An in-situ impact testing device and method for an anchor rod

Abstract

The application provides an anchor rod in-situ impact testing device and a testing method, which is installed on a to-be-tested anchor rod anchored in a rock mass in a roadway on site, and comprises an in-situ connector, a connecting steel strand, an impact system, an inclination support, a lifting and releasing system and a monitoring system; the in-situ connector comprises a uniform force ring, a baffle, a quick connector and a lock in sequence sleeved on the to-be-tested anchor rod; the quick connector is used for achieving quick, firm and accurate connection of the in-situ connector and the to-be-tested anchor rod; the inclination support and the connecting steel strand are used for achieving the function of in-situ impact testing of the to-be-tested anchor rod at different angles; the impact system is used for achieving impact testing of the anchor rod under different impact kinetic energy; and a pressure sensor, a laser displacement sensor and an acceleration sensor transmit data into a data collector for collection and storage. The application achieves in-situ impact testing of the anchor rod at different angles or under different impact energy in a load maintaining state on site.

Description

Technical Field

[0001] This invention belongs to the technical field of anchor bolt performance testing devices, specifically relating to an in-situ impact testing device and method for anchor bolts. Background Technology

[0002] As underground engineering projects such as mine roadways, traffic tunnels, and hydroelectric chambers extend deeper, dynamic disasters induced by complex geological conditions such as high ground stress and strong disturbances occur frequently, posing a significant threat to the safety of personnel and equipment. The prevention and control of dynamic disasters in deep engineering projects is a crucial research topic for experts and scholars both domestically and internationally.

[0003] Currently, dynamic disaster prevention and control mainly includes high-strength bolt support, U-shaped supports, and anti-impact brackets. Bolt support is convenient to construct, can significantly improve the mechanical properties of the surrounding rock mass, enhance the bearing capacity of the surrounding rock, and effectively protect the supported structure. It has become the main method for controlling the surrounding rock in dynamic disasters. Domestic and foreign scholars have successively developed new energy-absorbing bolts such as D-bolt, MCB-33, constant resistance large deformation bolts, Roofex bolts, and 2S-bolt. The development of new bolts has mitigated the destructive effects of dynamic disasters on roadways to a certain extent. However, during impact disasters, the phenomena of local bolt breakage and overall support failure still occur frequently. Therefore, conducting research on the impact resistance performance of bolt support systems, evaluating the impact resistance characteristics of bolt support systems, and establishing the mechanical response of bolts under dynamic loads are key technologies for solving dynamic disaster prevention and control.

[0004] Regarding the impact resistance of anchor bolts, domestic and international scholars mainly conduct laboratory studies. These studies utilize methods such as axial impact on the anchor bolt body, transverse shear impact on the anchor bolt body, and impact on the anchor bolt support system. However, the stress distribution of anchor bolts in laboratory tests differs significantly from actual underground working conditions. Furthermore, anchor bolts installed in roadways are often inclined, and current technology cannot perform impact tests on anchor bolts installed in roadways at different angles. Additionally, the use of a conveyor chain to transmit impact loads during testing is prone to rotation and eccentricity, directly affecting the accuracy of the test results.

[0005] In summary, there is currently limited research on in-situ impact of anchor bolts under working conditions, and existing in-situ testing devices lack multi-angle in-situ impact testing capabilities, which limits the study of the mechanical response and failure state of anchor bolts under dynamic loads during actual anchoring. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides an in-situ impact testing device and method for anchor bolts, solving the problem of the lack of in-situ impact testing devices for anchor bolts at different angles on construction sites. It enables in-situ impact testing of anchor bolts at different angles with different impact kinetic energies under maintained load conditions on site.

[0007] In view of this, the present invention provides an in-situ impact testing device for anchor bolts, which is installed on the anchor bolt to be tested, anchored in the rock mass within a roadway. The device includes an in-situ connector, connecting steel strands, an impact system, an inclination support, a lifting and release system, and a monitoring system.

[0008] The in-situ connector includes a force-equalizing ring, a baffle, a quick connector, and a lock, which are sequentially fitted onto the anchor rod to be tested. The force-equalizing ring is fixed to the outer wall of the nut on the anchor rod to be tested. A pressure sensor is provided between one end face of the force-equalizing ring and the baffle. The quick connector is a hollow cylinder, with its upper inner wall fitting against the outer wall of the force-equalizing ring and fixed to the outer wall of the force-equalizing ring by a snap-fit ​​method. The lower end of the quick connector is connected to a connecting steel strand. The lock fits against the other end face of the baffle and is locked onto the anchor rod to be tested.

[0009] The portion of the connecting steel strand near the anchor rod to be tested is on the same axis as the anchor rod to be tested, while the portion near the ground is vertically downward.

[0010] The impact system is placed perpendicular to the ground, and its upper end is connected to the lifting and releasing system.

[0011] The tilting bracket includes two cross-shaped support rods and foot brackets mounted on the support rods near the tunnel wall; the two support rods are rotatably connected to connecting steel strands at the V-shaped intersection and are fixed to the tunnel wall by the foot brackets.

[0012] One end of the lifting and releasing system is fixed to the tunnel wall, and the other end is connected to the impact system;

[0013] The monitoring system includes a data acquisition unit and a pressure sensor, a laser displacement sensor, and an acceleration sensor electrically connected to it; the pressure sensor is sleeved on the anchor rod to be tested, the laser displacement sensor is installed on a quick-connect fitting, and the acceleration sensor is installed on the impact system.

[0014] The impact system includes a guide rod, an impact rod, and an impact hammer; the upper end of the guide rod is connected to the ground end of the connecting steel strand, and an impact disc is fixed to the lower end of the guide rod; the impact rod is sleeved on the guide rod and slides along the axial direction of the guide rod, and the upper end of the impact rod is connected to the lifting and releasing system; the impact hammer is mounted on the impact rod.

[0015] The impact rod includes a hollow metal tube, a lifting ring, and a bearing plate. The hollow metal tube is sleeved on the outer wall of the guide rod. The lifting ring is fixed to the upper outer wall of the hollow metal tube and is connected to the lifting and release system. The bearing plate is fixed to the lower outer wall of the hollow metal tube.

[0016] It also includes an end lock, which has a groove at its center, and the annular protrusion at the end of the connecting steel strand and the annular boss at the end of the guide rod are respectively engaged in the groove.

[0017] The quick connector includes quick connector A and quick connector B, and quick connector B is fastened to quick connector A by a snap-fit.

[0018] The tilting bracket also includes a central shaft passing through the intersection of the two support rods, and a fixed pulley sleeved on the central shaft; the two support rods rotate relative to each other around the central shaft, the fixed pulley is placed between the two support rods, and the connecting steel strand is in contact with the fixed pulley and bends and deforms around the fixed pulley.

[0019] The lifting and release system includes a lifting device, an electromagnetic release device, and a lifting guide cable connecting the lifting device and the electromagnetic release device; the electromagnetic release device is connected to the impact system.

[0020] The tilting support also includes an auxiliary pulley, which is sleeved on the central shaft and installed on the side of the support rod away from the fixed pulley. The lifting guide cable passes around the auxiliary pulley to connect the lifting equipment and the electromagnetic release device.

[0021] The present invention provides an in-situ impact testing method for anchor bolts, employing the aforementioned in-situ impact testing device for anchor bolts, comprising the following steps:

[0022] Step 1: Conduct in-situ connection of the anchor bolt to be tested

[0023] The force equalizing ring, pressure sensor, baffle, quick connector and lock are sequentially mounted on the anchor rod to be tested on site. A pre-tightening force is applied to the baffle. The connecting steel strand is connected to the lower end of the quick connector. The quick connector is fixed by snap-fit. After the above operations are completed, the connection is completed by locking the fastener.

[0024] Step 2: Install the tilt bracket

[0025] Separate the two support rods at a certain angle so that the tilt bracket and the anchor rod to be tested are in the same roadway section and located on the roadway wall below the anchor rod to be tested. Adjust the position of the tilt bracket to ensure stability during the test. Fix the tilt bracket to the roadway wall through the feet of the tilt bracket.

[0026] Step 3: Allocate impact kinetic energy

[0027] According to the law of conservation of energy: Ep = mgh, where Ep is the gravitational potential energy, m is the mass, g is the gravitational acceleration, and h is the height; Adjust the impact rate, where V is the impact rate, g is the gravitational acceleration, and h is the height; design the mass and impact rate according to the above relationship, add counterweight to the impact system, and after the counterweight is added, put the impact system on the part of the connecting steel strand near the ground;

[0028] Step 4: Lifting Impact System

[0029] Connect the impact system to the lifting and release system, and use the lifting and release system to lift the impact system to the design height;

[0030] Step 5: Device alignment and pre-test adjustments

[0031] Keeping the device as a whole stationary, make fine adjustments to the components with eccentric tendencies so that all the components are in the same vertical cross section;

[0032] Step 6: Data Acquisition

[0033] The laser sensor is mounted on the quick connector, the acceleration sensor is mounted on the impact system, and the pressure sensor, laser sensor, and acceleration sensor are respectively connected to the data acquisition device.

[0034] Step 7: Start the test

[0035] After completing the above steps, evacuate the personnel to a safe location and control the lifting and releasing system to release the impact system, which will then undergo free fall.

[0036] Step 8: Test ends

[0037] After the impact event, the collected data is saved, the testing device is disassembled, and the test is completed.

[0038] The beneficial effects of this invention are as follows:

[0039] 1. This invention uses a quick connector, which, through a special snap-fit ​​structure, enables a quick, secure, and accurate connection between the in-situ connector and the anchor rod under test. This ensures the feasibility of conducting in-situ impact testing without unloading the anchor rod, while also providing a quick and convenient loading and unloading process, saving time and labor costs.

[0040] 2. This invention adopts a quick connection method between the in-situ connector and the anchor rod to be tested. By changing the size of the force equalizing ring, this device can perform in-situ impact tests on anchor rods of different specifications or sizes, demonstrating the high versatility of this device.

[0041] 3. The present invention, through the cooperation of two V-shaped support rods and foot bases, enables the device to adapt to tunnels with different structures and environments, and has high versatility.

[0042] 4. By setting up an inclined bracket and cooperating with the connecting steel structure, this invention solves the problem in the prior art that it is impossible to perform impact tests on anchor bolts installed in the roadway at different angles. This innovative design realizes the function of in-situ impact testing on anchor bolts at different angles. It has high versatility, high device utilization, wide application, and simple operation, making the evaluation of anchor bolt performance more comprehensive and accurate.

[0043] 5. This invention, by setting up an inclined support and cooperating with an impact hammer, solves the problem of the limited variety of anchor bolt types being tested on-site, and realizes the function of impact testing of anchor bolts under different impact energies. This increases the diversity of testing, making the evaluation of anchor bolt performance more comprehensive and accurate.

[0044] 6. This invention employs a force-equalizing ring, an impact plate, and a bearing plate to ensure uniform force distribution on the anchor rod under test during the impact process, thereby obtaining accurate and reliable test data.

[0045] 7. This invention effectively prevents the connecting rod from shaking and unspinning during the impact process by connecting the annular protrusion at the end of the steel strand, the annular boss of the guide rod, and the groove of the end lock through a cooperative connection. This achieves a stable connection, ensures the firmness and stability of the connection, avoids the problem of inaccurate test data, and also ensures the safety of the test. Attached Figure Description

[0046] Figure 1 This is a plan view of the in-situ impact test device for anchor bolts according to the present invention;

[0047] Figure 2 This is a three-dimensional schematic diagram of the in-situ impact test device for anchor bolts of the present invention;

[0048] Figure 3 This is a cross-sectional view of the in-situ connector of the present invention;

[0049] Figure 4 This is a three-dimensional schematic diagram of the force equalization ring of the present invention;

[0050] Figure 5 This is a three-dimensional schematic diagram of the quick connector of the present invention;

[0051] Figure 6 This is a partial exploded view of the lock of the present invention;

[0052] Figure 7 A three-dimensional schematic diagram of the end lock of the present invention;

[0053] Figure 8 This is a perspective view of the impact rod of the present invention;

[0054] Figure 9 This is a three-dimensional schematic diagram of the impact hammer of the present invention;

[0055] Figure 10 This is a three-dimensional schematic diagram of the tilt bracket of the present invention;

[0056] Among them, 1. Tunnel wall; 2. Anchor bolt to be tested; 21. Nut of anchor bolt to be tested; 3. In-situ connector; 31. Force equalizing ring; 32. Quick connector; 32a. Quick connector A; 32b. Quick connector B; 33. Baffle; 34. Lock; 341. Conical flap; 342. Steel sleeve; 4. Connecting steel strand; 5. End lock; 51. Concave part; 52. Convex part; 6. Impact system; 61. Guide rod; 62. Impact rod; 621. Hollow metal tube; 622. 623. Lifting ring; 63. Bearing plate; 64. Impact hammer; 65. Hammer body; 66. Assembly rod; 67. Nut; 68. Mounting pad; 79. Inclined bracket; 70. Support rod; 71. Foot; 72. Central shaft; 73. Fixed pulley; 74. Auxiliary pulley; 80. Lifting and release system; 81. Lifting equipment; 82. Electromagnetic release device; 83. Lifting guide cable; 94. Pressure sensor; 95. Laser displacement sensor; 96. Accelerometer; 97. Data acquisition device. Detailed Implementation

[0057] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted again that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0058] like Figure 1-9 The diagram illustrates an in-situ impact testing device for anchor bolts, comprising an in-situ connector 3, a connecting steel strand 4, an end lock 5, an impact system 6, an angle bracket 7, a lifting and release system 8, and a monitoring system.

[0059] like Figure 1 As shown, the in-situ connector 3 is fitted onto the exposed section of the anchor rod 2 to be tested, which is anchored in the rock mass of the roadway, to tightly connect the device to the anchor rod 2 to be tested. Figure 3 The diagram shows the connection structure between the in-situ connector 3 and the anchor rod 2 under test, including a force-equalizing ring 31, a quick-connect fitting 32, a baffle 33, and a locking device 34. Specifically, as shown... Figure 4As shown in the figure, the uniform-force ring 31 is generally in a convex-shaped ring shape, and is sleeved outside the nut 21 of the anchor rod to be tested; the inner side wall of the uniform-force ring 31 is closely attached to the outside of the nut 21 of the anchor rod to be tested, the end face of the uniform-force ring 31 with a smaller shaft diameter is in contact with the anchor rod tray or the roadway wall 1, and the end face with a larger shaft diameter is in contact with the pressure sensor 91, so as to ensure that the pressure sensor 91 is uniformly stressed. The quick connector 32 is hollow cylindrical and has an overall hollow structure. The inner side wall of the upper hollow part is attached to the outer side wall of the protruding end of the uniform-force ring 31, and provides an inward radial force to the uniform-force ring 31, which is used to wrap the uniform-force ring 31 and fasten the fitting connection between the uniform-force ring 31 and the anchor rod. The quick connector 32 is fixed on the outer side wall of the uniform-force ring by means of buckling, so as to realize quick and tight connection between the in-situ connector 3 and the anchor rod 2 to be tested on site; the inner side of the lower hollow part of the quick connector 32 is a stepped structure, which is buckled with the connecting steel strand 4, so as to realize quick and tight connection between the anchor rod 2 to be tested and the connecting steel strand 4 in-situ on site; preferably, as Figure 5 shown, the quick connector 32 is axially divided into two parts, namely a quick connector A 32a and a quick connector B 32b, which are buckled and connected via a buckle; the end face of the quick connector A 32a is C-shaped, the inner side of the upper shaft hole is clamped with the uniform-force ring 31, and the inner side of the lower shaft hole is clamped with the annular protrusion at the end of the connecting steel strand 4; after the quick connector B 32b and the quick connector A 32a are buckled and connected via the buckle, they are combined into a complete quick connector 32. The baffle 33 is a hollow disk, one end face of which is in contact with the pressure sensor 91 and applies an axial pressure toward the roadway wall 1 to the pressure sensor 91, which is used to fasten the connection among the pressure sensor 91, the uniform-force ring 31 and the quick connector 32; the other end face is in contact with the lock 34. As Figure 6 shown, the lock 34 is an anchor rod lock with conical petals 341, and the conical petals 341 are wrapped by the steel sleeve 342 of the lock, which plays a locking role and fixes the in-situ connector 3 on the anchor rod 2 to be tested. The baffle 33 and the lock 34 fix the pressure sensor 91 on the exposed section of the anchor rod 2 to be tested.

[0060] Both ends of the connecting steel strand 4 are respectively provided with completely identical annular protrusions, the annular protrusion at one end is buckled with the quick connector 32, and the other end is buckled with the guide rod 61 via an end lock 5. The connecting steel strand 4 is supported by the fixed pulley 74 of the inclination bracket 7, and produces bending deformation around the fixed pulley 74, so that the part of the connecting steel strand 4 close to the anchor rod 2 to be tested and the anchor rod 2 to be tested are on the same axis, and the part close to the ground is vertically downward, which is used for adjusting the test angle. The connecting steel strand 4 is made of high-rigidity steel strand, so that the yield load of the connecting steel strand 4 is 20% higher than the ultimate load of the anchor rod 2 to be tested, so as to ensure that the connecting steel strand 4 will not undergo plastic deformation when subjected to the impact load from the impact system 6 during the test. As Figure 7As shown, the end lock 5 has a hollow, spindle-shaped structure with a groove at its center. This groove is used to engage the annular protrusion at the end of the connecting steel strand 4 and the annular boss at the end of the guide rod 61, ensuring a secure connection between the connecting steel strand 4 and the guide rod 61. The end lock 5 is divided into a concave portion 51 and a convex portion 52 along the axial direction. After being joined together, they form a complete unit, ensuring that the connecting steel strand 4 and the guide rod 61 are fully engaged.

[0061] like Figure 2 As shown, the impact system 6 is perpendicular to the ground and includes a guide rod 61, an impact rod 62, and an impact hammer 63. The impact rod 62 is sleeved on the guide rod 61 and slides along the axial direction of the guide rod 61. The impact hammer 63 is mounted on the impact rod 62. Specifically, the guide rod 61 is a high-rigidity metal rod, preferably a steel rod, with a smooth surface, used to constrain the movement direction of the impact hammer 63 and the impact rod 62. An annular boss is fixed to the upper outer wall of the guide rod 61 for cooperating with the end lock 5; an impact disc is fixed to the lower outer wall, preferably, the impact disc and the guide rod 61 are integrally formed by casting or welding. Figure 8 As shown, the impact rod 62 includes a hollow metal tube 621, a lifting ring 622, and a support plate 623. The hollow metal tube 621 is preferably a hollow steel tube, fitted onto the outer wall of the guide rod 61. A lifting ring 622 is welded to the upper outer wall of the hollow metal tube 621. The lifting ring 622 is generally ear-shaped. The lifting device 81 and the electromagnetic release device 82, through connection with the lifting ring 622, complete the lifting and release of the impact rod 62 and the impact hammer. A support plate 623 is welded to the lower outer wall of the hollow metal tube 621, supporting the impact hammer 63. Figure 9 As shown, the impact hammer 63 includes a hammer body 631, an assembly rod 632, a nut 633, and a mounting plate 634. The hammer body 631 is a hollow cylinder with an opening on its side, allowing it to be fitted onto the impact rod 62 for easy on-site assembly and disassembly. It is made of carbon steel or lead. Four through holes are provided near the edge of the hammer body 631. The assembly rod 632 passes through these holes to stack and fix several hammer bodies 631. In this embodiment, when counterweighting the impact hammer 63, the number of hammer bodies 631 is adjusted. The assembly rod 632, in conjunction with the nut 633, connects and fixes three stacked hammer bodies 631 together to form a single unit, which is then placed on the bearing plate 623 of the impact rod 62. The bottom of the hammer body 631 is provided with a mounting plate 634 to reserve space for on-site installation, facilitating disassembly and installation. When the impact hammer 63 is released, the impact hammer 63 and the impact rod 62 are regarded as one unit and undergo free fall motion, striking the impact plate on the guide rod 61 as the impact kinetic energy.

[0062] like Figure 10As shown, an inclined support 7 is installed on the tunnel wall 1. The inclined support 7 includes two struts 71, feet 72, a central shaft 73, a fixed pulley 74, and an auxiliary pulley 75. The two struts 71 are placed in a V-shape and are rotatably connected at the intersection of the V-shapes through the central shaft 73, allowing the two struts 71 to rotate relative to each other to adapt to tunnels with different structures and environments. Each strut 71 is hinged to a foot 72 near the end of the tunnel wall 1. The foot 72 contacts the tunnel wall 1, and by adjusting the angle of the foot 72, it is made to fit tightly against the tunnel wall 1 and is fixed to the tunnel wall 1 with rivets to provide support. A fixed pulley 74 and two auxiliary pulleys 75 are also fitted on the central shaft 73. Preferably, the fixed pulley 74 is placed between the two support rods 71 ​​to support the connecting steel strand 4, so that the part of the connecting steel strand 4 near the anchor rod 2 to be tested is on the same axis as the anchor rod 2 to be tested, and the part near the ground remains vertically downward, so as to adjust the impact test angle according to the different angles of the anchor rod 2 to be tested. The two auxiliary pulleys 75 are respectively installed on the outside of the two support rods 71 ​​to support the lifting guide cable 83. The lifting guide cable 83 passes around the auxiliary pulleys 75 to connect the lifting device 81 and the electromagnetic release device 82.

[0063] like Figure 1 As shown, the lifting and release system 8 includes a lifting device 81, a lifting guide cable 83, and an electromagnetic release device 82. The lifting guide cable 83 passes around an auxiliary pulley 75, with one end connected to the lifting device 81 and the other end connected to the electromagnetic release device 82. The lifting device 81 lifts the impact hammer 63 through the lifting guide cable 83. The electromagnetic release device 82 is connected to the lifting ring 622 of the impact rod 62. The electromagnetic release device 82 releases the impact rod 62 and the impact hammer 63 instantaneously through a switch.

[0064] The monitoring system includes a data acquisition unit 94 and electrically connected pressure sensor 91, laser displacement sensor 92, and acceleration sensor 93. Pressure sensor 91 is a hollow cylinder inserted into the anchor rod 2 under test and fixed between the force equalizing ring 31 and the baffle 33, used to monitor impact loads. Laser displacement sensor 92 is mounted on quick-connect fitting 32, specifically on the outer wall of quick-connect fitting B32b, to monitor displacement changes in the anchor rod 2 under test. Acceleration sensor 93 is mounted on the impact hammer 63 to monitor impact kinetic energy. During the test, data from all the above sensors are collected and stored by the data acquisition unit 94.

[0065] The test method using the above-mentioned in-situ impact testing device for anchor bolts includes the following steps:

[0066] Step 1: In-situ connection of anchor rod 2 to be tested

[0067] Before conducting the in-situ impact test on the anchor bolt, the installation of the anchor bolt 2 to be tested should be completed. The force equalizing ring 31, pressure sensor 91, baffle 33, quick connector 32, and lock 34 are sequentially fitted onto the anchor bolt to be tested in the field. A pre-tightening force is applied to the baffle 33 to ensure tight contact between the force equalizing ring 31, pressure sensor 91, and baffle 33. The quick connector A32a is then fastened onto the force equalizing ring 31, and the annular protrusion on the connecting steel strand 4 is fastened to the lower opening of the quick connector A32a. Finally, the quick connector B32b is fastened onto the quick connector A32a, completing the overall connection. After completing the above operations, the lock 34 is used to secure the anchor bolt 2 and the connecting steel strand, ensuring a tight connection between the in-situ connector 3 and the anchor bolt 2, and between the in-situ connector 3 and the connecting steel strand.

[0068] Step 2: Install the tilt bracket 7

[0069] Install the foot 72 of the tilt bracket 7 onto the roadway wall 1 below the anchor rod 2 to be tested, so that the tilt bracket 7 and the anchor rod 2 to be tested are in the same roadway section. Adjust the position of the tilt bracket 7 to ensure stability during the test, and fix the tilt bracket 7 to the roadway wall 1 with rivets.

[0070] Step 3: Allocate impact kinetic energy

[0071] According to the law of conservation of energy: Ep = mgh, where Ep is the gravitational potential energy, m is the mass, g is the gravitational acceleration, and h is the height; Adjust the impact rate, where V is the impact rate, g is the gravitational acceleration, and h is the height; design the mass and impact rate according to the above relationship, and add counterweight to the impact hammer 63; after the counterweight is added, place the impact hammer 63 on the bearing plate 623 of the impact rod 62.

[0072] Step 4: Lifting and impact hammer 63

[0073] The lifting ring 622 on the electromagnetic release device 82 and the impact rod 62 are connected. The lifting guide cable 83 is connected to the electromagnetic release device 82. The lifting cable is controlled by the lifting equipment 81 to lift the impact hammer 63 to the design height. The annular boss on the guide rod 61 is tightly connected to the annular protrusion of the connecting steel strand 4 by the end lock 5.

[0074] Step 5: Device alignment and pre-test adjustments

[0075] Keep the entire device stationary and make minor adjustments to components with eccentric tendencies to ensure that all components are in the same vertical cross section.

[0076] Step 6: Data Acquisition

[0077] A laser sensor is mounted on quick-connect fitting 32, and an acceleration sensor 93 is mounted on the impact hammer 63. The pressure sensor 91, laser sensor, and acceleration sensor 93 are connected to the data acquisition unit 94. The collected data is transmitted to the data acquisition unit 94 via electrical signals, forming a data acquisition system. The pressure sensor 91 collects the impact load; the laser displacement sensor 92 collects the displacement information between the laser sensor and the anchor bolt tray in real time, thereby collecting the displacement changes of the anchor bolt during the impact process; the acceleration sensor 93 collects the momentum information of the impact hammer 63 during free fall.

[0078] Step 7: Start the test

[0079] After completing the above steps, evacuate the personnel to a safe location and control the electromagnetic release device 82 to release the impact hammer 63. The impact hammer 63 and the impact rod 62 form a whole, impacting the impact plate vertically under the constraint of the guide rod 61. After the impact hammer 63 collides and contacts the impact plate, the impact load is applied to the anchor rod 2 under test through the guide rod 61, the connecting steel strand 4, and the in-situ connector 3, thereby achieving the purpose of on-site testing of the impact mechanical properties of the in-situ anchor rod.

[0080] Step 8: Test ends

[0081] After the impact event, the collected data is saved, the testing device is disassembled, and the test is completed.

[0082] Taking a threaded steel anchor rod with an outer diameter of 20mm and an outer diameter of 36mm for the nut 21 of the anchor rod as an example, the specific dimensions of some components in the above testing device are as follows:

[0083] In the in-situ connector 3, the inner diameter of the force equalizing ring 31 is 37mm, which is 1mm larger than the outer diameter of the nut 21 of the anchor rod under test; its outer diameter is 90mm, which is 1mm smaller than the inner diameter of the quick connector 32; the height of the protruding part of the force equalizing ring 31 is 10mm. The outer diameter of the quick connector 32 is 120mm, the inner diameter is 91mm, and the height is 255mm. The thickness of the baffle 33 is 10mm, the inner diameter is 22mm, and the outer diameter is 90mm.

[0084] The diameter of the connecting steel strand 4 is 30mm, and the outer diameter of the annular protrusions at both ends of the connecting steel strand 4 is 50mm, and the height of the annular protrusions is 15mm.

[0085] The inner diameter of the end lock 5 is 31mm, which is slightly larger than the diameter of the connecting steel strand 4 and the guide rod 61. The diameter of the internal groove is 51mm and the depth is 32mm.

[0086] In the impact system 6, the guide rod 61 has a diameter of 30mm; the impact disc has an outer diameter of 200mm and a thickness of 50mm. The impact rod 62 has an inner diameter of 32mm, an outer diameter of 48mm, and a height of 500mm; the bearing disc 623 has an outer diameter of 300mm and a thickness of 20mm. The hammer body 631 has an outer diameter of 700mm, a height of 300mm, and a through hole diameter of 50mm.

[0087] Step 3 of the test method: The values ​​for adjusting the impact kinetic energy are as follows:

[0088] For the impact hammer 63 with a counterweight of m = 2t (i.e., 2000kg), when it is lifted to a height of h = 3m and released, the gravitational acceleration g is taken as 10m / s². 2 The impact kinetic energy is Ep = 60 kJ, and the impact velocity of the impact hammer is V = 7.75 m / s upon impact; or it can be lifted to a height h = 1.8 m, and upon release, the gravitational acceleration g is taken as 10 m / s². 2 The resulting impact kinetic energy is Ep = 36 kJ, and the impact velocity of the impact hammer during impact is V = 6 m / s.

[0089] The above description is only a part of the embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art under the principle and spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. An in-situ impact testing device for anchor bolts, installed on the anchor bolt to be tested, anchored in the rock mass within a roadway, characterized in that... This includes in-situ connectors, connecting steel strands, impact systems, tilt supports, lifting and release systems, and monitoring systems; among which, The in-situ connector includes a force-equalizing ring, a baffle, a quick connector, and a lock, which are sequentially fitted onto the anchor rod to be tested. The force-equalizing ring is fixed to the outer wall of the nut on the anchor rod to be tested. A pressure sensor is provided between one end face of the force-equalizing ring and the baffle. The quick connector is a hollow cylinder, with its upper inner wall fitting against the outer wall of the force-equalizing ring and fixed to the outer wall of the force-equalizing ring by a snap-fit ​​method. The lower end of the quick connector is connected to a connecting steel strand. The lock fits against the other end face of the baffle and is locked onto the anchor rod to be tested. The portion of the connecting steel strand near the anchor rod to be tested is on the same axis as the anchor rod to be tested, while the portion near the ground is vertically downward. The impact system is placed perpendicular to the ground, and its upper end is connected to the lifting and releasing system. The tilting bracket includes two cross-shaped support rods that can rotate relative to each other at the V-shaped intersection. Each support rod is hinged to a foot seat near the end of the tunnel wall. The two support rods are rotatably connected to the connecting steel strand at the V-shaped intersection and are fixed to the tunnel wall by the foot seat. One end of the lifting and releasing system is fixed to the tunnel wall, and the other end is connected to the impact system; The monitoring system includes a data acquisition unit and a pressure sensor, a laser displacement sensor, and an acceleration sensor electrically connected to it; the pressure sensor is sleeved on the anchor rod to be tested, the laser displacement sensor is mounted on a quick-connect fitting, and the acceleration sensor is mounted on the impact system; The impact system includes a guide rod, an impact rod, and an impact hammer; the upper end of the guide rod is connected to the ground end of the connecting steel strand, and an impact disc is fixed to the lower end of the guide rod; the impact rod is sleeved on the guide rod and slides along the axial direction of the guide rod, and the upper end of the impact rod is connected to a lifting and releasing system; the impact hammer is mounted on the impact rod. The impact rod includes a hollow metal tube, a lifting ring, and a bearing plate. The hollow metal tube is sleeved on the outer wall of the guide rod. The lifting ring is fixed to the upper outer wall of the hollow metal tube and is connected to the lifting and release system. The bearing plate is fixed to the lower outer wall of the hollow metal tube. The lifting and release system includes a lifting device, an electromagnetic release device, and a lifting guide cable connecting the lifting device and the electromagnetic release device; the electromagnetic release device is connected to the lifting ring.

2. The in-situ impact testing device for anchor bolts according to claim 1, characterized in that, It also includes an end lock, which has a groove at its center, and the annular protrusion at the end of the connecting steel strand and the annular boss at the end of the guide rod are respectively engaged in the groove.

3. The in-situ impact testing device for anchor bolts according to claim 1, characterized in that, The quick connector includes quick connector A and quick connector B, and quick connector B is fastened to quick connector A by a snap-fit.

4. The in-situ impact testing device for anchor bolts according to claim 1, characterized in that, The tilting bracket also includes a central shaft passing through the intersection of the two support rods, and a fixed pulley sleeved on the central shaft; the two support rods rotate relative to each other around the central shaft, the fixed pulley is placed between the two support rods, and the connecting steel strand is in contact with the fixed pulley and bends and deforms around the fixed pulley.

5. The in-situ impact testing device for anchor bolts according to claim 1, characterized in that, The tilting support also includes an auxiliary pulley, which is sleeved on the central shaft and installed on the side of the support rod away from the fixed pulley. The lifting guide cable passes around the auxiliary pulley to connect the lifting equipment and the electromagnetic release device.

6. A method for in-situ impact testing of anchor bolts, using the in-situ impact testing device for anchor bolts as described in claim 1, characterized in that, Includes the following steps: Step 1: Conduct in-situ connection of the anchor bolt to be tested The force equalizing ring, pressure sensor, baffle, quick connector and lock are sequentially mounted on the anchor rod to be tested on site. A pre-tightening force is applied to the baffle. The connecting steel strand is connected to the lower end of the quick connector. The quick connector is fixed by snap-fit. After the above operations are completed, the connection is completed by locking the fastener. Step 2: Install the tilt bracket Separate the two support rods at a certain angle so that the tilt bracket and the anchor rod to be tested are in the same roadway section and located on the roadway wall below the anchor rod to be tested. Adjust the position of the tilt bracket to ensure stability during the test. Fix the tilt bracket to the roadway wall through the feet of the tilt bracket. Step 3: Allocate impact kinetic energy According to the law of conservation of energy: Ep = mgh, where Ep is the gravitational potential energy, m is the mass, g is the gravitational acceleration, and h is the height; Adjust the impact rate, where V is the impact rate, g is the gravitational acceleration, and h is the height; design the mass and impact rate according to the above relationship, add counterweight to the impact system, and after the counterweight is added, put the impact system on the part of the connecting steel strand near the ground; Step 4: Lifting Impact System Connect the impact system to the lifting and release system, and use the lifting and release system to lift the impact system to the designed height; Step 5: Device alignment and pre-test adjustments Keeping the device as a whole stationary, make fine adjustments to the components with eccentric tendencies so that all the components are in the same vertical cross section; Step 6: Data Acquisition The laser sensor is mounted on the quick connector, the acceleration sensor is mounted on the impact system, and the pressure sensor, laser sensor, and acceleration sensor are respectively connected to the data acquisition device. Step 7: Start the test After completing the above steps, evacuate the personnel to a safe location and control the lifting and releasing system to release the impact system, which will then undergo free fall. Step 8: Test ends After the impact event, the collected data is saved, the testing device is disassembled, and the test is completed.

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