An experimental apparatus for drop hammer impact testing of anchor bolts in layered rock masses

Abstract

This invention provides an experimental device for drop hammer impact testing of anchor bolts in layered rock masses, comprising a lifting mechanism, a main frame, a hammer-grabbing device, a guide structure, a surrounding rock simulation sleeve, an anchor body, an impact force transmission mechanism, a hammer body, and a lifting rod. The main frame has a top plate at the top and a bottom plate at the bottom. The guide structure is located within the main frame, and the lifting mechanism is located on the upper surface of the top plate. The output end of the lifting mechanism is connected to the hammer-grabbing device, and the hammer body is located at the bottom of the hammer-grabbing device. Both the hammer-grabbing device and the hammer body are slidably engaged with the guide structure. This experimental device for drop hammer impact testing of anchor bolts in layered rock masses solves the problem that existing impact tests cannot accurately reflect the dynamic response characteristics of the layered rock mass-anchor bolt support system due to the lack of experimental devices capable of simulating the damage evolution process of the anchorage interface under dynamic impact conditions in related technologies.

Description

Technical Field

[0001] This utility model belongs to the field of anchor testing technology, and in particular relates to an experimental device for drop hammer impact testing of anchor bolts in layered rock masses. Background Technology

[0002] Rockbursts, a major hazard in deep coal mining, are characterized by their suddenness and destructive power, often causing serious casualties and significant property losses. As mining depths extend to the kilometer level, the complex mechanical environment of the rock mass—characterized by "three highs and one disturbance" (high ground stress, high osmotic pressure, high temperature, and strong mining disturbance)—significantly exacerbates the risk of rockbursts.

[0003] As shown in Figure 1, the Earth's crust contains numerous layered rock masses formed by sedimentation, with widespread layered coal, mudstone, sandstone, and shale distributed in mine strata. The strength of bedding between rock strata is usually much lower than the strength of the rock mass itself. When rock bursts occur, the presence of bedding becomes a weak point in the rock mass, leading to its failure. Therefore, revealing the dynamic mechanical response of anchor bolts (cables) under the constraints of layered rock mass structures is the theoretical foundation for constructing a precise rockburst prevention and control system.

[0004] However, the existing technology system has the following limitations: First, most existing impact test technology schemes are based on homogeneous rock mass models, which cannot reflect the influence of layered rock mass structure on the dynamic response of anchor support structure; second, current detection methods are limited to obtaining static mechanical parameters, making it difficult to capture the dynamic damage evolution process of the anchorage interface under dynamic impact conditions.

[0005] The lack of experimental equipment in related technologies to simulate the damage evolution process of the anchorage interface under dynamic impact conditions of layered rock mass structures means that existing impact tests cannot truly reflect the dynamic response characteristics of the layered rock mass-anchor support system, which in turn leads to a lack of key mechanical behavior data to support the impact resistance design of deep tunnel anchorage systems. Summary of the Invention

[0006] In view of this, the present invention aims to at least partially solve one of the related technical problems.

[0007] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0008] An experimental device for drop hammer impact testing of anchor bolts in layered rock masses includes a lifting mechanism, a main frame, a hammer-grabbing device, a guide structure, a surrounding rock simulation sleeve, an anchor body, an impact force transmission mechanism, a hammer body, and a lifting rod.

[0009] The main frame has a top plate at the top and a bottom plate at the bottom;

[0010] The guide structure is set inside the main frame, the lifting mechanism is set on the upper surface of the top plate, the output end of the lifting mechanism is connected to the grabbing and lifting hammer device, the bottom of the grabbing and lifting hammer device is set with a hammer body, and both the grabbing and lifting hammer device and the hammer body are slidably engaged with the guide structure.

[0011] The top of the boom is connected to the lower end face of the top plate, the boom passes through the grab hammer device and the hammer body, and the bottom of the boom is detachably connected to the surrounding rock simulation sleeve through a threaded structure.

[0012] An anchor body is installed inside the surrounding rock simulation casing. The inner wall of the anchor body has a rough surface. An anchor rod is installed inside the anchor body, with the bottom of the anchor rod located outside the anchor body. An annular slit is provided on the outer wall of the surrounding rock simulation casing.

[0013] An impact transmission mechanism is provided at the bottom of the anchor rod. The impact transmission mechanism is detachably connected to the anchor rod and is used to bear the impact of the hammer.

[0014] Furthermore, it also includes two side positioning mechanisms, symmetrically arranged on the front and rear sides of the main frame;

[0015] The side positioning mechanism includes a fixed base, two vertical guide rails, and two roller structures.

[0016] The fixed base is a Z-shaped steel, with the lower end face connected to the fixed end, the inner bent edge matching the outer edge of the base plate, and the outer bent edge having multiple reinforcing ribs.

[0017] Two vertical guide rails are symmetrically arranged on the fixed base, and two roller structures are symmetrically arranged on the side of the impact force transmission mechanism. Each roller structure is slidably engaged with one vertical guide rail.

[0018] Furthermore, the roller structure includes a positioning plate and two positioning rollers;

[0019] Two positioning rollers are symmetrically arranged on the positioning plate, and a vertical guide rail is located between the two positioning rollers and slides with them.

[0020] Furthermore, the impact transmission mechanism includes a tray and a locking nut;

[0021] An impact block is provided on the lower end face of the hammer body, and the tray cooperates with the impact block;

[0022] The pallet is connected to the bottom of the anchor rod by locking nuts, and the side of the pallet is connected to the positioning plate.

[0023] Furthermore, it also includes two protective structures, symmetrically arranged on the front and rear sides of the main frame;

[0024] The protective structure includes a horizontal plate, a transparent protective plate, two support bases, and two positioning slots;

[0025] The horizontal plate is set on the top of two vertical guide rails on the same side;

[0026] Two positioning grooves are symmetrically welded to the left and right ends of the horizontal plate, and the transparent protective plate slides in conjunction with the positioning grooves.

[0027] The bottom of the transparent protective plate is connected to the bottom end face of the fixed base via two support seats.

[0028] Furthermore, the transparent protective panel is a transparent acrylic panel.

[0029] Furthermore, the surrounding rock simulation casing is a concrete pipe or a steel pipe.

[0030] Furthermore, the lifting mechanism includes a lifting chain and a lifting motor;

[0031] The lifting motor drives the grabbing hammer device to move along the guide structure via the lifting chain. The lifting motor is located on the upper surface of the top plate.

[0032] Furthermore, the guide structure includes two column guide rails;

[0033] The column guide rails are arranged side by side inside the main frame, with the top connected to the top plate and the bottom connected to the bottom plate. The column guide rails slide in conjunction with the grabbing and lifting hammer device and the hammer body.

[0034] Furthermore, the lifting hammer device includes a lifting plate and a strong electromagnetic device;

[0035] The lifting plate is connected to the output end of the lifting mechanism, and the lifting rod passes through the lifting plate;

[0036] The strong electromagnetic device is installed inside the lifting plate. When the strong electromagnetic device is energized, it attracts the hammer body, and when the power is off, it releases the hammer body.

[0037] Compared with existing technologies, the experimental device for drop hammer impact testing of anchor bolts in layered rock masses described in this utility model has the following advantages:

[0038] 1. The surrounding rock simulation casing accurately reproduces the layered rock mass structure through annular slits on its outer wall. Combined with the material properties of concrete or steel pipes, it can not only adapt to the simulation requirements of different rock types, but also more effectively bear the shear slip and tensile fracture behavior along the bedding planes during impact load transmission, thus realistically reproducing the dynamic response mechanism of the anchor support structure in layered surrounding rock. The anchor body, through rough surface treatment of the inner wall and optional resin or grouting materials, reconstructs the bond strength distribution of the anchor-rock interface within a limited space, ensuring that impact energy is dissipated along the anchoring section in a gradient, and simultaneously reproducing the dynamic damage evolution process. Together, these two technologies overcome the limitations of traditional homogeneous rock mass models in representing the dynamic response of layered structures, providing a key physical simulation basis for the impact-resistant optimization design of anchoring systems.

[0039] 2. The side positioning mechanism effectively suppresses the horizontal displacement and deflection vibration of the impact force transmission mechanism under dynamic load through the rigid engagement of the Z-shaped fixed base and the edge of the base plate and the symmetrical constraint mechanism of the vertical guide rail-double roller, ensuring that the anchor rod axis is always precisely aligned with the impact trajectory of the hammer, thereby eliminating experimental errors caused by non-uniform stress.

[0040] 3. The protective structure utilizes a modular design of transparent acrylic panels and sliding positioning grooves to form a closed anti-splash barrier while maintaining visibility during the experiment. The three-dimensional frame formed by the bottom support and the top beam significantly weakens shock wave transmission through rigid energy dissipation, simultaneously mitigating the risks of fragment ejection and hammer rebound. The side positioning mechanism and the protective structure work together to ensure the high repeatability, operational safety, and reliable dynamic response data acquisition of the layered rock mass anchoring impact experiment. Attached Figure Description

[0041] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0042] Figure 1 This is a schematic diagram of the layered rock mass anchor support structure described in an embodiment of the present invention;

[0043] Figure 2 This is a cross-sectional schematic diagram of a steel pipe structure used in a simulated surrounding rock casing according to an embodiment of this utility model.

[0044] Figure 3 This is a cross-sectional schematic diagram of the surrounding rock simulation casing using a concrete pipe structure in an embodiment of this utility model;

[0045] Figure 4 This is a schematic diagram of the side positioning mechanism and protective structure described in an embodiment of the present utility model;

[0046] Figure 5 This is a schematic diagram of the side positioning mechanism described in an embodiment of the present utility model;

[0047] Figure 6 This is the impact force transmission mechanism described in the embodiment of this utility model.

[0048] Explanation of reference numerals in the attached figures:

[0049] 1. Lifting chain; 2. Column guide rail; 3. Circular slit; 4. Steel pipe; 5. Lifting motor; 6. Grab and lift hammer device; 7. Hammer body; 8. Hanging rod; 9. Main frame; 10. Anchor body; 11. Anchor bolt; 12. Concrete pipe; 110. Pallet; 111. Nut; 120. Fixed base; 210. Transparent protective plate; 220. Horizontal plate; 230. Positioning groove; 300. Roller structure; 330. Vertical guide rail. Detailed Implementation

[0050] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0051] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0052] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0053] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0054] An experimental apparatus for drop hammer impact testing of anchor bolts in layered rock masses, such as... Figure 2-3 As shown, it includes a lifting mechanism, a main frame 9, a grabbing hammer device 6, a guide structure, a surrounding rock simulation sleeve, an anchor body 10, an impact force transmission mechanism, a hammer body 7, and a boom 8; the main frame 9 has a top plate at the top and a bottom plate at the bottom; the guide structure is set inside the main frame 9, the lifting mechanism is set on the upper surface of the top plate, the output end of the lifting mechanism is connected to the grabbing hammer device 6, the bottom of the grabbing hammer device 6 is provided with a hammer body 7, and both the grabbing hammer device 6 and the hammer body 7 are slidably engaged with the guide structure; the top of the boom 8 is connected to the lower surface of the top plate, the boom 8 passes through the grabbing hammer device 6 and the hammer body 7, and the bottom of the boom 8 is detachably connected to the surrounding rock simulation sleeve through a threaded structure;

[0055] An anchor body 10 is installed inside the surrounding rock simulation casing. The inner wall of the anchor body 10 has a rough surface. Anchor rods 11 are installed inside the anchor body 10, with the bottom of the anchor rods 11 located outside the anchor body 10. An annular slit 3 is set on the outer wall of the surrounding rock simulation casing. The surrounding rock simulation casing accurately reproduces the layered rock mass bedding structure through the annular slit 3 on the outer wall. Combined with the material characteristics of concrete or steel pipe 4, it can not only adapt to the simulation requirements of different rock types, but also more effectively bear the shear slip and tensile fracture behavior along the bedding plane during the impact load transmission, thus realistically restoring the dynamic response mechanism of the anchor rod 11 support structure in the layered surrounding rock. The anchor body 10, with the help of the rough surface treatment of the inner wall and optional resin or grouting material filling, reconstructs the bond strength distribution of the anchor rod 11-rock mass interface in a limited space, ensuring that the impact energy is dissipated along the anchor section gradient, and simultaneously reproducing the dynamic damage evolution process. The two work together to overcome the limitations of traditional homogeneous rock mass models in representing the dynamic response of layered structures, and provide a key physical simulation basis for the impact-resistant optimization design of the anchor body 10 system. In this example, the surrounding rock simulation casing is steel pipe 4.

[0056] An impact transmission mechanism is provided at the bottom of the anchor bolt 11. The impact transmission mechanism is detachably connected to the anchor bolt 11 and is used to bear the impact of the hammer body 7. The impact transmission mechanism includes a tray 110 and a locking nut 111; an impact block is provided on the lower end face of the hammer body 7, and the tray 110 cooperates with the impact block; the tray 110 is connected to the bottom of the anchor bolt 11 through the locking nut 111, and the side of the tray 110 is connected to the positioning plate.

[0057] It also includes two side positioning mechanisms, symmetrically arranged on the front and rear sides of the main frame 9. Each side positioning mechanism includes a fixed base 120, two vertical guide rails 330, and two roller structures 300. The fixed base 120 is a Z-shaped steel, with its lower end face connected to the fixed end, its inner bent edge engaging with the outer edge of the base plate, and its outer bent edge having multiple reinforcing ribs. The two vertical guide rails 330 are symmetrically arranged on the fixed base 120, and the two roller structures 300 are symmetrically arranged on the side of the impact transmission mechanism. Each roller structure 300 slides with one vertical guide rail 330. Each roller structure 300 includes a positioning plate and two positioning rollers. The two positioning rollers are symmetrically arranged on the positioning plate, and the vertical guide rails 330 are located between the two positioning rollers and slide with them. The side positioning mechanism effectively suppresses the horizontal displacement and deflection vibration of the impact force transmission mechanism under dynamic load through the rigid engagement of the Z-shaped fixed base 120 with the edge of the base plate and the symmetrical constraint mechanism of the vertical guide rail 330-double rollers, ensuring that the axis of the anchor rod 11 is always precisely aligned with the impact trajectory of the hammer body 7, thereby eliminating experimental errors caused by non-uniform stress.

[0058] It also includes two protective structures, symmetrically arranged on the front and rear sides of the main frame 9. The protective structures include a horizontal plate 220, a transparent protective plate 210, two support bases, and two positioning slots 230. The horizontal plate 220 is positioned on top of two vertical guide rails 330 on the same side. The two positioning slots 230 are symmetrically welded to the left and right ends of the horizontal plate 220, and the transparent protective plate 210 slides into the positioning slots 230. The bottom of the transparent protective plate 210 is connected to the bottom end face of the fixed base 120 via two support bases. The transparent protective plate 210 is made of transparent acrylic. The modular design of the transparent acrylic plate and the sliding positioning slots 230 forms a closed anti-splash barrier while maintaining visibility during the experiment. The three-dimensional frame formed by the bottom support base and the top beam significantly weakens the shock wave transmission through rigid energy dissipation, simultaneously mitigating the risks of fragment ejection and hammer rebound. The side positioning mechanism and the protective structure work together to ensure the high repeatability, operational safety, and reliable dynamic response data acquisition of the layered rock mass anchoring impact experiment.

[0059] The lifting mechanism includes a lifting chain 1 and a lifting motor 5; the lifting motor 5 drives the grabbing hammer device 6 to move along the guide structure via the lifting chain 1, and the lifting motor 5 is mounted on the upper surface of the top plate. The guide structure includes two column guide rails 2; the column guide rails 2 are arranged side by side inside the main frame 9, with the top connected to the top plate and the bottom connected to the bottom plate, and the column guide rails 2 are slidably engaged with the grabbing hammer device 6 and the hammer body 7.

[0060] The lifting hammer device 6 includes a lifting plate and a strong electromagnetic device; the lifting plate is connected to the output end of the lifting mechanism, and the lifting rod 8 passes through the lifting plate; the strong electromagnetic device is installed inside the lifting plate, and the strong electromagnetic device attracts the hammer body 7 when the power is on and releases the hammer body 7 when the power is off.

[0061] The experimental setup also includes a data collection module for collecting experimental data and a computer module for processing the experimental data. The data collection module includes a laser displacement sensor for acquiring displacement data and a force sensor for acquiring impact force data.

[0062] The force sensor is directly integrated into the tray 110 body that bears the impact energy (zero transmission loss in impact force measurement); the laser displacement sensor focuses on the lower free section of the anchor rod 11 (avoiding interference from the anchoring section and capturing pure rod deformation); the high-speed camera orthogonally monitors the dynamic expansion of the annular slit 3.

[0063] How this example works

[0064] Step S1: Anchor the anchor rod 11 into the steel pipe 4 using the standard amount of resin anchoring agent and install the tray 110 and nut 111, and let it stand until the anchor body 10 reaches the predetermined strength.

[0065] Step S2: Make a circumferential cut 3 with a depth of 1-2 mm at the predetermined position of the steel pipe 4, ensuring that the cut only cuts through the pipe wall without damaging the anchor body 10 and the anchor rod 11.

[0066] Step S3: Connect the upper end of the assembled steel pipe 4 to the bottom of the hanging rod 8 with a thread. At the same time, align the monitoring end of the laser displacement sensor with the lower non-anchored section of the anchor rod 11, integrate the force sensor on the top impact surface of the tray 110, and slide the transparent protective plate 210 into the closed position along the positioning groove 230.

[0067] Step S4: The lifting chain 1 driven by the lifting motor 5 drives the lifting hammer device 6 to lift the hammer body 7 to the set height. The strong electromagnetic device inside the lifting hammer device 6 is energized to attract the hammer body 7. At the same time, the computer module is started to initialize the baseline data of the laser displacement sensor and the force sensor.

[0068] Step S5: The strong electromagnetic device is de-energized, causing the hammer 7 to fall freely along the column guide rail 2 and impact the tray 110. The impact force is transmitted to the anchor rod 11 through the force sensor at its bottom. At the same time, the roller structure 300 slides along the vertical guide rail 330 to suppress the sway of the tray 110. The laser displacement sensor captures the displacement time history of the anchor rod 11 in real time.

[0069] Step S6: The computer module synchronously processes the impact force waveform output by the force sensor, the deformation data recorded by the laser displacement sensor, and the dynamic cracking sequence of the annular slit 3 captured by the high-speed camera based on the unified timestamp, and generates the load-displacement-damage evolution correlation curve.

[0070] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An experimental apparatus for drop hammer impact testing of anchor bolts in layered rock masses, characterized in that: It includes a lifting mechanism, main frame (9), grab and lift hammer device (6), guide structure, surrounding rock simulation casing, anchor body (10), impact force transmission mechanism, hammer body (7) and lifting rod (8); The main frame (9) has a top plate at the top and a bottom plate at the bottom; The guide structure is set inside the main frame (9), the lifting mechanism is set on the upper surface of the top plate, the output end of the lifting mechanism is connected to the grabbing hammer device (6), the bottom of the grabbing hammer device (6) is provided with a hammer body (7), and the grabbing hammer device (6) and the hammer body (7) are both slidably engaged with the guide structure. The top of the boom (8) is connected to the lower end face of the top plate, the boom (8) passes through the grab hammer device (6) and the hammer body (7), and the bottom of the boom (8) is detachably connected to the surrounding rock simulation sleeve through a threaded structure; An anchor body (10) is installed inside the surrounding rock simulation casing. The inner wall of the anchor body (10) is rough. An anchor rod (11) is installed inside the anchor body (10). The bottom of the anchor rod (11) is located outside the anchor body (10). An annular slit (3) is provided on the outer wall of the surrounding rock simulation casing. An impact transmission mechanism is provided at the bottom of the anchor rod (11). The impact transmission mechanism is detachably connected to the anchor rod (11) and is used to bear the impact of the hammer (7).

2. The experimental apparatus for drop hammer impact testing of anchor bolts in layered rock masses according to claim 1, characterized in that: It also includes two side positioning mechanisms, symmetrically arranged on the front and rear sides of the main frame (9); The side positioning mechanism includes a fixed base (120), two vertical guide rails (330) and two roller structures (300); The fixed base (120) is a Z-shaped steel, with its lower end face connected to the fixed end. The inner bent edge is fitted with the outer edge of the base plate, and the outer bent edge is provided with multiple reinforcing ribs. Two vertical guide rails (330) are symmetrically arranged on the fixed base (120), and two roller structures (300) are symmetrically arranged on the side of the impact transmission mechanism. Each roller structure (300) is slidably engaged with a vertical guide rail (330).

3. The experimental apparatus for drop hammer impact testing of anchor bolts in layered rock masses according to claim 2, characterized in that: The roller structure (300) includes a positioning plate and two positioning rollers; Two positioning rollers are symmetrically arranged on the positioning plate, and the vertical guide rail (330) is located between the two positioning rollers and slides with them.

4. The experimental apparatus for drop hammer impact testing of anchor bolts in layered rock masses according to claim 3, characterized in that: The impact transmission mechanism includes a tray (110) and a locking nut (111); The lower end face of the hammer body (7) is provided with an impact block, and the tray (110) cooperates with the impact block; The tray (110) is connected to the bottom of the anchor rod (11) by a locking nut (111), and the side of the tray (110) is connected to the positioning plate.

5. The experimental apparatus for drop hammer impact testing of anchor bolts in layered rock masses according to claim 4, characterized in that: It also includes two protective structures, symmetrically arranged on the front and rear sides of the main frame (9); The protective structure includes a horizontal plate (220), a transparent protective plate (210), two support bases and two positioning grooves (230); The horizontal plate (220) is set on top of two vertical guide rails (330) on the same side; Two positioning grooves (230) are symmetrically welded to the left and right ends of the horizontal plate (220), and the transparent protective plate (210) slides in fit with the positioning grooves (230); The bottom of the transparent protective plate (210) is connected to the bottom end face of the fixed base (120) through two support seats.

6. The experimental apparatus for drop hammer impact testing of anchor bolts in layered rock masses according to claim 5, characterized in that: The transparent protective panel (210) is a transparent acrylic panel.

7. An experimental apparatus for drop hammer impact testing of anchor bolts in layered rock masses according to any one of claims 1-6, characterized in that: The surrounding rock simulation casing is a concrete pipe (12) or a steel pipe (4).

8. The experimental apparatus for drop hammer impact testing of anchor bolts in layered rock masses according to claim 7, characterized in that: The lifting mechanism includes a lifting chain (1) and a lifting motor (5); The lifting motor (5) drives the grabbing hammer device (6) to move along the guide structure through the lifting chain (1). The lifting motor (5) is set on the upper end face of the top plate.

9. The experimental apparatus for drop hammer impact testing of anchor bolts in layered rock masses according to claim 8, characterized in that: The guide structure includes two column guide rails (2); The column guide rails (2) are arranged side by side inside the main frame (9), with the top connected to the top plate and the bottom connected to the bottom plate. The column guide rails (2) are slidably engaged with the grabbing hammer device (6) and the hammer body (7).

10. The experimental apparatus for drop hammer impact testing of anchor bolts in layered rock masses according to claim 9, characterized in that: The grabbing and lifting hammer device (6) includes a lifting plate and a strong electromagnetic device; The lifting plate is connected to the output end of the lifting mechanism, and the lifting rod (8) passes through the lifting plate; The strong electromagnetic device is installed inside the lifting plate. When the strong electromagnetic device is powered on, it attracts the hammer body (7) and when the power is off, it releases the hammer body (7).

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