A model test system for freezing temperature field of nonlinear clay materials

Abstract

This invention relates to the field of clay freeze-thaw process research technology, and provides a model test system for the freezing temperature field of nonlinear clay materials. The system includes a model box and an adjustment component. The adjustment component is used to detect the soil inside the model box. The top of the model box is connected to the adjustment component. The model box includes a model frame, model plates, and a lid. Three model plates and an adjustment plate are respectively arranged on the outside of the model frame. The three model plates and the adjustment plate cover the model frame to form a test container for holding the soil. A first and second electric actuator are used to tilt the filter plate. Subsequently, the negative pressure generated by the movement of the piston plate causes water in the soil to migrate, allowing the water in the soil to quickly pass through the filter plate into the drainage chamber, thus completing the drainage purpose, reducing the degree of water accumulation inside the soil, and further ensuring the accuracy of experimental data during the freeze-thaw cycle experiment.

Description

Technical Field

[0001] This invention relates to the field of clay freeze-thaw process research technology, and in particular to a model test system for freezing temperature field of nonlinear clay materials. Background Technology

[0002] Seasonal changes, global warming, and temperature variations caused by various anthropogenic factors all affect the depth, strength, deformation, and stability of natural permafrost. In permafrost and seasonally frozen soil regions, strength, deformation, stability, and frost heave / thaw settlement calculations are crucial for evaluating their functionality and safe operation. Furthermore, with social and economic development, the freezing method is widely used in mining, water conservancy, transportation, and construction engineering. Before freezing construction, the soil in the construction area needs to be tested. The key equipment used in the testing phase is the freezing temperature field model test system for nonlinear clay materials, which is used to test the data on soil temperature field changes in the construction area.

[0003] Chinese patent application number CN202110477276.9 discloses an experimental system for simulating the thawing zone of high-altitude permafrost. The system includes a box device, which includes a box body filled with test soil; a temperature control device, which includes a temperature control chamber, in which the box body is placed, and the temperature control device is used to control the temperature inside the box body; and a water supply device, which is used to input water into the box body, and the water supply device includes a water supply pipe.

[0004] Based on the aforementioned existing technology, soil samples require frequent freeze-thaw cycles in the laboratory. This means that the water in the soil is constantly freezing and thawing. During this process, the water in the soil migrates, and under the influence of gravity, water from higher areas flows to lower areas and accumulates. This leads to water accumulation at the bottom of the soil. If the accumulated water is not cleaned and drained in time, it will form localized high-water-content areas in the soil. These areas thaw and settle faster, easily causing depressions and cracks on the soil surface, further damaging the integrity of the soil and affecting the experimental data.

[0005] Therefore, it is necessary to solve the above problems by using a model test system for the freezing temperature field of nonlinear clay. Summary of the Invention

[0006] The purpose of this invention is to provide a model test system for freezing temperature field of nonlinear clay materials, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a model test system for freezing temperature field of nonlinear clay, comprising a model box and an adjustment component, wherein the adjustment component is used to detect the soil inside the model box, the top of the model box is connected to the adjustment component, the model box includes a model frame, model plates and a lid, three model plates and adjustment plates are respectively arranged on the outside of the model frame, the three model plates and adjustment plates cover the model frame to form a test container for holding the soil, the lid is located on the top of the model frame and is used to seal the top of the model frame, and a temperature testing system is provided inside the model box, and the temperature testing system is used to detect the soil temperature during the soil experiment;

[0008] The adjustment component includes a circular tube, with a probe connected to the end of the circular tube near the box cover. The probe passes through the box cover and is located inside the model frame. The probe has an accommodating space inside, and a humidity sensor for detecting soil moisture is located inside the end of the probe away from the box cover. A waterproof pad is provided on the inner wall of the probe near the humidity sensor, and multiple through holes are provided on the outer surface of the probe.

[0009] Preferably, the end of the round tube away from the box cover is connected to a first conveying pipe, and the other end of the first conveying pipe extends outward along the outer surface of the box cover and is connected to a water pump. The water pump is fixed to one side of the model frame, and there are two of each first conveying pipe and round tube. Each first conveying pipe and round tube is symmetrically arranged on the upper part of the box cover, and both first conveying pipes are connected to the water pump.

[0010] A second delivery pipe is connected to one side of the water-air pump. The water-air pump is used to deliver or absorb gas and moisture to the first delivery pipe and the second delivery pipe respectively. A connector is provided at the connection between the water-air pump and the first delivery pipe and the second delivery pipe. The connector is used to thread the first delivery pipe and the second delivery pipe to the output end of the water-air pump respectively.

[0011] Preferably, the adjustment assembly further includes a drainage chamber located at the bottom of the model box. The drainage chamber is connected to the bottom of the model box via an elastic fastener, and one side of the drainage chamber is connected to the second conveying pipe.

[0012] An electromagnetic slide rail is provided on one side of the inner wall of the drainage chamber. The interior of the electromagnetic slide rail is connected to one side of the piston plate through an electromagnetic slider. A drive shaft is provided through the interior of the piston plate, and a micro motor is provided at the end of the drive shaft away from the piston plate. A mounting plate is provided on the outer surface of the micro motor, and the other side of the mounting plate is connected to the electromagnetic slider.

[0013] Preferably, the piston plate is provided with a sealing rubber strip at the top, the sealing rubber strip is folded and fitted inside the drainage chamber, the bottom of the inner wall of the drainage chamber is provided with a first electric actuator and a second electric actuator respectively, and the first electric actuator and the second electric actuator are symmetrically arranged inside the drainage chamber, and the outer sides of the first electric actuator and the second electric actuator are provided with waterproof material.

[0014] Preferably, a filter plate is provided on the top of the inner wall of the drainage chamber, and the edge of the filter plate is connected to the bottom of the model box. The bottom of the filter plate is connected to the output end of the first electric actuator and the second electric actuator. The filter plate is used to support the soil inside the model box.

[0015] Preferably, the surface of the filter plate is provided with a three-dimensional pressure cell and a three-dimensional strain rosette. The three-dimensional pressure cell is used to measure and record stress data in the soil, and the three-dimensional strain rosette is used to detect and record data on stress distribution changes in the soil.

[0016] Preferably, three freezing pipes are arranged laterally on one side of the model plate, and the three freezing pipes are used to cool the soil. Multiple reinforcing ribs are provided on the outer side of the model plate, and the reinforcing ribs are used to reinforce the model box.

[0017] Preferably, a connecting seat is symmetrically provided on one side of the model box, and a transverse support rod is fixed between the two connecting seats. Two threaded rods are symmetrically provided on one side of the transverse support rod. The two threaded rods pass through the transverse support rod and are connected to one side of the adjusting plate. The outer threads of the two threaded rods are connected to the inner threads of the transverse support rod. The adjusting plate is movably connected to one side of the model frame.

[0018] The technical effects and advantages of the present invention are as follows:

[0019] 1. This invention, through the cooperation of components such as piston plates and filter plates, uses first and second electric actuators to tilt the filter plates. Subsequently, the negative pressure generated by the movement of the piston plates causes water in the soil to migrate, allowing the water in the soil to quickly pass through the filter plates into the drainage chamber, thus completing the drainage purpose, reducing the degree of water accumulation inside the soil, and further ensuring the accuracy of experimental data during the soil freeze-thaw cycle experiment.

[0020] 2. This invention utilizes the coordinated operation of components such as a water pump, a first delivery pipe, a circular pipe, and a probe. The water pump, in conjunction with the first delivery pipe, controls the probe to blow or extract air, creating a pressure difference within the soil. This, combined with the tilting of the filter plate, guides the water from areas with higher water content to areas with lower water content, thereby achieving the purpose of water migration. This ensures that the water content in the experimental soil remains in a balanced state, guaranteeing the accuracy of data during the soil freeze-thaw experiment. Attached Figure Description

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 This is a front view of the overall structure of the mirror of the present invention;

[0023] Figure 3 This is a schematic diagram of the overall open state structure of the present invention;

[0024] Figure 4 This is a schematic diagram of the assembly structure of the circular tube and probe of the present invention;

[0025] Figure 5 This is a schematic diagram of the probe in the open state structure of the present invention;

[0026] Figure 6 This is a schematic diagram of the initial state of the piston plate and filter plate structure of the present invention;

[0027] Figure 7 This is a schematic diagram of the working structure of the second electric actuator and filter plate of the present invention;

[0028] Figure 8 This is a schematic diagram of the working structure of the first electric actuator and filter plate of the present invention.

[0029] In the diagram: 1. Model box; 101. Box cover; 102. Model frame; 103. Reinforcing rib; 104. Model plate; 105. Connecting seat; 106. Threaded rod; 107. Freezing pipe; 108. Three-dimensional strain rosette; 109. Three-dimensional pressure box; 110. Adjustment plate; 2. Adjustment assembly; 201. Circular pipe; 202. First conveying pipe; 203. Connector; 204. Water pump; 205. Second conveying pipe; 206. Drainage chamber; 207. First electric actuator; 208. Second electric actuator; 209. Probe; 210. Through hole; 211. Humidity sensor; 212. Elastic fastener; 213. Filter plate; 214. Piston plate; 215. Drive shaft; 216. Electromagnetic slide rail. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Example 1

[0031] This invention provides, for example Figures 1 to 8The diagram illustrates a model test system for the freezing-temperature field of nonlinear clay, comprising a model housing 1 and an adjustment component 2. The adjustment component 2 is used to monitor the soil within the model housing 1. The top of the model housing 1 is connected to the adjustment component 2. The model housing 1 includes a model frame 102, model plates 104, and a lid 101. Three model plates 104 and an adjustment plate 110 are respectively arranged on the outer side of the model frame 102. The three model plates 104 and the adjustment plate 110 cover the model frame 102 to form a test container for holding the soil. The model housing 1 is equipped with a temperature testing system, which is used to monitor the soil during the soil experiment. Temperature is detected. The box cover 101 is located on top of the model frame 102 and is used to seal the top of the model frame 102. The adjustment component 2 includes a round tube 201. The end of the round tube 201 near the box cover 101 is connected to a probe 209. The probe 209 penetrates the box cover 101 and is set inside the model frame 102. The inside of the probe 209 forms an accommodating space. The end of the probe 209 away from the box cover 101 is provided with a humidity sensor 211 for detecting soil moisture. The inner wall of the probe 209 near the humidity sensor 211 is provided with a waterproof pad. The outer surface of the probe 209 is provided with multiple through holes 210.

[0032] like Figure 1 , Figure 2 and Figure 3 As shown, one end of the circular tube 201 away from the box cover 101 is connected to a first conveying tube 202. The other end of the first conveying tube 202 extends outward along the outer surface of the box cover 101 and is connected to a water pump 204. The water pump 204 is fixed to one side of the model frame 102. There are two first conveying tubes 202 and two circular tubes 201. Each first conveying tube 202 and circular tube 201 are symmetrically arranged on the upper part of the box cover 101. Both first conveying tubes 202 are connected to the water pump 204. A second conveying tube 205 is connected to one side of the water pump 204. The water pump 204 is used to convey or absorb gas and water to the first conveying tube 202 and the second conveying tube 205 respectively. A connector 203 is provided at the connection between the water pump 204 and the first conveying tube 202 and the second conveying tube 205. The connector 203 is used to thread the first conveying tube 202 and the second conveying tube 205 to the output end of the water pump 204 respectively.

[0033] In use, by setting up a first delivery pipe 202 and a circular pipe 201, the water-air pump 204 can deliver or extract gas into the circular pipe 201 through the first delivery pipe 202. Since the probe 209 is connected to the circular pipe 201, when the water-air pump 204 delivers or extracts gas into the first delivery pipe 202, the probe 209 extracts moisture from the soil through multiple through holes 210 on its outer side. In addition, by setting a waterproof pad inside the probe 209, when the probe 209 absorbs moisture from the soil, the moisture will not come into contact with the humidity sensor 211 when it enters the first delivery pipe 202 through the through holes 210, thus avoiding damage or short circuit. Furthermore, by using the connector 203 set on the water-air pump 204, when it is necessary to fill the experimental soil or when the soil is removed after the experiment, the first delivery pipe 202 and the second delivery pipe 205 can be disconnected from the water-air pump 204 through the connector 203, and the box cover 101 can be removed for subsequent operations.

[0034] like Figure 3 As shown, the adjustment component 2 also includes a drainage chamber 206, which is located at the bottom of the model box 1. The drainage chamber 206 is connected to the bottom of the model box 1 through an elastic fastener 212. One side of the drainage chamber 206 is connected to the second conveying pipe 205. An electromagnetic slide rail 216 is provided on one side of the inner wall of the drainage chamber 206. The interior of the electromagnetic slide rail 216 is connected to one side of the piston plate 214 through an electromagnetic slider. A drive shaft 215 is provided through the interior of the piston plate 214. A micro motor is provided at the end of the drive shaft 215 away from the piston plate 214. A mounting plate is provided on the outer surface of the micro motor. The other side of the mounting plate is connected to the electromagnetic slider.

[0035] In use, by setting up a drainage chamber 206, the water accumulated in the experimental soil during repeated freeze-thaw cycles can flow to the bottom under the action of gravity and enter the interior of the drainage chamber 206. Then, the water in the drainage chamber 206 is discharged to the outside by the cooperation of the water pump 204 and the second delivery pipe 205. By setting an electromagnetic slide rail 216 on the inner wall of the drainage chamber 206, the piston plate 214 is controlled to slide left and right inside the drainage chamber 206. In addition, the piston plate 214 is controlled to flip by the cooperation of the micro motor set in the mounting plate and the drive shaft 215. This changes the negative pressure area generated when the water pump 204 is in the suction state by moving the piston plate 214, thereby further pumping out the accumulated water in time.

[0036] The piston plate 214 has a sealing rubber strip on its top, which is folded and fitted inside the drainage chamber 206. The bottom of the inner wall of the drainage chamber 206 is provided with a first electric actuator 207 and a second electric actuator 208, which are symmetrically arranged inside the drainage chamber 206. The outer sides of the first electric actuator 207 and the second electric actuator 208 are provided with waterproof material. The top of the inner wall of the drainage chamber 206 is provided with a filter plate 213, and the edge of the filter plate 213 is connected to the bottom of the model box 1. The bottom of the filter plate 213 is connected to the output ends of the first electric actuator 207 and the second electric actuator 208. The filter plate 213 is used to support the soil inside the model box 1. The surface of the filter plate 213 is provided with a three-dimensional pressure box 109 and a three-dimensional strain rosette 108. The three-dimensional pressure box 109 is used to measure and record stress data in the soil, and the three-dimensional strain rosette 108 is used to detect and record data on stress distribution changes in the soil.

[0037] In use, a sealing rubber strip is installed on the top of the piston plate 214 so that when the filter plate 213 is deflected by the first electric actuator 207 and the second electric actuator 208, the sealing rubber strip remains in contact with the top filter plate 213. This ensures that the piston plate 214 is always in a piston state during movement. In addition, waterproof material is installed on the outside of the first electric actuator 207 and the second electric actuator 208 to prevent the first electric actuator 207 and the second electric actuator 208 from being damaged by water accumulation due to prolonged contact with water in the drainage chamber 206. Furthermore, three-dimensional pressure boxes 109 and three-dimensional strain gauges 108 are respectively installed on the surface of the filter plate 213 to detect and record the pressure and stress changes generated by the soil during freeze-thaw cycles.

[0038] Three freezing pipes 107 are horizontally distributed on one side of the model plate 104. The three freezing pipes 107 are used to cool the soil. Multiple reinforcing ribs 103 are provided on the outer side of the model plate 104. The reinforcing ribs 103 are used to reinforce the model box 1. Connecting seats 105 are symmetrically provided on one side of the model box 1. A horizontal support rod is fixed between the two connecting seats 105. Two threaded rods 106 are symmetrically provided on one side of the horizontal support rod. The two threaded rods 106 pass through the horizontal support rod and are connected to one side of the adjusting plate 110. The outer threads of the two threaded rods 106 are connected to the inner threads of the horizontal support rod. The adjusting plate 110 is movably connected to one side of the model frame 102.

[0039] In use, three freezing pipes 107 are horizontally installed inside the model box 1. When the three freezing pipes 107 are in working condition, the experimental soil inside the model box 1 can be fully cooled to bring the experimental soil to the temperature required for the experiment, thereby better obtaining experimental data and conducting further research. At the same time, two threaded rods 106 and a horizontal support rod are set. By manually rotating the threaded rods 106, the threaded rods 106 slide inside the horizontal support rod, and push the adjusting plate 110 to move inside the model box 1, so as to adjust the required soil experimental area according to the experimental needs.

[0040] In this embodiment, the required three-dimensional pressure and three-dimensional strain gauge 108 are first pre-embedded inside the model box 1. Then, pre-prepared nonlinear clay is placed inside the model box 1. Next, according to the actual experimental requirements, the two threaded rods 106 are manually rotated to allow the adjusting plate 110 to slide inside the model box 1, thereby adjusting the experimental space inside the model box 1. Then, the freezing pipe 107 installed inside the model box 1 is turned on, allowing the freezing pipe 107 to begin cooling the soil inside the model box 1, causing the soil to quickly enter the boundary experimental process of freeze-thaw cycles. During this process, the three-dimensional pressure box 109 and three-dimensional strain gauge 108 pre-embedded in the model box 1 are used to detect and record the soil's frost heave and temperature changes in real time. By analyzing the stress changes and pressure intensity data during the thawing process, the various properties of the soil can be analyzed step by step. This achieves the purpose of conducting experiments based on the changes in the freezing temperature field of nonlinear clay. In addition, during the nonlinear clay experiment, a temperature testing system is used to continuously measure the temperature of the nonlinear clay at different freezing degrees during the experiment, and the measured temperature data is saved. Then, the temperature gradient is calculated based on the temperature points recorded at different freezing degrees. Subsequently, by combining the frost heave pressure data generated during the freezing process of nonlinear clay, the stress distribution during the freezing process, and the stress change data generated at different freezing degrees, the performance status of nonlinear clay can be obtained, and the nonlinear numerical calculation method for frozen soil can be further improved. Example 2

[0041] During freeze-thaw experiments on experimental soil, water migration occurs due to the freezing of the laboratory soil. During the thawing process, water from higher to lower areas flows and accumulates under gravity, causing water accumulation within the soil. Although the drainage chamber 206 at the bottom of model box 1 allows the accumulated water to flow downwards under its own weight and enter the drainage chamber 206, it is prone to re-accumulation at the bottom of the experimental soil during its movement, resulting in uneven water distribution. When the soil is refrozen, this affects the accuracy of the soil stress and stress distribution data. Based on this, Example 2 is proposed:

[0042] The moisture content of the experimental soil in the model box 1 is detected by two symmetrically distributed probes 209 set in the model box 1 and the humidity sensor 211 inside the probe 209. The detection areas of the two humidity sensors 211 are marked as T and T1 respectively.

[0043] After the soil freezing test and when it is in the thawing and settling state, the moisture content of the soil inside the model box 1 is detected by the humidity sensor 211 in the T area and T1 area respectively. If the moisture content data detected by the T area and T1 area is within the preset value, it means that there is no water accumulation in the experimental soil. At this time, the pressure and stress distribution data detected by the three-dimensional pressure box 109 and the three-dimensional strain rose 108 are relatively accurate. No adjustment is needed, and the freeze-thaw cycle test can be continued.

[0044] If the soil moisture content detected in region T is higher than the preset value, the data detected by the humidity sensor 211 in region T and region T1 are compared. If the data detected in region T is greater than that in region T1, it indicates that the soil moisture distribution is uneven, with region T having a higher moisture content and region T1 having a lower moisture content than the preset value. At this time, the second electric actuator 208 is extended and pressure is applied to one side of the filter plate 213, causing the filter plate 213 to pull the model box 1 through one side of the elastic fastener 212. At this time, the model box 1 tilts towards region T1, so that the moisture in region T will flow along the tilting direction of the filter plate 213 and the model box 1. The soil is then moved, and then the first delivery pipe 202 is controlled by the water-air pump 204 to blow air and pressurize the probe 209 in region T into the soil. The water-air pump 204 controls the probe 209 in region T and the probe 209 in region T1 respectively through the two first delivery pipes 202. In this way, by setting the water-air pump 204 to control the probe 209 in region T1 to generate suction into the soil, the pressure in region T will be higher than the pressure in region T1. With the help of the filter plate 213 and the tilt of the model box 1, the purpose of water migration is achieved, so that the water content in region T and region T1 is uniform, and the accuracy of the detection data during the soil freeze-thaw experiment is further ensured.

[0045] It is worth noting that the water pump 204 is a common existing device. The water pump 204 is equipped with multiple suction nozzles and exhaust nozzles, which are connected to the first delivery pipe 202 and the second delivery pipe 205 respectively. The water pump 204 can extract water and gas. The specific principle will not be elaborated here.

[0046] If the moisture content in the soil detected in region T1 is higher than the preset value, the data detected by the humidity sensor 211 in regions T and T1 are compared. If the data detected in region T1 is greater than the data detected in region T, it indicates that the moisture content of the soil is unevenly distributed, and the moisture content in region T1 is higher than the preset value, while the moisture content in region T is lower than the preset value. At this time, the first electric actuator 207 is extended and pressure is applied to the filter plate 213, causing the filter plate 213 and the model box 1 to tilt towards region T through the elastic fixing member 212. Then, the probe 209 in region T1 is controlled by the water pump 204 and the first delivery pipe 202 to blow air into the soil to increase the pressure, and the probe 209 in region T generates suction force on the soil. In this state, the pressure in region T will be lower than the pressure in region T1, and with the tilting of the filter plate 213, moisture migration is achieved, so that the moisture content in regions T and T1 is uniform, ensuring the accuracy of the detection data during the soil freeze-thaw experiment.

[0047] If the moisture content data detected in both regions T and T1 are higher than the preset value, it indicates that the moisture content in the soil is high, and drainage is required. At this time, the water pump 204 is controlled to draw air into the drainage chamber 206 through the second delivery pipe 205. Then, the electromagnetic slide rail 216 controls the piston plate 214 to move towards the first electric actuator 207 within the drainage chamber 206 via the electromagnetic slider. As the piston plate 214 moves, the pressure at the bottom of region T1 gradually increases. However, the pressure in region T gradually decreases and generates negative pressure during the interaction between the water pump 204 and the piston plate 214. Simultaneously, the first electric actuator 207 is extended to connect the filter plate 213 with the model box 1. The soil is tilted towards area T. At this point, the water in the soil of area T will quickly flow to the low-pressure area. Then, the water pump 204 and the first delivery pipe 202 are coordinated to cause the probe 209 in area T to blow air outwards. The probe 209 in area T1 is also in a blowing state. At this time, the water in the clay under molten sedimentation will be affected by the pressure difference created by the positive pressure from the probes 209 in areas T and T1 combined with the negative pressure in the bottom drainage chamber 206. This causes the water to be drawn into the drainage chamber 206 by the water pump 204. Then, the first electric actuator 207 is controlled to return to its initial state, bringing the filter plate 213 and the model box 1 to their initial state. Then, the piston plate 214 is moved towards the second electric actuator 208. As the piston plate 214 moves, it generates negative pressure suction on the soil above the drainage chamber 206 at the bottom of area T1. When the piston plate 214 moves to the position of the second electric actuator 208 in the drainage chamber 206, the micro motor is controlled to deflect the piston plate 214. Then, the piston plate 214 is quickly moved towards the first electric actuator 207. During this process, the water pump 204 generates negative pressure suction on the drainage chambers 206 of areas T and T1 through the second delivery pipe 205. This is to maintain a negative pressure state in area T1 even when the piston plate 214 deflects. When the piston plate 214 returns to its original position... After the initial position (the middle position of the filter plate 213), the water pump 204 is quickly switched to the blowing state, so that the pressure in the soil of area T and the drainage chamber 206 of area T is always higher than that in the soil of area T1 and the drainage chamber 206 of area T1. Then, the second electric actuator 208 is extended, so that the filter plate 213 and the model box 1 are tilted towards area T1. Then, the water pump 204 and the first delivery pipe 202 are coordinated to make the probe 209 in area T blow air outward, while the probe 209 in area T1 is also in the blowing state and coordinated with the tilting state of the filter plate 213 and the model box 1 at this time, so as to achieve the purpose of draining the water in area T and area T1 respectively.

[0048] Therefore, by tilting the filter plate 213 in conjunction with the movement of the piston plate 214 within the drainage chamber 206, the drainage chamber 206 generates a negative pressure on the bottom of the soil through the filter plate 213. Simultaneously, air is blown into the soil through the probe 209, creating a significant pressure difference between the upper and lower parts of the soil. This allows the water in the soil to flow smoothly through the filter plate 213 into the drainage chamber 206, thus cleaning up excess water in the soil, regulating the water content in the soil, and preventing excessive water from interfering with experimental data.

[0049] It is worth noting that during the thaw settlement process, the internal structure of clay is in a state of dynamic change. The cracks originally caused by the freeze-thaw cycle and the changes in the soil pore structure caused by thaw settlement will form some channels for gas flow, so gas molecules can migrate and diffuse in the clay along these channels.

[0050] If the probes 209 in regions T and T1 detect that the moisture content in the soil is lower than the preset value, it indicates that the soil moisture content is low. In this case, water needs to be injected into the soil to keep the moisture content within the preset value to ensure the accuracy of the soil test data. Then, manually rotate the connector 203 at the connection between the water pump 204 and the two first delivery pipes 202 to disconnect the two first delivery pipes 202 from the water pump 204. Then connect the two first delivery pipes 202 to an external water source and deliver water to the inside of the probe 209 through the two first delivery pipes 202. Water is then added to the soil through the through hole 210 on the outside of the probe 209 to keep the moisture content in the soil in regions T and T1 at the preset value, thereby avoiding errors in the soil freeze-thaw test data due to insufficient moisture.

[0051] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A model test system for freezing temperature field of nonlinear clay, comprising a model box (1) and an adjustment component (2), wherein the adjustment component (2) is used to detect the soil inside the model box (1), and the top of the model box (1) is connected to the adjustment component (2), characterized in that: The model box (1) includes a model frame (102), model plates (104) and a box cover (101). Three model plates (104) and an adjustment plate (110) are respectively provided on the outside of the model frame (102). The three model plates (104) and the adjustment plate (110) cover the model frame (102) to form a test container for holding soil. The box cover (101) is located on the top of the model frame (102) and is used to seal the top of the model frame (102). The model box (1) is equipped with a temperature testing system inside, and the temperature testing system is used to detect the soil temperature during the soil experiment. The adjustment component (2) includes a round tube (201). A probe (209) is connected to the end of the round tube (201) near the box cover (101). The probe (209) penetrates the box cover (101) and is located inside the model frame (102). An accommodating space is formed inside the probe (209). A humidity sensor (211) for detecting soil moisture is provided inside the end of the probe (209) away from the box cover (101). A waterproof pad is provided on the inner wall of the side of the probe (209) near the humidity sensor (211). A plurality of through holes (210) are provided on the outer surface of the probe (209). The adjustment component (2) also includes a drainage chamber (206), which is located at the bottom of the model box (1). The drainage chamber (206) is connected to the bottom of the model box (1) by an elastic fastener (212), and one side of the drainage chamber (206) is connected to the second conveying pipe (205). An electromagnetic slide rail (216) is provided on one side of the inner wall of the drainage chamber (206). The interior of the electromagnetic slide rail (216) is connected to one side of the piston plate (214) through an electromagnetic slider. A drive shaft (215) is provided through the interior of the piston plate (214). A micro motor is provided at the end of the drive shaft (215) away from the piston plate (214). A mounting plate is provided on the outer surface of the micro motor. The other side of the mounting plate is connected to the electromagnetic slider. The piston plate (214) is provided with a sealing rubber strip at the top. The sealing rubber strip is folded and fitted inside the drainage chamber (206). The bottom of the inner wall of the drainage chamber (206) is provided with a first electric push rod (207) and a second electric push rod (208). The first electric push rod (207) and the second electric push rod (208) are symmetrically arranged inside the drainage chamber (206). The outer sides of the first electric push rod (207) and the second electric push rod (208) are provided with waterproof material.

2. The experimental system for modeling the freezing temperature field of nonlinear clay according to claim 1, characterized in that: One end of the round tube (201) away from the box cover (101) is connected to a first conveying tube (202). The other end of the first conveying tube (202) extends outward along the outer surface of the box cover (101) and is connected to a water pump (204). The water pump (204) is fixed to one side of the model frame (102). There are two first conveying tubes (202) and two round tubes (201). Each first conveying tube (202) and round tube (201) are symmetrically arranged on the upper part of the box cover (101). Both first conveying tubes (202) are connected to the water pump (204). A second delivery pipe (205) is connected to one side of the water-air pump (204). The water-air pump (204) is used to deliver or absorb gas and moisture to the first delivery pipe (202) and the second delivery pipe (205). A connector (203) is provided at the connection between the water-air pump (204) and the first delivery pipe (202) and the second delivery pipe (205). The connector (203) is used to thread the first delivery pipe (202) and the second delivery pipe (205) to the output end of the water-air pump (204).

3. The experimental system for modeling the freezing temperature field of nonlinear clay according to claim 1, characterized in that: The top of the inner wall of the drainage chamber (206) is provided with a filter plate (213), and the edge of the filter plate (213) is connected to the bottom of the model box (1). The bottom of the filter plate (213) is connected to the output end of the first electric actuator (207) and the second electric actuator (208). The filter plate (213) is used to support the soil inside the model box (1).

4. The experimental system for modeling the freezing temperature field of nonlinear clay according to claim 3, characterized in that: The surface of the filter plate (213) is provided with a three-dimensional pressure cell (109) and a three-dimensional strain rosette (108). The three-dimensional pressure cell (109) is used to measure and record stress data in the soil, and the three-dimensional strain rosette (108) is used to detect and record data on stress distribution changes in the soil.

5. The experimental system for modeling the freezing temperature field of nonlinear clay according to claim 1, characterized in that: Three freezing pipes (107) are arranged horizontally on one side of the model plate (104). The three freezing pipes (107) are used to cool the soil. Multiple reinforcing ribs (103) are provided on the outside of the model plate (104), and the reinforcing ribs (103) are used to reinforce the model box (1).

6. The experimental system for modeling the freezing temperature field of nonlinear clay according to claim 5, characterized in that: The model box (1) is symmetrically provided with connecting seats (105) on one side. A transverse support rod is fixed between the two connecting seats (105). Two threaded rods (106) are symmetrically provided on one side of the transverse support rod. The two threaded rods (106) pass through the transverse support rod and are connected to one side of the adjusting plate (110). The outer threads of the two threaded rods (106) are connected to the inner threads of the transverse support rod. The adjusting plate (110) is movably connected to one side of the model frame (102).

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