily understood by those skilled in the art that, without conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

[0115] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for simulating the swelling-shrinkage deformation of an expansive soil during a drying-wetting cycle, characterized in that, The utility model relates to a soil sample dry-wet cycle device and a water supply and air supply device for the soil sample dry-wet cycle device. The utility model relates to a soil sample dry-wet cycle device (1) for containing a soil sample to be tested, which comprises a bottom plate (101), slidable side walls (105) and an elastic stretchable film (104). The middle of the bottom plate (101) is provided with water-permeable and air-permeable holes. The slidable side walls (105) are arranged in a closed manner on the bottom plate (101) and are provided in multiple pieces. The elastic stretchable film (104) is arranged at the corners of two adjacent slidable side walls (105) to connect the two adjacent slidable side walls (105). The water supply pressure device (2) is arranged outside the soil sample dry-wet cycle device (1) and comprises a water storage tank (201) provided with multiple water outlet holes, water receiving pipes (202), peristaltic pumps (203) and movable pistons (204). Each of the multiple water receiving pipes (202) is connected to one of the water outlet holes. Each of the multiple peristaltic pumps (203) is arranged on one of the water receiving pipes (202). Each of the multiple movable pistons (204) is connected to the other end of one of the water receiving pipes (202). The movable pistons (204) are connected to the slidable side walls (105) of the soil sample dry-wet cycle device (1) to apply pressure to the soil sample in the soil sample dry-wet cycle device (1) and control the expansion and contraction and time-dependent deformation of the soil sample. The water supply and air supply device (3) is arranged outside the soil sample dry-wet cycle device (1) and is used to quickly and fully saturate and dry the soil sample in the soil sample dry-wet cycle device (1). The weighing device (4) is arranged at the bottom of the soil sample dry-wet cycle device (1) to support the soil sample dry-wet cycle device (1) and weigh the mass change of the overlying device. The soil sample dry-wet cycle device (1) further comprises a sliding track (102) installed on the bottom plate (101) and a pulley (103) installed at the bottom of the slidable side wall (105). The slidable side wall (105) is made of acrylic plate. The water storage tank (201) is a graduated water tank.

2. The device for simulating the swelling-shrinkage deformation of an expansive soil during a drying-wetting cycle according to claim 1, characterized in that, The water supply and air supply device (3) comprises a leaching device (301) for supplying water to the soil sample in the soil sample dry-wet cycle device (1) to quickly and fully saturate the soil sample, a shooting device (302) for recording the surface crack development of the soil sample in real time, and an air supply device (303) for drying the water-supplied soil sample to accelerate the drying process of the soil sample. The water supply and air supply device (3) further comprises a bracket (304) on which the leaching device (301), the shooting device (302) and the air supply device (303) are installed and which is arranged directly above the soil sample dry-wet cycle device (1). ​ 3. The device for simulating the swelling-shrinkage deformation of the swelling soil in the drying-wetting cycle process according to claim 2, characterized in that, ​ 4. The device for simulating the swelling-shrinkage deformation of an expansive soil during a drying-wetting cycle according to claim 1, characterized in that, ​ 5. The device for simulating the swelling-shrinkage deformation of the swelling soil in the drying-wetting cycle according to claim 1, characterized in that, ​ ​ ​ ​ 6. The device for simulating the swelling-shrinkage deformation of an expansive soil during a drying-wetting cycle according to claim 5, characterized in that, ​ 7. The device for simulating the swelling-shrinkage deformation of an expansive soil during a drying-wetting cycle according to claim 5, characterized in that, The leaching device (301) comprises a leaching head, a water supply pipe and a switch, wherein the leaching head is in communication with the water supply pipe, and the switch is coupled with the water supply pipe to control water supply of the water supply pipe to the leaching head.

8. The device for simulating the swelling-shrinkage deformation of an expansive soil during a drying-wetting cycle according to claim 5, characterized in that, The air supply device (303) comprises at least one fan installed directly above the soil sample dry-wet cycle device (1).

9. A method for testing using the device for simulating the swelling-shrinkage deformation of expansive soil during dry-wet cycle according to any one of claims 5 to 8, characterized in that, The method comprises the following steps: S01: preparing a soil sample with a certain water content and compactness, and filling the soil sample into the soil sample dry-wet cycle device (1); S02: performing a dry-wet cycle on the soil sample, specifically comprising: S021: opening the switch of the peristaltic pump (203) to make water flow push the movable piston (204) to give a certain pressure to the soil sample dry-wet cycle device (1); S022: opening the leaching device (301) to start the first saturation of the soil sample, using the shooting device (302) to record the surface crack development of the soil sample in real time, and transmitting the data to the computer, using the graphic processing software to analyze, and calculating the preset water content of the test through the weighing device (4) to close the leaching device (301); S023: opening the air supply device (303) to start the first drying of the soil sample, using the shooting device (302) to record the surface crack development of the soil sample in real time, and transmitting the data to the computer, using the graphic processing software to analyze again, and calculating the preset water content of the test through the weighing device (4) to close the air supply device (303); S03: repeating step S02 according to the preset dry-wet cycle times to complete the multiple swelling soil sample dry-wet cycle test.

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