Variable angle hydrothermal coupling experimental device

Abstract

The application provides a variable-angle water-heat force coupling experimental device, and belongs to the technical field of frozen soil research related equipment. The device comprises a support, a sample bin, a water-permeable stone arranged in the sample bin, a sealed water tank, a water pump pressurizing device, and a heat-conducting plate. The water-permeable stone and the sealed water tank form a water supplement space. The water pump pressurizing device is in communication with the water supplement space. The heat-conducting plate is used for releasing cold energy of the inner soil sample. The variable-angle water-heat force coupling experimental device is mainly used for simulating the phenomenon that different direction water pressure produces frost heaving of the soil under low-temperature conditions. The variable-angle water-heat force coupling experimental device can be rotated to adjust the required angle, so as to achieve the purpose of pressurizing and supplementing water from different directions, and to measure the frost heaving displacement, water content, temperature, and frost heaving stress of the soil, and to analyze the frost heaving mechanism and the influencing factors.

Description

Technical Field

[0001] This invention relates to the technical field of equipment related to permafrost research, and more specifically, to a variable-angle hydrothermal coupling experimental device. Background Technology

[0002] Currently, the development and utilization of permafrost regions in my country is becoming increasingly widespread. In these regions, phenomena such as road surface bulges, canal cracks, tilted walls, and unstable building foundations are frequently observed. The reason for this is that when the soil freezes at low temperatures, it is affected by factors such as groundwater migration and load pressure. As a result, the ice particles in the soil gradually crystallize, causing the soil volume to expand and leading to damage to buildings due to frost heave.

[0003] To reduce the damage to buildings and facilities caused by soil frost heave, it is necessary to study the mechanism of soil frost heave and related influencing factors.

[0004] Traditional frost heave testing devices primarily apply vertical loading to soil samples, limiting their application to simulating frost heave phenomena in only one direction. This results in limited applicability of traditional frost heave testing devices. Furthermore, existing frost heave testing devices typically use conduits to replenish water to the soil samples, leading to poor uniformity of water replenishment and an inability to accurately simulate real soil conditions. Summary of the Invention

[0005] In summary, how to provide a novel frost heave experimental device with multi-angle loading function has become an urgent problem to be solved by those skilled in the art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a variable-angle water-thermal coupling experimental apparatus, which includes:

[0008] support;

[0009] The sample chamber is hinged to the support. One end of the sample chamber is a cooling end with a cooling window. The other end of the sample chamber is a water supply end with a water supply window. A permeable stone for sealing the water supply window is provided on the water supply window.

[0010] A sealed water tank is airtightly installed over the water supply end, and a water supply space for loading a water replenishing agent is formed between the permeable stone and the sealed water tank.

[0011] A water pump pressurization device, which is connected to the water replenishment space through a pipeline, is used to provide the water replenishment space with a pressurized water replenishment agent;

[0012] A heat-conducting plate is provided on the cooling end for releasing cold energy to the soil sample in the sample chamber.

[0013] Preferably, in the variable-angle hydrothermal coupling experimental device provided by the present invention, a waterproof displacement sensor is provided on the outer end face of the sealed water tank. The displacement sensor is connected to the permeable stone and is used to detect the displacement of the permeable stone.

[0014] Preferably, in the variable-angle hydrothermal coupling experimental device provided by the present invention, a stress sensor for contacting the soil sample in the sample chamber is provided on the inner side of the heat-conducting plate and opposite to the cooling window.

[0015] Preferably, in the variable-angle hydrothermal coupling experimental device provided by the present invention, a heat-insulating plate with heat preservation function is provided on the outer end face of the heat-conducting plate; and a heat-insulating layer with heat preservation function is covered on the inner side of the sample chamber.

[0016] Preferably, in the variable-angle hydrothermal coupling experimental device provided by the present invention, the heat-conducting plate has a heat-conducting plate compartment; it also includes a refrigeration system, which is connected to the heat-conducting plate compartment and forms a refrigeration circulation channel for refrigerant circulation.

[0017] Preferably, in the variable-angle hydrothermal coupling experimental device provided by the present invention, a temperature detection hole and a moisture detection hole are provided on the sample chamber. A temperature sensor for detecting the temperature of the soil sample in the sample chamber is provided in the temperature detection hole, and a moisture sensor for detecting the moisture of the soil sample in the sample chamber is provided in the moisture detection hole.

[0018] Preferably, in the variable-angle hydrothermal coupling experimental device provided by the present invention, multiple temperature detection holes are provided and are equally spaced along the axial direction of the sample chamber.

[0019] Preferably, in the variable-angle hydrothermal coupling experimental device provided by the present invention, multiple moisture detection holes are provided and are equally spaced along the axial direction of the sample chamber.

[0020] Preferably, in the variable-angle hydrothermal coupling experimental device provided by the present invention, the support includes a base frame and two support arms vertically arranged on the base frame. The two support arms are arranged at intervals. A hinge shaft is provided on the outside of the sample chamber, and the hinge shaft is rotatably connected to the support arm.

[0021] Preferably, in the variable-angle hydrothermal coupling experimental device provided by the present invention, at least one of the support arms is provided with an elevation angle scale.

[0022] Preferably, in the variable-angle hydrothermal coupling experimental device provided by the present invention, the sample chamber is a long straight cylindrical structure; the sample chamber is made of acrylic material; and the sample chamber is an integral structure.

[0023] Preferably, in the variable-angle hydrothermal coupling experimental device provided by the present invention, the sealed water tank and the heat-conducting plate are disposed on the sample chamber and fixedly connected by long bolts.

[0024] Preferably, in the variable-angle hydrothermal coupling experimental device provided by the present invention, at least two long bolts are provided, and all of the long bolts are equally spaced around the axis of the sample chamber on the outer side of the sample chamber.

[0025] Compared with the prior art, the beneficial effects of this application are as follows:

[0026] This invention provides a variable-angle hydrothermal coupling experimental device, comprising: a support frame; a sample chamber hinged to the support frame, one end of the sample chamber being a cooling end with a cooling window, and the other end being a water supply end with a water supply window, wherein a permeable stone is disposed on the water supply window for sealing the water supply window; a sealed water tank airtightly covering the water supply end, wherein a water supply space for loading a water-replenishing agent is formed between the permeable stone and the sealed water tank; a water pump pressurization device connected to the water supply space via a pipeline for supplying a pressurized water-replenishing agent to the water supply space; and a heat-conducting plate covering the cooling end for releasing cold energy to the soil sample in the sample chamber from the cooling end. The variable-angle hydrothermal coupling experimental device provided by this invention is designed to simulate the phenomenon of frost heave of soil under different directions of water pressure at low temperatures. This variable-angle hydrothermal coupling experimental device can be rotated to adjust the angle required for the experiment, so as to achieve the purpose of pressurizing and watering the soil from different directions. In this way, parameters such as frost heave displacement, water content, temperature and frost heave stress of the soil can be measured to explore the frost heave mechanism and analyze the influencing factors. Attached Figure Description

[0027] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0028] Figure 1 This is a schematic diagram of the overall structure of the variable-angle hydrothermal coupling experimental device in an embodiment of the present invention;

[0029] Figure 2This is a split view of the variable-angle hydrothermal coupling experimental device in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of the sealed water tank in an embodiment of the present invention;

[0031] Figure 4 This is a cross-sectional view of the sealed water tank in an embodiment of the present invention;

[0032] Figure 5 This is a partial structural diagram of the support arm in an embodiment of the present invention.

[0033] exist Figures 1 to 5 The correspondence between the component names and the reference numerals in the attached drawings is as follows:

[0034] 1. Insulation board; 2. Heat-conducting plate; 3. Stress sensor; 4. Sample chamber; 5. Permeable stone; 6. Sealed water tank; 7. Long bolt; 8. Steel frame base; 9. Scaled support arm; 10. Large nut; 11. Short bolt; 12. Small nut; 13. Displacement sensor; 14. Arc surface; 15. Scale. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present invention without departing from its scope or spirit. For example, shown or described

[0036] Features that are part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the invention encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0037] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0038] Please refer to Figures 1 to 5 ,in, Figure 1 This is a schematic diagram of the overall structure of the variable-angle hydrothermal coupling experimental device in an embodiment of the present invention; Figure 2This is a split view of the variable-angle hydrothermal coupling experimental device in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the sealed water tank in an embodiment of the present invention; Figure 4 This is a cross-sectional view of the sealed water tank in an embodiment of the present invention; Figure 5 This is a partial structural diagram of the support arm in an embodiment of the present invention.

[0039] This invention provides a variable-angle hydrothermal coupling experimental device, which includes a support frame, a sample chamber 4, a sealed water tank 6, and a heat-conducting plate 2. The sample chamber 4 has a compartment for loading soil samples. The sealed water tank 6 and the heat-conducting plate 2 are respectively located at both ends of the sample chamber 4. The sealed water tank 6 is used to supply a water-adding agent (the water-adding agent is pumped by a water pump pressurization device, and the water-adding agent has a certain water pressure, which is adjustable). The heat-conducting plate 2 is used to provide cooling, thereby freezing the soil sample. The support frame is used to install the sample chamber 4, thereby changing the elevation angle of the sample chamber 4 to more realistically simulate the soil frost heave process.

[0040] The variable-angle hydrothermal coupling experimental device provided by this invention is mainly used in the fields of soil and rock and artificial frozen soil research. It is an experimental device that can simulate the effect of groundwater freezing on soil and rock under low temperature conditions. The variable-angle hydrothermal coupling experimental device provided by this invention can pressurize and replenish water to soil samples in different directions, and can simultaneously measure various parameters of soil frost heave.

[0041] Specifically, the sample chamber 4 adopts a long, straight cylindrical (or tubular) structure, preferably a long, straight cylindrical structure. The sample chamber 4 is made of a rigid material, preferably acrylic, but stainless steel or other metal materials can also be used.

[0042] In the design of the long straight cylindrical structure, the sample chamber 4 has a hinge shaft at its axial midpoint (the hinge shaft is located on the outer surface of the sample chamber 4). There are two hinge shafts, which are coaxially arranged and located on both sides of the sample chamber 4, with their axes intersecting the axis of the sample chamber 4. The sample chamber 4 can be hinged to the support (the support arm) via the hinge shaft. The hinge shaft has an external thread, and a circular hole structure is provided at the top of the support arm (the circular hole structure is located on the support arm). The hinge shaft is assembled into the circular hole structure of the support arm, and a nut is threaded onto the hinge shaft, thus ensuring that the sample chamber 4 is reliably installed on the support arm without falling off.

[0043] As described above, the sample chamber 4 is hinged to the support, thereby allowing adjustment of its elevation angle. Along the axial direction of the sample chamber 4, one end of the sample chamber 4 is a cooling end, which has a cooling window (preferably a circular opening structure). The other end of the sample chamber 4 is a water supply end, which has a water supply window (preferably a circular opening structure). A permeable stone 5 for sealing the water supply window is provided on the water supply window. Sample chamber connecting ears are provided on the outer side of the sample chamber 4 and near the cooling end. At least two sample chamber connecting ears are provided (in a preferred embodiment of the present invention, two sample chamber connecting ears are provided). All sample chamber connecting ears are equally spaced around the axis of the sample chamber 4 on the outer side of the sample chamber 4 (preferably, when the sample chamber 4 is placed horizontally, one sample chamber connecting ear is provided at the highest point of the sample chamber 4 and one sample chamber connecting ear is provided at the lowest point of the sample chamber 4).

[0044] Furthermore, the sample chamber 4 adopts an integrated structural design, and the hinge shaft and sample chamber connecting ear can be set independently (and then fixed to the surface of the sample chamber 4 later). The hinge shaft and sample chamber connecting ear can also be integrally formed on the sample chamber 4.

[0045] In order to obtain the temperature and moisture content of the soil sample during the experiment, when the sample chamber 4 is filled with soil sample, the present invention provides a temperature detection hole and a moisture detection hole on the sample chamber 4. A temperature sensor for detecting the temperature of the soil sample in the sample chamber 4 is installed in the temperature detection hole, and a moisture sensor for detecting the moisture content of the soil sample in the sample chamber 4 is installed in the moisture detection hole.

[0046] Furthermore, multiple temperature detection holes are provided and are equally spaced along the axial direction of the sample chamber 4.

[0047] Furthermore, multiple moisture detection holes are provided and are equally spaced along the axial direction of the sample chamber 4.

[0048] Preferably, when the sample chamber 4 is placed horizontally, a temperature detection hole is provided at the highest point of the sample chamber 4, and a moisture detection hole is provided at the lowest point of the sample chamber 4.

[0049] In this invention, the permeable stone 5 is a water-permeable component that simulates geological structures such as rock layers. It allows the replenishing agent in the sealed water tank 6 to slowly and controllably permeate into the soil sample (the permeability of the permeable stone 5 is constant; increasing the water pressure in the sealed water tank 6 accelerates the permeation rate, while decreasing the water pressure slows it down). In this invention, the permeable stone 5 is a sheet-like structure of a certain thickness. The permeable stone 5 is designed according to the shape of the water replenishment window on the sample chamber 4 so that it fits snugly onto the window.

[0050] Specifically, the sealed water tank 6 is a shell structure that can cover the water replenishment end of the sample chamber 4 (the sealed water tank 6 can be fastened to the outside of the water replenishment end of the sample chamber 4). The sealed water tank 6 and the water replenishment end are connected by an airtight structure. A water replenishment space for loading the water replenishing agent is formed between the permeable stone 5 (the permeable stone 5 is loaded on the water replenishment window, the outer side of the permeable stone 5) and the sealed water tank 6 (the sealed water tank 6 is fastened to the sample chamber 4, the inner side and the inner bottom of the sealed water tank 6).

[0051] A water-additive container is installed outside the sample chamber 4, containing the water-additive. The invention also includes a water pump pressurization device that pumps the water-additive. This device pressurizes and regulates the water pressure of the water-additive. The invention features a water inlet on a sealed water tank 6. A flexible hose connects the water pump pressurization device, the sealed water tank 6, and the water-additive container, forming a water-additive replenishment pathway. The water-additive in the container is pumped into the sealed water tank 6 via the water pump pressurization device, and then permeates into the soil sample within the sample chamber 4 through the permeable stone 5.

[0052] The sealed water tank 6 should have a certain pressure bearing capacity. Therefore, the sealed water tank 6 is preferably made of stainless steel. The sealed water tank 6 adopts an integrated structure, which can improve the sealing performance of the sealed water tank 6 itself. When the sealed water tank 6 is installed on the sample chamber 4, its connection part should be equipped with a sealing structure (such as a sealing layer) to improve the airtightness of the connection between the sealed water tank 6 and the sample chamber 4.

[0053] Furthermore, the present invention provides sealing water tank connecting ears on the outer side of the sealing water tank 6. The number of sealing water tank connecting ears is the same as the number of sample chamber connecting ears. In addition, the number of sealing water tank connecting ears in the axial direction of the sample chamber 4 corresponds one-to-one with the number of sample chamber connecting ears.

[0054] The permeable stone 5 is placed at the water replenishment end of the sample chamber 4. As the moisture content of the soil sample increases and the soil sample temperature decreases, the water replenishing agent in the soil sample will condense into ice, causing the soil sample to expand. The permeable stone 5 will be displaced in the sample chamber 4 due to the expansion of the soil sample. To obtain accurate movement of the permeable stone 5, a waterproof displacement sensor 13 is installed in the sealed water tank 6. The displacement sensor 13 is connected to the permeable stone 5, and the displacement of the permeable stone 5 can be accurately obtained through the displacement sensor 13. Furthermore, two displacement sensors 13 are provided, and the two displacement sensors 13 are symmetrically arranged in the sealed water tank 6 with the axis of the sample chamber 4 as the axis of symmetry.

[0055] Compared to the sample chamber 4, the present invention has two systems set outside the sample chamber 4: one is a water replenishment system for providing water replenishment agent, and the other is a refrigeration system for providing cooling capacity.

[0056] In the water replenishment system, the present invention is equipped with a water pump pressurization device, which is a water pump pressurization device with a pressure gauge. The pressure gauge displays the pressure of the pumped water replenishing agent in real time (this pressure value is the water pressure of the water replenishing agent). The water pump pressurization device is connected to the water replenishment space (the space structure formed by the sealed water tank 6 and the permeable stone 5) through a pipeline (transparent flexible hose) to provide water replenishing agent with adjustable pressure (increasing the operating power of the water pump pressurization device can increase the water pressure of the water replenishing agent, and decreasing the operating power of the water pump pressurization device can decrease the water pressure of the water replenishing agent).

[0057] Specifically, the heat-conducting plate 2 is the structural device for releasing cold energy to the soil sample in this invention. The heat-conducting plate 2 is a cover structure with a heat-conducting plate compartment (cavity structure). A short pipe structure (connected to a pipeline for transporting refrigerant) is provided on the outer side (outer end face) of the heat-conducting plate 2. This invention also provides a refrigeration system capable of generating cold energy, which is carried and transported by the refrigerant. The refrigeration system is connected to the heat-conducting plate compartment, forming a refrigeration circulation channel for refrigerant circulation. After the refrigerant receives the cold energy and its temperature decreases, it can be transported into the heat-conducting plate 2, where a portion of the cold energy is released, and then circulated back into the refrigeration system to obtain more cold energy.

[0058] The heat-conducting plate 2 is placed over the cooling end, that is, the heat-conducting plate 2 is placed over the cooling end of the sample chamber 4 like a lid. A cooling window is provided on the cooling end. The soil sample in the sample chamber 4 is in contact with the inner side of the heat-conducting plate 2. The low-temperature refrigerant (a refrigerant containing a large amount of cold energy) can flow into the heat-conducting plate 2. Through the transfer of the inner side of the heat-conducting plate 2, the cold energy can be released to the soil sample in the sample chamber 4 from the cooling end.

[0059] Furthermore, the present invention provides a stress sensor 3 on the inner side of the heat-conducting plate 2, opposite to the cooling window, for contacting the soil sample in the sample chamber 4. The shape of the stress sensor 3 matches the shape of the cooling window and its size is smaller than the cooling window, so that the stress sensor 3 can be in complete contact with the soil sample in the sample chamber 4, thereby obtaining accurate stress information of the soil sample.

[0060] In this invention, the heat-conducting plate 2 is set on the sample chamber 4, and the permeable stone 5 is set at the other end of the sample chamber 4. When the soil sample in the sample chamber 4 undergoes frost heave deformation, the heat-conducting plate 2 remains stationary, while the permeable stone 5 moves. The displacement of the permeable stone 5 is obtained by the displacement sensor 13, and the expansion amount of the soil sample can be calculated. Furthermore, since the heat-conducting plate 2 is stationary relative to the sample chamber 4, accurate stress data can be obtained by the stress sensor 3.

[0061] Since it is necessary to release cold energy to the soil sample to achieve frost heave, in order to ensure the smooth progress of the experiment, the rate of cold energy loss from the soil sample should be as low as possible (the lower the rate, the more constant the soil sample temperature). Therefore, in order to reduce cold energy loss, the present invention provides a heat-insulating plate 1 with heat-insulating function on the outer end face of the heat-conducting plate 2. At the same time, the present invention covers the inner side of the sample chamber 4 with a heat-insulating layer.

[0062] The support frame is a structure for mounting the sample chamber 4 and adjusting its elevation angle. Specifically, the support frame includes a base frame (a rectangular frame structure) and two support arms vertically mounted on the base frame (at the midpoint of its length). The base frame and the support arms are both made of metal and are spaced apart. One support arm is fixed, and the other is detachable. The fixed support arm is located on one long side of the base frame, and a connecting plate is located on the other long side. The detachable support arm is bolted to the connecting plate. Each support arm has a circular hole at its top, and a hinge shaft is located on the outside of the sample chamber 4, rotatably connecting to the support arm. This structural design of the support arms (making one arm detachable) facilitates the installation of the sample chamber 4 on the support frame.

[0063] Specifically, the present invention has an elevation angle scale on at least one of the arms, which makes it very convenient to adjust the elevation angle of the sample chamber 4.

[0064] In this invention, a heat-conducting plate 2 and a sealed water tank 6 are provided on the sample chamber 4, and an insulation plate 1 is fixedly provided relative to the sample chamber 4. Specifically, after assembling the sealed water tank 6 (which has a sealing water tank connecting ear), the heat-conducting plate 2 (which has a heat-conducting plate connecting ear), and the insulation plate 1 (which has an insulation plate connecting ear), a long bolt 7 is installed through the insulation plate 1 connecting ear, the heat-conducting plate connecting ear, the sample chamber connecting ear, and the sealed water tank connecting ear. Then, the long bolt 7 is tightened by using a small nut 12, thereby achieving the fixed installation of the insulation plate 1, the heat-conducting plate 2, and the sealed water tank 6 on the sample chamber 4.

[0065] Furthermore, at least two (preferably two) long bolts 7 are provided, and all the long bolts 7 are equally spaced around the axis of the sample chamber 4 on the outer side of the sample chamber 4. By increasing the number of long bolts 7, the stability and firmness of each component on the sample chamber 4 can be improved.

[0066] This invention involves filling a soil sample chamber 4 with a sealed water tank 6 at one end of the sample chamber 4. The sealed water tank 6 provides a pressurized water-adding agent. Specifically, this invention provides an adjustable pressurization direction system, which includes a conduit, a water-adding agent, and the sealed water tank 6. The sealed water tank 6 is assembled at one end of the sample chamber 4 (acrylic sample chamber 4). A water pump pressurization device is connected to the conduit, which is connected to the sealed water tank 6. The joints between components are reinforced with Teflon tape to prevent leakage. The water tank contains the water-adding agent. Since soil may be subjected to water pressure from different directions within the strata, it is necessary to simulate water pressure from a specific direction during the experiment. This requires selecting the pressurization direction according to the water pressure required by the experimental plan, adjusting the rotation angle (elevation angle) of the sample chamber 4 to correspond to the scale on the graduated support arm 9, tightening the large nut 10 (the large nut 10 is threadedly connected to the hinge shaft, and tightening it can fix the posture of the sample chamber 4), adjusting and controlling the water pressure of the additive according to the instrument parameters of the water pump pressurization device, and starting the water pump pressurization device to pressurize the water tank. The adjustable pressurization direction system has the following functions: pressurizing the sealed water tank 6 through the water pump pressurization device can provide water pressure to the experimental device. The additive is loaded into the sealed water tank 6, the permeable stone 5 is installed in the sample chamber 4, and the sample chamber 4 is connected to the sealed water tank 6. By adjusting the tilt angle of the sample chamber 4 to correspond to the scale on the graduated support arm 9, and then tightening the large nut 10, the tilt direction of the sample chamber 4 can be controlled, thereby changing the water replenishment direction. The water in the sealed water tank 6 can replenish the soil sample through the permeable stone 5 under the pressure of the water pump pressurization device.

[0067] Specifically, the graduated support arm 9 has circular hole structures (mounting holes), and hinge shafts are provided on both sides of the sample chamber 4. The sample chamber 4 is mounted to the support arm 9 via the hinge shafts. The top end face of the support arm 9 is an arc surface 14, which is concentrically arranged with the circular hole structures on the support arm 9. The arc surface 14 is provided with a scale 15 (the scale corresponding to the sample chamber 4 being horizontal is 0°, and the scale corresponding to the sample chamber 4 being vertical is 90°). At the same time, an indicator is provided on the sample chamber 4. The indicator is used in conjunction with the scale 15 on the support arm 9 to display the current tilt angle of the sample chamber 4.

[0068] This invention includes a sample chamber 4, within which a thin film, made of plastic, is placed to prevent heat loss. The sample chamber 4 is connected to a sealed water tank 6. The film, attached to the inner wall of the sample chamber 4, further prevents heat loss and provides insulation. The sample chamber 4 provides an environment suitable for the sample collection device, allowing different types of sensors to be inserted into the soil sample through holes in the chamber 4 for data measurement.

[0069] This invention also includes an insulation board 1, a heat-conducting plate 2, long bolts 7, a steel frame base 8 (the base structure of the support), a graduated support arm, small nuts 12, and short bolts 11. Two long bolts 7 are passed through the insulation board 1, the heat-conducting plate 2, the sample chamber 4 (where soil samples have been loaded and stress sensors 3 and permeable stones 5 have been placed), and the sealed water tank 6, and secured with six small nuts 12 (top and bottom). The entire assembly is then connected to the support arm of the steel frame base 8 via studs (hinges) on the outer side of the sample chamber 4. The graduated support arm is passed through studs on the other side of the sample chamber 4 and connected to the small nuts 12 and the support arm via two pairs of short bolts 11. Finally, the graduations on the sample chamber 4 are aligned with the graduations on the graduated support arm 9 according to the desired angle, and the large nut 10 is tightened to secure the sample chamber 4. This invention is stable, simple, and reliable.

[0070] This invention also includes a refrigeration system, comprising a heat-conducting plate 2, an insulation plate 1, conduits (for transporting refrigerant), and refrigerant inlet and outlet ports (at the top and bottom). Two conduits are connected at one end to the refrigerant inlet and outlet ports and at the other end to a refrigeration machine. The heat-conducting plate 2, the insulation plate 1, and the sample chamber 4 are connected by long bolts 7. A stress sensor 3 is mounted on the side of the heat-conducting plate 2 facing the sample chamber 4. This invention circulates the refrigerant in the heat-conducting plate 2 through the refrigeration machine, lowering its temperature to the required experimental temperature for the experiment. The insulation plate 1 prevents heat loss.

[0071] This invention also provides a data acquisition system, which includes a computer, a stress sensor 3, a temperature sensor, a moisture sensor, a waterproof displacement sensor 13, and a data acquisition instrument. The temperature sensor and moisture sensor are respectively installed on the moisture detection holes and temperature detection holes on the upper and lower sides of the sample chamber 4 (the temperature sensor is located on the upper side of the sample chamber 4, and the moisture sensor is located on the lower side; or, the temperature sensor is located on the lower side of the sample chamber 4, and the moisture sensor is located on the upper side). The holes are covered with rubber membranes. The displacement sensor 13 is fixedly mounted on two supports of the sealed water tank 6. During the experiment, the sensors collect data in a timely manner and transmit it to the computer. The data acquisition system has the following functions: it can record experimental data in a timely manner through the computer; it can perform experimental data analysis using the computer, resulting in more accurate calculation results and reducing errors from manual measurement and reading of experimental data.

[0072] Compared to general frost heave measurement experimental devices, the variable-angle hydrothermal coupling experimental device provided by this invention can simulate unidirectional freezing of soil samples from left to right (or from right to left). The sample chamber 4 has been enhanced with rotatable adjustment and control (elevation angle control). This allows for directional pressurization and water replenishment via a water pump pressurization device in different directions. The water pressure of the replenishing agent is controlled and adjusted by the water pump pressurization device, and its pressure value can be read by an instrument. By pressurizing the water in the tank using the water pump pressurization device, the groundwater conditions in different directions in nature can be better simulated. The water replenishment system uses permeable stones 5 for water replenishment, effectively and evenly providing water migration. Furthermore, the water pressure is controlled by the water pump pressurization device, which can better control the frost heave of the soil sample under different water pressures. By adjusting the angle disc, groundwater in different directions can be simulated, which is closer to the actual situation.

[0073] This invention can also simultaneously measure parameters such as the amount of water added to the sample, moisture content, frost heave stress, frost heave amount, and temperature.

[0074] A thin film is laid inside the sample chamber 4, which can keep the soil sample warm and prevent moisture loss. The heat-conducting plate 2 is attached with an insulation plate 1 to prevent heat loss. The sample chamber 4 is installed on a support arm with an angle scale. The scaled support arm 9 is connected to the steel frame base 8. The entire fixing device system ensures the stability of the experimental device.

[0075] The invention has a reasonable overall design, clear structure, and simple manufacturing process. It can simulate the effect of water pressure on soil in different directions under low temperature conditions, as well as the water replenishment to soil in different directions. It can measure parameters such as frost heave displacement, water content, temperature, and frost heave stress of the soil, which is convenient for the analysis of frost heave mechanism and the exploration of influencing factors.

[0076] Specifically, in this invention, the variable-angle hydrothermal coupling experimental device is composed of a steel frame and acrylic material. The steel frame has strong load-bearing capacity and good stability, and is not easily deformed under external forces. The steel frame is mainly used in the external frame system of the experimental device (for making the support), playing a role in stabilizing and fixing the sample chamber 4. The acrylic material plate has good toughness, strong sealing performance, is not easily damaged, has good processing performance, and has a poor thermal conductivity, so it can be used as the material for making the sample chamber 4.

[0077] The sample chamber 4 has holes on both the top and bottom sides to facilitate the insertion of moisture and temperature sensors, allowing for the measurement of soil sample moisture content and frost heave parameters. The sample chamber 4 has hinge shafts on both sides. One hinge shaft can be directly inserted into the support arm of the bracket, while the other hinge shaft is fixed to the base via a support arm with a graduated dial and a bolt assembly. After determining the rotation angle of the sample chamber 4, tighten the large nut 10 to secure it. See the angle dial rotation device (i.e., the graduated support arm 9) for a specific example. Figure 5 As shown, the support arm connects to the base and can fix the entire frost heave experimental apparatus (sample chamber 4). Under the pressure of the replenishing agent, it ensures the stability of the experimental apparatus, improves the accuracy of experimental data, and reduces experimental errors.

[0078] One end of the sample chamber 4 is connected to a heat-conducting plate 2, and a waterproof stress sensor 3 is installed on the heat-conducting plate 2.

[0079] The heat-conducting plate 2 is connected to the sample chamber 4 using long bolts 7. The heat-conducting plate 2 has inlet and outlet holes connected to the circulation pipes. The heat-conducting plate 2 has an internal circulation pipe (or chamber structure). Refrigerant is poured into the pipes and circulates within them, allowing the heat-conducting plate 2 to be cooled to the required experimental temperature and maintained constant. One end of each of the two conduits is connected to one of the two holes, and the other end is connected to a refrigeration machine. The refrigeration machine ensures the required experimental temperature. An insulation plate 1 is then connected to the left side of the heat-conducting plate 2 using long bolts 7 to prevent heat loss from the heat-conducting plate 2.

[0080] This invention installs two waterproof displacement sensors 13 on the side of the permeable stone 5 to ensure the accuracy of displacement measurement. A stress sensor 3 is installed on the right side of the heat-conducting plate 2. During the experiment, data is collected through the stress sensor 3 to detect the stress changes of the soil sample under low-temperature freezing conditions. Multiple stress sensors 3 are also installed to ensure the accuracy of experimental stress measurement. Moisture sensors are placed on the upper side of the sample chamber 4, with multiple sensors arranged at equal intervals to measure the instantaneous moisture of different soil layers for timely water replenishment. Temperature sensors are placed on the lower side of the sample chamber 4, with multiple temperature sensors arranged at equal intervals to measure the instantaneous temperature of different soil layers. All temperature and moisture detection holes are connected to the sensors with rubber plugs (or rubber membranes) to prevent heat loss. All sensors are ultimately connected to a computer for detecting and statistically analyzing the experimental data from each sensor.

[0081] This invention can simulate the pressure of groundwater on soil and rock from different directions under low-temperature conditions. It can also simulate frost heave from different directions, whereas most existing frost heave measurement devices can only simulate vertical frost heave. This invention, by allowing for angle and direction adjustment, simulates groundwater pressure and moisture migration processes from different directions. It comprehensively considers factors influencing frost heave, promptly detects changes in frost heave parameters, and ultimately measures parameters such as temperature, moisture content, frost heave stress, and frost heave displacement. Therefore, this invention can more realistically simulate frost heave phenomena and provide more reliable and credible experimental data.

[0082] Through the above structural design, the variable-angle hydrothermal coupling experimental device provided by the present invention has at least the following advantages compared with the prior art:

[0083] 1. This invention has a reasonable design, clear structure, and is easy to process and manufacture. All parts in contact with the sample are made of acrylic material, which is easy to process and has poor thermal conductivity, preventing heat loss. This invention provides a refrigeration system that uses a refrigeration machine to provide cooling to the heat-conducting plate 2. Refrigerant circulates within the heat-conducting plate 2, allowing for temperature regulation. The heat-conducting plate 2 is wrapped with an insulation layer to ensure a constant temperature, guaranteeing a safe experimental environment and making the simulated data more reliable.

[0084] 2. The experimental data of this invention have smaller errors and more accurate results. All experimental parameters to be measured are transmitted to the computer via various sensors, avoiding errors that exist in manual measurement and data reading. Rubber wrapping is used for the connection between the temperature and moisture sensors and the acrylic plate, and a thin film is used to wrap the sample chamber 4 to prevent temperature and moisture loss. All conduit connections are wrapped with raw rubber tape to prevent water leakage, thus improving experimental details and reducing experimental errors.

[0085] 3. The present invention is equipped with permeable stone 5 for water replenishment, which effectively and evenly provides water migration, and uses a water pump pressurization device to control the water pressure, which can better control the frost heave of soil samples under different water pressures. By adjusting the angle plate, it can simulate groundwater in different directions, which is more in line with reality.

[0086] 4. The support structure is reasonably designed. The sample chamber 4 is installed through the support, ensuring the stability of the experimental device. The rotatable angle plate in the device has a novel design. The experimental device chamber is supported by a supporting steel frame, which is connected to the steel frame base 8. The entire fixing device system occupies little space and has strong stability.

[0087] Specific implementation steps of the present invention:

[0088] first step:

[0089] For sample preparation, soil samples were taken on-site using sampling tools. After drying, the soil parameters were measured, including unit weight, dry density, moisture content, liquid limit, and plastic limit. The required soil moisture content was prepared according to experimental needs. The soil samples were then wrapped in plastic film (to prevent moisture loss) and placed in a constant low-temperature chamber for curing until the required experimental temperature was reached.

[0090] Step Two:

[0091] Take out the sample from the constant low temperature chamber, smooth the film inside the sample chamber, place it in layers in the sample chamber 4 and compact it with a small hammer to ensure that the porosity between soils is small enough to prevent the phenomenon of discontinuity. During this process, wrap the temperature sensor and moisture sensor with rubber film and insert them into the soil to avoid affecting the compaction of the soil. Install the permeable stone 5 on the right side.

[0092] Step 3:

[0093] Assemble the experimental apparatus according to the instructions. First, fill the heat-conducting plate 2 with the coolant. Then, install the heat-conducting plate 2 with the acrylic sample chamber 4 and install multiple stress sensors 3. Connect the heat-conducting plate 2 with the refrigeration machine and turn on the refrigeration machine to lower the temperature of the coolant in advance.

[0094] Step 4: Adjust the tilt angle of the acrylic sample chamber 4 so that the scale line corresponds to the scale on the scaled support arm 9 to meet the groundwater pressurization direction and water replenishment direction that need to be simulated in the experimental scheme, and tighten the large nut 10 to fix it to the steel frame base 8.

[0095] Step 5: Install two waterproof displacement sensors 13 inside the water tank and adjust their measurement positions. Connect the sample chamber 4 to the sealed water tank 6, and wrap the joint with PTFE tape to prevent water leakage.

[0096] Step 6: Connect the water tank pipe on the right side and connect the water pump pressurization device. Fill the water tank with water and wait for the refrigeration unit to lower the temperature of the cryo-liquid to the temperature required by the experimental scheme. Gradually start the frost heave experiment. At this time, the computer software interface can be used to observe and record the moisture, temperature, frost heave displacement, moisture migration and frost heave stress of the frozen soil sample detected by the sensors. After the frost heave stress stabilizes, stop recording the experimental data of each parameter.

[0097] Step 7: Dismantle the experimental setup, remove the sample, analyze the frost heave of the sample and take photos for archiving, record and organize the final experimental data, analyze and summarize, and draw conclusions.

[0098] The variable-angle hydrothermal coupling experimental device provided by this invention is designed to simulate the phenomenon of frost heave of soil under different directions of water pressure at low temperatures. This variable-angle hydrothermal coupling experimental device can be rotated to adjust the angle required for the experiment, so as to achieve the purpose of pressurizing and watering the soil from different directions. In this way, parameters such as frost heave displacement, water content, temperature and frost heave stress of the soil can be measured to explore the frost heave mechanism and analyze the influencing factors.

[0099] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A variable angle hydrothermal force coupling experimental device, characterized in that, The device comprises: a support; a sample bin hinged to the support, which can be adjusted in the angle direction to simulate the groundwater pressure and water migration process in different directions, and finally measure the temperature, moisture content, frost heaving stress and frost heaving displacement parameter values, one end of the sample bin is a refrigeration end, the refrigeration end is provided with a refrigeration window, the other end of the sample bin is a water supplement end, the water supplement end is provided with a water supplement window, a water permeable stone is arranged on the water supplement window to close the water supplement window; a sealed water tank, which is air-tightly covered on the water supplement end, a water supplement space for loading water supplement agent is formed between the water permeable stone and the sealed water tank; a water pump pressurizing device, which communicates with the water supplement space through a pipeline to provide water supplement agent with adjustable pressure to the water supplement space; a heat conducting plate, which is covered on the refrigeration end to release cold energy to the soil sample in the sample bin at the refrigeration end; the water permeability of the water permeable stone is constant, when the water pressure of the water supplement agent in the sealed water tank is increased, the permeation speed of the water supplement agent is accelerated, and when the water pressure of the water supplement agent in the sealed water tank is reduced, the permeation speed of the water supplement agent is reduced; the water permeable stone is arranged at the water supplement end of the sample bin, when the water content of the soil sample increases and the temperature of the soil sample continuously decreases, the water supplement agent in the soil sample will freeze to make the soil sample swell, and the water permeable stone will be displaced in the sample bin under the swelling effect of the soil sample; a waterproof displacement sensor is arranged on the outer end surface of the sealed water tank, the displacement sensor is connected with the water permeable stone to detect the displacement amount of the water permeable stone; a stress sensor is arranged on the inner side surface of the heat conducting plate and opposite to the refrigeration window to contact the soil sample in the sample bin.

2. The variable angle water-heat force coupling experimental device according to claim 1, wherein a heat preservation plate with heat preservation function is arranged on the outer end surface of the heat conducting plate; a heat preservation layer with heat preservation function is arranged on the inner side surface of the sample bin.

3. The variable angle water-heat force coupling experimental device according to claim 1, wherein the heat conducting plate has a heat conducting plate bin; a refrigeration system is further included, which communicates with the heat conducting plate bin and forms a refrigeration circulation channel for the circulation flow of refrigerant.

4. The variable angle water-heat force coupling experimental device according to claim 1, wherein temperature detection holes and moisture detection holes are arranged on the sample bin, a temperature sensor for detecting the temperature of the soil sample in the sample bin is arranged in the temperature detection hole, and a moisture sensor for detecting the moisture content of the soil sample in the sample bin is arranged in the moisture detection hole; the temperature detection holes are arranged in multiple and are equally spaced along the axial direction of the sample bin; the moisture detection holes are arranged in multiple and are equally spaced along the axial direction of the sample bin.

5. The variable angle water-heat force coupling experimental device according to claim 1, wherein the support comprises a base frame and a support arm vertically arranged on the base frame, the support arm is arranged in two and is spaced apart. A hinged shaft is arranged outside the sample chamber and is rotationally connected with the support arm.

6. The variable angle hydrothermal coupling experimental device according to claim 5, characterized in that, At least one of the support arms is provided with an elevation angle scale.

7. The variable angle hydrothermal coupling experimental device according to any one of claims 1 to 6, characterized in that, The sample chamber is a long straight cylindrical structure. The sample chamber is made of acrylic material. The sample chamber is an integrated structure.

8. The variable angle hydrothermal coupling experimental device according to claim 1, characterized in that, The sealed water tank and the heat conducting plate are arranged on the sample chamber and are fixedly connected by long bolts. The long bolts are arranged at equal intervals outside the sample chamber around the axis of the sample chamber.

Images