Freeze-thaw cycle direct shear apparatus based on temperature regulation and control

Abstract

The utility model relates to a freezing and thawing cycle direct shear apparatus based on temperature regulation and control, which comprises a cabinet body, an operation box, a main machine, an upper shear box, a lower shear box, a water tank, an experiment box guide rail, a temperature control box and a water quantity regulation unit, the temperature control box, the operation box and the main machine are all arranged on the cabinet body, and the main machine is respectively in communication connection with the temperature control box and the operation box. The temperature control box is connected with the operation box, the experiment box guide rail is installed in the temperature control box, the lower shear box is installed on the experiment box guide rail, the upper shear box and the water tank are both installed on the lower shear box, and the water volume adjusting unit is installed in the water tank. The temperature control box, the water volume adjusting unit and the water tank are arranged, the temperature control box is used for adjusting the experiment temperature, the water volume in the water tank and the water content in a sample are controlled through the water volume adjusting unit, the problem that only the temperature can be adjusted and the water content cannot be adjusted is solved, and controllability and accuracy of the water content in the testing process are achieved.

Description

Technical Field

[0001] This utility model relates to the technical field of freeze-thaw cycle direct shear apparatus, and in particular to a freeze-thaw cycle direct shear apparatus based on temperature control. Background Technology

[0002] In fields such as cold-region engineering, frozen soil engineering, and underground engineering, the mechanical behavior of the soil-structure interface under freeze-thaw cycles directly affects the stability and safety of engineering structures. Freeze-thaw cycles cause significant changes in the physical and mechanical properties of soil, such as water content, porosity, and strength, which in turn affect the shear characteristics of the soil-structure interface. However, conventional direct shear instruments cannot simulate the freeze-thaw cycle environment and are difficult to accurately measure the impact of freeze-thaw cycles on the shear characteristics of the soil-structure interface, which poses a significant challenge to the design and construction of related projects.

[0003] Chinese patent application CN114324003A discloses a cyclic direct shear apparatus under temperature-controlled bidirectional dynamic load, comprising: a direct shear apparatus system, an insulated box, a temperature control system, a power control system, and a data monitoring and acquisition system; the direct shear apparatus system includes an upper shear box, a lower shear box, a fixed bracket, a loading plate, and a horizontal guide rail; the temperature control system includes a compressor, an evaporator, a condenser, a capillary tube, and a temperature control cabinet; the power control system includes a horizontal servo actuator, a vertical servo actuator, a thrust base, an electro-hydraulic servo oil tank, an oil pump, and an electrical control cabinet; the data monitoring and acquisition system includes a load sensor, a displacement sensor, a temperature sensor, and control equipment; although this patent can control the temperature, it cannot control changes in moisture content.

[0004] Therefore, providing a direct shear apparatus that can control moisture content is an urgent problem to be solved. Utility Model Content

[0005] The purpose of this invention is to overcome the defects of the existing technology and provide a freeze-thaw cycle direct shear device based on temperature control.

[0006] The objective of this utility model can be achieved through the following technical solutions:

[0007] According to one aspect of this utility model, a freeze-thaw cycle direct shear apparatus based on temperature control is provided, comprising a cabinet, an operation box, a main unit, an upper shear box, a lower shear box, a water tank, an experimental box guide rail, a temperature control box, and a water volume adjustment unit. The temperature control box, the operation box, and the main unit are all mounted on the cabinet. The main unit is communicatively connected to both the temperature control box and the operation box. The temperature control box and the operation box are connected. The experimental box guide rail is installed inside the temperature control box. The lower shear box is installed on the experimental box guide rail. The upper shear box and the water tank are both installed on the lower shear box. The water volume adjustment unit is installed in the water tank.

[0008] As a preferred technical solution, the water tank includes a water inlet pipe and a drain hole, both of which are installed on the tank wall.

[0009] As a preferred technical solution, the leveling unit includes a water guide pipe and a water stop valve. The water guide pipe is installed on the water injection hole, and the water stop valve is installed on the drain hole.

[0010] As a preferred technical solution, the water tank includes a template clamp.

[0011] As a preferred technical solution, the direct shearing device also includes a temperature adjustment panel, which is installed on the temperature control box and communicates with the host.

[0012] As a preferred technical solution, the direct shearing device also includes a power indicator light, an emergency stop switch, and a power switch. The power indicator light, emergency stop switch, and power switch are all installed on the control box, and the power indicator light, emergency stop switch, and power switch are respectively connected to the main unit for communication.

[0013] As a preferred technical solution, the direct shearing device further includes a force measuring ring and a vertical load rod, wherein the vertical load rod is mounted on the cabinet and the force measuring ring is mounted on the vertical load rod.

[0014] As a preferred technical solution, the straight shearing device further includes a horizontal loading unit and a clamping guide rail. The operation box is connected to the lower shearing box through the horizontal loading unit, and the clamping guide rail is connected to the lower shearing box.

[0015] As a preferred technical solution, the straight shearing device also includes a horizontal stop bar, which is installed on the cabinet and the horizontal push rod is connected to the upper shearing box.

[0016] As a preferred technical solution, the straight shearing device also includes a handwheel, which is connected to a horizontal stop bar.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. This utility model is equipped with a temperature control box, a water volume adjustment unit and a water tank. The temperature control box is used to adjust the experimental temperature, and the water volume adjustment unit controls the water volume in the water tank to control the moisture content of the sample. This solves the problem that only the temperature can be adjusted and not the moisture content, and realizes the controllability and accuracy of the moisture content in the testing process.

[0019] 2. This utility model regulates the amount of water in the water tank through a water guide pipe and a water stop valve. The water guide pipe controls the water inlet, and the water stop valve controls the water outlet. The water inlet and water outlet do not affect each other.

[0020] 3. This utility model is equipped with a power indicator light, an emergency stop switch, and a power switch. The power indicator light allows you to observe whether the shearing machine is working, and the emergency stop switch and power switch can shut down the shearing machine in time, improving safety.

[0021] 4. Both the upper and lower shear boxes of this utility model are installed in a temperature control chamber. The temperature control chamber can be used to cyclically regulate the temperature of the sample, thereby effectively simulating the high and low temperature changes in cold-region engineering and permafrost engineering areas. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0023] Figure 2 This is a right view of the direct shearing device of this utility model;

[0024] Figure 3 This is a schematic diagram of the water tank structure of this utility model;

[0025] Figure 4 This is a graph showing the shear stress-displacement curve of this invention.

[0026] 1. Main unit, 2. Power indicator light, 3. Emergency stop switch, 4. Power switch, 5. Fixture guide rail, 6. Upper shear box, 7. Force measuring ring, 8. Lower shear box, 9. Water tank, 10. Experiment box guide rail, 11. Handwheel, 12. Temperature control box, 13. Water pipe, 14. Temperature adjustment panel, 15. Water stop valve, 16. Template fixture. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present utility model.

[0028] This utility model's technical solution includes a power supply, a temperature control chamber, a shear box, a water tank, and a water pipe. A structural sample is fixedly installed at the bottom of the water tank, and an upper shear box is placed there. A certain thickness of experimental soil is filled into the upper shear box. Water can be added to the water tank to submerge the soil-structure interface, thereby increasing the moisture content of the soil-structure sample. The temperature inside the experimental chamber is lowered by regulating the temperature control chamber, thus achieving freezing of the soil and structure. Alternatively, water can be drained while the temperature control chamber is raised to achieve evaporation and a thawing cycle. The experimental objective of freeze-thaw cycles can be achieved by circulating water in and out of the water tank and controlling the temperature of the temperature tank.

[0029] The principle of this invention is as follows: A temperature-controlled chamber is used to cyclically regulate the temperature within the test chamber, raising and lowering the temperature of the soil-structure sample in the upper shear box. This high-low temperature cycle effectively simulates the high-low temperature changes in cold-region and permafrost engineering areas. Adding water to the water tank alters the moisture content of the soil-structure sample, simulating rainfall during climate change. Temperature control further enables freeze-thaw cycles. Combining these two methods allows for the simulation of freeze-thaw cycles on cover systems during climate change.

[0030] This invention provides a freeze-thaw cycle direct shear apparatus based on temperature control. It comprises a temperature control box, a water volume adjustment unit, and a water tank. The temperature control box regulates the experimental temperature, while the water volume adjustment unit controls the water volume in the tank, thus controlling the moisture content of the sample. This solves the problem of only being able to adjust temperature and not moisture content, achieving controllability and accuracy of moisture content during the testing process. The water volume in the tank is adjusted via a water inlet pipe and a stop valve. The water inlet pipe controls the water inflow, and the stop valve controls the water outflow; the inflow and outflow are independent of each other. The invention includes a power indicator light, an emergency stop switch, and a power switch. The power indicator light shows whether the direct shear apparatus is operating, and the emergency stop switch and power switch allow for timely shutdown, improving safety. Both the upper and lower shear boxes are installed within the temperature control box, which allows for cyclical temperature control of the sample, effectively simulating high and low temperature changes in cold-region and permafrost engineering areas.

[0031] Example 1

[0032] like Figures 1-3 As shown, a temperature-controlled freeze-thaw cycle direct shear apparatus includes a cabinet, an operation box, a main unit 1, an upper shear box 6, a lower shear box 8, a water tank 9, an experimental box guide rail 10, a temperature control box 12, and a water volume adjustment unit. The temperature control box 12, the operation box, and the main unit 1 are all mounted on the cabinet. The main unit 1 is communicatively connected to both the temperature control box 12 and the operation box. The temperature control box 12 is connected to the operation box. The experimental box guide rail 10 is installed inside the temperature control box 12. The lower shear box 8 is installed on the experimental box guide rail 10. The upper shear box 6 and the water tank 9 are both installed on the lower shear box 8. The water volume adjustment unit is installed in the water tank 9.

[0033] The water tank 9 includes a water inlet and a drain hole, both of which are installed on the tank wall. The leveling unit includes a water guide pipe 13 and a water stop valve 15, with the water guide pipe 13 installed on the water inlet and the water stop valve 15 installed on the drain hole.

[0034] In this embodiment, the water tank 9 has a drain hole on the left side, which is connected to a stop valve 15. The stop valve 15 is connected to a transparent PVC drain pipe, which is two meters long. There is a water inlet hole on the left wall of the water tank 9, and a water guide pipe 13 is connected to the water inlet hole. Water is injected into the water tank 9 through a water pump. The stop valve 13 can be opened and closed at any time to strictly control the drainage volume. The upper shear box 6 and the lower shear box 8 are built into the temperature control box 12. By circulating water into and out of the water tank 9 and controlling the temperature of the temperature control box, heating and cooling are performed to achieve the purpose of freeze-thaw cycle.

[0035] The water tank 9 includes a template clamp 16. The template clamp 16 is used for fixing.

[0036] The direct shear apparatus also includes a temperature control panel 14, which is mounted on the temperature control box 12 and communicates with the main unit 1. The temperature control box 12 has an electronic screen that can display the heating temperature, and the temperature control box 12 has a temperature control panel 14 for adjusting the temperature required for the experiment.

[0037] The direct shearing device also includes a power indicator light 2, an emergency stop switch 3, and a power switch 4. The power indicator light 2, emergency stop switch 3, and power switch 4 are all installed on the control box, and the power indicator light 2, emergency stop switch 3, and power switch 4 are respectively connected to the main unit 1 for communication.

[0038] The direct shearing device also includes a force measuring ring 7 and a vertical load rod. The vertical load rod is installed on the cabinet, and the force measuring ring 7 is installed on the vertical load rod.

[0039] The straight shearing device also includes a horizontal loading unit and a clamping guide rail 5. The operation box is connected to the lower shearing box 8 through the horizontal loading unit, and the clamping guide rail 5 is connected to the lower shearing box 8.

[0040] The straight shearing device also includes a horizontal stop bar, which is mounted on the cabinet. The horizontal push rod is connected to the upper shearing box 6. The straight shearing device also includes a handwheel 11, which is connected to the horizontal stop bar.

[0041] In this embodiment, the experimental procedure is as follows:

[0042] Step 1: Pre-experiment preparation, instrument inspection and initialization. Confirm that all instrument components (main unit 1, temperature control box 12, water tank 9, upper shear box 6, lower shear box, etc.) are properly connected and that power indicator light 2 is green. Turn on power switch 4 to preheat temperature control box 12 to room temperature (default initial state).

[0043] Step 2: Sample Preparation. Lay the geogrid (330×450mm) flat on the bottom right side of the water tank 9, and fix it with template clamps 16 and bolts, ensuring the geogrid surface is flat and wrinkle-free. Fill the upper shear box 6 with a clay sample, 75mm thick, and compact it in layers to the target density. Moisture Content Control. Inject an appropriate amount of clean water into the water tank 9 through the water pipe 13, submerging the geogrid-clay interface (i.e., the soil-structure interface), and let it stand for 1 hour to allow the water to penetrate evenly. Open the water stop valve 15 and adjust the water level to the target moisture content (e.g., saturation) through the drain pipe.

[0044] Step 3: Freeze-thaw cycle simulation. ① During the freezing stage, close the stop valve 15 and set the target temperature of the temperature control chamber 12 to -20℃ (or other specified low temperature) via the temperature control panel 14. Activate the cooling function of the temperature control chamber, continuously lowering the temperature to the set temperature and maintaining stability (the screen displays the real-time temperature). Maintain the low-temperature environment for 2–3 hours to ensure the clay-grid interface (i.e., the soil-structure interface) is completely frozen. ② During the thawing stage, raise the temperature of the temperature control chamber to 100℃ (or other specified high temperature), open the stop valve 15, and drain the residual water in the water tank 9 until the sample is completely thawed. Repeat the above freeze-thaw cycle (e.g., 3 cycles) to simulate long-term freeze-thaw action.

[0045] Step 4: Set the parameters for the direct shear test. Operate the computer control system and set the normal stress (e.g., 20 kPa). Apply a vertical load to the sample surface by driving the force measuring ring 7 through the vertical pressure controller. Control the shear rate and displacement, setting the shear rate of the horizontal loading device to 1 mm / min (or other specified rate). Adjust the handwheel 11 to make the horizontal stop contact the upper shear box 6.

[0046] Step 5: Perform the shear test. Set the temperature of the temperature control chamber 12 to the ambient temperature required for the shear test, simulating the shear failure condition under extreme conditions after different cycles. Start the shear process by clicking the "Start" button on the control system. The horizontal loading device automatically pushes the lower shear box 8 to move horizontally along the guide rail 10. Real-time monitoring of the shear force data of the force measuring ring 7 and the displacement amount fed back by the displacement sensor. The system automatically records key parameters such as the shear stress-displacement curve, maximum shear strength, and residual strength. If cyclic shearing is required, set the number of cycles (e.g., 10 times) and start the cyclic mode. Figure 4 As shown.

[0047] Step 6: Post-test processing. After the test, click the "Stop" button to turn off the horizontal loading device. Unload the normal stress, remove the upper shear box 6 and the sample. Clean the instrument, drain the residual water in the water tank 9, and clean the clay residue on the surface of the shear box and fixtures. Turn off the temperature control box 12 and the main power supply, and reset the emergency stop switch 3. This operation will achieve the experimental requirement of measuring the influence of freeze-thaw cycles on the mechanical shear properties of the soil-structure interface.

[0048] The aforementioned water tank 9 is preferably made of high-strength alloy steel with a coated surface, making it resistant to high temperatures and corrosion. The upper shear box 6 is located on top of the water tank 9, and the lower shear box 6 is connected to the water tank 9 via nuts. The water tank 9 is positioned between the upper and lower shear boxes, and its height is sufficient to submerge the soil-structure interface when filled with water. The aforementioned water guide pipe and drain pipe are preferably made of high-temperature resistant, high-hardness plastic material, capable of withstanding the discharge of high-temperature water during experiments.

[0049] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A temperature-regulated freeze-thaw cycle direct shear apparatus, comprising: The direct shear apparatus comprises a cabinet, an operation box, a main machine (1), an upper shear box (6), a lower shear box (8), a water tank (9), an experimental box guide rail (10), a temperature control box (12) and a water quantity adjusting unit, the temperature control box (12), the operation box and the main machine (1) are all installed on the cabinet, the main machine (1) is in communication connection with the temperature control box (12) and the operation box respectively, the temperature control box (12) is connected with the operation box, the experimental box guide rail (10) is installed in the temperature control box (12), the lower shear box (8) is installed on the experimental box guide rail (10), the upper shear box (6) and the water tank (9) are both installed on the lower shear box (8), and the water quantity adjusting unit is installed in the water tank (9).

2. A temperature-regulated freeze-thaw cycle direct shear apparatus based on claim 1, wherein, The water tank (9) comprises a water injection pipe hole and a drain hole, and the water injection pipe hole and the drain hole are both installed on the tank wall of the water tank (9).

3. A temperature-regulated freeze-thaw cycle direct shear apparatus according to claim 2, wherein, The water quantity adjusting unit comprises a water guide pipe (13) and a water stop valve (15), the water guide pipe (13) is installed on the water injection pipe hole, and the water stop valve (15) is installed on the drain hole.

4. The temperature-regulated freeze-thaw cycle direct shear apparatus of claim 1, wherein, The water tank (9) comprises a sample plate clamp (16).

5. The temperature-regulated freeze-thaw cycle direct shear apparatus of claim 1, wherein, The direct shear apparatus further comprises a temperature adjusting panel (14), which is installed on the temperature control box (12) and in communication connection with the main machine (1).

6. A temperature-regulated freeze-thaw cycle direct shear apparatus based on claim 1, wherein, The direct shear apparatus further comprises a power indicator light (2), an emergency stop switch (3) and a power switch (4), which are all installed on the operation box and in communication connection with the main machine (1) respectively.

7. The temperature-regulated freeze-thaw cycle direct shear apparatus of claim 1, wherein, The direct shear apparatus further comprises a force ring (7) and a vertical load rod, the vertical load rod is installed on the cabinet, and the force ring (7) is installed on the vertical load rod.

8. The temperature-regulated freeze-thaw cycle direct shear apparatus of claim 1, wherein, The direct shear apparatus further comprises a horizontal loading unit and a clamp guide rail (5), the operation box is connected with the lower shear box (8) through the horizontal loading unit, and the clamp guide rail (5) is connected with the lower shear box (8).

9. The temperature-regulated freeze-thaw cycle direct shear apparatus of claim 1, wherein, The direct shear apparatus further comprises a horizontal stop rod, which is installed on the cabinet and connected with the upper shear box (6).

10. A temperature-regulated freeze-thaw cycle direct shear apparatus according to claim 9, wherein, The direct shear apparatus further comprises a hand wheel (11), which is connected with the horizontal stop rod.

Images