Uniaxial compression rock mechanics testing machine for non-uniform axial load and testing method

Abstract

The application provides a kind of non-uniform axial load uniaxial compression rock mechanics testing machine and test method, including rack, pressurizing platform, power part, test piece with inclined surface on top surface, rigid outer cover nested in test piece and monitoring device, pressure is applied to rigid outer cover by power part, and then rigid outer cover uniformly extrudes the inclined surface of test piece, resulting in internal strain gradient due to height difference of inclined surface, which causes axial non-uniform load in test piece, and then strain information in test process is monitored by monitoring device, which changes the existing rock mechanics test, which is mostly testing single test piece or regular combined test piece, and then simulates the mechanical properties of rock in deep well under non-uniform high stress condition, providing sufficient theoretical basis for deep well roadway support technology, with the advantages of simple structure, convenient test operation, simple and easy test data and reference significance.

Description

Technical Field

[0001] This application belongs to the field of rock mechanics testing technology, specifically relating to a uniaxial compression rock mechanics testing machine and testing method under non-uniform axial load. Background Technology

[0002] In rock mining operations, the difficulty of supporting deep shafts increases with the depth of mining. To ensure the safety of mining operations in deep shafts during rock mining, the mining industry spends a lot of manpower and money on support projects every year. The high difficulty of deep shaft mining operations is fundamentally due to the lack of understanding of the mechanical properties of rocks under high stress conditions. Therefore, conducting thorough research on the deformation characteristics and failure features of rocks under different stress conditions, and providing a sufficient theoretical basis for deep shafts, is the key to solving the difficulties of supporting deep shafts or complex shafts.

[0003] Most existing rock mechanics experiments test single specimens or regular combinations of specimens, studying the constitutive relationship between load and deformation of rock specimens by changing factors such as loading rate, dynamic / static loading method, or temperature. However, after the start of rock mining operations, the release of stress in the surrounding rock near the tunnel leads to localized stress non-uniformity in the rock mass. At this time, the load on both sides of the tunnel has a very significant non-uniform characteristic. Existing rock mechanics tests treat the rock specimen as a whole and cannot perform non-uniform loading on a single intact rock. Therefore, there is an urgent need for a uniaxial rock mechanics testing machine that can apply non-uniform axial loads to the specimen. Summary of the Invention

[0004] To address the lack of understanding of the mechanical properties of rocks in deep wells under high stress conditions in the current ore mining industry, and the technical problem that existing rock mechanics tests treat rock specimens as a whole for loading, making it impossible to perform non-uniform loading on a single intact rock, this application proposes a uniaxial compression rock mechanics testing machine and testing method for non-uniform axial load.

[0005] This application adopts the following scheme: a uniaxial compression rock mechanics testing machine for non-uniform axial load, including a frame, a pressure platform for placing test specimens on the frame, a power component located above the pressure platform on the frame, an inclined surface on the top surface of the test specimen, and a rigid outer cover nested on the pressure platform. The power component is used to apply pressure to the rigid outer cover to uniformly compress the inclined surface, causing a strain gradient inside the test specimen due to the height difference of the inclined surface, thereby generating an axial non-uniform load. The inner wall of the rigid outer cover is provided with a monitoring device for monitoring the stress information of the test specimen.

[0006] Preferably, the bottom two sides of the rigid outer cover abut against the pressure table. When the power component presses the rigid outer cover downward, the two sides of the rigid outer cover can be displaced equally. As a result, due to the height difference of the inclined surface, the test piece is subjected to uniform compression by the rigid outer cover, resulting in a strain gradient inside the test piece and thus generating an axial non-uniform load.

[0007] Preferably, the rigid outer cover is provided with a sloping pressure surface that matches the inclined surface.

[0008] Preferably, the monitoring device includes a stress sensor disposed on the contact surface between the rigid outer cover and the inclined surface, and acoustic emission probes disposed on both sides of the inner wall of the rigid outer cover, wherein the stress sensor and the acoustic emission probes are electrically connected to the monitoring unit.

[0009] Preferably, the rigid outer cover is made of a rigid material, and the contact surface between the rigid outer cover and the inclined surface does not undergo plastic deformation during the uniform compression of the power component.

[0010] Preferably, the pressure table includes a chassis mounted on the frame, a balance plate mounted on the upper part of the chassis, a track rod between the balance plate and the chassis, and a pad mounted on the balance plate. The two sides of the balance plate abut against the two sides of the rigid outer cover. After the rigid outer cover is subjected to uniform pressure from the power component, the balance plate can move along the axial direction of the track rod.

[0011] Preferably, the balance plate is mounted on the track rod by a horizontal clamp, and a spring groove for accommodating the spring is provided in the middle of the track rod. After the rigid cover is subjected to uniform pressure from the power component, the rigid cover uniformly squeezes the test piece. The elastic force of the spring can ensure that the balance plate is uniformly displaced along the track rod, and ensure that the displacement on both sides of the rigid cover is equal.

[0012] Preferably, the horizontal clamp has a clamping block in the middle that can slide onto the spring groove, and the balance plate has sliding grooves on both sides that can slide onto the clamping block.

[0013] Preferably, the horizontal clamp clamps the balance plate between the horizontal clamps by placing the clamping block in the sliding groove, and the horizontal clamps press down the spring to place the clamping block in the spring groove so that the balance plate is placed on the track rod.

[0014] Another objective of this application is to provide a test method for a uniaxial compression rock mechanics testing machine under non-uniform axial load. The test method includes the following steps:

[0015] Step 1: Place the test specimen on the pressure table;

[0016] Step 2: Place the rigid cover onto the test specimen and ensure that the rigid cover abuts against the pressure table;

[0017] Step 3: Start the power unit and evenly compress the rigid outer cover until the rigid outer cover is completely and tightly pressed against the pressure table to achieve preloading;

[0018] Step 4: The dynamic component begins to be loaded, and the relevant data of the test piece during the static loading process are monitored using a monitoring device, thus completing the static loading test.

[0019] This application provides a uniaxial compression rock mechanics testing machine and method for non-uniform axial load, including a frame, a pressure table, a power component, a test specimen with an inclined surface on the top, a rigid outer casing nested within the test specimen, and a monitoring device. The power component applies pressure to the rigid outer casing, causing it to uniformly compress the inclined surface of the test specimen. This results in a strain gradient within the test specimen due to the height difference of the inclined surface, generating an axial non-uniform load. The monitoring device then monitors the strain information during the test. This method changes the current practice of testing mostly on single specimens or regular combinations of specimens, thus simulating the mechanical properties of rocks in deep wells under non-uniform high stress conditions. It provides a sufficient theoretical basis for deep well roadway support technology and has the advantages of simple structure, convenient operation, and readily available and meaningful test data. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0021] Figure 1 This is a front view of the uniaxial compression rock mechanics testing machine for non-uniform axial load of this application;

[0022] Figure 2 This is a structural schematic diagram of the rigid outer casing of this application;

[0023] Figure 3 This is a structural schematic diagram of the rigid outer casing from another perspective of this application;

[0024] Figure 4 This is a schematic diagram of the pressurization table in this application;

[0025] Figure 5 This is a schematic diagram of the structure of the pressure table after the disassembly and balancing plate of this application. Detailed Implementation

[0026] like Figure 1-5As shown, a uniaxial compression rock mechanics testing machine for non-uniform axial load includes a frame 1. The frame 1 is provided with a pressure platform 4 for placing a test specimen 2. A power component 5 is provided on the frame 1 above the pressure platform 4. The top surface of the test specimen 2 is provided with an inclined surface 20. The pressure platform 4 is provided with a rigid outer cover 6 nested within the test specimen 2. The power component 5 is used to apply pressure to the rigid outer cover 6 to uniformly compress the inclined surface 20, so that there is a strain gradient inside the test specimen 2 due to the height difference of the inclined surface 20, thereby generating an axial non-uniform load. The inner wall of the rigid outer cover 6 is provided with a monitoring device 3 for monitoring the stress information of the test specimen 2.

[0027] This application provides a uniaxial compression rock mechanics testing machine and method for non-uniform axial load, including a frame, a pressure table, a power component, a test specimen with an inclined surface on the top, a rigid outer casing nested within the test specimen, and a monitoring device. The power component applies pressure to the rigid outer casing, causing the rigid outer casing to uniformly compress the inclined surface of the test specimen. This results in a strain gradient within the test specimen due to the height difference of the inclined surface, leading to an axial non-uniform load. The monitoring device then monitors the strain information during the test. This method changes the current situation where most rock mechanics tests are conducted on single specimens or regular combinations of specimens. It simulates the mechanical properties of rocks in deep wells under non-uniform high stress conditions, providing a sufficient theoretical basis for deep well roadway support technology. It has the advantages of simple structure, convenient operation, and readily available and meaningful test data.

[0028] Preferably, the bottom two sides of the rigid outer cover 6 abut against the pressure table 4. When the power member 5 presses down on the rigid outer cover 6, the two sides of the rigid outer cover 6 can be displaced equally. As a result, due to the height difference of the inclined surface 20, the test piece 2 is subjected to uniform compression by the rigid outer cover 6, resulting in a strain gradient inside and thus generating an axial non-uniform load.

[0029] In the actual test, after placing the test specimen 2 on the pressure table 4, the rigid outer cover 6 is nested on the test specimen 2. The inner wall of the rigid outer cover 6 is embedded with stress sensors 7 and acoustic emission probes 8, and it can be directly put into the test. At this time, the two sides of the rigid outer cover 2 are exactly abutting against the two wings of the pressure table 4, ensuring that when the power component 5 applies a load to the rigid outer cover, the downward displacement of the two wings of the pressure table 4 is equal during the process of the power component 5 applying pressure to the rigid outer cover 6. Therefore, the strain magnitude of the test specimen with the inclined surface 20 on the side close to the power component 5 is different at different heights, thus forming a non-uniformly distributed axial load. According to the rock stress-strain curve, the stress distribution between different height sections is different. This changes the situation where most existing rock mechanics experiments are conducted on single specimens or regular combination specimens, and provides a sufficient theoretical basis for deep well roadway support technology. It has the advantages of simple structure, convenient test operation, and simple and easy-to-obtain test data with reference significance.

[0030] Preferably, the rigid outer cover 6 is provided with an inclined pressure surface 60 that matches the inclined surface 20;

[0031] In the actual test, after placing the test specimen 2 on the pressure table 4, the rigid outer cover 6 is nested on the test specimen 2. The inclined pressure surface 60 of the rigid outer cover 6 is embedded with a stress sensor 7, and the two sides of the inner wall of the rigid outer cover 6 are embedded with acoustic emission probes 8. At this time, the two sides of the rigid outer cover 2 are exactly abutting against the two wings of the pressure table 4, ensuring that when the power component 5 applies a load to the rigid outer cover, the inclined pressure surface 60 uniformly squeezes the inclined surface 20 during the process of the power component 5 applying pressure to the rigid outer cover 6. The downward displacement of the two wings of the pressure table 4 is equal. Therefore, the strain magnitude of the test specimen with the inclined surface 20 on the side closer to the power component 5 is different, thus forming a non-uniformly distributed axial load. According to the rock stress-strain curve, the stress distribution between different height sections is different. This changes the situation where most existing rock mechanics experiments are tested on single specimens or regular combination specimens. It provides a sufficient theoretical basis for deep well roadway support technology and has the advantages of simple structure, convenient test operation, and simple and easy-to-obtain test data with reference significance.

[0032] Preferably, the monitoring device 3 includes a stress sensor 7 disposed on the contact surface between the rigid outer cover 6 and the inclined surface 20, and acoustic emission probes 8 disposed on both sides of the inner wall of the rigid outer cover 6. The stress sensor 7 and the acoustic emission probes 8 are electrically connected to the monitoring unit 9.

[0033] In the actual test, after placing the test piece 2 on the pressure table 4, a rigid outer cover 6 is fitted onto the test piece 2. A stress sensor 7 and an acoustic emission probe 8 are embedded in the inner wall of the rigid outer cover 6. The stress sensor 7 and the acoustic emission probe 8 are electrically connected to the monitoring unit 9, allowing direct monitoring of stress distribution changes during the test, eliminating the need to install additional sensors on the surface of the test piece 2. At this time, the two sides of the rigid outer cover 2 are exactly abutted against the two wings of the pressure table 4, ensuring that when the power component 5 applies a load to the rigid outer cover, the downward displacement of the two wings of the pressure table 4 is equal, resulting in a strain difference in the test piece 2, forming a non-uniformly distributed strain. Axial load is applied to the rigid outer cover 6 through the power component 5. During this process, the downward displacement of the two wings of the pressure table 4 is equal. Therefore, the strain magnitude of the test specimen with an inclined surface 20 on the side near the power component 5 is different at different heights. According to the rock stress-strain curve, the stress distribution between different height sections is different. This changes the situation where most existing rock mechanics experiments test single specimens or regular combination specimens. It provides a sufficient theoretical basis for deep well roadway support technology and has the advantages of simple structure, convenient test operation, and simple and easy-to-obtain test data with reference significance.

[0034] Preferably, the rigid outer cover 6 is made of a rigid material, and the contact surface between the rigid outer cover 6 and the inclined surface 20 does not undergo plastic deformation during the uniform compression of the power component 5.

[0035] In actual testing, the rigid outer cover 6 is made of rigid material. The deformation of the inclined pressure surface 60 during the uniform compression process with the inclined surface 20 is minimal and negligible. This avoids the deformation between the inclined pressure surface 60 and the inclined surface 20, which would generate additional stress and affect the accuracy of the experimental data. It changes the situation where most existing rock mechanics experiments are conducted on single specimens or regular combinations of specimens. It provides a sufficient theoretical basis for deep well roadway support technology and has the advantages of simple structure, convenient test operation, and concise and easily obtainable test data with reference value.

[0036] Preferably, the pressure table 4 includes a chassis 40 mounted on the frame 1, a balance support plate 41 mounted on the upper part of the chassis 40, a track rod 42 mounted between the balance support plate 41 and the chassis 40, and a pad plate 46 mounted on the balance support plate 41. The two sides of the balance support plate 41 abut against the two sides of the rigid outer cover 6. After the rigid outer cover 6 is subjected to uniform pressure from the power component 5, the balance support plate 41 can move along the axial direction of the track rod 42.

[0037] In the actual test, after placing the test piece 2 on the pad 46 on the balance support plate 41, the rigid outer cover 6 is fitted onto the test piece 2. The inner wall of the rigid outer cover 6 is embedded with a stress sensor 7 and an acoustic emission probe 8, which can be directly put into the test without installing sensors on the surface of the test piece 2. At this time, the two sides of the rigid outer cover 2 are exactly abutting against the two wings of the balance support plate 41, so as to ensure that when the power component 5 applies a load to the rigid outer cover, the two wings of the balance support plate 46 will be uniformly displaced towards the chassis 40 along the track rod 42 under the action of the rigid outer cover. The test piece 2 will generate a strain difference due to the inclined surface 20, forming a non-uniform strain. A uniformly distributed axial load is applied to the rigid outer cover 6 through the power component 5. During this process, the downward displacement of the two wings of the pressure table 4 is equal. Therefore, the strain magnitude of the test specimen with an inclined surface 20 on the side near the power component 5 is different at different heights. According to the rock stress-strain curve, the stress distribution between different height sections is different. This changes the situation where most existing rock mechanics experiments test single specimens or regular combination specimens. It provides a sufficient theoretical basis for deep well roadway support technology and has the advantages of simple structure, convenient test operation, and simple and easy-to-obtain test data with reference significance.

[0038] Preferably, the balance plate 41 is mounted on the track rod 42 via a horizontal clamp 43. The track rod 42 has a spring groove 45 in its middle for accommodating the spring 44. When the rigid outer cover 6 is subjected to uniform pressure from the power component 5, the rigid outer cover 6 uniformly compresses the test piece 2. The elastic force of the spring 44 ensures that the balance plate 41 moves uniformly along the track rod 42, ensuring equal displacement on both sides of the rigid outer cover 6. More preferably, the horizontal clamp 43 has a clamping block 430 in its middle that can slide onto the spring groove 45, and the balance plate 41 has sliding grooves 410 on both sides that can slide onto the clamping block 430. Even more preferably, the horizontal clamp 43 clamps the balance plate 41 between the horizontal clamps 43 by placing the clamping block 430 within the sliding grooves 410. The horizontal clamp 43 presses down the spring 44 to place the clamping block 430 in the spring groove 45, so that the balance plate 41 is placed on the track rod 42. In the actual test, the power component 5 applies pressure to the rigid cover 6, thereby causing the rigid cover 6 to be tightly attached to the balance plate 41 and then move along the track rod 42 towards the chassis 40. The spring 44 in the spring groove 45 on the track rod 42 can ensure that the balance plate 41 moves slowly and evenly along the track rod 42 towards the chassis 40, which is conducive to clearly analyzing the internal stress of the test piece 2. The horizontal clamp 43 uses the clamping block 430 to cooperate with the sliding groove 410 and the spring groove 45 to install the balance plate 41 on the track rod 42. It has the advantages of simple structure, convenient test operation, and simple and easy-to-obtain test data with reference significance.

[0039] This application also provides a uniaxial compression rock mechanics test method under non-uniform axial load, using the aforementioned uniaxial compression rock mechanics testing machine under non-uniform axial load, and the test method includes the following steps:

[0040] Step 1: Place test specimen 2 on pressure table 4;

[0041] Step 2: Nest the rigid outer cover 6 onto the test piece 2 and make the rigid outer cover 6 abut against the pressure table 4;

[0042] Step 3: Start the power component 5 and evenly compress the rigid outer cover 6 until the rigid outer cover 6 and the pressure table 4 are completely and tightly pressed together, thus achieving preloading;

[0043] Step 4: The power component 5 begins loading. The stress sensor 7 and acoustic emission probe 8 are used to monitor the relevant data of the test piece during the static loading process and record them in the monitoring unit 9, thus completing the static loading test.

[0044] In the actual test, after placing the test piece 2 on the pad 46 on the balance support plate 41, the rigid outer cover 6 is fitted onto the test piece 2. The inner wall of the rigid outer cover 6 is embedded with a stress sensor 7 and an acoustic emission probe 8 connected to the monitoring unit 9, which can monitor the stress condition of the test piece 2. It can be directly put into test use without installing sensors on the surface of the test piece 2. At this time, the two sides of the rigid outer cover 2 are exactly abutting against the two wings of the balance support plate 41, so as to ensure that when the power component 5 applies a load to the rigid outer cover 6, the two wings of the balance support plate 46 are uniformly displaced towards the chassis 40 along the track rod 42 under the action of the rigid outer cover 6 and with the help of the spring 44. The test piece 2 has an inclined surface 20. The height difference generates a strain difference, forming a non-uniformly distributed axial load under the compression of the inclined pressure surface 60 of the rigid outer cover 6. During the process of applying pressure to the rigid outer cover 6 through the power component 5, the downward displacement of the two wings of the pressure table 4 is equal. Therefore, the strain generated by the test specimen with the inclined surface 20 on the side near the power component 5 at different heights is not uniform. According to the rock stress-strain curve, the stress distribution between different height sections is different. This provides a sufficient theoretical basis for deep well roadway support technology, and changes the situation where most existing rock mechanics experiments are tested on single specimens or regular combination specimens. It has the advantages of simple structure, convenient test operation, and simple and easy-to-obtain test data with reference significance.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A uniaxial compression rock mechanics testing machine under non-uniform axial load, comprising a frame (1), characterized in that, The frame (1) is provided with a pressure table (4) for placing the test piece (2). A power component (5) is provided on the frame (1) above the pressure table (4). The top surface of the test piece (2) is provided with an inclined surface (20). The pressure table (4) is provided with a rigid outer cover (6) nested around the test piece (2). The power component (5) is used to apply pressure to the rigid outer cover (6) to uniformly squeeze the inclined surface (20), so that there is a strain gradient inside the test piece (2) due to the height difference of the inclined surface (20), thereby generating an axial non-uniform load. The inner wall of the rigid outer cover (6) is provided with a monitoring device (3) for monitoring the stress information of the test piece (2). The rigid outer cover (6) is provided with a sloping pressure surface (60) that matches the inclined surface (20). The pressurizing platform (4) includes a chassis (40) mounted on the frame (1), a balance plate (41) mounted on the upper part of the chassis (40), a track rod (42) between the balance plate (41) and the chassis (40), and a pad (46) mounted on the balance plate (41). The two sides of the balance plate (41) abut against the two sides of the rigid outer cover (6). After the rigid outer cover (6) is subjected to uniform pressure from the power component (5), the balance plate (41) can move along the axial direction of the track rod (42).

2. The uniaxial compression rock mechanics testing machine for non-uniform axial load according to claim 1, characterized in that, The bottom sides of the rigid outer cover (6) abut against the pressure table (4). When the power component (5) presses down on the rigid outer cover (6), the displacement of the two sides of the rigid outer cover (6) is equal. As a result, the test piece (2) is subjected to uniform compression by the rigid outer cover (6) due to the height difference of the inclined surface (20). During this process, there is a strain gradient inside the test piece (2), which in turn generates an axial non-uniform load.

3. The uniaxial compression rock mechanics testing machine for non-uniform axial load according to claim 1, characterized in that, The monitoring device (3) includes a stress sensor (7) disposed on the contact surface between the rigid outer cover (6) and the inclined surface (20), and acoustic emission probes (8) disposed on both sides of the inner wall of the rigid outer cover (6). The stress sensor (7) and the acoustic emission probes (8) are electrically connected to the monitoring unit (9).

4. The uniaxial compression rock mechanics testing machine for non-uniform axial load according to claim 1, characterized in that, The rigid outer cover (6) is made of rigid material. During the uniform compression process of the power component (5), the rigid outer cover (6) does not undergo plastic deformation at the contact surface between the rigid outer cover (6) and the inclined surface (20).

5. The uniaxial compression rock mechanics test under non-uniform axial load according to claim 1, characterized in that, The balance plate (41) is mounted on the track rod (42) by a horizontal clamp (43). The track rod (42) has a spring groove (45) in the middle for accommodating the spring (44). After the rigid cover (6) is subjected to uniform pressure from the power component (5), the rigid cover (6) uniformly squeezes the test piece (2). The elastic force of the spring (44) can ensure that the balance plate (41) moves uniformly along the track rod (42) and ensure that the displacement on both sides of the rigid cover (6) is equal.

6. The uniaxial compression rock mechanics testing machine for non-uniform axial load according to claim 5, characterized in that, The horizontal clamp (43) has a clamping block (430) in the middle that can slide onto the spring groove (45), and the balance plate (41) has sliding grooves (410) on both sides that can slide onto the clamping block (430).

7. The uniaxial compression rock mechanics testing machine for non-uniform axial load according to claim 6, characterized in that, The horizontal clamp (43) clamps the balance plate (41) between the horizontal clamps (43) by placing the clamping block (430) in the sliding groove (410). The horizontal clamp (43) presses down the spring (44) to place the clamping block (430) in the spring groove (45) so that the balance plate (41) is placed on the track rod (42).

8. A rock mechanics test method for uniaxial compression under non-uniform axial load, characterized in that, The test method using the uniaxial compression rock mechanics testing machine with non-uniform axial load as described in any one of claims 1-7 includes the following steps: Step 1: Place the test piece (2) on the pressure table (4); Step 2: Nest the rigid cover (6) onto the test piece (2) and make the rigid cover (6) fit against the pressure table (4); Step 3: Start the power unit (5) and evenly compress the rigid outer cover (6) until the rigid outer cover (6) and the pressure table (4) are completely and tightly pressed together to achieve preloading; Step 4: The power component (5) begins loading. The monitoring device (3) monitors the relevant data of the test piece (2) during the static loading process, thus completing the static loading test.

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