High-efficiency rock heat conductivity coefficient test device and test method for simulating natural confining pressure environment

Abstract

The invention provides an efficient rock heat conductivity coefficient test device and test method for simulating a natural confining pressure environment, the test device comprises an upper computer, and also comprises a confining pressure loading system and a test measurement system, and the confining pressure loading system and the test measurement system are arranged up and down and are controlled by the upper computer. An efficient and accurate test method can be provided for simulating the change rule of the heat conductivity coefficient of the rock in the natural stress environment, the confining pressure loading system is designed and adopted, true triaxial confining pressure can be applied to the sample, and the stress environment where the natural rock mass is located is simulated; the confining pressure loading system comprises four confining pressure loading bins, four samples can be measured at the same time, the test efficiency is improved, and a contrast test is formed; the heat conductivity coefficient of the sample is tested by adopting an optical scanning technology based on a moving point heat source principle, the test speed is high, and the precision is high; the test requirements can be met when the cubic test piece is small in height difference of a test surface and the size is larger than that of a scanning channel.

Description

Technical Field

[0001] The invention relates to the fields of rock thermophysical properties and rock mechanics, and in particular to a high-efficiency rock thermal conductivity test device and a test method for simulating a natural confining pressure environment. Background Art

[0002] In key fields such as geotechnical engineering, geothermal energy mining, and radioactive nuclear waste disposal, the thermodynamic parameters of rocks, especially thermal conductivity, play a vital role in understanding the thermal-solid coupling mechanism of rock mass and evaluating the long-term stability and safety of engineering. Thermal conductivity is an important physical quantity that reflects the thermal conductivity of rock materials. It determines the speed and efficiency of heat transfer inside the rock. Therefore, accurate determination of the thermal conductivity of rocks has important reference value for the design, construction, and maintenance of rock mass engineering.

[0003] In the existing technology, triaxial test devices are mainly used to test the mechanical properties of rocks under complex stress states, such as compressive strength, elastic modulus, etc. However, these devices often cannot simultaneously measure the thermal parameters of rocks, such as thermal conductivity. Although there are some devices that can measure the thermal conductivity of rocks, they usually cannot take into account the confining pressure environment of natural rocks, and the test efficiency is low, which makes it difficult to meet the needs of rapid and accurate measurement of rock thermodynamic parameters. For this reason, it is necessary to design an efficient and accurate rock thermal conductivity test device that can simulate the natural confining pressure environment to complete related testing work. Summary of the invention

[0004] The first object of the present invention is to provide an efficient rock thermal conductivity test device for simulating a natural confining pressure environment in response to the above-mentioned problems.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A high-efficiency rock thermal conductivity test device for simulating a natural confining pressure environment, comprising a host computer, a confining pressure loading system and a test measurement system, wherein the confining pressure loading system and the test measurement system are arranged on top and on the bottom, and there is a certain spacing between the two along the longitudinal direction, and the spacing can be 0;

[0007] The confining pressure loading system comprises an outer box of the confining pressure loading system, wherein a first confining pressure loading chamber, a second confining pressure loading chamber, a third confining pressure loading chamber, and a fourth confining pressure loading chamber are arranged in the outer box of the confining pressure loading system, and a first probe scanning channel is opened at the bottom of the outer box of the confining pressure loading system, and the length of the first probe scanning channel covers the contours of the first confining pressure loading chamber, the second confining pressure loading chamber, the third confining pressure loading chamber, and the fourth confining pressure loading chamber;

[0008] The test measurement system includes a test measurement system outer box, a mobile probe conveyor belt is arranged in the test measurement system outer box, and the transmission direction of the mobile probe conveyor belt is consistent with the arrangement direction of the first confining pressure loading bin, the second confining pressure loading bin, the third confining pressure loading bin and the fourth confining pressure loading bin; a mobile probe is arranged on the mobile probe conveyor belt and is controlled by a host computer, a raised pedestal is arranged on the test measurement system outer box, a first standard sample card slot and a second standard sample card slot are arranged on both sides of the pedestal, the test measurement system outer box and the pedestal are hollowed out in the middle and are provided with a second probe scanning channel, and the extension direction of the second probe scanning channel is consistent with the mobile probe conveyor belt and the first probe scanning channel.

[0009] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0010] As a preferred technical solution of the present invention: a lifting mechanism is provided around the confining pressure loading system and the test measurement system, and the lifting mechanism is used to lift the confining pressure loading system to adjust the distance between the confining pressure loading system and the test measurement system.

[0011] As a preferred technical solution of the present invention: the lifting mechanism includes a threaded guide rail and a high-rigidity threaded guide rail column, a confining pressure loading system is fixed on the high-rigidity threaded guide rail column, and the high-rigidity threaded guide rail column is lifted and lowered on the threaded guide rail under the drive of a motor.

[0012] As a preferred technical solution of the present invention: the first confining pressure loading bin, the second confining pressure loading bin, the third confining pressure loading bin and the fourth confining pressure loading bin are provided with samples to be tested, and the size specifications and preparation materials of the confining pressure loading bins are exactly the same.

[0013] As a preferred technical solution of the present invention: the standard samples in the first standard sample slot and the second standard sample slot are rectangular or cubic specimens made of standard materials with known thermal conductivity values.

[0014] As a preferred technical solution of the present invention: a first infrared temperature sensor, a laser point heat source, and a second infrared temperature sensor are sequentially arranged along the detection channel on the mobile probe, a third infrared temperature sensor is arranged next to the second infrared temperature sensor, and the second infrared temperature sensor and the third infrared temperature sensor are arranged side by side along the detection channel.

[0015] The second object of the present invention is to provide a test method for high-efficiency rock thermal conductivity under a simulated natural confining pressure environment.

[0016] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0017] A high-efficiency rock thermal conductivity test method for simulating a natural confining pressure environment, characterized in that: the test method is based on the test device described above and includes the following steps:

[0018] S1: Turn on the host computer and start the servo hydraulic press in the test measurement system to make the confining pressure loading system rise to a certain height along the threaded guide column;

[0019] S2: four rectangular parallelepiped specimens are sequentially loaded into the first confining pressure loading chamber, the second confining pressure loading chamber, the third confining pressure loading chamber, and the fourth confining pressure loading chamber, and then closed;

[0020] S3: placing the first and second standard samples into the first standard sample slot and the second standard sample slot respectively;

[0021] S4: The upper computer controls the servo hydraulic press in the test measurement system to make the confining pressure loading system descend along the threaded guide rail column until the bottom depression of the outer box of the confining pressure loading system is matched and fixed with the top protrusion of the pedestal;

[0022] S5: Start the servo hydraulic press in the confining pressure loading system, and set the speed and size of the confining pressure loading through the host computer;

[0023] S6: Start the motor and the mobile probe in the test measurement system, drive the mobile probe to move through the mobile probe conveyor belt, and scan and test the first standard sample, the samples in the four confining pressure loading chambers, and the second standard sample in sequence through the second probe scanning channel and the first probe scanning channel.

[0024] S7: Calculate the thermal conductivity of the sample through the built-in software of the host computer. If the value is too different from the standard sample, replace the corresponding standard sample, control the motor to reverse, and drive the moving probe back to the initial position through the moving probe conveyor belt, and repeat S3-S6 until the value is close to the end of the test. If the value is close, the test is over and the next step is directly carried out;

[0025] S8: After the test is completed, the servo hydraulic press in the confining pressure loading system is controlled by the host computer to unload the confining pressure in the X, Y, and Z directions;

[0026] S9: The upper computer controls the confining pressure loading system to control the servo hydraulic press in the test measurement system so that the confining pressure loading system rises to a certain height along the threaded guide column;

[0027] S10: The upper computer controls the confining pressure loading system to control the motor in the test measurement system to reverse, and the moving probe is driven back to the initial position by the moving probe conveyor belt.

[0028] S11: Turn off the mobile probe, the motor and servo hydraulic press in the test measurement system, and the servo hydraulic press in the confining pressure loading system;

[0029] S12: taking out four rectangular parallelepiped specimens from the first confining pressure loading bin, the second confining pressure loading bin, the third confining pressure loading bin, and the fourth confining pressure loading bin;

[0030] S13: Clean the confining pressure loading chamber, the pedestal, the first probe scanning channel and the second probe scanning channel.

[0031] S14: Process data through the host computer.

[0032] The present invention provides an efficient rock thermal conductivity test device and method for simulating a natural confining pressure environment, which has the following beneficial effects: the present invention can provide an efficient and accurate test method for simulating the thermal conductivity variation law of rocks in a natural stress environment, and is designed to adopt a confining pressure loading system, which can apply true triaxial confining pressure to a sample to simulate the stress environment of a natural rock mass; the confining pressure loading system comprises four confining pressure loading chambers, which can measure four samples at the same time, improve the test efficiency, and form a comparative test; the optical scanning technology based on the principle of a moving point heat source is adopted to test the thermal conductivity of the sample, and the test speed is fast and the accuracy is high; there is little restriction on the sample size, and a cubic specimen with a small height difference of the test surface and a size larger than a scanning channel can meet the test needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of a high-efficiency rock thermal conductivity test device for simulating a natural confining pressure environment provided by the present invention.

[0034] Figure 2 Schematic diagram of the confining pressure loading system.

[0035] Figure 3 Schematic diagram of the experimental measurement system.

[0036] Figure 4 Schematic diagram of the arrangement of the mobile probe infrared temperature sensor and the laser point heat source.

[0037] In the figure: 1-host computer; 2-confining pressure loading system; 3-test measurement system; 4-threaded guide column; 21-outer box of confining pressure loading system; 22-first confining pressure loading chamber; 23-second confining pressure loading chamber; 24-third confining pressure loading chamber; 25-fourth confining pressure loading chamber; 26-first probe scanning channel; 31-outer box of test measurement system; 32-movable probe conveyor belt; 33-movable probe; 34-pedestal; 35-first standard sample slot; 36-second standard sample slot; 37-second probe scanning channel; 331-first infrared temperature sensor; 332-laser point heat source; 333-second infrared temperature sensor; 334-third infrared temperature sensor. DETAILED DESCRIPTION

[0038] The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

[0039] like Figure 1-4 As shown, a high-efficiency rock thermal conductivity test device for simulating a natural confining pressure environment includes a host computer 1, a confining pressure loading system 2 and a test measurement system 3, the confining pressure loading system 2 and the test measurement system 3 are arranged on top and bottom, and there is a certain distance between the two along the longitudinal direction, and the distance can be 0;

[0040] The confining pressure loading system 2 includes a confining pressure loading system outer box 21, in which a first confining pressure loading chamber 22, a second confining pressure loading chamber 23, a third confining pressure loading chamber 24, and a fourth confining pressure loading chamber 25 are arranged. A first probe scanning channel 26 is provided at the bottom of the confining pressure loading system outer box 21, and the length of the first probe scanning channel 26 covers the contours of the first confining pressure loading chamber 22, the second confining pressure loading chamber 23, the third confining pressure loading chamber 24, and the fourth confining pressure loading chamber 25;

[0041] The test measurement system 3 includes a test measurement system outer box 31, in which a mobile probe conveyor belt 32 is arranged, and the transmission direction of the mobile probe conveyor belt 32 is consistent with the arrangement direction of the first confining pressure loading bin 22, the second confining pressure loading bin 23, the third confining pressure loading bin 24, and the fourth confining pressure loading bin 25; a mobile probe 33 is arranged on the mobile probe conveyor belt 32 and is controlled by the host computer 1, and a raised pedestal 34 is arranged on the test measurement system outer box 31, and a first standard sample card slot 35 and a second standard sample card slot 36 are arranged on both sides of the pedestal 34. The test measurement system outer box 31 and the pedestal 34 are hollowed out in the middle and provided with a second probe scanning channel 37, and the extension direction of the second probe scanning channel 37 is consistent with the mobile probe conveyor belt 32 and the first probe scanning channel 26.

[0042] A lifting mechanism is provided around the confining pressure loading system 2 and the test measurement system 3 , and the lifting mechanism is used to lift the confining pressure loading system 2 to adjust the distance between the confining pressure loading system 2 and the test measurement system 3 .

[0043] The lifting mechanism includes a threaded guide rail and a high-rigidity threaded guide rail column 4. The confining pressure loading system 2 is fixed on the high-rigidity threaded guide rail column 4. The high-rigidity threaded guide rail column 4 is lifted and lowered on the threaded guide rail under the drive of a motor. In this embodiment, the high-rigidity threaded guide rail column 4 is a screw with a motor at one end.

[0044] The first confining pressure loading chamber 22, the second confining pressure loading chamber 23, the third confining pressure loading chamber 24, and the fourth confining pressure loading chamber 25 are provided with samples to be tested, and the size specifications and preparation materials of the confining pressure loading chambers are exactly the same. The confining pressure loading device appearing in Dr. Shan Kun's thesis "Study on the Influencing Factors and Seismic Characteristics of EGS Fluid Injection Induced Earthquakes" and the confining pressure loading forms in Chinese patents CN207636416U and CN116183377A can be adopted. The confining pressure loading devices of the first confining pressure loading chamber 22, the second confining pressure loading chamber 23, the third confining pressure loading chamber 24, and the fourth confining pressure loading chamber 25 are arranged and controlled and connected through the upper computer 1 to provide true triaxial confining pressure in the X, Y, and Z directions for the samples in the four loading chambers.

[0045] The standard samples in the first standard sample slot 35 and the second standard sample slot 36 are rectangular or cubic specimens made of standard materials with known thermal conductivity values, and the bottom surface size thereof is larger than the first probe scanning channel 26 of the confining pressure loading system 2 .

[0046] A first infrared temperature sensor 331, a laser point heat source 332, and a second infrared temperature sensor 333 are sequentially arranged along the detection channel (the first probe scanning channel 26, the second probe scanning channel 37) on the mobile probe 33. A third infrared temperature sensor 334 is arranged next to the second infrared temperature sensor 333. The second infrared temperature sensor 333 and the third infrared temperature sensor 334 are arranged side by side along the detection channel. The laser point heat source 332 heats the rock sample, and the temperature difference between the standard sample and the test sample before and after heating is compared. Based on the principle of a mobile point heat source, the thermal conductivity of the sample is calculated by the built-in software of the host computer 1.

[0047] The host computer 1 is connected with the servo hydraulic press, the motor, the laser point heat source, and the temperature sensor through corresponding connecting lines, and can coordinately control the test, display the corresponding values ​​in real time, store data, and process data.

[0048] Specifically, the above-mentioned high-efficiency rock thermal conductivity test device for simulating natural confining pressure environment is implemented by the following test method:

[0049] S1: Turn on the host computer 1, start the servo hydraulic press in the test measurement system 3, and make the confining pressure loading system 2 rise to a certain height along the threaded guide column 4;

[0050] S2: four rectangular parallelepiped specimens are sequentially loaded into the first confining pressure loading chamber 22, the second confining pressure loading chamber 23, the third confining pressure loading chamber 24, and the fourth confining pressure loading chamber 25 and then closed;

[0051] S3: Place the first and second standard samples into the first standard sample slot 35 and the second standard sample slot 36 respectively;

[0052] S4: The upper computer 1 controls the servo hydraulic press in the test measurement system 3, so that the confining pressure loading system 2 is lowered along the threaded guide rail column 4 until the bottom depression of the confining pressure loading system outer box 21 is matched and fixed with the top protrusion of the pedestal 34;

[0053] S5: Start the servo hydraulic press in the confining pressure loading system 2, and set the speed and size of the confining pressure loading through the host computer 1;

[0054] S6: Start the motor and the mobile probe 33 in the test measurement system 3, drive the mobile probe 33 to move through the mobile probe conveyor belt 32, and scan and test the first standard sample, the samples in the four confining pressure loading chambers, and the second standard sample in sequence through the second probe scanning channel 37 and the first probe scanning channel 26.

[0055] S7: Calculate the thermal conductivity of the sample through the built-in software of the host computer 1. If the value is too different from the standard sample, replace the corresponding standard sample, control the motor to reverse, and drive the mobile probe 33 back to the initial position through the mobile probe conveyor belt 32, and repeat S3-S6 until the value is close to the end of the test. If the value is close, the test is over and the next step is directly performed;

[0056] S8: After the test is completed, the servo hydraulic press in the confining pressure loading system 2 is controlled by the host computer 1 to unload the confining pressure in the X, Y, and Z directions;

[0057] S9: controlling the confining pressure loading system 2 through the upper computer 1 to control the servo hydraulic press in the test measurement system 3 so that the confining pressure loading system 2 rises to a certain height along the threaded guide column 4;

[0058] S10: The upper computer 1 controls the confining pressure loading system 2 to control the motor in the test measurement system 3 to reverse, and the mobile probe 33 is driven back to the initial position by the mobile probe conveyor belt 32.

[0059] S11: Turn off the mobile probe 33, the motor and the servo hydraulic press in the test measurement system 3, and the servo hydraulic press in the confining pressure loading system 2;

[0060] S12: taking out four rectangular parallelepiped specimens from the first confining pressure loading chamber 22, the second confining pressure loading chamber 23, the third confining pressure loading chamber 24, and the fourth confining pressure loading chamber 25;

[0061] S13: Clean the confining pressure loading chamber, the pedestal 34 , the first probe scanning channel 26 and the second probe scanning channel 37 .

[0062] S14: Processing data through the host computer 1.

[0063] The above-mentioned specific implementation methods are used to explain the present invention and are only preferred embodiments of the present invention, rather than limiting the present invention. Any modifications, equivalent substitutions, improvements, etc. made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. An efficient rock thermal conductivity test device for simulating a natural confining pressure environment, comprising a host computer (1), characterized in that: It also includes a confining pressure loading system (2) and a test measurement system (3), wherein the confining pressure loading system (2) and the test measurement system (3) are arranged on top and bottom, and there is a certain distance between the two along the longitudinal direction; The confining pressure loading system (2) comprises a confining pressure loading system outer box (21), wherein a first confining pressure loading chamber (22), a second confining pressure loading chamber (23), a third confining pressure loading chamber (24), and a fourth confining pressure loading chamber (25) are arranged in the confining pressure loading system outer box (21), and a first probe scanning channel (26) is provided at the bottom of the confining pressure loading system outer box (21), and the length of the first probe scanning channel (26) covers the contours of the first confining pressure loading chamber (22), the second confining pressure loading chamber (23), the third confining pressure loading chamber (24), and the fourth confining pressure loading chamber (25); The test measurement system (3) comprises a test measurement system outer box (31), a mobile probe conveyor belt (32) is arranged in the test measurement system outer box (31), and the transmission direction of the mobile probe conveyor belt (32) is consistent with the arrangement direction of the first confining pressure loading bin (22), the second confining pressure loading bin (23), the third confining pressure loading bin (24), and the fourth confining pressure loading bin (25); a mobile probe (33) is arranged on the mobile probe conveyor belt (32) and is controlled by the host computer (1); a raised pedestal (34) is arranged on the test measurement system outer box (31), and a first standard sample card slot (35) and a second standard sample card slot (36) are arranged on both sides of the pedestal (34); the test measurement system outer box (31) and the pedestal (34) are hollowed out in the middle and provided with a second probe scanning channel (37), and the extension direction of the second probe scanning channel (37) is consistent with the mobile probe conveyor belt (32) and the first probe scanning channel (26).

2. The high-efficiency rock thermal conductivity test device for simulating natural confining pressure environment according to claim 1 is characterized in that: A lifting mechanism is provided around the confining pressure loading system (2) and the test measurement system (3), and the lifting mechanism is used to lift the confining pressure loading system (2) to adjust the distance between the confining pressure loading system (2) and the test measurement system (3).

3. The high-efficiency rock thermal conductivity test device for simulating natural confining pressure environment according to claim 2 is characterized in that: The lifting mechanism comprises a threaded guide rail and a high-rigidity threaded guide rail column (4), a confining pressure loading system (2) is fixed on the high-rigidity threaded guide rail column (4), and the high-rigidity threaded guide rail column (4) is lifted and lowered on the threaded guide rail under the drive of a motor.

4. The high-efficiency rock thermal conductivity test device for simulating natural confining pressure environment according to claim 1 is characterized in that: The first confining pressure loading chamber (22), the second confining pressure loading chamber (23), the third confining pressure loading chamber (24), and the fourth confining pressure loading chamber (25) are provided with samples to be tested, and the size specifications and preparation materials of the confining pressure loading chambers are completely the same.

5. The high-efficiency rock thermal conductivity test device for simulating natural confining pressure environment according to claim 1 is characterized in that: The standard samples in the first standard sample slot (35) and the second standard sample slot (36) are rectangular or cubic specimens made of standard materials with known thermal conductivity values.

6. The high-efficiency rock thermal conductivity test device for simulating natural confining pressure environment according to claim 1 is characterized in that: A first infrared temperature sensor (331), a laser point heat source (332), and a second infrared temperature sensor (333) are sequentially arranged along a detection channel on the mobile probe (33); a third infrared temperature sensor (334) is arranged next to the second infrared temperature sensor (333); and the second infrared temperature sensor (333) and the third infrared temperature sensor (334) are arranged side by side along the detection channel.

7. A test method for thermal conductivity of high-efficiency rocks under a simulated natural confining pressure environment, characterized in that: The test method is based on the high-efficiency rock thermal conductivity test device for simulating a natural confining pressure environment as claimed in claim 1, and comprises the following steps: S1: Turn on the host computer (1), start the servo hydraulic press in the test measurement system (3), and make the confining pressure loading system (2) rise to a certain height along the threaded guide column (4); S2: four rectangular parallelepiped specimens are sequentially loaded into the first confining pressure loading chamber (22), the second confining pressure loading chamber (23), the third confining pressure loading chamber (24), and the fourth confining pressure loading chamber (25), and then closed; S3: placing the first and second standard samples into the first standard sample slot (35) and the second standard sample slot (36) respectively; S4: The upper computer (1) controls the servo hydraulic press in the test measurement system (3) so that the confining pressure loading system (2) is lowered along the threaded guide rail column (4) until the bottom depression of the confining pressure loading system outer box (21) is matched and fixed with the top protrusion of the pedestal (34); S5: starting the servo hydraulic press in the confining pressure loading system (2), and setting the speed and magnitude of the confining pressure loading through the host computer (1); S6: Start the motor and the mobile probe (33) in the test measurement system (3), drive the mobile probe (33) to move through the mobile probe conveyor belt (32), and scan and test the first standard sample, the samples in the four confining pressure loading chambers, and the second standard sample in sequence through the second probe scanning channel (37) and the first probe scanning channel (26). S7: Calculate the thermal conductivity of the sample by the built-in software of the host computer (1). If the value is too different from that of the standard sample, replace the corresponding standard sample, control the motor to reverse, and drive the mobile probe (33) back to the initial position through the mobile probe conveyor belt (32), and repeat S3-S6 until the value is close to the end of the test. If the value is close, the test is over and the next step is directly carried out; S8: After the test is completed, the servo hydraulic press in the confining pressure loading system (2) is controlled by the upper computer (1) to release the confining pressure in the X, Y and Z directions; S9: controlling the confining pressure loading system (2) through the upper computer (1) to control the servo hydraulic press in the test measurement system (3) to make the confining pressure loading system (2) rise to a certain height along the threaded guide column (4); S10: The upper computer (1) controls the confining pressure loading system (2) to control the motor in the test measurement system (3) to reverse, and drives the mobile probe (33) back to the initial position through the mobile probe conveyor belt (32). S11: Turn off the mobile probe (33), the motor and the servo hydraulic press in the test measurement system (3), and the servo hydraulic press in the confining pressure loading system (2); S12: taking out four rectangular parallelepiped specimens from the first confining pressure loading chamber (22), the second confining pressure loading chamber (23), the third confining pressure loading chamber (24), and the fourth confining pressure loading chamber (25); S13: Cleaning the confining pressure loading chamber, the pedestal (34), the first probe scanning channel (26) and the second probe scanning channel (37). S14: Processing data through the host computer (1).

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