Device and method for testing anisotropic mechanical properties of strong heterogeneity rock

Abstract

The invention discloses a device and a method for testing anisotropic mechanical properties of strong heterogeneity rocks, the device comprises a rotatable rock sample fixing device, a workbench and a sliding track, and a scratching cutter control and data monitoring system, the workbench and the sliding track device main body are fixed on a table top and are convenient to support and move; the slidable scratching system moving track supports the slidable scratching system to move left and right; the rotatable rock sample fixing device is located on the left side above the table top and can fix the position of a rock sample and change the rock scratch angle. The scratching tool control and data monitoring system is located on the right side of the table top and connected with the sliding rail, the slidable scratching system can scratch rocks, and the data monitoring system can monitor and collect tangential force data borne by a tool bit and displacement data of the tool bit in real time; the device and the method for testing the anisotropy of the shale based on the scratches can be researched so as to judge the anisotropy mechanical property of the strong heterogeneity rock.

Description

Technical Field

[0001] This invention belongs to the field of rock mechanical property testing technology, specifically relating to a testing device and method for the anisotropic mechanical properties of strongly heterogeneous rocks. Background Technology

[0002] Rock mechanical properties are crucial fundamental parameters in geotechnical engineering, oil and gas extraction, and geological disaster prevention. Rocks containing weak structural planes such as bedding, cleavage, and laminae exhibit different compressive failure strengths under different stress directions, displaying anisotropic characteristics. These anisotropy is a necessary factor to consider when evaluating the mechanical properties of such rocks. Generally, rock anisotropy is obtained by testing the compressive strength of the rock at multiple angles. However, this method requires a large number of rock samples, and the success rate of sampling rocks with weak structural planes is low, making the method time-consuming, labor-intensive, and with limited accuracy. Scratch testing technology, as an emerging method for determining rock mechanical parameters, has developed rapidly in the field of rock mechanics due to its advantages such as simple sample preparation, non-destructive nature, and high testing efficiency. This technology can continuously obtain the distribution characteristics of rock strength parameters by recording the load-displacement curve during the scratching process and combining it with the corresponding mechanical model. However, existing scratch testing technologies mainly focus on the determination of uniaxial strength parameters of rocks, and the systematic testing and characterization of rock anisotropic characteristics are still insufficient.

[0003] In summary, this technology has developed a testing device and method for the anisotropic mechanical properties of strongly heterogeneous rocks. It can test the anisotropy of a rock sample, requires fewer rock samples, and the testing process is simple and quick. This device and method have important theoretical and engineering significance for evaluating the mechanical properties of rocks with weak surface structures. Summary of the Invention

[0004] The purpose of this invention is to address the problem of testing the anisotropic mechanical properties of rocks with complex weak surface structures by proposing a testing device and method for the anisotropic mechanical properties of strongly heterogeneous rocks. This device and method can test the uniaxial compressive strength of the same rock at different angles and evaluate the mechanical anisotropy of the rock.

[0005] This invention provides a device for testing the anisotropic mechanical properties of strongly heterogeneous rocks based on scratches. Its structure mainly includes a rotatable rock sample fixing device, a worktable and sliding rail, and a scratch tool control and data monitoring system.

[0006] The rotatable rock sample fixing device includes an outer base fixing screw 1, a front baffle 2, a bearing base 3, a rear baffle 4, a lateral baffle 5, fixing screws for each side baffle 6, and a support block 7.

[0007] The workbench and sliding rail include a desktop 8, a 360-degree angle dial 9, a drive motor 10, a sliding scratch system moving rail 11, a sliding scratch system fixing base 12, and base fixing screws 13.

[0008] The sliding scratching system includes a transverse moving seat 14, double-sided brackets 15, a tool mounting seat 16, a tool head 17, a computer 18, and a data acquisition unit 19.

[0009] Furthermore, the rotatable rock sample fixing device includes an outer base fixing screw 1, a front baffle 2, a bearing base 3, a rear baffle 4, a lateral baffle 5, fixing screws 6 for each side baffle, and a support block 7. The bearing base 3 of the rotatable rock sample fixing device is used for placing and fixing the rock sample 20, and different angles of the rock sample 20 can be scratched by rotating the base. The outer base fixing screw 1 is used to fix the position of the bearing base 3 after rotation. The front baffle 2, together with the rear baffle and the lateral baffle 5, fixes the rock sample 20, and the distance between the baffles can be adjusted to accommodate rock samples 20 of different sizes. The fixing screws 6 for each side baffle fix the position of the baffle after the baffle clamps the rock. The support block 7 is used when the height of the rock sample 20 does not exceed the baffle, and at the same time adjusts the vertical distance between the rock sample 20 and the cutter head 17 so that the part of the upper surface of the rock sample 20 that exceeds the baffle can be scratched.

[0010] Furthermore, the workbench and sliding track include a desktop 8, a 360-degree angle dial 9, a drive motor 10, a sliding scratch system moving track 11, a sliding scratch system fixing base 12, and a base fixing screw 13. The drive motor 10 can precisely control the left and right sliding speed of the sliding scratch system, increasing or decreasing it. The sliding scratch system moving track 11 allows the sliding scratch system to move left and right. The desktop 8 supports a rotatable rock sample fixing device, and the sliding track and sliding scratch system are suspended below. The sliding scratch system fixing base 12 and the base fixing screw 13 fix the sliding scratch system to the sliding scratch system moving track 11. The 360-degree angle dial 9 is located directly below the rotatable rock sample fixing device, defining the angle of the rock sample 20°.

[0011] Furthermore, the scratching tool control and data monitoring system includes a lateral moving base 14, double-sided supports 15, a tool mounting base 16, and a tool head 17. The double-sided supports 15 support the entire sliding scratching system, ensuring that the tool head 17 remains stable during the scratching process and also preventing interference between the sliding scratching system and the rotatable rock sample fixing device during the movement of the device. The lateral moving base 14 provides auxiliary support for the sliding scratching system, allowing the entire system to move left and right on the sliding track. The tool mounting base 16 fixes the position of the tool head 17, ensuring the stability of the tool head 17 throughout the scratching experiment. The tool head 17 can be selected as a pointed tool head or a blunt tool head. The computer 18 is used to control the movement of the sliding scratching system, collect the data collected during the experiment, and process the relevant data after the experiment. The data acquisition unit 19 collects the force on the tool head 17 during the scratching process.

[0012] Furthermore, this device, when combined with the following method, can perform anisotropic mechanical property testing of strongly heterogeneous rocks, including the following steps: S1: Prepare the corresponding rock sample 20 according to the experimental requirements, so that the rock sample 20 has a flat surface. The length of the rock sample 20 is between 15cm and 30cm, the width is between 10cm and 25cm, and the height is between 5cm and 13cm. S2: Before the experiment, take a picture of the sample, rotate the fixing device to align the center line of the device with the target angle, tighten the four outer ring fixing screws, place the processed sample on the fixing device, if the height of the rock sample 20 is too low, place the support block 7 on the base so that the upper surface of the rock sample 20 exceeds the four baffles, and at the same time observe the position of the upper surface of the rock sample 20 and the cutter head 17 so that the cutter head 17 can scratch the rock sample 20. Adjust the size of the fixing device so that the fixing device and the sample fit together, and tighten the fixing screws of the four baffles. S3: Use the computer to start the machine, observe the distance between the blade and the rock sample, and after the machine moves to the end, use the computer to return the blade to its original position. S4: Start using the computer. After the cutter head 17 has completed one full pass, reset and repeat the operation. At the same time, observe the data on the computer. After continuous data appears, record the data. Then start the cutter head 17 again and repeat the operation three times. S5: After the test is completed, reset the cutter head 17, remove the sample, take a picture to record the scratched position of the sample, and record the scratch length, scratch depth, shear strength, and tensile strength data. Using the rock anisotropic compressive strength formula, calculate the compressive strength of each anisotropic scratch on the same rock obtained from the experiment. The anisotropy of the rock is determined by the compressive strength obtained from the scratches, and the anisotropy of the rock is obtained by the following formula; ; In the formula: The anisotropic compressive strength of the rock; This represents the maximum anisotropic compressive strength of the rock at the angles already obtained on the same rock surface; This represents the minimum anisotropic compressive strength of the rock at the angles already obtained on the same rock surface; At the same time, we can further explore the anisotropy of several scratches located at a certain depth point. This is a method for calculating the anisotropy on the same rock based on continuous scratches. If the scratch falls on the short side, the length can be calculated and represented by the following formula. ; In the formula: This is the sampling line segment when the scratch angle is 0°; scratch start point When the edges are different and the scratch angle is The sampling line segment at that time; for and The angle between them; If the scratch falls on the long side, the length can be calculated using the following formula; ; In the formula: This is the sampling line segment when the scratch angle is 0°; The starting point of the scratch and When the sides are different and the scratch angle is The sampling line segment at that time; To and A line segment parallel to the long side of the rock sample; for and The angle between them.

[0013] Compared with the prior art, the advantages of the present invention are: (1) This device can test the mechanical anisotropy of a rock on a single sample, solving the problem of low success rate of multi-angle sample sampling in conventional mechanical anisotropy testing of rocks with complex weak surface structures. (2) This method is based on the relationship between rock scratches and their mechanical properties. The data obtained by the device can obtain the rock mechanical anisotropy at a specific depth point. The measured results are more refined and have better practical engineering application value. Compared with conventional multi-sample sampling and testing methods, this device uses the relationship between rock scratches and their mechanical parameters. (3) Compared with conventional multi-sample testing methods, this method can better reflect the anisotropy on the same rock and is more accurate than that on different blocks; (4) This device can better explain the anisotropy of the same rock by using the relationship between rock scratches and their mechanical parameters.

[0014] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the anisotropic mechanical property testing device for strongly heterogeneous rocks according to the present invention. Figure 2 This is a front view structural schematic diagram of the anisotropic mechanical property testing device for strongly heterogeneous rocks according to the present invention. Figure 3This is a side view structural schematic diagram of the anisotropic mechanical property testing device for strongly heterogeneous rocks according to the present invention; Figure 4 This is a top view schematic diagram of the anisotropic mechanical property testing device for strongly heterogeneous rocks according to the present invention. Figure 5 This is a schematic diagram of the rotatable rock sample fixing device of the anisotropic mechanical property testing device for strongly heterogeneous rocks of the present invention. Figure 6 A schematic diagram of the scratch tool control and data monitoring system of the anisotropic mechanical property testing device for strongly heterogeneous rocks of the present invention; Figure 7 This is a schematic diagram of the worktable and sliding track structure of the anisotropic mechanical property testing device for strongly heterogeneous rocks according to the present invention. Figure 8 This is a diagram illustrating the connection structure between the sliding track and the scratching tool in the anisotropic mechanical property testing device for strongly heterogeneous rocks according to the present invention. Figure 9 An experimental scratch diagram of the device for testing the anisotropic mechanical properties of strongly heterogeneous rocks invented; In the diagram: 1. Side base fixing screws; 2. Front baffle; 3. Bearing base; 4. Rear baffle; 5. Side baffle; 6. Fixing screws for each side baffle; 7. Support block; 8. Desktop; 9. 360-degree angle dial; 10. Drive motor; 11. Sliding scratch system moving track; 12. Sliding scratch system fixing base; 13. Base fixing screws; 14. Lateral moving seat; 15. Double-sided bracket; 16. Tool mounting base; 17. Tool head; 18. Computer; 19. Data acquisition unit; 20. Rock sample. Detailed Implementation

[0016] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0017] In the accompanying drawings, the dimensions and thicknesses of each component are shown arbitrarily. The present invention does not limit the dimensions and thickness of each component. In order to make the illustration clearer, the dimensions of the components are appropriately exaggerated in some places in the drawings.

[0018] As shown in the figure, this invention provides a device and method for testing the anisotropic mechanical properties of strongly heterogeneous rocks. A sliding scratch system moving track 11 is installed below the tabletop 8. A drive motor 10 is connected to the right side of the sliding scratch system moving track 11. The sliding scratch system fixing base 12 on the sliding scratch system moving track 11 is fixed to the sliding scratch system by base fixing screws 13. The transverse moving seat 14 and the double-sided brackets 15 on the sliding scratch system jointly support the sliding scratch system. A blade mounting seat is connected to the top of the double-sided brackets 15, and the blade mounting seat is connected to the blade head. 17. Next to the cutter head 17 is a data acquisition unit 19, which is connected to the computer 18 to record data during the scribing process of the rock sample 20. On the right side of the desktop 8, there is a 360-degree angle dial 9, which provides a specific rotation angle. The 360-degree angle dial 9 is close to the support base 3. The support base 3 is connected to the front baffle 2, the rear baffle 4, and the side baffle 5 for fixing the rock sample 20. The support base 3 itself can rotate and has fixing screw positions around it. There are two fixing screws on the front baffle 2, the rear baffle 4, and the side baffle 5 to fix the rock sample 20 together.

[0019] This example also discloses a method for testing the anisotropic mechanical properties of strongly heterogeneous rocks. Taking the same rock sample at 20 different angles as an example, the method includes the following steps: S1: Prepare the corresponding rock sample 20 according to the experimental requirements, so that the rock sample 20 has a flat surface. The length of the rock sample 20 is between 15cm and 30cm, the width is between 10cm and 25cm, and the height is between 5cm and 13cm. S2: Before the experiment, take a picture of the sample, rotate the fixing device to align the center line of the device with the target angle, tighten the four outer ring fixing screws, place the processed sample on the fixing device, if the height of the rock sample 20 is too low, place the support block 7 on the base so that the upper surface of the rock sample 20 exceeds the four baffles, and at the same time observe the position of the upper surface of the rock sample 20 and the cutter head 17 so that the cutter head 17 can scratch the rock sample 20. Adjust the size of the fixing device so that the fixing device and the sample fit together, and tighten the fixing screws of the four baffles. S3: Use the computer to start the machine, observe the distance between the blade and the rock sample, and after the machine moves to the end, use the computer to return the blade to its original position. S4: Start using the computer. After the cutter head 17 has completed one full pass, reset and repeat the operation. At the same time, observe the data on the computer. After continuous data appears, record the data. Then start the cutter head 17 again and repeat the operation three times. S5: After the test is completed, reset the cutter head 17, remove the sample, take a picture to record the scratched position of the sample, and record the scratch length, scratch depth, shear strength, and tensile strength data. Using the rock anisotropic compressive strength formula, calculate the compressive strength of each anisotropic scratch on the same rock obtained from the experiment. ; In the formula: The compressive strength of rock with anisotropy; The horizontal tangential force exerted on the blades mounted on the experimental apparatus; The width of the blade mounted on the device; The depth marked by the apparatus in the experiment; The anisotropy of the rock is determined by the compressive strength obtained from the scratches, and the anisotropy of the rock is obtained by the following formula; ; In the formula: The compressive strength of rock with anisotropy; This represents the maximum anisotropic compressive strength of the rock at the angles already obtained on the same rock surface; This represents the minimum anisotropic compressive strength of the rock at the angles already obtained on the same rock surface; At the same time, we can further explore the anisotropy of several scratches located at a certain depth point. This is a method for calculating the anisotropy on the same rock based on continuous scratches. If the scratch falls on the short side, the length can be calculated and represented by the following formula. ; In the formula: This is the sampling line segment when the scratch angle is 0°; scratch start point When the edges are different and the scratch angle is The sampling line segment at that time; for and The angle between them; If the scratch falls on the long side, the length can be calculated using the following formula; ; In the formula: This is the sampling line segment when the scratch angle is 0°; The starting point of the scratch and When the sides are different and the scratch angle is The sampling line segment at that time; To and A line segment parallel to the long side of the rock sample; for and The angle between them.

[0020] The results and implementation effects obtained from the tests conducted in the above embodiments are analyzed as follows: The anisotropic mechanical properties of strongly heterogeneous rocks were tested using this device, and the results show that: exist It is 5mm. Scratch data and uniaxial compression data obtained for 0.18mm; Table 1 Comparison of this method with conventional uniaxial compression experiments ; The experimental results obtained by this method are shown in the table above, which compares them with those obtained by conventional uniaxial compression experiments. It can be seen that there are some differences in the parameter values ​​obtained by this method compared to those obtained by uniaxial compression, but the basic trend is the same: both achieve their minimum values ​​at 45° and their maximum values ​​at 0°. While conventional uniaxial compression is a commonly used and widely accepted method, it requires large sampling and is complex, and it is difficult to characterize the same rock. This device and method, however, can characterize the same rock with scratches, making the experiment more accurate. By comparing the final anisotropy results, there are only minor differences between the results obtained by conventional uniaxial compression and those obtained by this method, proving that the anisotropy obtained by this method on the same rock is valid.

Claims

1. A testing device for the anisotropic mechanical properties of strongly heterogeneous rocks, wherein the method employs an adjustable multi-angle rock scratch device, characterized in that... The method includes the following steps: S1: The rock is processed into a rectangular sample, so that the upper surface of the rock sample is a flat surface and perpendicular to the weak structure surface of the rock for scratch test. The length of the rock sample (20) is between 15cm and 30cm, the width is between 10cm and 25cm, and the height is between 5cm and 13cm. S2: Before the experiment, take a picture of the sample, rotate the fixing device to align the center line on the device with the target angle, tighten the four outer ring fixing screws, place the processed rock sample (20) on the fixing device, if the rock sample (20) is too low, place a support block (7) on the base so that the upper surface of the rock sample (20) exceeds the four baffles, and observe the position of the upper surface of the rock sample (20) and the cutter head (17) so that the cutter head (17) can scratch the rock sample (20), adjust the size of the fixing device so that the fixing device and the sample fit together, and tighten the fixing screws of the four baffles; S3: Use the computer to start the machine, observe the distance between the blade and the rock sample, and after the machine moves to the end, use the computer to return the blade to its original position. S4: Start the computer, and after the cutter head (17) has completed one round of scraping, reset and repeat the operation. At the same time, observe the data on the computer. After continuous data appears, record the data of scratch length, scratch depth, shear strength, and tensile strength. Then start the cutter head (17) again and repeat the operation three times. S5: After the test is completed, reset the cutter head (17), remove the sample, take a picture to record the scratched position of the sample, record the scratch length, scratch depth, shear strength and tensile strength data, and use the rock anisotropic compressive strength formula to calculate the compressive strength of each anisotropic scratch on the same rock obtained from the experiment. The anisotropy of the rock is determined by the compressive strength obtained from the scratches, and the anisotropy of the rock is obtained by the following formula; ； In the formula: The anisotropic compressive strength of the rock; This represents the maximum anisotropic compressive strength of the rock at the angles already obtained on the same rock surface; This represents the minimum anisotropic compressive strength of the rock at the angles already obtained on the same rock surface; At the same time, we can further explore the anisotropy of several scratches located at a certain depth point. This is a method for calculating the anisotropy on the same rock based on continuous scratches. If the scratch falls on the short side, the length can be calculated and represented by the following formula. ； In the formula: This is the sampling line segment when the scratch angle is 0°; scratch start point When the edges are different and the scratch angle is The sampling line segment at that time; for and The angle between them; If the scratch falls on the long side, the length can be calculated using the following formula; ； In the formula: This is the sampling line segment when the scratch angle is 0°; The starting point of the scratch and When the sides are different and the scratch angle is The sampling line segment at that time; To and A line segment parallel to the long side of the rock sample; for and The angle between them; The test device was used to carry out rock strength scratch tests at different angles. The results showed that: by preparing a small number of rock samples (20) at low cost and adjusting the rotation angle of the fixing device, rock strength data at any angle from 0° to 360° can be obtained on the same sample. The fixing device can be rotated to the required position according to the required experimental angle. The angle can be selected at any angle from 0° to 360° without repeatedly disassembling the rock sample (20), which can save a lot of time. Finally, the anisotropy of the rock was calculated and the obtained data was compared with the data obtained by the rock strength scratch device.

2. The testing device for the anisotropic mechanical properties of strongly heterogeneous rocks according to claim 1, characterized in that, The experimental apparatus includes: a rotatable rock sample fixing device, a worktable and sliding rail, and a scratching tool control and data monitoring system.

3. The testing device for the anisotropic mechanical properties of strongly heterogeneous rocks according to claim 2, characterized in that, The rotatable rock sample fixing device consists of an outer base fixing screw (1), a front baffle (2), a bearing base (3), a rear baffle (4), a side baffle (5), fixing screws (6) for each side baffle, and a support block (7). The bearing base (3) is used to place and fix the sample, and can be rotated to the corresponding angle. The front baffle (2), the rear baffle (4), and the side baffle (5) assist in fixing the sample position. The fixing screws on each side are tightened on their respective baffle bases to fix the baffles and fix the rock sample (20). The outer base fixing screw (1) fixes the bearing base (3) after it is rotated to the required angle. The support block (7) can help raise the rock sample (20) if it is not high enough, and adjust the height between the rock sample (20) and the cutter head (17).

4. The testing device for the anisotropic mechanical properties of strongly heterogeneous rocks according to claim 2, characterized in that, The sliding track and supporting tabletop consist of a tabletop (8), a 360-degree angle dial (9), a drive motor (10), a sliding scratch system moving track (11), a sliding scratch system fixing base (12), and base fixing screws (13); the tabletop (8) is used to support the rotatable rock sample fixing device; the 360-degree angle dial (9) is located on the outer ring of the rotatable rock sample fixing device and is used to determine the rotation angle, which is 360 degrees; the drive motor (10) can controllably adjust the moving speed of the sliding scratch system to speed up or decrease the sliding speed; The sliding scratch system moving track (11) allows the sliding scratch system to move on the sliding scratch system moving track (11), and the sliding scratch system fixing base (12) and the base fixing screw (13) fix the sliding scratch system on the sliding scratch system moving track (11).

5. The testing device for the anisotropic mechanical properties of strongly heterogeneous rocks according to claim 2, characterized in that, The sliding scratch system and data monitoring system consist of a transverse moving seat (14), a double-sided support (15), a tool mounting seat (16), a tool head (17), a computer (18), and a data acquisition unit (19). The transverse moving seat (14) moves on the sliding scratch system moving track (11), allowing the tool head (17) to scratch. The double-sided support (15) supports the entire sliding scratch system and ensures that the sliding scratch system and the rotatable rock sample fixing device do not interfere with each other, while stabilizing the tool head (17) during the scratching process. The tool mounting seat (16) is used to install the tool head (17). The tool head (17) can be replaced with a pointed tool head (17) and a blunt tool head (17). The computer (18) is connected to the data acquisition unit (19) to realize real-time monitoring and acquisition of the tangential force data and displacement data of the tool head (17).

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