A cooling device for testing the freezing temperature of soil samples

Abstract

The invention discloses a cooling device for testing the freezing temperature of soil samples, and relates to the technical field of soil sample freezing temperature experiments. The invention comprises a cold bin, wherein a vertical partition is arranged in the middle of the bottom of the inner cavity of the cold bin, and liquid separation holes are symmetrically arranged inside the bottom of the vertical partition, and the top of the connecting part of the two liquid separation holes is a pointed cone structure, and a connecting port is arranged at the bottom of the vertical partition, and a cold bath liquid inlet pipe is arranged at the bottom of the connecting port, and soil samples are symmetrically arranged at the bottom of the inner cavity of the cold bin about the vertical partition, and temperature sensors are inserted in the soil samples, and the temperature sensors are inserted in the center of the soil samples, and a cold bath liquid outlet pipe is arranged at the upper part of the cold bin, and a bin cover is hinged at the top of the cold bin. The invention reduces the temperature in the box by the cold bath liquid inside the cold bin, thereby achieving a cooling effect, and the cooling of the soil sample is relatively uniform and stable, which helps to capture the phenomenon that the crystallization latent heat released when the pore water undergoes a phase change causes a temperature mutation, thereby obtaining the freezing temperature of the soil.

Description

Technical Field

[0001] The invention belongs to the technical field of soil sample freezing temperature experiments, and in particular relates to a cooling device for testing the freezing temperature of a soil sample. Background Art

[0002] The freezing temperature of soil is the highest temperature or the starting freezing temperature at which the pore water in the soil freezes. The freezing temperature is not only affected by many internal factors such as soil particle size, mineral composition, water content, but also by external pressure. Therefore, the freezing temperature is a comprehensive indicator that reflects whether pore ice is formed in the soil when the temperature drops below zero under the influence of various comprehensive factors. It is an important criterion for distinguishing frozen soil from unfrozen soil. In engineering practice, the freezing temperature is also an important parameter for determining the freezing depth and melting depth of the soil. Therefore, how to measure the freezing temperature is a prerequisite for understanding the physical properties of frozen soil and is the basis for utilizing and improving frozen soil.

[0003] Although there are several methods for measuring soil freezing temperature, the temperature measurement method is widely used in indoor freezing temperature testing due to its advantages such as low cost and simple operation. The so-called temperature measurement method is based on the principle that when the water in the soil undergoes a phase change, it will release the latent heat of crystallization, causing a sudden change in temperature. By monitoring the temperature during the cooling process of the soil, the highest and most stable temperature in the soil after the temperature jump is captured to obtain the initial freezing temperature of the soil. Therefore, whether in laboratory research or engineering practice, there is an urgent need for a test device for measuring the freezing temperature of high-pressure soil with a simple structure, easy operation, high pressure bearing and high accuracy to deeply study the freezing process of deep soil.

[0004] However, there is no widely accepted experimental device for testing the freezing temperature of soil samples. Many researchers in this field usually design simple devices by themselves in the process of studying the freezing temperature, and there is no comparison of the experimental effects of the devices. There are also some self-designed devices that divide the device into two layers, upper and lower, by partitions for comparative experiments. However, when such devices are filled with cold bath liquid, the two layers are in contact with the cold bath liquid for different times, which is not conducive to comparison. Therefore, the present invention mainly invents an experimental device for measuring the freezing temperature of soil samples, which is widely used by researchers.

[0005] Currently, no effective solution has been proposed for the problems in the related technologies. Summary of the invention

[0006] In view of the problems in the related art, the present invention proposes a cooling device for testing the freezing temperature of soil samples to overcome the above technical problems existing in the existing related art.

[0007] To solve the above technical problems, the present invention is achieved through the following technical solutions:

[0008] The present invention is a cooling device for testing the freezing temperature of soil samples, comprising a cold bin, a vertical partition is arranged in the middle of the bottom end of the inner cavity of the cold bin, liquid separation through holes are symmetrically arranged inside the bottom end of the vertical partition, the top of the connecting point of two liquid separation through holes is a pointed cone structure, a connecting port is arranged at the bottom end of the vertical partition, a cold bath liquid inlet pipe is arranged at the bottom end of the connecting port, soil samples are symmetrically arranged at the bottom end of the inner cavity of the cold bin with respect to the vertical partition, temperature sensors are inserted in the soil samples, the temperature sensors are inserted in the center of the soil samples, a cold bath liquid outlet pipe is arranged at the upper part of the cold bin, and a bin cover is hinged at the top of the cold bin.

[0009] Furthermore, a sealing ring is provided at the bottom of the bin cover and located on the inner side of the cold bin, an elastic rubber pad is provided on one side of the bottom of the bin cover and located above the bin wall of the cold bin, a magnet is provided at the bottom of the elastic rubber pad, and a handle is provided on the top of the bin cover close to the elastic rubber pad.

[0010] Furthermore, a notch matching the elastic rubber pad is provided at the top of the cold storage, and a second magnet attracted to the first magnet is provided in the notch.

[0011] Furthermore, the ends of the temperature sensors are provided with wires, a sealing hole is provided on one side of the cold storage, the wires pass through the sealing hole and extend to the outside thereof, a support plate is provided on one side of the middle of the cold storage, a data acquisition device is provided on the top of the support plate, and the wires are connected to the data acquisition device.

[0012] Furthermore, the connecting port is located in the bottom wall of the cold storage bin, and the connecting point of the two liquid separation holes is located directly above the connecting port and at the center of the connecting port, that is, the pointed cone structure is located at the center above the connecting port.

[0013] Furthermore, the cold bath liquid inlet pipe is located in the bottom wall of the cold bin, and the cold bath liquid inlet pipe passes through the cold bin and extends to the outside thereof.

[0014] Furthermore, the outer side of the soil sample is sealed with a latex film.

[0015] The present invention has the following beneficial effects:

[0016] Tables 1 and 2 below list the basic physical parameters and ion contents of the soil samples, respectively. According to the Unified Soil Classification System, soil samples HC-1, HC-2, CS-1 and CS-2 belong to low plasticity fine clay (CL). The total salt content of the four groups of soil samples ranges from 2% to 36%.

[0017] HC-1 and HC-2 represent two groups of saline soils with high chloride content (≥15%) and low sulfate content (≤0.5%), while CS-1 and CS-2 represent two groups of saline soils with low chloride content (≤5%) but relatively high sulfate content. All four groups of soil samples are unsaturated soils with a saturation of 60-95%.

[0018] Table 1 Physical property parameters of saline soil

[0019]

[0020]

[0021] Table 2 Content of different salts in saline soil

[0022]

[0023] According to China Highway Engineering Standard (JTG E40-2007), under room temperature, at the optimal moisture content, 4 groups of soil samples were compacted to a relative compaction degree of 96%, and the samples were compacted again with a ring cutter with an inner diameter of 61.8 mm and a height of 20 mm, and the volume change test and the direct shear test during the cooling process were respectively carried out. In the experiment, the freezing temperature of the soil sample was tested using the cooling device of the present invention (the schematic diagram of the cooling device is shown in the figure below), the soil sample size was 40 mm in diameter and 90 mm in height, and the soil sample was sealed with a latex film before being placed in the cooling chamber. The temperature sensor is connected to the data acquisition device through a wire. The cold bath liquid in the cold chamber is circulated to the device through the cold bath liquid inlet pipe at the bottom of the device and the cold bath liquid outlet pipe at the top. In addition, a walk-in low-temperature constant temperature chamber is used for temperature adjustment and testing. The walk-in low-temperature constant temperature chamber is thermostatically controlled by a computer internal ventilation cooling device, and its temperature change can be maintained within ±0.5°C of the set temperature as low as -22°C. The prepared soil samples were sealed with latex film and then placed in a low temperature thermostat at the preselected test temperature for at least 24 hours to allow the temperature to equilibrate. The test temperature was from 20°C to -20°C in 10°C intervals.

[0024] Take one soil sample each from CS-1 and CS-2, and determine the freezing temperature of saline soil by cooling method according to (JTG E40-2007). The specific process is as follows:

[0025] 1) The soil sample is sealed in a cold chamber, initially set at 2°C; 2) After reaching thermal equilibrium, the cold bath temperature is adjusted to -20°C. During the cooling process, the temperature data of the soil sample is collected once per second; 3) When the soil sample reaches the target temperature, the experiment is completed. The CS-1 target temperature is set at -20°C, considering the in-situ soil temperature in winter and the expected freezing temperature calculated for high salt content. Due to the lower salt content of the soil sample CS-2, the expected freezing temperature is set to -10°C. Figure 5It reflects the change of soil temperature with time during the cooling process. The cooling curve of CS-2 soil sample clearly shows the different stages of soil pore water cooling and freezing: pore water is supercooled at 0-1.75h; free water freezes at 1.75h-3.5h; after 3.5h, the frozen bound water or unfrozen water film is around the soil particles. The freezing temperature of CS-2 was determined to be -2.66℃, which is about 3% higher than the predicted freezing temperature. However, when the temperature reached -20.5℃, the temperature drop curve of soil sample CS-1 did not show any signs of freezing or latent heat release, and it can be seen that its freezing temperature is lower than -20℃, which is consistent with the prediction. Table 3 summarizes the predicted and measured freezing temperatures of the four groups of soil samples. In fact, the field survey data of the Chag Expressway showed that the salt content of the soil is generally 10%, which means that most of the saline soils on this route will not freeze in winter.

[0026] Table 3 Prediction and test of freezing temperature of soil samples

[0027] Soil Grouping Test freezing temperature (℃) Predicted freezing temperature (℃) HC-1 — -170.99 HC-2 — -108.41 CS-1 <-20.5 -23.34 CS-2 -2.66 -2.75

[0028] Through the above technical scheme, 1. The temperature inside the cold bin is lowered by the cold bath liquid inside the cold bin, thereby achieving a cooling effect, and because the soil sample is completely wrapped by the cold bath liquid, the cooling of the soil sample is relatively uniform and stable, which helps to capture the phenomenon that the temperature mutation is caused by the crystallization latent heat released when the pore water undergoes a phase change, thereby obtaining the freezing temperature of the soil; 2. Through the coordinated use of the vertical partition, the liquid separation hole, and the pointed cone structure, the pointed cone structure can evenly disperse the cold bath liquid flow into the two liquid separation holes, effectively solving the problem that the contact time between the contrasting soil samples and the cold bath liquid is different, which is not conducive to comparison; 3. Through the coordinated use of magnet one, magnet two, and elastic rubber pads, the bin cover and the cold bin are more tightly fitted, which is more conducive to the control of experimental factors; 4. The device has a simple structure, is easy to operate, and has strong applicability.

[0029] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the invention, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 A perspective view of the present invention;

[0032] Figure 2 It is a structural schematic diagram of the present invention;

[0033] Figure 3 This is an enlarged view of the structure at A of the present invention;

[0034] Figure 4 It is an enlarged view of the structure at B of the present invention;

[0035] Figure 5 This is a graph showing the change of soil temperature over time.

[0036] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0037] 1. Cold chamber; 101. Sealing hole; 102. Support plate; 103. Data acquisition device; 104. Notch; 105. Magnet 2; 2. Vertical partition; 3. Liquid separation hole; 4. Cone structure; 5. Connecting port; 6. Cold bath liquid inlet pipe; 7. Soil sample; 8. Temperature sensor; 801. Wire; 9. Cold bath liquid outlet pipe; 10. Chamber cover; 1001. Sealing ring; 1002. Elastic rubber pad; 1003. Magnet 1; 1004. Handle. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the invention to clearly and completely describe the technical solutions in the embodiments of the invention. Obviously, the described embodiments are only part of the embodiments of the invention, not all of the embodiments. Based on the embodiments in the invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the invention.

[0039] In the description of the present invention, it should be understood that the terms "opening", "upper", "lower", "top", "middle", "inside", "all around" and the like indicating orientation or positional relationship are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the invention.

[0040] See also Figure 1-5 As shown, the present invention is a cooling device for testing the freezing temperature of soil samples, comprising a cold bin 1, a vertical partition 2 is arranged in the middle of the bottom end of the inner cavity of the cold bin 1, liquid separation holes 3 are symmetrically arranged inside the bottom end of the vertical partition 2, the top of the connecting point of the two liquid separation holes 3 is a pointed cone structure 4, a connecting port 5 is arranged at the bottom end of the vertical partition 2, a cold bath liquid inlet pipe 6 is arranged at the bottom end of the connecting port 5, soil samples 7 are symmetrically arranged at the bottom end of the inner cavity of the cold bin 1 with respect to the vertical partition 2, temperature sensors 8 are inserted in the soil samples 7, and the temperature sensors 8 are inserted in the center of the soil samples 7, a cold bath liquid outlet pipe 9 is arranged on the upper part of the cold bin 1, and a bin cover 10 is hinged on the top of the cold bin 1.

[0041] In one embodiment, for the above-mentioned bin cover 10, a sealing ring 1001 is provided at the bottom of the bin cover 10 and located on the inner side of the cold bin 1, an elastic rubber pad 1002 is provided on one side of the bottom end of the bin cover 10 and located above the bin wall of the cold bin 1, a magnet 1003 is provided at the bottom end of the elastic rubber pad 1002, and a handle 1004 is provided on the top of the bin cover 10 close to the elastic rubber pad 1002. Therefore, through the setting of the sealing ring 1001, the sealing effect at the bin cover 10 is better, and the temperature dissipates more slowly; through the coordinated attraction of magnet 1 1003 and magnet 2 105, the bin cover 10 and the cold bin 1 are more tightly fitted, which is more conducive to the control of experimental factors.

[0042] In one embodiment, for the above-mentioned cold warehouse 1, a recess 104 matching the elastic rubber pad 1002 is provided at the top of the cold warehouse 1, and a second magnet 105 attracted to the first magnet 1003 is provided in the recess 104, so that when the warehouse cover 10 is closed, the elastic rubber pad 1002 and the magnet 1 1003 on the warehouse cover 10 are inserted into the recess 104. At this time, the magnet 1 1003 and the magnet 2 105 want to attract each other to stretch the elastic rubber pad 1002, thereby making the warehouse cover 10 and the cold warehouse 1 fit more closely, which is more conducive to the control of experimental factors.

[0043] In one embodiment, for the above-mentioned temperature sensor 8, the end of the temperature sensor 8 is provided with a wire 801, a sealing hole 101 is provided on one side of the cold chamber 1, the wire 801 passes through the sealing hole 101 and extends to the outside thereof, a support plate 102 is provided on one side of the middle part of the cold chamber 1, a data acquisition device 103 is provided on the top of the support plate 102, the wire 801 is connected to the data acquisition device 103, so that the setting of the sealing hole 101 can prevent the cold bath liquid in the cold chamber 1 from flowing out from the wire 801, and the temperature sensor 8 is connected to the data acquisition device 103 through the wire 801, so as to measure the temperature in the soil sample 7 in real time.

[0044] In one embodiment, for the above-mentioned connecting port 5, the connecting port 5 is located in the bottom warehouse wall of the cold warehouse 1, and the connecting point of the two liquid separation holes 3 is located directly above the connecting port 5 and at the center of the connecting port 5, that is, the pointed cone structure 4 is located at the center above the connecting port 5, so that when the cold bath liquid enters from the connecting port 5, it hits the pointed cone structure 4. Since the pointed cone structure 4 is located in the center, the pointed cone structure 4 will evenly disperse the cold bath liquid flow into the two liquid separation holes 3, which effectively solves the problem that the comparison soil samples are in contact with the cold bath liquid for different times, which is not conducive to comparison.

[0045] In one embodiment, for the above-mentioned cold bath liquid inlet pipe 6, the cold bath liquid inlet pipe 6 is located in the bottom warehouse wall of the cold warehouse 1, and the cold bath liquid inlet pipe 6 passes through the cold warehouse 1 and extends to the outside thereof, so that the cold bath liquid is introduced through the cold bath liquid inlet pipe 6, and then the cold bath liquid in the cold warehouse 1 is circulated to the equipment through the cold bath liquid inlet pipe 6 at the bottom of the equipment and the cold bath liquid outlet pipe 9 at the top. The cold bath liquid inside the cold warehouse 1 reduces the temperature inside the warehouse, thereby achieving a cooling effect. Since the soil sample 7 is completely wrapped by the cold bath liquid, the cooling of the soil sample 7 is relatively uniform and stable, which helps to capture the phenomenon that the temperature mutation is caused by the crystallization latent heat released when the pore water undergoes a phase change, thereby obtaining the freezing temperature of the soil.

[0046] In one embodiment, for the soil sample 7, the outer side of the soil sample 7 is sealed with a latex film, so that the soil sample 7 is wrapped by the latex film.

[0047] In summary, with the aid of the above technical solution of the present invention, the following Tables 1 and 2 list the basic physical parameters and ion contents of the soil samples, respectively. According to the unified soil classification system, the soil samples HC-1, HC-2, CS-1 and CS-2 belong to low plastic fine clay (CL). The total salt content of the four groups of soil samples is between 2% and 36%.

[0048] HC-1 and HC-2 represent two groups of saline soils with high chloride content (≥15%) and low sulfate content (≤0.5%), while CS-1 and CS-2 represent two groups of saline soils with low chloride content (≤5%) but relatively high sulfate content. All four groups of soil samples are unsaturated soils with a saturation of 60-95%.

[0049] Table 1 Physical property parameters of saline soil

[0050]

[0051] Table 2 Content of different salts in saline soil

[0052]

[0053] According to China Highway Engineering Standard (JTG E40-2007), under room temperature conditions, at the optimal moisture content, 4 groups of soil samples were compacted to a relative compaction degree of 96%, and the samples were compacted again with a ring cutter with an inner diameter of 61.8 mm and a height of 20 mm, and the volume change test and the direct shear test during the cooling process were respectively carried out. In the experiment, the freezing temperature of the soil sample was tested using the cooling device of the present invention (the schematic diagram of the cooling device is shown in the figure below), and the soil sample 7 had a diameter of 40 mm and a height of 90 mm. The soil sample was sealed with a latex film before being placed in the cooling chamber. The temperature sensor 8 was connected to the data acquisition device 103 through a wire 801. The cold bath liquid in the cold chamber 1 was circulated into the device through the cold bath liquid inlet pipe 6 at the bottom of the device and the cold bath liquid outlet pipe 9 at the top. In addition, a walk-in low-temperature constant temperature chamber was used for temperature adjustment and testing. The walk-in low-temperature constant temperature chamber was controlled by a computer internal ventilation cooling device, and its temperature change could be kept within ±0.5°C of the set temperature as low as -22°C. The prepared soil sample 7 was sealed with a latex film and then placed in a low temperature thermostat at a preselected test temperature for at least 24 hours to allow the temperature to equilibrate. The test temperature was from 20°C to -20°C in 10°C intervals.

[0054] Take one soil sample each from CS-1 and CS-2, and determine the freezing temperature of saline soil by cooling method according to (JTG E40-2007). The specific process is as follows:

[0055] 1) Soil sample 7 is sealed in a cold chamber and initially set at 2°C; 2) After reaching thermal equilibrium, the cold bath temperature is adjusted to -20°C. During the cooling process, the temperature data of soil sample 7 is collected once per second; 3) When soil sample 7 reaches the target temperature, the experiment is completed. The CS-1 target temperature is set at -20°C, considering the in-situ soil temperature in winter and the expected freezing temperature calculated for high salt content. Due to the lower salt content of soil sample CS-2, the expected freezing temperature is set to -10°C. Figure 5 It reflects the change of soil temperature with time during the cooling process. The cooling curve of CS-2 soil sample clearly shows the different stages of soil pore water cooling and freezing: pore water is supercooled at 0-1.75h; free water freezes at 1.75h-3.5h; after 3.5h, the frozen bound water or unfrozen water film is around the soil particles. The freezing temperature of CS-2 was determined to be -2.66℃, which is about 3% higher than the predicted freezing temperature. However, when the temperature reached -20.5℃, the temperature drop curve of soil sample CS-1 did not show any signs of freezing or latent heat release, and it can be seen that its freezing temperature is lower than -20℃, which is consistent with the prediction. Table 3 summarizes the predicted and measured freezing temperatures of the four groups of soil samples. In fact, the field survey data of the Chag Expressway showed that the salt content of the soil is generally 10%, which means that most of the saline soils on this route will not freeze in winter.

[0056] Table 3 Prediction and test of freezing temperature of soil samples

[0057]

[0058]

[0059] Through the above technical scheme, 1. The temperature inside the cold bin 1 is lowered by the cold bath liquid inside the cold bin, so as to achieve the cooling effect, and because the soil sample 7 is completely wrapped by the cold bath liquid, the cooling of the soil sample 7 is relatively uniform and stable, which helps to capture the phenomenon that the temperature mutation is caused by the crystallization latent heat released when the pore water undergoes a phase change, so as to obtain the freezing temperature of the soil; 2. Through the coordinated use of the vertical partition 2, the liquid separation hole 3, and the pointed cone structure 4, the pointed cone structure 4 can evenly disperse the cold bath liquid flow into the two liquid separation holes 3, effectively solving the problem that the contact time between the contrasting soil samples and the cold bath liquid is different, which is not conducive to comparison; 3. Through the coordinated use of magnet 1 1003, magnet 2 105, and elastic rubber pad 1002, the bin cover 10 and the cold bin 1 are more tightly fitted, which is more conducive to the control of experimental factors; 4. The device has a simple structure, convenient operation, and strong applicability.

[0060] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0061] The preferred embodiments of the invention disclosed above are only used to help illustrate the invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the invention, so that those skilled in the art can better understand and use the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for cooling a test soil sample at freezing temperature, using a test soil sample at freezing temperature cooling device, the device comprising a cold chamber (1), characterized in that: A vertical partition (2) is arranged in the middle of the bottom end of the inner cavity of the cold bin (1), and liquid separation holes (3) are symmetrically arranged inside the bottom end of the vertical partition (2), and the top of the connecting point of the two liquid separation holes (3) is a pointed cone structure (4). A connecting port (5) is arranged at the bottom end of the vertical partition (2), and a cold bath liquid inlet pipe (6) is arranged at the bottom end of the connecting port (5). Soil samples (7) are symmetrically arranged at the bottom end of the inner cavity of the cold bin (1) with respect to the vertical partition (2), and temperature sensors (8) are inserted in the soil samples (7), and the temperature sensors (8) are inserted in the center of the soil samples (7). A cold bath liquid outlet pipe (9) is arranged at the top of the cold bin (1), and a bin cover (10) is hinged at the top end of the cold bin (1); The ends of the temperature sensors (8) are each provided with a wire (801); a sealing hole (101) is provided on one side of the cold storage (1); the wire (801) passes through the sealing hole (101) and extends to the outside thereof; a support plate (102) is provided on one side of the middle of the cold storage (1); a data acquisition device (103) is provided on the top of the support plate (102); and the wire (801) is connected to the data acquisition device (103); The connecting port (5) is located in the bottom wall of the cold storage (1), and the connecting point of the two liquid separation through holes (3) is located directly above the connecting port (5) and at the center of the connecting port (5), that is, the pointed cone structure (4) is located at the center above the connecting port (5); The outer side of the soil sample (7) is sealed with a latex film; A sealing ring (1001) is provided at the bottom of the bin cover (10) and located on the inner side of the cold bin (1); an elastic rubber pad (1002) is provided on one side of the bottom of the bin cover (10) and located above the bin wall of the cold bin (1); a magnet (1003) is provided at the bottom of the elastic rubber pad (1002); and a handle (1004) is provided at the top of the bin cover (10) and close to the elastic rubber pad (1002); The top of the cold storage (1) is provided with a notch (104) matching the elastic rubber pad (1002), and a second magnet (105) attracted to the first magnet (1003) is provided in the notch (104); Under room temperature conditions and at an optimal moisture content, the soil sample is compacted to a relative compaction degree of 96%. The sample is compacted again with a ring cutter having an inner diameter of 61.8 mm and a height of 20 mm. A volume change test and a direct shear test during the cooling process are respectively carried out. In the experiment, the freezing temperature of the soil sample is tested using the cooling device. The soil sample (7) has a diameter of 40 mm and a height of 90 mm. The soil sample is sealed with a latex film before being placed in the cooling chamber. The temperature sensor (8) is connected to the data acquisition device (103) through a wire (801). The cold bath liquid in the cold chamber (1) is circulated into the device through a cold bath liquid inlet pipe (6) at the bottom of the device and a cold bath liquid outlet pipe (9) at the top. In addition, a walk-in low-temperature constant temperature chamber is used for temperature adjustment and testing. The walk-in low-temperature constant temperature chamber is temperature-controlled by a computer internal ventilation cooling device, and its temperature change is maintained at ±0.05°C of a set temperature as low as -22°C. The prepared soil sample (7) was sealed with a latex film and then placed in a low temperature incubator at a preselected test temperature for at least 24 hours to allow the temperature to equilibrate within .5°C. The test temperature was varied from 20°C to -20°C at intervals of 10°C.

2. A method for cooling a test soil sample to freezing temperature according to claim 1, characterized in that: The cold bath liquid inlet pipe (6) is located in the bottom wall of the cold bin (1), and the cold bath liquid inlet pipe (6) passes through the cold bin (1) and extends to the outside thereof.

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