Rock shear strength test device, test system and test method

Abstract

The invention relates to the technical field of rock shearing, in particular to a rock shearing strength test device, test system and test method.The test device comprises a counter-force base, a horizontal loading device, a horizontal bearing plate, a vertical loading box, a vertical fixing box and a vertical loading device; the counter-force base is provided with a loading chamber, a pair of horizontal loading devices are symmetrically arranged on two opposite side walls of the loading chamber, and each horizontal loading device is connected with a horizontal bearing plate; the grooves in the vertical loading box and the vertical fixing box jointly form a space for placing a rock sample, and a pin roller is arranged on the contact surface of the vertical loading box and the vertical fixing box; and the vertical loading device applies a load to the sample through the vertical loading box. In the test process, the deformation and fracture characteristics of the rock shearing surface can be directly observed, and compared with an existing rock shearing device, the rock shearing device is more visual and closer to actual engineering, and has the characteristics of being convenient to operate and low in cost.

Description

Technical Field

[0001] This invention relates to the field of rock shear technology, and in particular to a rock shear strength testing device, testing system and testing method. Background Technology

[0002] A direct shear tester for rocks is a device used to determine the shear strength of rocks. Its working principle involves placing a rock sample between upper and lower shear boxes, applying a certain vertical pressure, and then applying a horizontal thrust to the lower shear box. Since the upper shear box remains stationary, the lower shear box moves horizontally under the thrust, causing relative displacement of the rock sample until shear failure, thus obtaining the shear strength parameters of the rock. However, when using existing direct shear testers to determine the shear strength of rocks, although the upper and lower shear boxes can move relative to each other, the gap between them is very small, making it impossible to directly observe the deformation and failure characteristics of the shear surface during the shearing process. Summary of the Invention

[0003] The present invention aims to overcome the shortcomings of the prior art and provide a rock shear strength testing device that can directly observe the deformation and fracture characteristics of the rock shear surface, which is more intuitive than existing rock shearing devices.

[0004] To achieve the above objectives, the present invention provides a rock shear strength testing device, comprising a reaction base, a horizontal loading device, a horizontal bearing plate, a vertical loading box, a vertical fixing box, and a vertical loading device; the reaction base has a loading chamber with a top opening, and a pair of horizontal loading devices for simulating horizontal pressure at different underground depths are symmetrically arranged on the left and right opposite side walls of the loading chamber, each horizontal loading device having a horizontal bearing plate at its front end; the vertical loading box and the vertical fixing box both have a U-shaped cross-section; the vertical fixing box is fixedly mounted on the bottom plate of the loading chamber with its opening facing upwards; the first and second side walls of the vertical fixing box each have a first through hole for the output end of the horizontal loading device to pass through, and the vertical fixing box... A first receiving groove is also provided on the inner side of the first sidewall; the vertical loading box is disposed above the vertical fixing box with its opening facing downwards. The first and second sidewalls of the vertical loading box are each provided with a second through hole for the output end of the horizontal loading device to pass through. The second sidewall of the vertical loading box is movably inserted into the opening of the vertical fixing box, and the first sidewall of the vertical fixing box is movably disposed in the opening of the vertical loading box. A second receiving groove corresponding to the first receiving groove is provided on the inner side of the second sidewall of the vertical loading box. The second receiving groove and the first receiving groove together form a sample testing space for placing the rock sample. The vertical loading device is connected to the vertical loading box and is used to drive the vertical loading box to apply a load to the rock sample.

[0005] Furthermore, several rollers are provided on the side wall where the vertical loading box and the vertical fixing box contact each other to reduce the friction between them.

[0006] Furthermore, the inner side of the first side wall of the vertical loading box is provided with a plurality of first mounting slots, and the inner side of the first side wall and the second side wall of the vertical fixing box are each provided with a plurality of second mounting slots, and rollers are respectively provided in the plurality of first mounting slots and the plurality of second mounting slots.

[0007] Furthermore, the horizontal bearing plate is disposed within the test space of the sample, and the outer side of the horizontal bearing plate has a connecting part; the front end of the loading rod of the horizontal loading device is provided with a connecting groove for cooperating with the connecting part, the connecting part is inserted into the connecting groove, and is connected to the horizontal loading device by a screw.

[0008] Furthermore, the loading chamber has openings on both the front and rear sides; the sample testing space is an open space with openings at the front and rear.

[0009] Furthermore, multiple positioning connecting rods perpendicular to the loading direction of the horizontal loading device are horizontally arranged on the bottom plate of the loading chamber; multiple positioning mounting slots are opened on the bottom surface of the vertical fixing box, and the multiple positioning mounting slots are matched with the multiple positioning connecting rods one by one for installation.

[0010] Furthermore, the horizontal loading device is fixedly connected to the side wall of the loading chamber.

[0011] This invention also provides a rock shear strength testing system, including the rock shear strength testing device, loading control system, DIC non-contact measurement system, and camera as described above; the horizontal loading device and the vertical loading device in the rock shear strength testing device are respectively connected to the loading control system; the camera is set on one side of the rock shear strength testing device to acquire images of the deformation and fracture changes of the rock sample shear surface during the test; the DIC non-contact measurement system is connected to the camera via a connecting line to monitor the deformation and fracture characteristics and strain change law of the rock sample shear surface in real time.

[0012] The present invention also provides a method for testing the shear strength of rock, using the above-described rock shear strength testing system, the method comprising the following steps:

[0013] S1. First, connect the vertical fixing box and the reaction base by inserting them through the positioning mounting groove and positioning connecting rod to ensure that the vertical fixing box will not move during the test; then insert the vertical loading box and set rollers on the contact surface between the vertical loading box and the vertical fixing box to reduce the friction between the vertical loading box and the vertical fixing box.

[0014] S2. Pass the horizontal loading device through the through holes on the vertical loading box and the vertical fixing box, and connect the horizontal bearing plate to the corresponding horizontal loading device through the screw; place the rock sample into the sample test space;

[0015] S3. Connect the horizontal loading device to the loading control system through a pressure-bearing oil pipe, and apply a horizontal load to the rock sample through the horizontal loading device.

[0016] S4. Connect the camera to the DIC non-contact measurement system via a connecting cable; and adjust the camera to align it with the rock sample.

[0017] S5. Connect the vertical loading device to the loading control system via a pressure-bearing oil pipe;

[0018] S6. Simultaneously start the DIC non-contact measurement system and the vertical loading device to ensure that the DIC non-contact measurement system and the vertical loading device record test data synchronously. The vertical loading device applies a vertical load to the rock sample until the rock sample is sheared and broken, and the test ends.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) A rock vertical shear test apparatus of the present invention includes a reaction base, a horizontal loading device, a horizontal bearing plate, a vertical loading box, a vertical fixing box, rollers, and a vertical loading device. The horizontal loading device is connected to the reaction base by bolts, and the horizontal bearing plate is connected to the horizontal loading device by screws. The rollers are arranged on the contact surface between the vertical loading box and the vertical fixing box. The vertical loading device applies a load to the sample through the vertical loading box. The first receiving groove on the vertical fixing box and the second receiving groove on the vertical loading box together form the sample test space, and the horizontal bearing plate is located in the sample test space. The horizontal pressure at different depths is simulated by adjusting the horizontal loading pressure. The vertical loading device applies a load to the vertical loading box, and the vertical loading box applies a load to the sample under the action of the vertical loading device until the sample fails in shear, thereby measuring the magnitude of the rock vertical shear strength. The test apparatus of the present invention has a reasonable structural design, and the deformation and fracture characteristics of the rock shear surface can be directly observed from the side of the sample test space.

[0021] (2) A rock vertical shear test system of the present invention includes a test device, a camera, a DIC non-contact measurement system, and a loading control system; the camera is used to acquire images of the deformation and fracture changes of the rock sample shear surface during the test; the DIC non-contact measurement system is used to monitor the deformation and fracture characteristics and strain change law of the rock sample shear surface in real time. The test system of the present invention can directly observe the deformation and fracture characteristics of the rock shear surface, and is closer to actual engineering, with the characteristics of convenient operation and low cost.

[0022] (3) The rock shear strength test method of the present invention uses a DIC non-contact measurement system to monitor the deformation and fracture characteristics of the rock shear surface and its strain variation law in real time. The DIC non-contact measurement system and the vertical loading device record the test data synchronously, ensuring that the deformation, strain and stress are unified in real time during the test, making the test results more accurate. The test method of the present invention can directly observe the deformation and fracture characteristics of the rock shear surface, which is more intuitive than the existing rock shearing device, and is a brand-new rock shear strength test method.

[0023] The vertical shear test system for rocks can directly observe the deformation and fracture characteristics of the rock shear surface, which is more intuitive than existing rock shear devices.

[0024] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0025] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0026] Figure 1 This is a schematic cross-sectional view of a rock vertical shearing test device according to the present invention;

[0027] Figure 2 This is a front structural diagram of the vertical loading box in this invention;

[0028] Figure 3 This is a side view of the vertical loading box in this invention.

[0029] Figure 4 This is a schematic diagram of the vertical fixing box in this invention;

[0030] Figure 5 This is a schematic diagram of the combined structure of the reaction base, horizontal loading device and horizontal bearing plate in this invention;

[0031] Figure 6 yes Figure 5A schematic diagram of the I-I cross-sectional structure in the middle;

[0032] Figure 7 This is a schematic diagram of the horizontal loading device in this invention;

[0033] Figure 8 This is a schematic diagram of the horizontal pressure plate in this invention;

[0034] Figure 9 This is a schematic diagram of the structure of a rock vertical shearing test system according to the present invention;

[0035] In the attached diagram: 1-Reaction base; 1a-Loading chamber; 2-Horizontal loading device; 2a-Connecting groove; 2b-Inlet / outlet oil port; 3-Horizontal pressure plate; 5-Vertical loading box; 5a-Second through hole; 5b-Second receiving groove; 6-Vertical fixing box; 6a-First through hole; 6b-First receiving groove; 6c-Positioning mounting groove; 7-Roller; 8-Bolt; 9-Positioning connecting rod; 10-Vertical loading device; 11-Camera; 12-Connecting line; 13-DIC non-contact measurement system; 14-Pressure oil pipe; 15-Loading control system. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent transformations or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0037] Please see Figures 1 to 8 This embodiment provides a rock shear strength testing device, including a reaction base 1, a horizontal loading device 2, a horizontal bearing plate 3, a screw 4, a vertical loading box 5, a vertical fixing box 6, a roller 7, and a vertical loading device 10; the specific structure is as follows:

[0038] The reaction base 1 has a loading chamber 1a with a top opening. A pair of horizontal loading devices 2 are symmetrically arranged on the left and right opposite side walls of the loading chamber 1a to simulate horizontal pressure at different underground depths. The horizontal loading devices 2 are fixedly connected to the reaction base 1 by bolts 8. Each of the two horizontal loading devices 2 has a horizontal bearing plate 3 at its front end. The vertical loading box 5 and the vertical fixing box 6 both have a U-shaped cross-section. The vertical fixing box 6 is fixedly mounted on the bottom plate of the loading chamber 1a with its opening facing upwards. The first and second side walls of the vertical fixing box 6 each have a first through hole 6a for the output end of the horizontal loading device 2 to pass through. The inner side of the first side wall of the vertical fixing box 6 also has a first receiving groove 6b. The vertical loading box 5 is positioned above the vertical fixing box 6 with its opening facing downwards. The first and second side walls of the vertical loading box 5 each have a mounting plate for the horizontal loading device 2. The output end of the vertical loading box 5 is movably inserted into the opening of the vertical fixing box 6 through its second side wall, while the first side wall of the vertical fixing box 6 is movably disposed inside the opening of the vertical loading box 5. A second receiving groove 5b, corresponding to the first receiving groove 6b, is provided on the inner side of the second side wall of the vertical loading box 5. The second receiving groove 5b and the first receiving groove 6b together form a test space for placing the rock sample A. The vertical loading device 10 is connected to the vertical loading box 5 and is used to drive the vertical loading box 5 to apply a load to the rock sample A. The rock sample A can be a cubic rock sample with a side length of 100 mm.

[0039] In one specific embodiment, a plurality of rollers 7 are provided on the sidewalls of the vertical loading box 5 and the vertical fixing box 6 that are in contact with each other. Specifically, a plurality of first mounting grooves are provided on the inner side of the first sidewall of the vertical loading box 5, and a plurality of second mounting grooves are provided on the inner sides of both the first and second sidewalls of the vertical fixing box 6. Rollers 7 are respectively installed in the plurality of first mounting grooves and the plurality of second mounting grooves. The rollers 7 not only reduce the friction between the vertical loading box 5 and the vertical fixing box 6, but also avoid the occurrence of bias pressure, i.e., stress deflection, during the test, thereby reducing systematic errors in the test and improving the test accuracy.

[0040] In one specific embodiment, a horizontal bearing plate 3 is disposed within the test space of the sample, and a connecting portion is provided on the outer side of the horizontal bearing plate 3. The loading rod of the horizontal loading device 2 has a connecting groove 2a for mating with the connecting portion. The connecting portion is inserted into the connecting groove 2a and connected to the horizontal loading device 2 via a screw 4. Specifically, the horizontal loading device 2 and the horizontal bearing plate 3 are connected by a screw 4, which ensures that the horizontal loading device 2 will not be damaged due to excessive deformation of the vertical loading box 5 and the vertical fixing box 6 when the rock sample A undergoes shear failure, resulting in a reasonable structural design.

[0041] In one specific embodiment, openings are provided on both the front and rear sides of the loading chamber 1a; the sample testing space is an open space with openings at both the front and rear. This structural design facilitates the combination and installation of the vertical fixing box 6 and the reaction base 1, and also facilitates the acquisition of data on the changes in the rock sample by the camera during the test.

[0042] In one specific embodiment, multiple positioning connecting rods 9 are horizontally arranged on the bottom plate of the loading chamber 1a, perpendicular to the loading direction of the horizontal loading device 2; multiple positioning mounting slots 6c are formed on the bottom surface of the vertical fixing box 6, and the multiple positioning mounting slots 6c are matched one-to-one with the multiple positioning connecting rods 9 for installation. During the test, the positioning mounting slots 6c of the vertical fixing box 6 are inserted into the positioning connecting rods 9 on the reaction base 1 to ensure that the vertical fixing box 6 will not move. The horizontal loading device 2 is fixedly connected to the side wall of the loading chamber 1a by bolts 8; both the horizontal loading device 2 and the vertical loading device 10 are hydraulically driven.

[0043] Please see Figure 9 This invention also provides a rock shear strength testing system, comprising the aforementioned rock shear strength testing device, camera 11, DIC non-contact measurement system 13, and loading control system 15; the horizontal loading device 2 and vertical loading device 10 in the rock shear strength testing device are respectively connected to the loading control system 15. Depending on the needs, one or more cameras 11 can be configured. The camera 11 is positioned on one side of the rock shear strength testing device via a triangular support device and aimed at the rock sample A to acquire images of the deformation and fracture changes of the shear surface of the rock sample A during the test. The DIC non-contact measurement system is connected to the camera via a connecting line and is used to monitor the deformation and fracture characteristics and strain change law of the shear surface of the rock sample A in real time. The rock vertical shear testing system can simulate horizontal pressure (lateral pressure) at different depths within the range of 0~300m by adjusting the horizontal loading pressure; the vertical loading device applies a load to the vertical loading box, and the vertical loading box applies a load to the sample until the sample fails in shear, thus measuring the magnitude of the rock vertical shear strength; this testing system allows direct observation of the deformation and fracture characteristics of the rock shear surface.

[0044] This invention also provides a method for testing the shear strength of rock, using the aforementioned rock shear strength testing system. The method includes the following steps:

[0045] S1. First, insert the positioning mounting groove 6c of the vertical fixing box 6 into the positioning connecting rod 9 on the reaction base 1 to ensure that the vertical fixing box 6 will not move during the test; then insert the vertical loading box 5 and set rollers 7 on the contact surface between the vertical loading box 5 and the vertical fixing box 6.

[0046] S2. Pass the horizontal loading device 2 through the first through hole on the side wall of the vertical loading box 5 and the first through hole on the side wall of the vertical fixing box 6, and connect the horizontal bearing plate 3 to the corresponding horizontal loading device 2 through the screw 4. The horizontal bearing plate is located in the sample test space formed by the first accommodating groove and the second accommodating groove. Then, place the cubic rock sample A with a side length of 100mm into the sample test space.

[0047] S3. Connect the inlet and outlet ports 2b of the horizontal loading device 2 to the loading control system 15 through the pressure-bearing oil pipe 14, and apply a horizontal load to the rock sample A through the horizontal loading device 2; select the load size according to the actual formation depth to simulate the horizontal pressure at different depths in the range of 0~300m.

[0048] S4. Connect camera 11 to DIC non-contact measurement system 13 via connecting cable 12; adjust camera 11 to align with rock sample A.

[0049] S5. Connect the inlet and outlet oil ports of the vertical loading device 10 to the loading control system 15 through the pressure oil pipe 14.

[0050] S6. Simultaneously activate the DIC non-contact measurement system 13 and the vertical loading device 10 to ensure that the DIC non-contact measurement system 13 and the vertical loading device 10 record test data synchronously. The vertical loading device 10 applies a vertical load to the rock sample A until the rock sample A is sheared and fails, at which point the test ends. The DIC non-contact measurement system 13 can monitor the deformation and fracture characteristics of the rock shear surface and its strain change law in real time; the synchronous recording of test data by the DIC non-contact measurement system 13 and the vertical loading device 10 ensures that deformation, strain, and stress are unified in real time during the test, making the test results more accurate.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rock shear strength testing device, characterized in that, The system includes a reaction base (1), a horizontal loading device (2), a horizontal pressure plate (3), a vertical loading box (5), a vertical fixing box (6), and a vertical loading device (10). The reaction base (1) has a loading chamber (1a) with a top opening. A pair of horizontal loading devices (2) for simulating horizontal pressure at different depths underground are symmetrically arranged on the left and right opposite side walls of the loading chamber (1a). Each horizontal loading device (2) has a horizontal pressure plate (3) at its front end. The vertical loading box (5) and the vertical fixing box (6) have U-shaped cross-sections. The vertical fixing box (6) is fixedly mounted on the bottom plate of the loading chamber (1a) with its opening facing upwards. The first and second side walls of the vertical fixing box (6) are provided with a first through hole (6a) for the output end of the horizontal loading device (2) to pass through. The inner side of the first side wall of the vertical fixing box (6) is also provided with a first receiving groove. (6b); The vertical loading box (5) is positioned above the vertical fixing box (6) with its opening facing downwards. The first and second side walls of the vertical loading box (5) are each provided with a second through hole (5a) through which the output end of the horizontal loading device (2) can pass. The second side wall of the vertical loading box (5) is movably inserted into the opening of the vertical fixing box (6), and the first side wall of the vertical fixing box (6) is movably positioned inside the opening of the vertical loading box (5). The inner side of the second side wall of the vertical loading box (5) is provided with a second receiving groove (5b) corresponding to the first receiving groove (6b). The second receiving groove (5b) and the first receiving groove (6b) together form a test space for placing the rock sample (A). The vertical loading device (10) is connected to the vertical loading box (5) and is used to drive the vertical loading box (5) to apply a load to the rock sample (A).

2. The rock shear strength testing device according to claim 1, characterized in that, Several rollers (7) are provided on the side wall that contacts the vertical loading box (5) and the vertical fixing box (6) to reduce the friction between them.

3. The rock shear strength testing device according to claim 2, characterized in that, The vertical loading box (5) has a plurality of first mounting slots on the inner side of its first side wall, and the vertical fixing box (6) has a plurality of second mounting slots on the inner side of its first and second side walls. Rollers (7) are respectively provided in the plurality of first mounting slots and the plurality of second mounting slots.

4. The rock shear strength testing device according to claim 1, characterized in that, The horizontal bearing plate (3) is set in the test space of the sample, and the outer side of the horizontal bearing plate (3) has a connecting part; the front end of the loading rod of the horizontal loading device (2) is provided with a connecting groove (2a) for cooperating with the connecting part, the connecting part is inserted into the connecting groove (2a) and connected to the horizontal loading device (2) through a screw (4).

5. The rock shear strength testing device according to claim 1, characterized in that, Multiple positioning connecting rods (9) are horizontally arranged on the bottom plate of the loading chamber (1a) and perpendicular to the loading direction of the horizontal loading device (2); multiple positioning mounting slots (6c) are opened on the bottom surface of the vertical fixing box (6), and the multiple positioning mounting slots (6c) are matched with the multiple positioning connecting rods (9) one by one.

6. The rock shear strength testing apparatus according to claim 1, characterized in that, The horizontal loading device (2) is fixedly connected to the side wall of the loading chamber (1a).

7. A rock shear strength testing system, characterized in that, The test apparatus includes a rock shear strength test device as described in any one of claims 1-6, a loading control system (15), a DIC non-contact measurement system (13), and a camera (11). The horizontal loading device (2) and the vertical loading device (10) in the rock shear strength test apparatus are respectively connected to the loading control system (15) via connecting lines (12). The camera (11) is set on one side of the rock shear strength test apparatus to acquire images of the deformation and fracture changes of the shear surface of the rock sample (A) during the test. The DIC non-contact measurement system (13) is connected to the camera (11) via connecting lines (12) to monitor the deformation and fracture characteristics and strain change law of the shear surface of the rock sample (A) in real time.

8. A method for testing the shear strength of rock, characterized in that, The rock shear strength testing system as described in claim 7 is used to conduct the test, and the test method includes the following steps: S1. First, insert and connect the vertical fixing box (6) and the reaction base (1) through the positioning mounting groove (6c) and the positioning connecting rod (9) to ensure that the vertical fixing box (6) will not move during the test; then insert the vertical loading box (5) and set rollers (7) on the contact surface between the vertical loading box (5) and the vertical fixing box (6) to reduce the friction between the vertical loading box and the vertical fixing box; S2. Pass the horizontal loading device (2) through the through holes on the vertical loading box (5) and the vertical fixing box (6), and connect the horizontal bearing plate (3) to the corresponding horizontal loading device (2) through the screw (4); place the rock sample (A) into the sample test space; S3. Connect the horizontal loading device (2) to the loading control system (15) through the pressure-bearing oil pipe (14), and apply a horizontal load to the rock sample (A) through the horizontal loading device (2); S4. Connect the camera (11) to the DIC non-contact measurement system (13) via the connecting cable (12); and adjust the camera (11) to align it with the rock sample (A); S5. Connect the vertical loading device (10) to the loading control system (15) through the pressure-bearing oil pipe (14); S6. Simultaneously start the DIC non-contact measurement system (13) and the vertical loading device (10) to ensure that the DIC non-contact measurement system (13) and the vertical loading device (10) record the test data synchronously; the vertical loading device (10) applies a vertical load to the rock sample (A) until the rock sample (A) is sheared and destroyed, and the test ends.

Images