Annular rock sample circumferential loading test device

Abstract

The utility model belongs to the technical field of rock-soil body physical mechanics experiments, and particularly relates to an annular rock sample circumferential loading test device. The test device comprises a device frame. The circumferential pressurizing units are arranged in parallel in the axial direction of the rock sample, and the circumferential pressurizing units are arranged on the periphery of the rock sample in a sleeving mode and used for applying circumferential confining pressure to the rock sample; the annular pressurizing units at different axial positions are used for applying annular confining pressure of different magnitudes; the circumferential pressurizing unit comprises a flexible pressure equalizing plate, the flexible pressure equalizing plate surrounds the periphery of the rock sample, and after surrounding the rock sample, the flexible pressure equalizing plate is provided with mutually lapped parts; a plurality of tightening ropes surround the periphery of the flexible pressure equalizing plate, and each tightening rope at least surrounds the flexible pressure equalizing plate by one circle; and the two ends of the tightening rope are tightened to tighten the flexible pressure equalizing plate so as to apply confining pressure to the rock sample. The test device can more truly and effectively simulate the working condition that the circular shaft is subjected to peripheral ground stress and load application, so that a more accurate and effective test result is obtained.

Description

Technical Field

[0001] This utility model belongs to the field of physical and mechanical experimental technology of soil and rock, and specifically relates to a circular loading test device for a circular rock sample. Background Technology

[0002] Rock mechanics experiments are an important means of studying the mechanical properties of rock masses under different conditions, and are widely used in geology, mining engineering, civil engineering, and other fields. These experiments, by simulating natural geological environments, help researchers gain a deeper understanding of the strength, deformation characteristics, and fracture mechanisms of rocks, providing a scientific basis for engineering design and disaster prevention.

[0003] Existing GCTS and SHPB testing systems can only achieve loading in one direction, and cannot realistically simulate the complex geostress in engineering practice; they also cannot apply circumferential loads to cylindrical specimens. However, circumferential loading of cylindrical or annular specimens can simulate the application of surrounding geostress and loads to circular shafts in coal mines or surface gas extraction, and there is currently no testing device for this specific condition.

[0004] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Utility Model Content

[0005] The purpose of this invention is to provide a circumferential loading test device for annular rock samples, so as to at least solve the above-mentioned problems existing in the prior art.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A circular loading test apparatus for annular rock samples, the test apparatus comprising:

[0008] The device frame has an axial loader at its top, a top pressure plate at the output end of the axial loader, and a bottom pressure plate below the corresponding top pressure plate of the device frame, on which the rock sample is placed.

[0009] A circumferential pressurization unit is provided, with multiple circumferential pressurization units arranged in parallel along the axial direction of the rock sample. The circumferential pressurization units are sleeved around the rock sample and are used to apply circumferential confining pressure to the rock sample. Circumferential pressurization units at different axial positions are used to apply circumferential confining pressure of different magnitudes.

[0010] The circumferential pressurization unit includes a flexible pressure equalization plate, which surrounds the rock sample and has overlapping portions after surrounding the rock sample.

[0011] The flexible pressure equalizing plate is surrounded by multiple tightening ropes, and each tightening rope wraps around the flexible pressure equalizing plate at least once; tightening the two ends of the tightening ropes compresses the flexible pressure equalizing plate to apply confining pressure to the rock sample.

[0012] In the circular loading test device for annular rock samples described above, preferably, multiple rows of guide rings are arranged axially on the outer surface of the flexible equalizing plate, and each of the tightening ropes is threaded through one row of guide rings.

[0013] In the circular loading test device for annular rock samples described above, preferably, two steering rods are also provided on the frame of the device, and the two steering rods are symmetrically arranged along the axis of the rock sample.

[0014] In the circular loading test device for annular rock samples described above, preferably, after the flexible equalizing plate surrounds the rock sample, there is a row of guide rings between the axis of any steering rod and the line connecting the axis of the rock sample.

[0015] In the circular loading test device for the annular rock sample described above, preferably, after the tightening rope has been wrapped around the rock sample at least once, both ends of the tightening rope pass through the guide ring between the axis of the steering rod and the axis of the rock sample, and are connected to the tensioning unit after passing around the guide ring, so that the two ends of the tightening rope passing through the guide ring are on the same straight line passing through the axis of the rock sample and extend in opposite directions.

[0016] In the circular loading test device for annular rock samples described above, preferably, the tensioning unit is a winch and the tensioning rope is a steel strand;

[0017] After the two ends of the tightening rope are passed over the steering rods on both sides of the rock sample, they are connected to the same winch.

[0018] In the circular loading test apparatus for annular rock samples as described above, preferably, the winch is located on the perpendicular bisector of the line connecting the axes of the two steering rods.

[0019] In the above-described annular rock sample circumferential loading test device, preferably, the rock sample has multiple axially extending boreholes inside, and each borehole contains a monitoring unit.

[0020] In the circular loading test device for annular rock samples as described above, preferably, the monitoring unit includes a distributed optical fiber sensor, a distributed acoustic sensor, and an inclinometer.

[0021] The distributed fiber optic sensor is used to detect the deformation and stress of the rock sample;

[0022] The distributed acoustic sensor is used to detect the development and evolution of cracks in rock samples under load.

[0023] The inclinometer is used to monitor the internal deformation and tilt data of the rock sample.

[0024] Beneficial effects:

[0025] In this triaxial testing device, multiple circumferential pressurizing units along the axial direction apply confining pressures of different magnitudes to the rock sample to simulate the actual law of gradual change in confining pressure on the rock sample as the burial depth increases. Moreover, the circumferential pressurizing units along the axial direction can operate independently without interfering with each other, allowing each circumferential pressurizing unit to independently and effectively apply different magnitudes of surrounding rock to different axial positions of the rock sample. This ensures that the annular rock sample circumferential loading test device can more realistically and effectively simulate the working conditions of a circular shaft in a coal mine or surface gas extraction under the application of surrounding geostress and loads, thus obtaining more accurate and effective test results.

[0026] Each tightening rope is threaded through a row of guide rings to better maintain its position and prevent significant positional deviation, thus ensuring that each tightening rope can stably and reliably perform its tightening function in the preset position.

[0027] The two ends of the tightening rope pass through the guide ring and are wrapped around the steering rod. Since the guide ring through which the tightening rope passes is located between the axis of the steering rod and the axis of the rock sample, and the two steering rods are symmetrically arranged relative to the axis of the rock sample, that is, the two ends of the tightening rope are on the same straight line passing through the axis of the rock sample and extend in opposite directions, when the two ends of the tightening rope are tightened, the forces in opposite directions along the same straight line of the rock sample axis at both ends of the tightening rope can cancel each other out while the tightening rope tightens the flexible equalizing plate. Therefore, it will not produce other forces that deviate from the axis of the rock sample and will ensure the stability of the circumferential loading test of the annular rock sample.

[0028] The monitoring unit monitors data in real time on the stress, strain, crack development process, and borehole inclination of the rock sample. Attached Figure Description

[0029] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. Wherein:

[0030] Figure 1 This is a front view of the test apparatus according to an embodiment of the present invention;

[0031] Figure 2 for Figure 1 A magnified view of a portion of the image;

[0032] Figure 3 This is a top view of the test apparatus according to an embodiment of the present invention;

[0033] Figure 4 for Figure 3 A magnified view of a portion of the image;

[0034] In the diagram: 1. Rock sample; 2. Device frame; 3. Axial loader; 4. Top pressure plate; 5. Bottom pressure plate; 6. Flexible equalizing plate; 7. Guide ring; 8. Tightening rope; 9. Steering rod; 10. Monitoring unit; 11. Winch. Detailed Implementation

[0035] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art are within the protection scope of this utility model.

[0036] In the description of this utility model, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and do not require that this utility model be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model. The terms "connected" and "linked" used in this utility model should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0037] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0038] According to specific embodiments of this utility model, such as Figure 1-4 As shown, this utility model provides a circumferential loading test device for a circular rock sample, the test device comprising:

[0039] The device frame 2 has an axial loader 3 at its top and a top pressure plate 4 at its output end. A bottom pressure plate 5 is located below the corresponding top pressure plate 4 of the device frame 2, and the rock sample 1 is placed on the bottom pressure plate 5.

[0040] The circumferential pressure unit consists of multiple circumferential pressure units arranged in parallel along the axial direction of rock sample 1. The circumferential pressure unit is sleeved around the rock sample 1 and is used to apply circumferential confining pressure to the rock sample 1. Circumferential pressure units at different axial positions are used to apply circumferential confining pressure of different magnitudes.

[0041] The circumferential pressurization unit includes a flexible pressure equalization plate 6, which surrounds the rock sample 1 and has overlapping portions after surrounding the rock sample 1. In this embodiment, the flexible pressure equalization plate 6 is made of bent iron plate or steel plate. After surrounding the rock sample 1, the flexible pressure equalization plate 6 only overlaps each other and is not fixed, so as to ensure that the flexible pressure equalization plate 6 can be further compressed to apply confining pressure to the rock sample 1.

[0042] The flexible pressure equalizing plate 6 is surrounded by multiple tightening ropes 8, and each tightening rope 8 wraps around the flexible pressure equalizing plate 6 at least once; the two ends of the tightening ropes 8 are tightened to compress the flexible pressure equalizing plate 6 and apply confining pressure to the rock sample 1.

[0043] In this triaxial testing device, axial pressure can be applied to rock sample 1 through axial loader 3. In the circumferential pressurization unit, a tightening rope 8 is wrapped around the flexible pressure equalizing plate 6. After tightening the tightening rope 8, the flexible pressure equalizing plate 6 is gradually locked. As the tension of the tightening rope 8 increases, the confining pressure of the flexible pressure equalizing plate 6 on rock sample 1 gradually increases. By controlling multiple circumferential pressurization units in the axial direction to apply confining pressure of different magnitudes to rock sample 1, the actual law of the gradual change of confining pressure on rock sample 1 with the increase of burial depth can be simulated. Moreover, each circumferential pressurization unit in the axial direction can be independent and effective, so that each circumferential pressurization unit can independently and effectively apply different magnitudes of surrounding rock to different axial positions of rock sample 1. This ensures that the annular rock sample circumferential loading test device can more realistically and effectively simulate the working conditions of circular shafts in coal mines or surface gas extraction under the application of surrounding ground stress and load, thus obtaining more accurate and effective test results.

[0044] Multiple rows of guide rings 7 are arranged axially on the outer surface of the flexible pressure equalizing plate 6, and each tightening rope 8 is threaded through one row of guide rings 7. In one embodiment of this application, each tightening rope 8 is threaded through one row of guide rings 7 so that the tightening rope 8 can better maintain its position and will not have a large positional deviation, thereby ensuring that each tightening rope 8 can stably and reliably perform its respective tightening function in the preset position.

[0045] In this embodiment, each row of guide rings 7 is provided with at least 8 rings to better guide and limit the tensioning rope 8.

[0046] Two steering rods 9 are also provided on the device frame 2, and the two steering rods 9 are symmetrically arranged along the axis of the rock sample 1.

[0047] After the flexible equalizing plate 6 surrounds the rock sample 1, there is a row of guide rings 7 between the axis of any steering rod 9 and the axis of the rock sample 1.

[0048] After the tightening rope 8 has circled the rock sample 1 at least once, both ends of the tightening rope 8 pass through the guide ring 7 between the axis of the steering rod 9 and the axis of the rock sample 1, and pass around the guide ring 7 to connect to the tensioning unit, so that the two ends of the tightening rope 8 that pass through the guide ring 7 are on the same straight line passing through the axis of the rock sample 1 and extend in opposite directions. In one embodiment of this application, the two ends of the tightening rope 8 pass through the guide ring 7 and are wrapped around the steering rod 9. Since the guide ring 7 through which the tightening rope 8 passes is located between the axis of the steering rod 9 and the axis of the rock sample 1, and the two steering rods 9 are symmetrically arranged relative to the axis of the rock sample 1, that is, the two ends of the tightening rope 8 are on the same straight line passing through the axis of the rock sample 1 and extend in opposite directions, when the two ends of the tightening rope 8 are tightened, while the tightening rope 8 tightens the flexible equalizing plate 6, the forces in opposite directions at the two ends of the tightening rope 8 along the same straight line of the axis of the rock sample 1 can cancel each other out, so that no other force affecting the rock sample 1 deviates from the axis of the rock sample 1 will be generated, thus ensuring the stability of the circumferential loading test of the annular rock sample.

[0049] The tensioning unit is a winch 11, and the tensioning rope 8 is a steel strand. Both ends of the tensioning rope 8 pass over the turning rods 9 on both sides of the rock sample 1 and are connected to the same winch 11. In one embodiment of this application, both ends of a tensioning rope 8 pass over two turning rods 9 and are connected to the same winch 11. When the winch 11 rotates, both ends of the tensioning rope 8 are subjected to the same tension force, thus facilitating the mutual cancellation of the tension forces at both ends of the tensioning rope 8.

[0050] The winch 11 is located on the perpendicular bisector of the line connecting the axes of the two steering rods 9. In one embodiment of this application, the winch 11 is configured such that the two ends of the tension rope 8 are equidistant from the same winch 11, so that the two ends of the tension rope 8 can be subjected to the same tension force.

[0051] The rock sample 1 has multiple boreholes extending along the axial direction, and each borehole is equipped with a monitoring unit 10.

[0052] The monitoring unit 10 includes a distributed optical fiber sensor, a distributed acoustic wave sensor, and an inclinometer; the distributed optical fiber sensor is used to detect the deformation and stress of the rock sample 1; so as to finally draw a plottable distribution cloud map and values ​​of stress and strain from top to bottom, thereby recording and analyzing the stress and strain change law of the circular sample during the loading process.

[0053] The distributed acoustic wave sensor is used to detect the development and evolution of cracks in rock sample 1 under load; specifically, the distributed acoustic wave sensor detects the entire development and evolution process of crack initiation, propagation, arrest, and crack path inside rock sample 1.

[0054] The inclinometer is used to monitor the internal deformation and tilt data of rock sample 1. It is used to calculate and monitor different tilting failure conditions of the borehole in rock sample 1 in real time.

[0055] The test method for the above-mentioned circular ring rock sample circumferential loading test device is as follows, and the test method includes:

[0056] Step 1: Prepare a rock sample 1 of a set size and drill holes in the rock sample 1; In this embodiment, the rock sample 1 can be made into a cylindrical or annular shape, wherein the cylindrical shape is a special annular shape with an inner diameter of zero; Taking the cylindrical rock sample 1 as an example, its size is 50mm (diameter) × 100mm (height); and four drill holes are symmetrically drilled in the cylindrical rock sample 1.

[0057] Step 2: Place rock sample 1 between the bottom pressure plate 5 and the top pressure plate 4 of the axial loader 3, and adjust the axis of rock sample 1 to coincide with the axis of the axial loader 3; to ensure that the axial load is applied in the axial direction of rock sample 1.

[0058] Step 3: Install multiple circumferential pressure units at different axial positions of rock sample 1. In this embodiment, five circumferential pressure units are installed around rock sample 1 along the axial direction, and the surrounding rock pressure applied by the five circumferential pressure units is gradually increased. First, the flexible pressure equalizing plate 6 is wrapped around the rock sample 1, and then the tightening rope 8 is wrapped around a row of guide rings 7. After the tightening rope 8 is wrapped around rock sample 1 at least once, both ends of the tightening rope 8 are passed around the steering rod 9 and connected to the tensioning unit.

[0059] Step 4: Apply axial pressure to rock sample 1 through axial loader 3, and apply surrounding rock to rock sample 1 by tightening the tightening rope 8 through the tensioning unit; the surrounding pressure applied by multiple circumferential pressure units gradually increases from top to bottom;

[0060] Step 5: During the process of rock sample 1 being subjected to axial pressure and circumferential confining pressure load, the monitoring unit 10 monitors the stress, strain, crack development process and borehole inclination data of rock sample 1 in real time.

[0061] It is understood that the above description is merely exemplary and the embodiments of this application do not limit the scope of the application.

[0062] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be within the scope of protection of the pending claims of the present utility model.

Claims

1. A circumferential loading test device for annular rock samples, characterized in that, The test device comprises: a device frame, a top of the device frame is provided with an axial loader, an output end of the axial loader is provided with a top pressing plate, a bottom pressing plate is arranged below the corresponding top pressing plate of the device frame, and a rock sample is placed on the bottom pressing plate; a ring pressure unit, a plurality of ring pressure units are arranged in parallel along the axial direction of the rock sample, the ring pressure units are sleeved on the periphery of the rock sample, and are used for applying a ring confining pressure to the rock sample; ring pressure units at different axial positions are used for applying ring confining pressures of different sizes; the ring pressure unit comprises a flexible equalizing plate, the flexible equalizing plate is wrapped around the periphery of the rock sample, and the flexible equalizing plate has a portion that overlaps after being wrapped around the rock sample; a plurality of tightening ropes are wrapped around the periphery of the flexible equalizing plate, and each tightening rope wraps around the flexible equalizing plate at least once; the ends of the tightening rope are pulled tight to shrink the flexible equalizing plate and apply a confining pressure to the rock sample.

2. The torus ring-shaped rock sample hoop loading test device according to claim 1, characterized in that, a plurality of rows of guide rings are arranged on the peripheral surface of the flexible equalizing plate along the axial direction, and each tightening rope is arranged in a row of guide rings.

3. The torus ring-shaped rock sample hoop loading test device according to claim 2, characterized in that, two steering rods are further arranged on the device frame, and the two steering rods are arranged symmetrically about the axis of the rock sample.

4. The torus ring-shaped rock sample hoop loading test device according to claim 3, characterized in that, after the flexible equalizing plate is wrapped around the periphery of the rock sample, a row of guide rings is arranged between the axis of any steering rod and the axis of the rock sample.

5. The torus ring-shaped rock sample hoop loading test device according to claim 4, characterized in that, after the tightening rope is wrapped around the rock sample at least once, the two ends of the tightening rope are pulled out from the guide rings between the axes of the steering rods and the rock sample, and are connected to the tensioning unit by passing around the guide rings, so that the two ends of the tightening rope pulled out from the guide rings are on the same straight line passing through the axis of the rock sample, and extend towards opposite directions.

6. The torus ring-shaped rock sample hoop loading test device according to claim 5, characterized in that, the tensioning unit is a winch, and the tightening rope is a steel strand; after the two ends of the tightening rope pass around the steering rods on both sides of the rock sample, the two ends are connected to the same winch.

7. The torus ring-shaped rock sample hoop loading test device according to claim 6, characterized in that, the winch is located on the perpendicular bisector of the line connecting the axes of the two steering rods.

8. The torus ring-shaped rock sample hoop loading test device according to claim 5, characterized in that, a plurality of drill holes extending in the axial direction are arranged in the rock sample, and a monitoring unit is arranged in each drill hole.

9. The torus ring-shaped rock sample hoop loading test device according to claim 8, characterized in that, the monitoring unit comprises a distributed optical fiber sensor, a distributed acoustic wave sensor, and an inclinometer; the distributed optical fiber sensor is used for detecting the deformation and stress of the rock sample; the distributed acoustic wave sensor is used for detecting the crack development and evolution process of the rock sample under load; the inclinometer is used for monitoring the internal deformation and inclination data of the rock sample.

Images