A high-efficiency rock thermal conductivity test device and test method for simulating a natural confining pressure environment

Abstract

The application provides a high-efficiency rock thermal conductivity test device and test method for simulating a natural confining pressure environment. The test device comprises an upper computer, a confining pressure loading system and a test measurement system, and the confining pressure loading system and the test measurement system are arranged above and below and controlled by the upper computer. The application can provide a high-efficiency and accurate test method for simulating the change rule of the thermal conductivity of rocks under a natural stress environment. The confining pressure loading system is adopted in the design, and true triaxial confining pressure can be applied to the sample to simulate the stress environment of the natural rock mass. The confining pressure loading system contains four confining pressure loading bins, and four samples can be measured at the same time to improve the test efficiency and form a comparative test. The optical scanning technology based on the mobile point heat source principle is adopted to test the thermal conductivity of the sample, and the test speed is fast and the precision is high. The sample size is small, the cubic sample is small, the test surface height difference is small, and the size is greater than the scanning channel, which can meet the test needs.

Description

Technical Field

[0001] This invention relates to the fields of rock thermophysical properties and rock mechanics, specifically to an efficient rock thermal conductivity testing device and method for simulating natural confining pressure environments. Background Technology

[0002] In critical fields such as geotechnical engineering, geothermal energy extraction, and radioactive waste disposal, the thermodynamic parameters of rocks, especially thermal conductivity, play a vital role in understanding the thermo-solid coupling mechanism of rock masses and assessing the long-term stability and safety of engineering projects. Thermal conductivity is an important physical quantity reflecting the heat transfer performance of rock materials, determining the rate and efficiency of heat transfer within the rock. Therefore, accurately measuring the thermal conductivity of rocks is of significant reference value for the design, construction, and maintenance of rock mass engineering projects.

[0003] In existing technologies, triaxial testing devices are mainly used to test the mechanical properties of rocks under complex stress states, such as compressive strength and elastic modulus. However, these devices often cannot simultaneously measure the thermal parameters of rocks, such as thermal conductivity. Although some devices can measure the thermal conductivity of rocks, they usually cannot take into account the confining pressure environment of natural rocks, and their testing efficiency is low, making it difficult to meet the need for rapid and accurate measurement of rock thermodynamic parameters. Therefore, it is necessary to design an efficient and accurate rock thermal conductivity testing device that can simulate the natural confining pressure environment to complete the relevant testing work. Summary of the Invention

[0004] The first objective of this invention is to provide an efficient experimental device for simulating the thermal conductivity of rocks under natural confining pressure, addressing the aforementioned problems.

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

[0006] An efficient rock thermal conductivity testing device for simulating natural confining pressure environment includes 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 vertically and horizontally, and the two are spaced apart along the longitudinal direction, the distance between them can be 0;

[0007] The confining pressure loading system includes a confining pressure loading system outer box, and the confining pressure loading system outer box is provided with 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. A first probe scanning channel is opened at the bottom of the confining pressure loading system outer box, and the length of the first probe scanning channel covers the outline 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 an outer casing, inside which is a moving probe conveyor belt. The conveying direction of the moving probe conveyor belt is consistent with the arrangement direction of the first, second, third, and fourth confining pressure loading chambers. A moving probe is mounted on the moving probe conveyor belt and controlled by a host computer. The outer casing of the test measurement system has a raised platform, with a first standard sample slot and a second standard sample slot on both sides of the platform. The outer casing and platform are hollowed out and have a second probe scanning channel. The extension direction of the second probe scanning channel is consistent with the moving 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 on the periphery of the confining pressure loading system and the test measurement system. 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 chamber, the second confining pressure loading chamber, the third confining pressure loading chamber, and the fourth confining pressure loading chamber are filled with the sample to be tested, and the size, specifications, and preparation materials of the confining pressure loading chambers are completely identical.

[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 cuboid or cubic specimens made of standard materials with known thermal conductivity values.

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

[0015] The second objective of this invention is to provide a test method for simulating the thermal conductivity of rocks under natural confining pressure.

[0016] Therefore, the above-mentioned objective of the present invention is achieved through the following technical solution:

[0017] An efficient test method for measuring the thermal conductivity of rocks under simulated natural confining pressure, characterized in that: the test method is based on the test apparatus 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: After loading the four cuboid samples 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 in sequence, close the chamber.

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

[0021] S4: The servo hydraulic press in the test and measurement system is controlled by the host computer to make the confining pressure loading system descend along the threaded guide column until the bottom of the confining pressure loading system box is recessed and the top of the platform is convex and fixed.

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

[0023] S6: Start the motor and moving probe in the test measurement system. The moving probe is driven to move by the moving probe conveyor belt. The first standard sample, the sample in the four confining pressure loading chambers and the second standard sample are scanned and tested in sequence through the second probe scanning channel and the first probe scanning channel.

[0024] S7: Calculate the thermal conductivity of the sample using the built-in software of the host computer. If the value differs too much 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. Repeat S3-S6 until the value is close to the end of the test. If the value is close, the test ends and proceed to the next step directly.

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

[0026] S9: The host computer controls the confining pressure loading system to control the servo hydraulic press in the test measurement system, causing the confining pressure loading system to rise to a certain height along the threaded guide column;

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

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

[0029] S12: Remove the four cuboid samples from 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;

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

[0031] S14: Process data via host computer.

[0032] This invention provides an efficient testing device and method for simulating the thermal conductivity of rocks under natural confining pressure, which has the following advantages: This invention provides an efficient and accurate testing method for simulating the variation law of thermal conductivity of rocks under natural stress conditions. The design adopts a confining pressure loading system, which can apply true triaxial confining pressure to the sample to simulate the stress environment of natural rock masses. The confining pressure loading system contains four confining pressure loading chambers, which can simultaneously measure four samples, improving testing efficiency and forming a comparative test. The optical scanning technology based on the principle of moving point heat source is used to test the thermal conductivity of the sample, which has a fast testing speed and high accuracy. There are few restrictions on the sample size; cubic specimens with small height differences on the test surface and a size larger than the scanning channel are sufficient to meet the test requirements. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the efficient rock thermal conductivity testing device for simulating natural confining pressure environments provided by the present invention.

[0034] Figure 2 This is a schematic diagram of the confining pressure loading system.

[0035] Figure 3 This is a schematic diagram of the experimental measurement system.

[0036] Figure 4 This is a schematic diagram showing the arrangement of the moving probe infrared temperature sensor and the laser point heat source.

[0037] In the diagram: 1-Host computer; 2-Confining pressure loading system; 3-Test and measurement system; 4-Threaded guide rail column; 21-Outer casing of the 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 casing of the test and measurement system; 32-Moving probe conveyor belt; 33-Moving probe; 34-Stage; 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 Implementation

[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, an efficient rock thermal conductivity test device for simulating 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 of each other and have a certain distance between them 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. The confining pressure loading system outer box 21 is provided with 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. A first probe scanning channel 26 is opened at the bottom of the confining pressure loading system outer box 21. The length of the first probe scanning channel 26 covers the outline 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 casing 31. Inside the test measurement system outer casing 31, there is a moving probe conveyor belt 32. The transmission direction of the moving probe conveyor belt 32 is consistent with the arrangement direction 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. A moving probe 33 is provided on the moving probe conveyor belt 32 and controlled by the host computer 1. A raised platform 34 is provided on the test measurement system outer casing 31. A first standard sample slot 35 and a second standard sample slot 36 are provided on both sides of the platform 34. The test measurement system outer casing 31 and the platform 34 are hollowed out and a second probe scanning channel 37 is provided. The extension direction of the second probe scanning channel 37 is consistent with the moving probe conveyor belt 32 and the first probe scanning channel 26.

[0042] The confining pressure loading system 2 and the test measurement system 3 are provided with lifting mechanisms on their periphery. The lifting mechanisms are used to raise and lower the confining pressure loading system 2 in order 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 post 4. The high-rigidity threaded guide rail post 4 is fixed with a confining pressure loading system 2. The high-rigidity threaded guide rail post 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 post 4 is a lead 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 contain samples to be tested, and the size, specifications, and materials of the confining pressure loading chambers are completely identical. The confining pressure loading device that appeared in Dr. Shan Kun's dissertation "Study on the Influencing Factors and Seismic Characteristics of EGS Injected Fluid-Induced Earthquakes" and the confining pressure loading forms in Chinese patents CN207636416U and CN116183377A can be arranged in 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 connected to 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 cuboid or cubic specimens made of standard materials with known thermal conductivity values, and their bottom dimensions are larger than the first probe scanning channel 26 of the confining pressure loading system 2.

[0046] Along the detection channel (first probe scanning channel 26, second probe scanning channel 37) on the moving probe 33, a first infrared temperature sensor 331, a laser point heat source 332, and a second infrared temperature sensor 333 are arranged in sequence. 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. The temperature difference between the standard sample and the test sample before and after heating is compared. Based on the principle of the moving 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 to the servo hydraulic press, motor, laser point heat source, and temperature sensor via corresponding connection cables, enabling it to coordinate the control of the experiment, display 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 through the following test method:

[0049] S1: Open the host computer 1 and start 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;

[0050] S2: After loading the four cuboid samples 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 in sequence, close the chamber.

[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 host computer 1 controls the servo hydraulic press in the test measurement system 3 to make the confining pressure loading system 2 descend along the threaded guide column 4 until the bottom recess of the confining pressure loading system outer box 21 matches and is fixed to the top protrusion of the platform 34.

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

[0054] S6: Start the motor and moving probe 33 in the test measurement system 3. Move the moving probe 33 through the moving probe conveyor belt 32. Scan the first standard sample, the sample 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 using the built-in software of the host computer 1. If the value differs too much from the standard sample, replace the corresponding standard sample, control the motor to reverse, and drive the moving probe 33 back to the initial position through the moving probe conveyor belt 32. Repeat S3-S6 until the value is close to the end of the test. If the value is close, the test ends 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 remove the confining pressure in the X, Y and Z directions;

[0057] S9: The host computer 1 controls the confining pressure loading system 2 and the servo hydraulic press inside the test measurement system 3 to make the confining pressure loading system 2 rise along the threaded guide column 4 to a certain height.

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

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

[0060] S12: Remove the four cuboid samples 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, platform 34, first probe scanning channel 26 and second probe scanning channel 37.

[0062] S14: Process data via host computer 1.

[0063] The above specific embodiments are used to explain and illustrate the present invention, and are only preferred embodiments of the present invention, not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A high-efficiency rock thermal conductivity testing device for simulating natural confining pressure environments, 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 of each other and have a certain distance between them along the longitudinal direction; The confining pressure loading system (2) includes a confining pressure loading system outer box (21), and the confining pressure loading system outer box (21) is provided with 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). A first probe scanning channel (26) is opened at the bottom of the confining pressure loading system outer box (21), and the length of the first probe scanning channel (26) covers the outline 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) includes a test measurement system outer box (31), and a moving probe conveyor belt (32) is provided inside the test measurement system outer box (31). The transmission direction of the moving probe conveyor belt (32) is consistent with the arrangement direction 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). A moving probe (33) is provided on the moving probe conveyor belt (32) and controlled by the host computer (1). A raised platform (34) is provided on the test measurement system outer box (31). A first standard sample slot (35) and a second standard sample slot (36) are provided on both sides of the platform (34). The test measurement system outer box (31) and the platform (34) are hollowed out and a second probe scanning channel (37) is provided. The extension direction of the second probe scanning channel (37) is consistent with the moving probe conveyor belt (32) and the first probe scanning channel (26). The confining pressure loading system (2) and the test measurement system (3) are provided with lifting mechanisms on their periphery. The lifting mechanisms are 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). The moving probe (33) is provided with a first infrared temperature sensor (331), a laser point heat source (332), and a second infrared temperature sensor (333) in sequence along the detection channel. A third infrared temperature sensor (334) is provided 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.

2. The efficient rock thermal conductivity testing device for simulating natural confining pressure environments according to claim 1, characterized in that: The lifting mechanism includes 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). The high-rigidity threaded guide rail column (4) moves up and down on the threaded guide rail under the drive of a motor.

3. The high-efficiency rock thermal conductivity testing device for simulating natural confining pressure environments according to claim 1, 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) contain the sample to be tested, and the size and materials of the confining pressure loading chambers are exactly the same.

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

5. A test method for simulating the thermal conductivity of highly efficient rocks under natural confining pressure, characterized in that: The experimental method is based on the high-efficiency rock thermal conductivity testing device for simulating natural confining pressure environments as described in claim 2, and includes the following steps: S1: Open 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: After loading the four cuboid samples 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) in sequence, close the chamber. S3: Place the first and second standard samples into the first standard sample slot (35) and the second standard sample slot (36) respectively; S4: By controlling the servo hydraulic press in the test measurement system (3) through the host computer (1), the confining pressure loading system (2) is lowered along the threaded guide column (4) to the bottom recess of the outer box (21) of the confining pressure loading system and the top protrusion of the platform (34) to be fixed. S5: Start the servo hydraulic press in the confining pressure loading system (2), and set the speed and magnitude of the confining pressure loading through the host computer (1); S6: Start the motor and moving probe (33) in the test measurement system (3), and drive the moving probe (33) to move through the moving probe conveyor belt (32). Scan the first standard sample, the sample 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 using 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 moving probe (33) back to the initial position through the moving probe conveyor belt (32). Repeat S3-S6 until the value is close to the end of the test. If the value is close, the test ends and the next step is carried out directly. S8: After the test is completed, the confining pressure in the X, Y and Z directions is removed by the servo hydraulic press in the confining pressure loading system (2) controlled by the host computer (1); S9: The host computer (1) controls the servo hydraulic press inside 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 motor in the test measurement system (3) is reversed by the host computer (1), and the moving probe (33) is driven back to the initial position by the moving probe conveyor belt (32); S11: Turn off the motor and servo hydraulic press in the moving probe (33), the test measurement system (3), and the servo hydraulic press in the confining pressure loading system (2); S12: Remove the four cuboid samples 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: Clean the confining pressure loading chamber, the platform (34), the first probe scanning channel (26), and the second probe scanning channel (37); S14: Process data via host computer (1).

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