A point load test apparatus for measuring rock deformation parameters

Abstract

This invention discloses a point load experimental device for measuring rock deformation parameters, comprising a frame, a loading device, and a control and monitoring system, both mounted on the frame. The frame mainly consists of profiles, T-shaped connecting plates, right-angle connectors, and cylindrical connecting circles. The loading device mainly consists of an upper point load head, a lower point load head, a receiving plate, a hydraulic jack, a first quick connector, a manual pump, a second quick connector, an unloading valve, and connecting pipes. The control and monitoring system consists of a pressure sensor, a laser rangefinder, bearing plates, a lead screw, a linear guide, a slider, stabilizing bearing plates, a motor connecting plate, a coupling, a motor, a power supply, and a control box. By combining traditional point load experiments with mechanical transmission, hydraulic transmission, sensor technology, and automated control technology, this invention enables the determination of rock point load strength, rock deformation parameters under point load, and the corresponding stress-strain curves.

Description

Technical Field

[0001] This invention relates to the field of rock mechanics experimental technology, and in particular to a point load experimental device for measuring rock deformation parameters. Specifically, it is designed for use in point load experiments to measure rock mechanical parameters, including point load strength and point load deformation parameters. Background Technology

[0002] The strength and deformation parameters of rocks are fundamental mechanical parameters for the development of various mineral resources and the construction of mining engineering projects. In experiments determining rock mechanical parameters, point load experiments are applicable to both laboratories and engineering sites due to their smaller applied loads, simpler operation, and portable equipment. Therefore, point load experiments are a more practical, simpler, time-saving, and economical method for obtaining rock mechanical parameters, and they allow for extensive testing at mining sites, making the test data more representative and reliable. However, currently, the rock mechanical parameters obtained through point load experiments are only the strength parameters under the point load; the deformation parameters of the rock during the point load application process and the corresponding stress-strain curves are not measured. This, to some extent, fails to fully utilize the advantages of point load experiments, hindering scientific research on the mechanical properties of rocks under point loads and impeding guidance for engineering practice, thus hindering the further promotion and application of point load experiments. Summary of the Invention

[0003] The purpose of this invention is to provide a point load experimental device for measuring rock deformation parameters, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A point load experimental apparatus for measuring rock deformation parameters includes a frame, a loading device, and a control and monitoring system, both mounted on the frame. The frame mainly consists of profiles, T-shaped connecting plates, right-angle connectors, and cylindrical connecting rings. The loading device mainly consists of an upper point load head, a lower point load head, a receiving plate, a hydraulic jack, a first quick connector, a manual pump, a second quick connector, an unloading valve, and connecting pipes. The control and monitoring system consists of a pressure sensor, a laser rangefinder, bearing plates, a lead screw, a linear guide, a slider, stabilizing bearing plates, a motor connecting plate, a coupling, a motor, a power supply, and a control box.

[0006] Preferably, the T-shaped connecting plate is fixedly mounted on the profile at the lower position, the right-angle connector is mounted on the profile at both the vertical and horizontal positions, and the columnar connecting circle is mounted on the bottom of the profile at the top position.

[0007] Preferably, the point load upper pressure head is installed at the bottom of the cylindrical connecting circle, the hydraulic jack is installed on the profile at the bottom, the point load lower pressure head is installed at the top of the hydraulic jack, the receiving plate is also installed on the hydraulic jack, one end of the connecting pipe is connected to the hydraulic jack through a first quick connector, one end of the manual pump is connected to the other end of the connecting pipe through a second quick connector, and the unloading valve is installed on the manual pump.

[0008] Preferably, the pressure sensor is installed at the bottom of the cylindrical connecting circle and is connected to the pressure head on the point load. The laser rangefinder is installed on the profile at the bottom. The bearing plate is installed at the bottom of the profile at the top. The lead screw is inserted into the inner ring of the bearing plate. A linear guide is installed between the upper and lower profiles. A slider is fitted on the outer ring of the linear guide. A vertical plate is fixedly installed between the upper and lower profiles and on the side of the linear guide. The stabilizing bearing plate is fitted on the bottom of the outer ring of the lead screw, and the side of the stabilizing bearing plate is fixed to the vertical plate. A motor connecting plate is fixedly installed at the bottom of the side of the vertical plate. A motor is installed at the top of the profile at the bottom. The output shaft of the motor is connected to the lead screw through a coupling.

[0009] Preferably, the power supply is mounted on the left side of the front of the device frame via a fastener structure, and the control box is mounted on the right side of the front of the device frame via a fastener structure.

[0010] Preferably, a display screen is provided on the front of the control box, and an operation button is provided at the bottom of the front of the control box. A rock sample is placed in the inner cavity of the receiving plate.

[0011] Compared with the prior art, the beneficial effects of the present invention are:

[0012] 1. This point load test device for measuring rock deformation parameters combines traditional point load testing with mechanical transmission, hydraulic transmission, sensor technology, and automated control technology. It not only realizes the determination of rock point load strength, but also the determination of rock deformation parameters and corresponding stress-strain curves under point load.

[0013] 2. This point load experimental apparatus for measuring rock deformation parameters uses three high-frequency, high-precision laser displacement ranging sensors to measure the deformation of rock specimens in the vertical and horizontal directions, ultimately determining the point load strength, rock deformation parameters, and corresponding stress-strain curves. Except for the loading process, automated control is achieved, standardizing the experiment and greatly reducing the influence of human factors, significantly improving both efficiency and accuracy.

[0014] 3. One of the advantages of this point load test device for measuring rock deformation parameters is that the equipment is portable and can be tested on the engineering site. However, traditional point load devices are integrated, which is inconvenient during long-distance transportation. This test device realizes modularization of each part, which can be disassembled or assembled, making it easier to transport parts separately. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention;

[0016] Figure 2 This is a top view of the present invention;

[0017] Figure 3 This is a schematic diagram of the receiving disk structure of the present invention;

[0018] Figure 4 The point load is the upper and lower pressure head of the present invention;

[0019] Figure 5 This is a schematic diagram of the initial state of the present invention;

[0020] Figure 6 This is a schematic diagram of the pre-compression state of the present invention;

[0021] Figure 7 This is a schematic diagram illustrating the state described in this invention.

[0022] In the diagram: 1. Profile; 2. T-shaped connecting plate; 3. Right-angle connector; 4. Columnar frustum; 5. Point load upper pressure head; 6. Point load lower pressure head; 7. Receiving plate; 8. Hydraulic jack; 9. First quick connector; 10. Manual pump; 11. Second quick connector; 12. Unloading valve; 13. Connecting pipe; 14. Pressure sensor; 15. Laser rangefinder sensor; 16. Bearing plate; 17. Lead screw; 18. Linear rail; 19. Slider; 20. Stabilizing bearing plate; 21. Motor connecting plate; 22. Coupling; 23. Motor; 24. Power supply; 25. Control box; 26. Display screen; 27. Operating button; 28. Rock sample. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example: Please refer to Figure 1 The present invention provides a technical solution: a point load test device for measuring rock deformation parameters.

[0025] The point load test device mainly consists of three parts: the device frame, the loading device, and the control and monitoring system.

[0026] The device frame is the main framework, and all mechanical parts are fixed on the device frame;

[0027] The loading device is the pressure source of the experimental setup, enabling the application of point loads to the rock specimens;

[0028] The control and monitoring system connects the frame and the loading device to achieve automatic real-time monitoring of pressure and deformation parameters, as well as data processing and analysis.

[0029] The frame is mainly composed of profile 1, T-shaped connecting plate 2, right-angle connector 3, and columnar connecting circle 4, such as Figure 1 As shown, the T-shaped connecting plate 2 is installed and fixed on the profile 1 at the lower position, the right-angle connector 3 is installed on the profile 1 at the vertical and bottom horizontal positions, and the columnar connecting circle 4 is installed at the bottom of the profile 1 at the top position. Specifically, profiles 1 of different lengths are connected and fixed by the right-angle connector 3 and the T-shaped connecting plate 2, and the columnar connecting circle 4 is connected to the profile 1 by screws.

[0030] The loading device applies point loads to the rock specimen. The loading device mainly consists of an upper point load head (5), a lower point load head (6), a receiving plate (7), a hydraulic jack (8), a first quick connector (9), a manual pump (10), a second quick connector (11), an unloading valve (12), and a connecting pipe (13). Figure 1 As shown, the point load lower pressure head 6, receiving plate 7 and hydraulic jack 8 are connected, the point load upper pressure head 5 is connected to the pressure sensor, the hydraulic jack 8 is connected to the profile 1 on the device frame and is located at the lower part, the receiving plate 7 is used to receive the debris after the rock is broken, the hydraulic jack 8 and the manual pump 10 are both equipped with quick connectors, the pipe 13 is connected to the quick connectors, and the hydraulic jack 8 and the manual pump 10 are connected together.

[0031] The control and monitoring system controls all components. It consists of a pressure sensor 14, a laser rangefinder 15, a bearing plate 16, a lead screw 17, a linear guide 18, a slider 19, a stabilizing bearing plate 20, a motor connecting plate 21, a coupling 22, a motor 23, a power supply 24, and a control box 25. The lower part of the pressure sensor 14 is connected to the pressure head 5 of the point load, and the upper part of the pressure sensor 14 is connected to the cylindrical connecting frustum 4. The pressure sensor 14 is used to monitor the applied point load value.

[0032] The linear guide 18 is connected and fixed to the device frame. The upper part of the linear guide 18 is connected to the bearing plate 16, and the lower part of the linear guide 18 is connected to the motor connecting plate 21.

[0033] The lead screw 17 is connected to the bearing plate 16 and the stabilizing bearing plate 20. The slider 19 connects the lead screw 17 and the linear guide 18 together.

[0034] The lower part of the motor 23 is fixedly connected to the device frame, and the upper part of the motor 23 is connected to the motor connecting piece 21. At the same time, the coupling 22 connects the lead screw 17 to the motor 23.

[0035] There are three laser rangefinders 15, which are fixed to the lower part of the device frame to monitor the position of the receiving disk 7, thereby determining the deformation of the rock specimen in the vertical direction under point load. The laser rangefinders 15 are connected to the sliders on the left and right sides respectively to monitor the deformation of the rock specimen in the horizontal direction (or vertical loading direction) under point load.

[0036] Power supply 24 is fixed on the device frame and provides power to the entire experimental setup.

[0037] The control box 25 is fixed on the device frame. The surface of the control box 25 is equipped with a display screen 26 and operation buttons 27. The programmable controller and motor driver are both fixed inside the control box 25. The display screen 26 is used to display the applied load value, stress-strain curve, point load strength parameters, and deformation parameters (in both vertical and horizontal directions) in real time. The pressure sensor 14 monitors the applied point load value and inputs the analog signal into the programmable controller inside the control box 25. The laser rangefinder 15 monitors the deformation value of the rock and simultaneously inputs the analog signal into the programmable controller inside the control box 25.

[0038] The specific measurement principle is as follows:

[0039] Initial state as Figure 5 As shown, the pre-compression state is as follows Figure 6 As shown, the loading status is as follows Figure 7 As shown. In the initial state (which returns to the initial state after each experiment), the distance between the two laser rangefinders 15 in the horizontal direction is w1, the height from the upper pressure head 5 of the point load to the upper part of the device frame is h1, the height from the lower laser rangefinder 15 to the receiving disk 7 is h2, the height between the upper pressure head 5 and the lower pressure head 6 of the point load is h3, and the height from the measuring point of the two laser rangefinders 15 in the horizontal direction to the upper part of the device frame is h4.

[0040] In the pre-compression state (with the rock specimen tightened), the height from the lower laser rangefinder 15 to the receiving disk 7 is h6. Therefore, the vertical dimension of the specimen is h = h3 - (h6 - h2). The horizontal distance between the two laser rangefinders 15 (aligned with the center of the specimen in the vertical direction) is h5 = h1 + 0.5[h3 - (h6 - h2)] - h4. At this time, the horizontal distances from the left and right laser rangefinders 15 to the surface of the rock specimen are w2 and w3 respectively. Therefore, the horizontal dimension of the rock specimen is w = w1 - w2 - w3. h5 can be controlled by the running time t of the motor 23. If the lead of the lead screw is p and the speed of the motor 23 is n, t = h5 / pn can be calculated according to h5 = pnt.

[0041] Under loading (if the applied point load is Pi), the distance from the lower laser rangefinder 15 to the receiving disk becomes hi6'. At this time, the horizontal distances from the surface of the rock specimen measured by the left and right laser rangefinders 15 are wi2' and wi3', respectively. Therefore, the deformation of the rock specimen in the vertical direction is Δhi = hi6' - h6, and the strain is εi. z =Δhi / h. The deformation of the rock specimen in the horizontal direction is Δwi = w2 - wi2' + w3 - wi3', and the strain is εi. x =Δwi / w. This experimental setup is for standard cylindrical specimens, so the applied load can be converted into applied stress, calculated using the formula:

[0042]

[0043] Record and plot the stress σi and strain εi at different points under load. z By finding the relationship curve between the two points, the stress-strain curve of the rock under point load can be obtained. If the rock fails, i.e., the applied point load is Pimax, then the corresponding σimax is the point load strength Is(50)=σimax. At the same time, the point load stress when the applied point load is 50%Pimax (50% of the maximum applied load) can be found to be 50%σimax, and the strain in the vertical direction is ε. z50 The strain in the horizontal direction is ε x50 Then, the rock deformation modulus under point load (the ratio of stress to strain at half the maximum applied load) E = 50%σimax / ε z50 Poisson's ratio of rock under point load (the ratio of horizontal strain to vertical strain at half the maximum applied load) μ = ε x50 / ε z50 .

[0044] The testing steps for the point load device for measuring rock deformation parameters are as follows:

[0045] ① Assemble and connect the various parts of the device.

[0046] ② Press the start / stop button to start the experiment. The entire experimental setup will begin, and the initial state will be as follows: Figure 5 As shown.

[0047] ③ Install the rock specimen and operate the manual pump to preload the rock specimen (generally, a load of 0 to 0.5 kN is sufficient to preload the rock specimen).

[0048] ④ Turn on the experiment button. The control and monitoring system first controls the rotation time t of motor 23 to lower the two laser rangefinders 15 horizontally by a distance h5. Then, the display shows "Formal Experiment". Next, operate the manual pump to load the specimen according to the experimental requirements until the rock specimen fails. During the loading process, the screen will display in real time the applied point load Pi and stress σi, and the deformation Δhi and strain εi of the rock specimen in the vertical direction. z The deformation Δwi and strain εi of the rock specimen in the horizontal direction are... x And record and plot the load stress σi and strain εi at different points in real time. z The relationship curve between them. After the rock specimen fails, the maximum applied load Pimax of the rock specimen will be displayed, the point load strength Is(50)=σimax, the rock deformation modulus E under point load, and the rock Poisson's ratio μ under point load.

[0049] ⑤ Press the button for the next set of experiments, and the device will return to its initial state. Figure 5 As shown, the previous set of experimental data will be saved (the data can be exported), and then the unloading valve will be opened to restore the hydraulic jack to its initial state.

[0050] ⑥ After cleaning the experimental setup, you can proceed to the next set of experiments. Turning the start / end button on again will shut down the entire setup. If you are no longer planning to conduct experiments, you can also disassemble the setup for easy transport over long distances.

[0051] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A point load test method for measuring rock deformation parameters, comprising an experimental apparatus, the apparatus including a frame, a loading device, and a control and monitoring system, characterized in that: The loading device and the control and monitoring system are both installed on the device frame. The device frame is mainly composed of profile (1), T-shaped connecting plate (2), right angle connector (3) and columnar connecting circle. The loading device is mainly composed of point load upper pressure head (5), point load lower pressure head (6), receiving plate (7), hydraulic jack (8), first quick connector (9), manual pump (10), second quick connector (11), unloading valve (12) and pipe (13). The control and monitoring system is composed of pressure sensor (14), laser range sensor (15), bearing plate (16), lead screw (17), linear guide (18), slider (19), stabilizing bearing plate (20), motor connecting plate (21), coupling (22), motor (23), power supply (24) and control box (25). The T-shaped connecting plate (2) is installed and fixed on the profile (1) at the lower position. The right-angle connector (3) is installed on the profile (1) at the vertical and horizontal positions. The columnar connecting circle (4) is installed at the bottom of the profile (1) at the top position. The point load pressing head (6) is installed at the top position of the hydraulic jack (8). The receiving plate (7) is also installed on the hydraulic jack (8). The point load pressure head (5) is installed at the bottom of the columnar connecting circle (4), the hydraulic jack (8) is installed on the profile (1) at the bottom, one end of the connecting pipe (13) is connected to the hydraulic jack through the first quick connector (9), one end of the manual pump (10) is connected to the other end of the connecting pipe (13) through the second quick connector (11), and the unloading valve (12) is installed on the manual pump (10). The pressure sensor (14) is installed at the bottom of the cylindrical connecting circle (4) and is connected to the pressure head (5) on the point load. The laser rangefinder (15) is installed on the profile (1) at the bottom position and the bearing plate (16) is installed at the bottom of the profile (1) at the top position. The specific testing method is as follows: In the initial state, the distance between the two laser rangefinders in the horizontal direction is w1, the height from the upper pressure head (5) of the point load to the upper part of the device frame is h1, the height from the lower laser rangefinder (15) to the receiving plate (7) is h2, the height between the upper pressure head (5) and the lower pressure head (6) of the point load is h3, and the height from the measuring point of the two laser rangefinders (15) in the horizontal direction to the upper part of the device frame is h4. In the pre-compression state, the height from the lower laser rangefinder (15) to the receiving disk (7) is h6. Then the vertical dimension of the specimen is h = h3 - (h6 - h2). The horizontal distance between the two laser rangefinders is h5, h5 = h1 + 0.5[h3 - (h6 - h2)] - h4. At this time, the horizontal distances between the left and right laser rangefinders and the surface of the rock specimen can be measured as w2 and w3 respectively. Then the horizontal dimension of the rock specimen is w = w1 - w2 - w3. h5 can be controlled by controlling the running time t of the motor. If the lead of the lead screw is p and the motor speed is n, t = h5 / pn can be calculated according to h5 = pnt.

2. The point load test method for measuring rock deformation parameters according to claim 1, characterized in that: The power supply (24) is mounted on the left side of the front of the device frame via a fastener structure, and the control box (25) is mounted on the right side of the front of the device frame via a fastener structure.

3. The point load test method for measuring rock deformation parameters according to claim 1, characterized in that: The control box (25) has a display screen (26) on the front and an operation button (27) on the bottom of the front. A rock sample (28) is placed in the inner cavity of the receiving plate (7).

4. The point load test method for measuring rock deformation parameters according to claim 1, characterized in that: The lead screw (17) is inserted into the inner ring of the bearing plate (16), and a linear guide (18) is installed between the profiles (1) at the upper and lower ends.

5. The point load test method for measuring rock deformation parameters according to claim 1, characterized in that: The stabilizing bearing plate (20) is fitted at the bottom of the outer ring of the lead screw (17), and the side of the stabilizing bearing plate (20) is fixed on the vertical plate. A motor connecting plate (21) is installed and fixed at the bottom of the side of the vertical plate. A motor (23) is installed at the top of the profile (1) at the bottom. The output shaft of the motor (23) is connected to the lead screw (17) through a coupling (22).

6. The point load test method for measuring rock deformation parameters according to claim 4, characterized in that: A slider (19) is fitted on the outer ring of the linear guide (18), and a vertical plate is fixedly installed between the upper and lower profiles (1) and on the side of the linear guide (18).

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