Device and method for simulating frosting of gaseous water in frozen rock fractures

Abstract

The invention belongs to the technical field of frozen rock fracture frosting, and particularly relates to a device and method for simulating frosting of gaseous water in frozen rock fracture.The device comprises a constant-temperature box, an observation box, an upper refrigeration table and a telescopic device, the observation box is located in the constant-temperature box, and a saline solution kit and a temperature and humidity sensor are arranged on the inner wall of the observation box; an upper refrigerating table and a lower refrigerating table are arranged in the observation box, the upper refrigerating table is connected with a telescopic device, a fixing device is arranged below the upper refrigerating table, a weight sensor is arranged on the lower refrigerating table, the upper refrigerating table and the lower refrigerating table are connected with an external circulating device through pipelines, an observation device is further connected outside the constant-temperature box, and a rock slice sample is placed on the fixing device. And another rock slice sample is placed on the weight sensor. The device has the advantages that the frosting process of the vaporous water in the fractures of the frozen rock is monitored in real time, and when the device is used for researching frosting of the vaporous water in the fractures of the frozen rock, the device has the characteristics of accurate environmental condition control, sample replacement, real-time monitoring and the like.

Description

Technical Field

[0001] The present application belongs to the technical field of frost formation in frozen rock fissures, and specifically relates to a device and method for simulating frost formation of gaseous water in frozen rock fissures. Background Art

[0002] The appearance and growth of ice layers in rock cracks are the main causes of frost heave and weathering of bedrock in cold regions. For unsaturated rock, there are often two forms of water in the cracks: liquid and gaseous. Current research focuses on the migration of liquid water in rock cracks and the mechanism of ice formation. However, for unsaturated rock, the migration of gaseous water in cracks often accounts for the majority of water migration. In some studies involving the sublimation of gaseous water into frost, the one-way freezing device in traditional frozen soil tests is often used to test artificially prefabricated fractured rock. The main problems of this test method are: (1) it is difficult to accurately control the humidity in the test environment; (2) the specimen processing is difficult, and the width of the crack is difficult to accurately control; (3) it is difficult to quantitatively distinguish between liquid water and gaseous water in the test; and (4) it is difficult to accurately observe and describe the growth process of the frost layer. Summary of the invention

[0003] Based on the above problems, the present application provides a device and application for studying the frost formation of gaseous water in frozen rock fissures, which aims to simulate the temperature and humidity of the environment, use a fixing device to clamp rock pieces of different sizes, use a telescopic device to adjust the distance between rock pieces, use a refrigeration table to cool the rock pieces, and use a side observation device to observe the frost formation on the surface of the rock pieces, so as to achieve the purpose of studying the frost formation of gaseous water in frozen rock fissures. Its technical solution is:

[0004] A device for simulating the frost formation of gaseous water in frozen rock fissures, comprising a constant temperature box, an observation box, an upper refrigeration table and a telescopic device, wherein the observation box is located inside the constant temperature box, and a salt solution test kit and a temperature and humidity sensor are arranged on the inner wall of the observation box; an upper refrigeration table and a lower refrigeration table are arranged inside the observation box, the upper refrigeration table is connected to the telescopic device, a fixing device is arranged below the upper refrigeration table, a weight sensor is arranged on the lower refrigeration table, the upper refrigeration table and the lower refrigeration table are connected to an external circulation device through pipelines, an observation device is also connected to the outside of the constant temperature box, a rock slice sample is placed on the fixing device, and another rock slice sample is placed on the weight sensor.

[0005] Preferably, the fixing device comprises a connecting block, a slide and a support, a sliding groove is provided on the lower end surface of the connecting block, a sliding rail is provided at the lower part of the connecting block, a sliding plate is provided at the lower end of the sliding rail, and the sliding plate is connected to the support.

[0006] Preferably, the observation device includes an objective lens and an eyepiece, a fine adjustment knob is provided between the objective lens and the eyepiece, the objective lens extends into the constant temperature box and is fixed on a support at the bottom, and the eyepiece is connected to a CCD industrial camera.

[0007] Preferably, the salt solution reagent box is a transparent glass reagent box, and a plurality of through holes are provided on the upper end surface.

[0008] A method for simulating frost formation of gaseous water in frozen rock fissures comprises the following steps:

[0009] S1. Initialize equipment parameters, including experimental temperature, humidity and crack width;

[0010] S2. Start the telescopic device to drive the upper cooling table to move downward. When the distance between the two rock pieces reaches the preset value of the experiment, stop the telescopic device;

[0011] S3. Turn on the circulation device, adjust the temperature of the upper and lower cooling stages, and maintain the temperature of the cooling stage when the surface of the rock slice reaches the preset value of the experiment;

[0012] S4. After the time required for the experiment is reached, the real-time data is recorded by the temperature and humidity sensor and the weight sensor, and the frost layer image on the surface of the rock slice is collected by the industrial CCD camera;

[0013] S5. Stop the experiment, restore the equipment to the initial state, and calculate the frost weight W.

[0014] Preferably, the initialization parameters include calculating the volume of the required saturated salt solution, the steps are as follows:

[0015] According to the current temperature t, calculate the saturated water vapor pressure E at this humidity:

[0016]

[0017] E 0 =611 Pascal, a and b are empirical coefficients;

[0018] Absolute humidity ρ:

[0019]

[0020] RH is the relative humidity at that temperature, R is the specific gas constant of water vapor, and T is the thermodynamic temperature;

[0021] According to the above formula, the current absolute humidity of the air ρ is calculated according to the current temperature 1 , calculate the target absolute humidity ρ according to the temperature required for the experiment 2 ;

[0022] Then the water vapor mass m that needs to be absorbed or released in the observation box space is:

[0023] m=V*(ρ 1 -ρ 2 )

[0024] V is the volume of the observation box space;

[0025]

[0026] k is an empirical value, and the volume of the required solution can be calculated according to the formula.

[0027] Preferably, the calculation method of the frost weight W is as follows:

[0028] w 1 =ρ f *d*s

[0029]

[0030] ρ f is the frost density, d is the frost thickness, s is the frost area on the lower cooling table, w 1 To calculate the frost weight, T fs is the temperature of the frost surface;

[0031]

[0032] w 2 Measured value of the weight sensor.

[0033] Preferably, before the experiment begins, check whether the temperature and humidity sensor in the constant temperature box, the weight sensor in the lower cooling table, and the CCD industrial camera can work normally, and adjust the temperature of the constant temperature box to the preset value;

[0034] According to the environmental humidity required by the experiment, select a suitable saturated salt solution and load it into the salt solution kit. The saturated salt solution will keep the humidity in the specified area at a constant value at a constant temperature;

[0035] Adjust the slide in the fixing device to the appropriate position, place the edge of the rock piece on the support platform, close to the upper cooling table, and tighten the fixing screws to fix the position of the rock piece.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1) This device is designed with a fixing device, which can realize the study of frost formation in parallel plate cracks of different materials and different gap widths;

[0038] 2) This device uses a saturated salt solution to control humidity. The saturated salt solution can precipitate salt crystals under temperature changes to absorb water vapor from the air or release water vapor into the air to achieve the effect of controlling environmental humidity. This control method has low cost, little pollution to the sample, a wide control range and high control accuracy. The control error of the traditional constant temperature and humidity chamber for environmental humidity is generally 2%, while the use of some saturated salt solutions can control the error to 1% or even lower;

[0039] 3) This device integrates a constant temperature box, humidity control, refrigeration device, and observation device, with high precision and visible process;

[0040] 4) The sensor monitoring data and the image data taken by the CCD industrial camera in this device are real-time data and can be uploaded to the cloud data platform. It has the characteristics of process automation, data storage, and flexible call.

[0041] 5) Use the least squares method to eliminate the errors between the measured and calculated values ​​to make the results more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic diagram of the structure of this application;

[0043] Figure 2 A schematic diagram of the structure of the present application in an experiment;

[0044] Figure 3 is a schematic diagram of the structure of the fixing device;

[0045] Figure 4 is a schematic diagram of the structure of the observation device;

[0046] In the figure, 1-constant temperature box, 2-telescopic device, 3-upper cooling table, 4-fixing device, 5-external circulation device, 6-pipeline, 7-weight sensor, 8-salt solution reagent kit, 9-observation device, 10-temperature and humidity sensor, 11-connecting block, 12-slide rail, 13-fastening screw, 14-slide, 15-support, 16-objective lens, 17-fine adjustment distance knob, 18-eyepiece, 19-CCD industrial camera, 20-coarse adjustment lifting knob, 21-support, 22-observation box, 23-lower cooling table. DETAILED DESCRIPTION

[0047] The technical solution of the present application is described in detail below through specific embodiments and drawings. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations on the technical solution of the present application, and the specific technical features may be combined with each other.

[0048] A device for simulating frost formation of gaseous water in frozen rock fissures, comprising a constant temperature box 1, an observation box 22 made of transparent material, an upper cooling table 3 and a telescopic device 2, wherein the observation box 22 is located inside the constant temperature box 1, and a salt solution reagent kit 8 and a temperature and humidity sensor 10 are arranged on its inner wall; an upper cooling table 3 and a lower cooling table 23 are arranged inside the observation box 18, the upper cooling table 3 is connected to the telescopic device 2, a fixing device 4 is arranged below the upper cooling table 3, a weight sensor 7 is arranged on the lower cooling table 23, the upper cooling table 3 and the lower cooling table 23 are connected to an external circulation device 5 through a pipeline 6, an observation device 9 is also connected to the outside of the constant temperature box, a rock slice sample is placed on the fixing device 4, and another rock slice sample is placed on the weight sensor 7.

[0049] The fixing device 4 includes a connecting block 11, a slide 14 and a support 15. The lower end surface of the connecting block 11 is provided with a slide groove, and the lower part of the connecting block 11 is provided with a slide rail 12. The lower end of the slide rail 12 is provided with a slide 14, and the slide 14 is connected to the support 15. The edge of the rock piece is placed on the support 15, close to the upper refrigeration table 3, and the fastening screw 13 is tightened at this time to fix the position of the rock piece. The setting of the slide rail 12 and the slide groove can adapt to rock pieces of different sizes.

[0050] The observation device includes an objective lens 16 and an eyepiece 18, a fine adjustment knob 17 is provided between the objective lens 16 and the eyepiece 18, the objective lens 16 extends into the constant temperature box 1, and is fixed on a support 21 at the bottom, and the eyepiece 18 is connected to a CCD industrial camera 19. The microscope objective lens contacts and seals the opening of the constant temperature box 1. The fine adjustment knob 17 is located on the coarse adjustment lifting knob 20, and the coarse adjustment lifting knob 20 is fixed on the support 21.

[0051] The salt solution test kit is a transparent glass test kit, and the upper end surface is provided with through holes arranged in a rice shape.

[0052] The method of using the device for studying frost formation of gaseous water in frozen rock fissures to monitor frost formation on the surface of a rock slice comprises the following steps:

[0053] Experimental preparation stage:

[0054] Before the experiment begins, check whether the temperature and humidity sensors in the constant temperature and humidity chamber, the weight sensor in the lower cooling table, and the CCD industrial camera can work properly. If there are no problems, adjust the temperature of the constant temperature and humidity chamber to the preset value;

[0055] According to the environmental humidity required by the experiment, select a suitable saturated salt solution and load it into the salt solution kit. The saturated salt solution will keep the humidity in the specified area at a constant value at a constant temperature;

[0056] To calculate the volume of saturated salt solution required, follow these steps:

[0057] According to the current temperature t, calculate the saturated water vapor pressure E at this humidity:

[0058]

[0059] E 0 =611 Pascal, a and b are empirical coefficients, take a=7.5, b=237.3.

[0060] Absolute humidity ρ:

[0061]

[0062] RH is the relative humidity at that temperature, R is the specific gas constant of water vapor, and T is the thermodynamic temperature;

[0063] According to the above formula, the current absolute humidity of the air ρ is calculated according to the current temperature 1 , calculate the target absolute humidity ρ according to the temperature required for the experiment 2 ;

[0064] Then the water vapor mass m that needs to be absorbed or released in the observation box space is:

[0065] m=V*(ρ 1 -ρ 2 )

[0066] V is the volume of the observation box space;

[0067]

[0068] k is an empirical value, and the volume of the required solution can be calculated according to the formula.

[0069] Adjust the slide in the fixing device to the appropriate position, place the edge of the rock piece on the support platform, close to the upper cooling table, and tighten the fixing screws to fix the position of the rock piece.

[0070] Experimental stage:

[0071] Start the telescopic device to drive the upper cooling table to move downward. When the distance between the rock slices reaches the preset value of the experiment, stop the telescopic device.

[0072] Select the lens with the magnification required for the experiment and install it in the objective position. Use the coarse adjustment knob and the fine adjustment knob to adjust the height of the objective and the distance from the experimental area. Turn on the CCD industrial camera.

[0073] Turn on the circulation device, adjust the temperature of the cooling table, and maintain the temperature of the cooling table when the surface of the rock slice reaches the preset value of the experiment;

[0074] After the experiment time is reached, the data collected by the temperature and humidity sensor and the weight sensor and the images taken by the CCD industrial camera are recorded;

[0075] Stop the experiment and restore the equipment to its initial state.

[0076] Calculate the frost weight W:

[0077] w 1 =ρ f *d*s

[0078]

[0079] ρ f is the frost density, d is the frost thickness, s is the frost area on the lower cooling table, w 1 To calculate the frost weight, T fs is the temperature of the frost surface;

[0080]

[0081] w 2 Measured value of the weight sensor.

[0082] The refrigeration device is used to study frost formation in frozen rock fissures. Under different temperature and humidity conditions, the frost formation process of gaseous water in frozen rock fissures is monitored in real time. The device used to study the frost formation of gaseous water in frozen rock fissures has the characteristics of precise control of environmental conditions, replaceable samples, and real-time monitoring.

[0083] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A device for simulating the formation of frost by gaseous water in frozen rock fissures, characterized in that: It includes a constant temperature box, an observation box, an upper cooling table and a telescopic device. The observation box is located inside the constant temperature box, and a salt solution test kit and a temperature and humidity sensor are arranged on the inner wall of the observation box. An upper cooling table and a lower cooling table are arranged inside the observation box. The upper cooling table is connected to the telescopic device, and a fixing device is arranged below the upper cooling table. A weight sensor is arranged on the lower cooling table. The upper cooling table and the lower cooling table are connected to an external circulation device, and an observation device is also connected to the outside of the constant temperature box. A rock sample is placed on the fixing device, and another rock sample is placed on the weight sensor.

2. The device for simulating frost formation of gaseous water in frozen rock fissures according to claim 1, characterized in that: The fixing device comprises a connecting block, a sliding piece and a supporting platform. The lower end surface of the connecting block is provided with a sliding groove, the lower part of the connecting block is provided with a sliding rail, the lower end of the sliding rail is provided with a sliding piece, and the sliding piece is connected to the supporting platform.

3. The device for simulating frost formation of gaseous water in frozen rock fissures according to claim 1, characterized in that: The observation device comprises an objective lens and an eyepiece, a fine adjustment knob for distance is arranged between the objective lens and the eyepiece, the objective lens extends into the constant temperature box, the lower part is fixed on a support, and the eyepiece is connected with a CCD industrial camera.

4. The device for simulating frost formation of gaseous water in frozen rock fissures according to claim 1, characterized in that: The salt solution reagent box is a transparent glass reagent box, and a plurality of through holes are arranged on the upper end surface.

5. A method for simulating frost formation of gaseous water in frozen rock fissures, using the frost formation device provided in claims 1-4, characterized in that: The following steps are involved: S1. Initialize equipment parameters, including experimental temperature, humidity and crack width; S2. Start the telescopic device to drive the upper cooling table to move downward. When the distance between the two rock pieces reaches the preset value of the experiment, stop the telescopic device; S3. Turn on the circulation device, adjust the temperature of the upper and lower cooling stages, and maintain the temperature of the cooling stage when the surface of the rock slice reaches the preset value of the experiment; S4. After the time required for the experiment is reached, the real-time data is recorded by the temperature and humidity sensor and the weight sensor, and the frost layer image on the surface of the rock slice is collected by the industrial CCD camera; S5. Stop the experiment, restore the equipment to the initial state, and calculate the frost weight W.

6. The method for simulating frost formation of gaseous water in frozen rock fissures according to claim 5, characterized in that: Initializing the parameters involves calculating the volume of the required saturated salt solution, as follows: According to the current temperature t, calculate the saturated water vapor pressure E at this humidity: E0 = 611 Pascal, a and b are empirical coefficients; Absolute humidity ρ: RH is the relative humidity at that temperature, R is the specific gas constant of water vapor, and T is the thermodynamic temperature; According to the above formula, the current air absolute humidity ρ1 is calculated according to the current temperature, and the target absolute humidity ρ2 is calculated according to the temperature required for the experiment; Then the water vapor mass m that needs to be absorbed or released in the observation box space is: m=V*(ρ1-ρ2) V is the volume of the observation box space; k is an empirical value, and the volume of the required solution can be calculated according to the formula.

7. The device for simulating frost formation of gaseous water in frozen rock fissures according to claim 5, characterized in that: The calculation method of frost weight W is as follows: w1=ρ f *d*s ρ f is the frost density, d is the frost thickness, s is the frost area on the lower cooling table, w1 is the calculated frost weight, T fs is the temperature of the frost surface; w2 is the weight sensor measurement value.

8. The method for simulating frost formation of gaseous water in frozen rock fissures according to claim 5, characterized in that: Before the experiment begins, check whether the temperature and humidity sensors in the constant temperature box, the weight sensor in the lower cooling table, and the CCD industrial camera are working properly, and adjust the temperature of the constant temperature box to the preset value; According to the environmental humidity required by the experiment, select a suitable saturated salt solution and load it into the salt solution kit. The saturated salt solution will keep the humidity in the specified area at a constant value at a constant temperature; Adjust the slide in the fixing device to the appropriate position, place the edge of the rock piece on the support platform, close to the upper cooling table, and tighten the fixing screws to fix the position of the rock piece.

Images