Anchor rod / cable shear performance testing device and operation method under complex working conditions

Abstract

The present invention discloses a device and an operating method for testing the shear performance of anchor rods / cables under complex working conditions, which are particularly suitable for the anchor rod / cable support fields of water conservancy, tunnels, and mines. Based on a universal testing machine, the device comprises a base, on which a low side seat and a high side seat are vertically provided in parallel, wherein a height-adjustable pad is provided between the base and the low side seat, and a spacing adjustment device for changing the shear gap is provided between the low side seat and the high side seat. An anchor rod / cable clamping mechanism for fixing the anchor rod / cable to be tested is provided on both the low side seat and the high side seat. The anchor rod / cable clamping mechanism of the low side seat changes the horizontal angle of the anchor rod / cable clamped by the low side seat and the high side seat by adjusting pads of different heights, and a shear head is vertically provided in the shear gap between the low side seat and the high side seat. The device has a simple structure, is easy to use, has good functional scalability, and is well applicable.

Description

Technical Field

[0001] The present invention relates to a device and an operating method for testing the shear performance of an anchor rod / cable under complex working conditions, and is particularly suitable for anchor rod / cable support testing in water conservancy, tunnels and mines. Technical Background

[0002] Currently, anchor / cable support technology is widely used both domestically and internationally, with a significant volume of anchors / cables used. However, anchor / cable breakage is a common occurrence underground. Shear and tensile shear failure are the primary causes of anchor / cable failure, severely impacting safe and efficient underground production. However, most basic mechanical testing for anchor / cables consists solely of pullout tests. Shear tests on anchors are rare, shear tests on cables are virtually nonexistent, and tensile shear tests on anchors / cables are even rarer. Most tests are limited to shear tests with anchored solids or consider only a single factor. However, underground anchor / cable installation conditions are extremely complex. Different placement angles, rock displacement widths, preload forces, and shear gaps can all lead to variations in anchor / cable shear performance. Therefore, a test apparatus and operating method for testing anchor / cable shear performance under complex conditions is designed. This approach can effectively reduce anchor / cable support failure, ensuring safe and efficient underground production, while also preventing over-support and reducing support costs.

[0003] Patent CN109115632A proposes a comprehensive anchor shear test device and method. This device uses three concrete test blocks to perform shear tests on anchor rods. While this device has some reference value, it can only bend anchor rods, not cut them, making it of limited use for in-situ anchor support in underground mines. Patent CN108387459B proposes an anchor rod / cable shear performance test device and method, capable of testing the shear performance of all common anchor rod / cable products. However, underground anchor rods / cables are subject to complex forces, generally experiencing both tension and shear. This device cannot simulate tension and shear testing of anchor rods / cables, providing limited data for the safe and efficient use of anchor rods in complex underground stress environments. Patent CN105954098A proposes an anchor rod tensile shear test device and method, which are of great significance for understanding the failure mechanism of anchor rods under the combined effects of tension and shear in a horizontal state. However, anchor rods / cables are usually installed at an angle at the side corners and shoulder corners of underground tunnels, and anchor rods / cables often break at these locations. It is obviously insufficient to only conduct horizontal tensile shear tests on anchor rods and cables.

[0004] In response to the above problems, there is still a lack of a device and related testing method that can perform shear tests under different rock displacement widths, different shear gaps, different rod angles and pre-tensions, making it impossible to achieve truly safe and efficient support. Summary of the Invention

[0005] In view of the shortcomings of the above technologies, a device and an operating method for testing the shear performance of anchor rods / cables under complex working conditions are provided, which have a simple structure, are easy to use, and have wide applicability.

[0006] In order to achieve the above technical objectives, the present invention provides a device for testing the shear performance of anchor rods / cables under complex working conditions, which is arranged on a universal testing machine for use, and includes a base, on which a low side seat and a high side seat are vertically provided in parallel, wherein a height-adjustable pad is provided between the base and the low side seat, and the height of the low side seat is adjusted by adjusting the pad; a spacing adjustment device for changing the shear gap is provided between the low side seat and the high side seat, and the relative positions of the low side seat and the high side seat on the base are changed by adjusting the spacing adjustment device to achieve different shear gaps for the test specimens; an anchor rod / cable clamping mechanism for fixing the anchor rod / cable to be tested is provided on the low side seat and the high side seat, and the anchor rod / cable clamping mechanism of the low side seat changes the horizontal angle of the anchor rod / cable to be tested clamped by the low side seat and the high side seat by adjusting pads of different heights; a shear head is vertically provided in the shear gap between the low side seat and the high side seat, and the shear head is provided with a through hole allowing the anchor rod / cable to be tested to pass through, and the angle of the through hole matches the clamping angle of the anchor rod / cable to be tested on the anchor rod / cable clamping mechanism.

[0007] Furthermore, upper pads a and b are installed between the lower and higher side seats on either side of the shearing head, respectively, to match the shearing gap. Their thicknesses are set as needed; if the shearing gap is the same as the shearing head, they are not required. A U-shaped guide plate is installed horizontally between the two plates, physically constraining the shearing head to a single downward degree of freedom.

[0008] Furthermore, a baffle a is provided on the outer side of the side low seat with the upper pad a through a horizontally arranged bolt a to prevent the liner from sliding.

[0009] Furthermore, the anchor rod / cable clamping mechanism includes a pair of bushings arranged on the side low seat and the side high seat, and the paired bushings are provided with through holes allowing the anchor rod / cable to pass through. The through holes of different paired bushings have different angles. The height of the pad under the side low seat is adjusted to install bushings of different angles, thereby changing the clamping angle of the anchor rod / cable to be measured. The height of the side low seat is adjusted specifically by replacing pads of different heights. After adjusting the different bushings, the shear head matching the angle of the bushing is replaced at the same time to achieve shear testing of the anchor rod / cable at different angles to be measured. The outer side of the bushing is also provided with a lock that is screwed onto the anchor rod / cable to be measured to ensure that the anchor rod / cable to be measured is fixed in the bushing and will not move. A stress and strain sensor is also provided between the lock on one side and the bushing.

[0010] Furthermore, the spacing adjustment device includes a bolt b horizontally arranged on one side of the side high seat. By rotating the bolt b, the length of the bolt passing through the side high seat and pointing to the side low seat is changed and the side low seat is pushed, thereby changing the spacing between the side low seat and the side high seat.

[0011] Furthermore, a baffle b is provided at the connection between the bolt b and the side height seat to prevent the liner from sliding.

[0012] Furthermore, the bottom of the side low seat together with the pad is connected to the base plate by a screw b set vertically upward, and the side high seat is connected to the base plate by a screw a set vertically upward, wherein the connection between the base plate and the screw b is a waist-shaped hole, so that the screw b has an adjustment margin along the length direction, which is convenient for matching according to the size change of the pad.

[0013] Furthermore, multiple pairs of eye screws for installation and transportation are provided on both sides of the anchor rod / cable shear performance testing device under complex working conditions.

[0014] Furthermore, a guide structure is provided around the shear head, which can complete experiments based on the MTS servo universal testing machine. It can simulate the displacement of the rod / anchor cable by rock layers of different thicknesses by changing the width of the shear head. The maximum thickness of the simulated rock layer is determined by the space of the MTS servo universal testing machine.

[0015] A method for operating an anchor rod / cable shear performance testing device under complex working conditions, the specific steps of which are as follows:

[0016] Assemble the anchor rod / cable shear performance test device, and adjust the height of the low seat on the opposite side by directly replacing the pad according to the adjustment needs to achieve control of the anchor rod / cable stress angle;

[0017] Select the appropriate shear head according to the anchor rod / cable stress angle and install the matching shear head;

[0018] Insert the anchor rod / cable to be tested into the liner and place it in the test bench. The anchor rod / cable to be tested needs to be threaded at both ends and fixed with two sets of locks. Use a torque wrench or a single drill to pre-tighten the locks to achieve different pre-tensions on the anchor rod to be tested. The anchor rod / cable to be tested is locked and fixed on both sides with locks. Use a tensioning pump to tension the test sample on one side to achieve different pre-tensions on the anchor rod / cable to be tested:

[0019] Place the assembled anchor rod / cable shear performance test device into the MTS servo universal testing machine, and equip it with strain gauges and acoustic emission equipment to monitor data as needed. Operate the universal testing machine using the shear head to perform a tensile shear test on the anchor rod / cable under test, and record its breaking load, elongation, and stress-strain curve.

[0020] Adjust the width of the shear head to adjust the shear width of the anchor rod / cable to be tested, and repeat the above steps for testing the anchor rod / cable to be tested;

[0021] Adjust bolt b to adjust the shear gap between the side high seat and the side low seat, and match and install upper pad a and upper pad b of corresponding sizes to control the shear gap of the anchor rod / cable being tested, and repeat the above steps for testing the anchor rod / cable being tested. Beneficial effects

[0022] This device overcomes the defect that traditional anchor rods / cables can only be tested in pure shear and pure tension-shear tests. It can test the influence of multiple factors such as different materials, different pre-tensions, different angles, different lengths, different shear widths, and different shear gaps on the overall tensile-shear performance of anchor rods / cables. It is especially valuable for stress testing of anchor rods / cables arranged at angles at the shoulder and bottom angle positions of simulated on-site tunnels and for testing the shear resistance of anchor rods / cables after sliding of rock formations of different widths under support conditions. The experimental results are reliable, providing a low-cost, highly practical, and easy-to-operate test research device and method for the efficient and safe use of underground anchor rods / cables, improvement of anchor rod / cable production processes, and analysis of anchor rod / cable disasters and accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the three-dimensional structure of the anchor rod / cable shear performance testing device under complex working conditions of the present invention;

[0024] Figure 2 This is a front view structural diagram of the anchor rod / cable shear performance testing device under complex working conditions of the present invention;

[0025] Figure 3 This is a side structural schematic diagram of the anchor rod / cable shear performance testing device under complex working conditions of the present invention;

[0026] Figure 4 1. It is a schematic top view of the structure of the anchor rod / cable shear performance testing device under complex working conditions of the present invention;

[0027] Figure 5 This is a schematic diagram of the main structure of the side low seat portion of the present invention;

[0028] Figure 6 This is a schematic diagram of the main structure of the side elevated seat portion of the present invention;

[0029] Figure 7 This is a schematic side view of the side elevated seat portion of the present invention;

[0030] Figure 8 This is a schematic diagram of the main structure of the baffle part a of the present invention;

[0031] Figure 9 This is a schematic diagram of the main structure of the guide plate portion of the present invention;

[0032] Figure 10It is a schematic diagram of the top view of the guide plate portion of the present invention;

[0033] Figure 11 This is a schematic diagram of the main structure of the bottom plate portion of the present invention;

[0034] Figure 12 This is a schematic diagram of the bottom plate structure of the present invention from a top view;

[0035] Figure 13 It is a schematic diagram of the top view of the backing plate portion of the present invention;

[0036] Figure 14 This is a schematic diagram of the main structure of the shearing head of the present invention;

[0037] Figure 15 This is a schematic diagram of the front view structure after the shearing width is changed according to the present invention;

[0038] Figure 16 This is a schematic diagram of the front view structure after the shearing angle is changed in the present invention.

[0039] In the figure: 1-eye screw; 2-side low seat; 3-measured anchor rod / cable; 4-lock; 5-base; 6-bolt a; 7-baffle a; 8-upper pad a; 9-guide plate; 10-shear head; 11-upper pad b; 12-side high seat; 13-stress and strain sensor; 14-baffle b; 15-bolt b; 16-screw a; 17-screw b; 18-base plate; 19-pad; 20-screw c. DETAILED DESCRIPTION

[0040] An embodiment of the present invention will be further described below with reference to the accompanying drawings:

[0041] like Figure 1 、 Figure 2 、 Figure 3 、 Figure 3 、 Figure 14 and Figure 15As shown, a device for testing the shear performance of anchor rods / cables under complex working conditions of the present invention is set on a universal testing machine for use, comprising a base 18, on which a side low seat 2 and a side high seat 12 arranged in parallel are vertically provided, wherein a height-adjustable pad 19 is provided between the base 18 and the side low seat 2, and the height of the side low seat 2 is adjusted by adjusting the pad 19; a spacing adjustment device for changing the shear gap is provided between the side low seat 2 and the side high seat 12, and the relative positions of the side low seat 2 and the side high seat 12 on the base 18 are changed by adjusting the spacing adjustment device, so as to achieve the target Different shear gaps are tested on the specimen. Both the lower side seat 2 and the higher side seat 12 are equipped with anchor / cable clamping mechanisms for securing the anchor / cable 3 under test. The anchor / cable clamping mechanism of the lower side seat 2 changes the horizontal angle of the anchor / cable 3 clamped by the lower side seat 2 and the higher side seat 12 by adjusting pads 19 at different heights. A shearing head 10 is vertically positioned in the shear gap between the lower side seat 2 and the higher side seat 12. The shearing head 10 includes a through hole for the anchor / cable 3 under test. The angle of the through hole matches the clamping angle of the anchor / cable 3 under test in the anchor / cable clamping mechanism. Upper pads a8 and b11 are installed between the lower side seat 2 and the higher side seat 12 on either side of the shearing head 10, respectively, according to the shear gap. The thickness of the upper pads a8 and b11 is set as needed. If the shear gap is the same as that of the shearing head 10, the upper pads a8 and b11 are not required. A U-shaped guide plate 9 is installed horizontally between upper pads a8 and b11, physically constraining the shearing head 10 to a single downward degree of freedom. The lower side seat 2, which houses upper pad a8, is secured with a stopper a7 on the outside by horizontal bolts a6 to prevent the liner 5 from sliding. Stopper b14 also prevents the liner 5 from sliding at the connection between bolts b15 and the upper side seat 12.

[0042] The anchor rod / cable clamping mechanism includes a liner 5 arranged in pairs on the side low seat 2 and the side high seat 12. The paired liner 5 is provided with a through hole allowing the anchor rod / cable 3 to pass through. The through holes of different paired liner 5 have different angles. The height of the pad 19 under the side low seat 2 is adjusted to install the liner 5 at different angles, thereby changing the clamping angle of the anchor rod / cable 3 to be measured. The height of the side low seat 2 is adjusted specifically by replacing the pads 19 of different heights. After adjusting the different liner 5, the shear head 10 matching the angle of the liner 5 is replaced at the same time to realize shear testing of the anchor rod / cable 3 at different angles to be measured. The outer side of the liner 5 is also provided with a lock 4 screwed on the anchor rod / cable 3 to be measured to ensure that the anchor rod / cable 3 to be measured is fixed in the liner 5 and will not move. A stress and strain sensor 13 is also provided between the lock 4 on one side and the liner 5. The spacing adjustment device includes a bolt b15 horizontally arranged on one side of the side high seat 12. By rotating the bolt b15, the length of the bolt passing through the side high seat 12 and pointing to the side low seat 2 is changed and the side low seat 2 is pushed, thereby changing the spacing between the side low seat 2 and the side high seat 12.

[0043] The bottom of the lower side seat 2, along with the backing plate 19, is connected to the base plate 18 via vertically extending screws b17. The higher side seat 12 is connected to the base plate 18 via vertically extending screws a16. The connection between the base plate 18 and the screws b17 is a waist-shaped hole, allowing for adjustment along the length of the screws b17 to accommodate variations in the size of the backing plate 19. Multiple pairs of eyebolts 1 are provided on both sides of the anchor / cable shear performance test device for complex working conditions, allowing for installation and handling.

[0044] The shear head 10 is surrounded by a guide structure, which can complete experiments based on an MTS servo universal testing machine. By changing the width of the shear head 10, it can simulate the displacement of the rod / anchor cable by rock layers of different thicknesses. The maximum simulated rock layer width is determined by the space of the MTS servo universal testing machine.

[0045] A method for operating an anchor rod / cable shear performance testing device under complex working conditions, the specific steps of which are as follows:

[0046] Assemble the anchor rod / cable shear performance test device, and adjust the height of the opposite low seat 2 by directly replacing the pad 19 according to the adjustment needs to achieve the control of the anchor rod / cable stress angle;

[0047] Select the appropriate shear head 10 according to the anchor rod / cable stress angle and install the matching shear head 11;

[0048] Insert the anchor rod / cable 3 under test into the liner 5 and place it in the test bench. The anchor rod 3 under test needs to be threaded at both ends and fixed with two sets of locks 4. Use a torque wrench or a single drill to pre-tighten the locks 4 to achieve different pre-tensions on the anchor rod under test. The cable body of the test sample 3 is locked and fixed on both sides using the locks 4. Use a tensioning pump to tension the test sample 3 on one side to achieve different pre-tensions on the test sample:

[0049] Place the assembled anchor rod / cable shear performance test device into an MTS servo universal testing machine, and optionally equip it with a strain gauge and acoustic emission equipment to monitor data as needed. Operate the universal testing machine using the shear head 10 to perform a tensile shear test on the anchor rod / cable 3 under test, and record its breaking load, elongation, and stress-strain curve.

[0050] Adjust the width of the shear head 10 to adjust the shear width of the anchor rod / cable 3 to be tested, and repeat the above steps of testing the anchor rod / cable 3 to be tested;

[0051] Adjust the bolt b15 to adjust the shear gap between the side high seat 12 and the side low seat 2, and match and install the upper pad a8 and upper pad b11 of corresponding sizes to control the shear gap of the anchor rod / cable 3 under test, and repeat the above steps to detect the anchor rod / cable 3 under test.

Claims

1. A device for testing the shear performance of anchor rods and cables under complex working conditions, characterized by: The invention is set up for use on a universal testing machine, comprising a base (18), a side low seat (2) and a side high seat (12) arranged in parallel vertically on the base (18), a liner (5) arranged in pairs on the side low seat (2) and the side high seat (12), a through hole for allowing the anchor rod / cable (3) to pass through is provided in the paired liner (5), wherein a height-adjustable pad (19) is provided between the base (18) and the side low seat (2), and the height of the side low seat (2) is adjusted by adjusting the pad (19); a spacing adjustment device for changing the shear gap is provided between the side low seat (2) and the side high seat (12), and the spacing between the side low seat (2) and the side high seat (12) on the base is changed by adjusting the spacing adjustment device. (18) on the side, so as to realize different shear gaps for the test specimens; the side low seat (2) and the side high seat (12) are both provided with an anchor rod / cable clamping mechanism for fixing the anchor rod / cable (3) to be tested, and the anchor rod / cable clamping mechanism of the side low seat (2) changes the horizontal angle of the anchor rod / cable (3) to be tested clamped by the side low seat (2) and the side high seat (12) by adjusting the pads (19) of different heights, and a shear head (10) is vertically provided in the shear gap between the side low seat (2) and the side high seat (12), and a through hole is provided in the shear head (10) for allowing the anchor rod / cable (3) to be tested to pass through, and the angle of the through hole matches the clamping angle of the anchor rod / cable (3) to be tested on the anchor rod / cable clamping mechanism.

2. The anchor rod / cable shear performance testing device under complex working conditions according to claim 1, characterized in that: An upper pad a (8) and an upper pad b (11) are respectively provided between the side low seat (2) and the side high seat (12) on both sides of the shearing head (10) according to the shearing gap. The thickness of the upper pad a (8) and the upper pad b (11) are set as required. If the shearing gap is the same as that of the shearing head (10), the upper pad a (8) and the upper pad b (11) do not need to be provided. A U-shaped structural guide plate (9) is horizontally provided between the upper pad a (8) and the upper pad b (11), which physically constrains the shearing head (10) so that it has only one downward degree of freedom.

3. The anchor rod / cable shear performance testing device under complex working conditions according to claim 2, characterized in that: A baffle a (7) for preventing the liner (5) from sliding is provided on the outer side of the side low seat (2) provided with an upper pad a (8) through a horizontally arranged bolt a (6).

4. The anchor rod / cable shear performance testing device under complex working conditions according to claim 1, characterized in that: The through holes of different paired liner seats (5) have different angles. By adjusting the height of the pad (19) below the side low seat (2) to install the liner seats (5) at different angles, the clamping angle of the anchor rod / cable (3) to be tested can be changed. The height of the side low seat (2) is adjusted by replacing the pad (19) of different heights. After adjusting different liner seats (5), the shear head (10) matching the angle of the liner seat (5) is replaced at the same time to achieve shear testing of the anchor rod / cable (3) at different angles. The outer side of the liner seat (5) is also provided with a lock (4) screwed on the anchor rod / cable (3) to be tested, thereby ensuring that the anchor rod / cable (3) to be tested is fixed in the liner seat (5) and does not move. A stress and strain sensor (13) is also provided between the lock (4) on one side and the liner seat (5).

5. The anchor rod / cable shear performance testing device under complex working conditions according to claim 3, characterized in that: The spacing adjustment device comprises a bolt b (15) horizontally arranged on one side of the high side seat (12). By rotating the bolt b (15), the length of the bolt passing through the high side seat (12) and pointing to the low side seat (2) is changed and the low side seat (2) is pushed, thereby changing the spacing between the low side seat (2) and the high side seat (12).

6. The anchor rod / cable shear performance testing device under complex working conditions according to claim 5, characterized in that: A baffle b (14) is provided at the connection between the bolt b (15) and the side height seat (12) to prevent the liner seat (5) from sliding.

7. The anchor rod / cable shear performance testing device under complex working conditions according to claim 5, characterized in that: The bottom of the side low seat (2) together with the pad (19) is connected to the bottom plate (18) by a screw b (17) arranged vertically upward, and the side high seat (12) is connected to the bottom plate (18) by a screw a (16) arranged vertically upward, wherein the connection between the bottom plate (18) and the screw b (17) is a waist-shaped hole, so that the screw b (17) is provided with an adjustment margin along the length direction, which is convenient for matching according to the size change of the pad (19).

8. The anchor rod / cable shear performance testing device under complex working conditions according to claim 1, characterized in that: Multiple pairs of eyebolts (1) for installation and transportation are provided on both sides of the anchor rod / cable shear performance test device under complex working conditions.

9. The anchor rod / cable shear performance testing device under complex working conditions according to claim 1, characterized in that: The shear head (10) is provided with a guide structure around it, and can complete the experiment based on the MTS servo universal testing machine. It can simulate the displacement of the anchor rod / cable by rock layers of different thicknesses by changing the width of the shear head (10). The maximum thickness of the simulated rock layer is determined by the space of the MTS servo universal testing machine.

10. An operating method of the anchor rod / cable shear performance testing device under complex working conditions according to claim 5, characterized in that The specific steps are as follows: Assemble the anchor rod / cable shear performance test device, and adjust the height of the lower seat (2) on the opposite side by directly replacing the pad (19) according to the adjustment requirements, so as to realize the control of the anchor rod / cable stress angle; Select a suitable shear head (10) according to the anchor rod / cable stress angle, and install the matching liner (5), upper pad a (8) and upper pad b (11); Insert the anchor rod / cable (3) to be tested into the liner (5) and place it in the test bench, wherein the anchor rod / cable (3) to be tested needs to be threaded at both ends and fixed with two sets of locks (4), and the locks (4) are pre-tightened by a torque wrench or a single drilling rig to achieve different pre-tensions on the anchor rod to be tested; the anchor rod / cable (3) to be tested is locked and fixed on both sides by the locks (4), and the anchor rod / cable (3) to be tested is tensioned on one side by a tensioning pump to achieve different pre-tensions on the test sample; Place the assembled anchor rod / cable shear performance test device into the MTS servo universal testing machine, and select and equip it with a strain gauge and acoustic emission equipment to monitor data as needed. Operate the universal testing machine to perform a tensile shear test on the anchor rod / cable (3) using the shear head (10), and record its breaking load, elongation and stress-strain curve; Adjust the width of the shearing head (10) to adjust the shear width of the anchor rod / cable (3) to be tested, and repeat the above steps of testing the anchor rod / cable (3); The bolt b (15) is adjusted to adjust the shear gap between the side high seat (12) and the side low seat (2), and the upper pad a (8) and the upper pad b (11) of corresponding size are matched and installed to control the shear gap of the anchor rod / cable (3) to be tested, and the above steps of testing the anchor rod / cable (3) to be tested are repeated.

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