An anchor pull-out test apparatus and test method for implementing graded confining pressure loading

Abstract

This invention relates to a device and method for conducting anchor bolt pull-out tests using graded confining pressure loading, belonging to the technical field of anchor bolt support testing in mine roadways. The device includes a frame, a lifting system, a loading system, and a data measurement system. The lifting system is housed within the frame. The loading system includes a confining pressure loading mechanism and an axial pull-out loading mechanism. The confining pressure loading mechanism is fixed to the bottom of the frame, and the axial pull-out loading mechanism is positioned above it, connected to the lifting system and the data measurement system. This invention applies non-uniform confining pressure to the specimen through the graded confining pressure loading mechanism, which can more realistically reproduce the mechanical state and failure characteristics of anchor bolts and anchor bodies under non-uniform confining pressure, resulting in more accurate test results. Furthermore, it is convenient and easy to use.

Description

Technical Field

[0001] This invention relates to an anchor pull-out test device and test method for implementing graded confining pressure loading, belonging to the technical field of anchor support test in mine roadways. Background Technology

[0002] Rock bolt support technology is an important component of roadway support technology. Compared with other support technologies, rock bolt support not only has technical advantages such as minimal disturbance to the original rock, high safety and reliability, and rapid support speed, but also low cost and significant economic benefits. However, in recent years, with the continuous increase in coal mining depth, the geological conditions encountered have become increasingly complex, and engineering disasters such as rock bursts and rockbursts caused by high stress have become more frequent. Under these conditions, understanding the anchoring effect of rock bolt support under different confining pressures is crucial to ensuring roadway stability.

[0003] From the perspective of on-site anchoring performance, confining pressure is a crucial factor affecting the anchoring force of anchor bolts, and its changes directly impact the ultimate bearing capacity of the anchoring system. To study the influence of confining pressure on anchoring effectiveness, many scholars have conducted extensive research, developed corresponding experimental equipment, and proposed new research methods. For example, Chinese patent document CN109297810B discloses a device and method for simulating deep strata anchor pull-out testing, using a rubber-water bag wrapped in concrete to simulate the surrounding rock pressure in a roadway; Chinese patent document CN110186760A discloses a device and method for testing the pull-out of soil anchor bolts by changing confining pressure conditions, simulating roadway confining pressure by adjusting the water pressure in the pressure chamber. In engineering sites, the confining pressure on the anchor body is related to its distance from the roadway, meaning the confining pressure is non-uniformly distributed. However, most studies apply uniformly distributed confining pressure to the anchor body, which makes the anchor bolts differ significantly from the actual engineering conditions and cannot accurately reflect the impact of on-site confining pressure on the anchor bolt anchoring effect. Therefore, the mechanism of action of non-uniformly distributed confining pressure on anchor bolts and anchor bolt support systems needs further research. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an anchor pull-out test device for implementing graded confining pressure loading. By applying non-uniform confining pressure to the specimen through the graded confining pressure loading mechanism, it can more realistically reproduce the mechanical state and failure characteristics of the anchor rod and anchor body under non-uniform confining pressure, making the test results more accurate. Moreover, it is convenient to use and simple to operate.

[0005] The present invention also provides a test method for the above-mentioned anchor pull-out test device for implementing graded confining pressure loading.

[0006] The technical solution of the present invention is as follows:

[0007] An anchor bolt pull-out test device for implementing graded confining pressure loading includes a frame, a lifting system, a loading system, and a data measurement system, wherein...

[0008] The frame is equipped with a lifting system, and the loading system includes a confining pressure loading mechanism and an axial pull-out loading mechanism. The confining pressure loading mechanism is fixed to the bottom of the frame, and the axial pull-out loading mechanism is installed above the confining pressure loading mechanism. The axial pull-out loading mechanism is connected to the lifting system and is connected to a data measurement system.

[0009] According to a preferred embodiment of the present invention, the frame includes a base and an outer frame. A rectangular outer frame is provided on the base, and a lifting system is provided inside the rectangular outer frame. A base guard plate is provided on one side of the base, and an outer frame baffle is provided on one side of the outer frame.

[0010] According to a preferred embodiment of the present invention, the lifting system includes a lead screw, a bearing housing, a movable crossbeam, and a lifting motor. Lead screws are respectively arranged on both sides of the frame, and a movable crossbeam is arranged between the two lead screws. The top of the lead screw passes through the frame and is provided with a bearing housing. A rolling bearing is arranged in the bearing housing to make the lead screw perform circumferential motion, restrict vertical movement, and at the same time play a supporting and fixing role. A lifting motor is arranged at the bottom of the frame, and the lifting motor is connected to the bottom end of the lead screw through a gear set.

[0011] According to a preferred embodiment of the present invention, the axial pulling loading mechanism includes a pulling cylinder base, a hollow cylinder pressure head, a pulling nut, and a pull rod. The pulling cylinder base is disposed on the upper side of the movable crossbeam and is fixedly connected by bolts. The hollow cylinder pressure head is disposed on the top of the pulling cylinder. The pull rod passes through the hollow cylinder pressure head and the pulling cylinder base in sequence. A pulling nut is disposed on the pull rod, and the pulling nut contacts the upper side of the hollow cylinder pressure head.

[0012] According to a preferred embodiment of the present invention, a cylindrical clamp is provided at the lower end of the tie rod, and a T-shaped opening is provided at the lower end of the cylindrical clamp for connecting the anchor body specimen.

[0013] According to a preferred embodiment of the present invention, the confining pressure loading mechanism includes a pressure chamber base, a top pressure chamber, an intermediate pressure chamber, a bottom pressure chamber, a pressure chamber cover, and a pad. The pressure chamber base is disposed within the frame. The bottom pressure chamber, the intermediate pressure chamber, and the top pressure chamber are sequentially disposed on the upper side of the pressure chamber base. Multiple intermediate pressure chambers are disposed, and the specific number can be determined according to the test length. The bottom pressure chamber, the intermediate pressure chamber, and the top pressure chamber constitute a pressure chamber. A pad is disposed inside the top pressure chamber, and a pressure chamber cover penetrating the pad is disposed on the upper side of the top pressure chamber.

[0014] According to a further preferred embodiment of the present invention, the top pressure chamber, the middle pressure chamber, and the bottom pressure chamber are all hollow cylinders, the hollow cylinders are metal parts, the inner wall of the hollow cylinders is provided with a rubber layer, and an annular pressurizing oil chamber is provided between the rubber layer and the hollow cylinder. The top pressure chamber, the middle pressure chamber, and the bottom pressure chamber are connected sequentially from top to bottom by threads. The outer walls of the top pressure chamber, the middle pressure chamber, and the bottom pressure chamber are provided with inlet valves and outlet valves that communicate with the pressurizing oil chamber.

[0015] According to a preferred embodiment of the present invention, the pad includes a circular plate and an arc-shaped outer wall. A through hole is provided at the center of the circular plate, and arc-shaped outer walls are symmetrically arranged on the circular plate. The circular plate is disposed in the top pressure chamber, and the arc-shaped outer walls pass through the pressure chamber cover.

[0016] According to a preferred embodiment of the present invention, the data measurement system includes a load sensor, a displacement sensor, a data acquisition instrument, and a data analyzer. The load sensor is a spoke-type sensor, which is fixed to the lower surface of the moving crossbeam. The bottom end of the tie rod passes through the load sensor, and the lower surface of the load sensor contacts the top of the pad. A displacement sensor is installed on the moving crossbeam to monitor the displacement of the anchor bolt. Both the displacement sensor and the load sensor are connected to the data acquisition instrument. After collecting the monitoring data, the data acquisition instrument transmits it to the data analyzer. The data analyzer outputs the load and displacement during the simulated pull-out process.

[0017] According to a preferred embodiment of the present invention, an L-shaped limit stop pin connected to a limit switch is provided on the moving crossbeam, and limit components are respectively provided on the upper and lower parts of one side of the outer frame. The limit stop pin moves up and down with the moving crossbeam. When the limit stop pin moves to the upper or lower limit position with the moving crossbeam, it touches the limit component, and the limit stop pin presses down the limit switch, cutting off the lifting motor circuit, thereby achieving the function of limiting and preventing excessive displacement from damaging the device.

[0018] The test method for the above-mentioned anchor pull-out test device for implementing graded confining pressure loading includes the following steps:

[0019] A. Fabrication of anchor solid specimens

[0020] Rock samples are prepared based on the mechanical properties of the rocks in the coal mine roadway. Anchoring holes are drilled in the center of the rock samples and the holes are cleaned. Then, the anchor rod is placed in the anchoring hole and the anchoring agent is added to obtain the anchor body specimen. The size of the anchor body specimen is determined according to the size of the confining pressure loading mechanism.

[0021] B. Installation of pressure chamber and anchored solid specimen

[0022] Start the lifting motor and move the moving beam upward to reserve the position of the pressure chamber. Install the pressure chamber base, bottom pressure chamber, middle pressure chamber, top pressure chamber, anchor body specimen, pad, and pressure chamber cover in sequence inside the frame. Adjust the position of the moving beam and fix the anchor rod in the T-shaped opening inside the column clamp. Fix the anchor rod to the T-shaped opening by installing a washer and clamping nut at the top of the anchor rod. At the same time, adjust the position of the pull-out nut so that it is tightly against the hollow oil cylinder pressure head.

[0023] C. Pressurize the pressure chamber to simulate the stress state of the rock mass.

[0024] The inlet valve and outlet valve in the pressure chamber are connected to the oil pump in sequence. Then, the oil pump is controlled by the servo controller to pressurize the pressure chamber to the preset value. By applying different pressures to the top pressure chamber, the middle pressure chamber and the bottom pressure chamber, the graded confining pressure loading is achieved, and the real stress environment of the anchor body is restored.

[0025] D. Conduct a pull-out test and record the test data.

[0026] After the confining pressure stabilizes, oil is introduced into the base of the pull-out cylinder. Force is applied to the pull rod through the hollow cylinder pressure head and the pull-out nut, thereby applying a static load to the anchor body specimen to simulate the pull-out load effect on the surrounding rock in the deep roadway. Then, the experimental data measured by the load sensor and displacement sensor are recorded and saved.

[0027] E. Disassembly test apparatus

[0028] First, release the residual stress in the tie rod and anchor rod. Then, control the oil pump through the servo controller to unload the confining pressure, open the drain valve to drain the oil and relieve pressure, raise the moving crossbeam, and then remove the pressure chamber cover, pad, anchor body specimen, top pressure chamber, middle pressure chamber, bottom pressure chamber and pressure chamber base in sequence.

[0029] The confining pressure described in this invention refers to radial pressure, while the axial direction is the anchor pull-out load. This test more closely resembles the clamping and holding effect of radially compressed anchor boreholes on anchor bolts in engineering. The confining pressure typically referred to in rock mechanics testing includes the pressure on the upper and lower end faces of the rock sample and the circumferential pressure, which is inconsistent with the actual situation of anchor pull-out tests.

[0030] The beneficial effects of this invention are as follows:

[0031] 1. This invention applies non-uniform confining pressure to the specimen through a graded confining pressure loading mechanism, and simultaneously applies a continuous axial static load to the specimen through an axial pull-out loading mechanism. This enables the determination of the static pull-out mechanical properties of anchor bodies under non-uniform confining pressure stress environment in indoor conditions. It can well simulate the failure characteristics of deep roadway anchoring structures under the influence of confining pressure and static load. Moreover, it is convenient to use and simple to operate.

[0032] 2. The test apparatus and test method of the present invention adopt a solid-liquid separation confining pressure loading method, which avoids the error caused by direct contact between pressurized liquid and rock sample and rock debris mixed with liquid, making the test more convenient and accurate. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the present invention;

[0034] Figure 2 This is a cross-sectional structural schematic diagram of the present invention;

[0035] Figure 3This is a schematic diagram of the pressure chamber structure of the present invention;

[0036] Figure 4 This is a schematic diagram of the cross-sectional structure of the pressure chamber of the present invention;

[0037] Figure 5 This is a schematic diagram of the cylindrical clamp connection structure of the present invention;

[0038] The components are as follows: 1-base, 2-outer frame, 3-lead screw, 4-moving crossbeam, 5-pull rod, 6-pull cylinder base, 7-hollow cylinder pressure head, 8-pull nut, 9-load sensor, 10-limit stop pin, 11-limiting component, 12-lifting motor, 13-gear set, 14-base guard plate, 15-outer frame baffle, 16-bearing seat, 17-displacement sensor, 18-pressure chamber base, 19-bottom pressure chamber, 20-middle pressure chamber, 21-top pressure chamber, 22-pressure chamber cover, 23-anchor rod, 24-pad, 25-pressurizing oil chamber, 26-rubber layer, 27-clamping nut, 28-inlet valve, 29-outlet valve; 30-rock sample; 31-cylindrical clamp; 32-gasket.

[0039] 100-Pressure chamber. Detailed Implementation

[0040] The present invention will be further described below with reference to the embodiments and accompanying drawings, but is not limited thereto.

[0041] Example 1:

[0042] like Figure 1-5 As shown, this embodiment provides an anchor pull-out test device for implementing graded confining pressure loading, including a frame, a lifting system, a loading system, and a data measurement system, wherein...

[0043] The frame is equipped with a lifting system, and the loading system includes a confining pressure loading mechanism and an axial pull-out loading mechanism. The confining pressure loading mechanism is fixed to the bottom of the frame, and the axial pull-out loading mechanism is installed above the confining pressure loading mechanism. The axial pull-out loading mechanism is connected to the lifting system and is connected to a data measurement system.

[0044] The frame includes a base 1 and an outer frame 2. A rectangular outer frame 2 is provided on the base 1. A lifting system is provided inside the rectangular outer frame 2. A base guard plate 14 is provided on one side of the base 1, and an outer frame baffle 15 is provided on one side of the outer frame 2.

[0045] The lifting system includes a lead screw 3, a bearing housing 16, a moving crossbeam 4, and a lifting motor 12. Lead screws 3 are respectively installed on both sides of the frame. The moving crossbeam 4 is threaded between the two lead screws 3. The top of the lead screw 3 passes through the frame and is installed at the bearing housing 16. The bearing housing 16 is equipped with a rolling bearing, which makes the lead screw move in a circular motion, restricts vertical movement, and also provides support and fixation. The lifting motor 12 is installed at the bottom of the frame. The lifting motor 12 is connected to the bottom end of the lead screw 3 through a gear set 13.

[0046] The axial pulling loading mechanism includes a pulling cylinder base 6, a hollow cylinder pressure head 7, a pulling nut 8, and a pull rod 5. The pulling cylinder base 6 is located on the upper side of the movable crossbeam 4 and is fixedly connected by bolts. The hollow cylinder pressure head 7 is located on the top of the pulling cylinder. The pull rod 5 passes through the hollow cylinder pressure head 7 and the pulling cylinder base 6 in sequence. The pull nut 8 is provided on the pull rod 5 and contacts the upper side of the hollow cylinder pressure head 7.

[0047] A cylindrical clamp 31 is provided at the lower end of the tie rod 5. A T-shaped opening is provided at the lower end of the cylindrical clamp 31. The T-shaped opening is used to connect the anchor body specimen.

[0048] The confining pressure loading mechanism includes a pressure chamber base 18, a top pressure chamber 21, a middle pressure chamber 20, a bottom pressure chamber 19, a pressure chamber cover 22, and a pad 24. The pressure chamber base 18 is located inside the frame. The bottom pressure chamber 19, the middle pressure chamber 20, and the top pressure chamber 21 are arranged sequentially on the upper side of the pressure chamber base 18. There are multiple middle pressure chambers 20, and the specific number can be determined according to the test length. The bottom pressure chamber 19, the middle pressure chamber 20, and the top pressure chamber 21 form a pressure chamber 100. The pad 24 is arranged inside the top pressure chamber 21, and the pressure chamber cover 22 that penetrates the pad 24 is arranged on the upper side of the top pressure chamber 21.

[0049] The top pressure chamber 21, the middle pressure chamber 20, and the bottom pressure chamber 19 are all hollow cylinders made of metal. The inner wall of the hollow cylinder is provided with a rubber layer 26, and an annular pressurized oil chamber 25 is provided between the rubber layer 26 and the hollow cylinder. The top pressure chamber 21, the middle pressure chamber 20, and the bottom pressure chamber 19 are connected sequentially from top to bottom by threads. The outer walls of the top pressure chamber 21, the middle pressure chamber 20, and the bottom pressure chamber 19 are provided with an inlet valve 28 and a drain valve 29 that connect to the pressurized oil chamber 25.

[0050] The data measurement system includes a load sensor 9, a displacement sensor 17, a data acquisition unit, and a data analyzer. The load sensor 9 is a spoke-type sensor and is fixed to the lower surface of the moving crossbeam 4. The bottom end of the tie rod 5 passes through the load sensor, and the lower surface of the load sensor 9 contacts the top of the pad 24. The displacement sensor 17 is installed on the moving crossbeam 4 to monitor the displacement of the anchor rod 23. Both the displacement sensor and the load sensor 9 are connected to the data acquisition unit. After collecting the monitoring data, the data acquisition unit transmits it to the data analyzer. The data analyzer outputs the load and displacement during the pull-out process.

[0051] The test method for the above-mentioned anchor pull-out test device for implementing graded confining pressure loading includes the following steps:

[0052] A. Fabrication of anchor solid specimens

[0053] Based on the rock mechanical properties at the coal mine roadway site, a rock sample 30 is prepared. An anchoring hole is drilled in the center of the rock sample 30 and the hole is cleaned. Then, the anchor rod 23 is placed in the anchoring hole and the anchoring agent is put in to obtain the anchor body specimen. The size of the anchor body specimen is determined according to the size of the confining pressure loading mechanism.

[0054] B. Installation of pressure chamber and anchored solid specimen

[0055] Start the lifting motor 12 and move the moving beam 4 upward to reserve the position of the pressure chamber 100. Install the pressure chamber base 18, bottom pressure chamber 19, middle pressure chamber 20, top pressure chamber 21, anchor solid specimen, pad 24 and pressure chamber cover 22 in sequence in the frame. Adjust the position of the moving beam 4 and fix the anchor rod 23 in the T-shaped opening in the column clamp 31. Fix the anchor rod 23 to the T-shaped opening by installing the washer 32 and clamping nut 27 at the top of the anchor rod 23. At the same time, adjust the position of the pull-out nut 8 so that it is close to the hollow oil cylinder pressure head 7.

[0056] C. Pressurize the pressure chamber to simulate the stress state of the rock mass.

[0057] The inlet valve 28 and outlet valve 29 in the pressure chamber 100 are connected to the oil pump in sequence. Then, the oil pump is controlled by the servo controller to pressurize the pressure chamber 100 to the preset value. By applying different pressures to the top pressure chamber 21, the middle pressure chamber 20 and the bottom pressure chamber 19, the graded confining pressure loading is achieved, and the real stress environment of the anchor body is restored.

[0058] D. Conduct a pull-out test and record the test data.

[0059] After the confining pressure stabilizes, oil is introduced into the base of the pull-out cylinder. Force is applied to the pull rod through the hollow cylinder pressure head and the pull-out nut, thereby applying a static load to the anchor body specimen to simulate the pull-out load effect on the surrounding rock in the deep roadway. Then, the experimental data measured by the load sensor and displacement sensor are recorded and saved.

[0060] E. Disassembly of the test apparatus

[0061] First, release the residual stress of tie rod 5 and anchor rod 23. Then, control the oil pump through the servo controller to unload the confining pressure, open the drain valve 29 to drain oil and relieve pressure, raise the moving crossbeam 4, and remove the pressure chamber cover 22, pad 24, anchor body specimen, top pressure chamber 21, middle pressure chamber 20, bottom pressure chamber 19 and pressure chamber base 18 in sequence.

[0062] Example 2:

[0063] An anchor pull-out test device for implementing graded confining pressure loading has the structure described in Example 1, except that the pad 24 includes a circular plate and an arc-shaped outer wall. A through hole is provided in the center of the circular plate for the anchor to pass through. The arc-shaped outer wall is symmetrically arranged on the circular plate. The circular plate is placed in the top pressure chamber, and the arc-shaped outer wall passes through the pressure chamber cover.

[0064] Example 3:

[0065] An anchor pull-out test device for graded confining pressure loading is structured as described in Example 1, except that an L-shaped limit stop pin 10 connected to a limit switch is provided on the moving crossbeam 4, and limit components 11 are respectively provided on the upper and lower parts of one side of the outer frame 2. The limit stop pin moves up and down with the moving crossbeam. When the limit stop pin moves to the upper and lower limit positions with the moving crossbeam, it touches the limit component, and the limit stop pin presses down the limit switch, cutting off the lifting motor circuit, thereby achieving the function of limiting and preventing excessive displacement from damaging the device.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention shall be within the scope of protection of the pending claims of the present invention.

Claims

1. An anchor rod pull-out test device that enables hierarchical confining pressure loading, characterized by, The rack, the lifting system, the loading system and the data measurement system are included, wherein, The lifting system is arranged in the rack, the loading system includes a confining pressure loading mechanism and an axial pulling loading mechanism, the confining pressure loading mechanism is fixed to the bottom of the rack, the axial pulling loading mechanism is arranged above the confining pressure loading mechanism, the axial pulling loading mechanism is connected to the lifting system, and the axial pulling loading mechanism is connected with the data measurement system. The confining pressure loading mechanism includes a pressure chamber base, a top layer pressure chamber, a middle layer pressure chamber, a bottom layer pressure chamber, a pressure chamber cover and a pad plate, the pressure chamber base is arranged in the rack, the bottom layer pressure chamber, the middle layer pressure chamber and the top layer pressure chamber are sequentially arranged on the upper side of the pressure chamber base, the middle layer pressure chamber is provided with a plurality of layers, the bottom layer pressure chamber, the middle layer pressure chamber and the top layer pressure chamber form a pressure chamber, the pad plate is arranged in the top layer pressure chamber, and the pressure chamber cover is arranged on the upper side of the top layer pressure chamber and penetrates the pad plate. The top layer pressure chamber, the middle layer pressure chamber and the bottom layer pressure chamber are all hollow cylinders, the hollow cylinders are metal pieces, a rubber layer is arranged on the inner wall of the hollow cylinder, an annular pressurized oil cavity is arranged between the rubber layer and the hollow cylinder, the top layer pressure chamber, the middle layer pressure chamber and the bottom layer pressure chamber are sequentially connected by threads from top to bottom, and the outer wall of the top layer pressure chamber, the middle layer pressure chamber and the bottom layer pressure chamber is provided with a liquid inlet valve and a liquid outlet valve which communicate with the pressurized oil cavity.

2. The apparatus for performing a jacked-in-place anchor pullout test that achieves a confining pressure loading according to claim 1, wherein, The rack includes a base and an outer frame, the rectangular outer frame is arranged on the base, the lifting system is arranged in the rectangular outer frame, the base guard plate is arranged on one side of the base, and the outer frame baffle is arranged on one side of the outer frame.

3. The apparatus for performing a jacked-in-place anchor pullout test that achieves a confining pressure loading according to claim 1, wherein, The lifting system includes lead screws, bearing seats, a moving cross beam and a lifting motor, two lead screws are respectively arranged on the two sides of the rack, the moving cross beam is arranged between the two lead screws, the bearing seats are arranged on the top ends of the lead screws after penetrating the rack, the rolling bearings are arranged in the bearing seats, the lifting motor is arranged on the bottom of the rack, and the bottom end of the lead screw is connected with the lifting motor through a gear set.

4. The apparatus for performing a jacked-in-place anchor pullout test that achieves a confining pressure loading according to claim 3, wherein, The axial pulling loading mechanism includes a pulling oil cylinder base, a hollow oil cylinder pressurized head, a pulling nut and a pull rod, the pulling oil cylinder base is arranged on the upper side of the moving cross beam and fixedly connected through bolts, the hollow oil cylinder pressurized head is arranged on the top of the pulling oil cylinder, the pull rod penetrates the hollow oil cylinder pressurized head and the pulling oil cylinder base in sequence, the pulling nut is arranged on the pull rod and in contact with the upper side of the hollow oil cylinder pressurized head.

5. The apparatus for performing a jacked-in-place anchor pullout test that achieves a confining pressure loading according to claim 4, wherein, The lower end of the pull rod is provided with a cylindrical clamp, and the lower end of the cylindrical clamp is provided with a T-shaped opening.

6. The apparatus for performing a jacked-in-place anchor pullout test that achieves a confining pressure loading according to claim 5, wherein, The pad plate includes a circular plate and a circular arc outer wall, a through hole is arranged in the center of the circular plate, the circular arc outer wall is symmetrically arranged on the circular plate, the circular plate is arranged in the top layer pressure chamber, and the circular arc outer wall penetrates the pressure chamber cover.

7. The apparatus for performing a jacked-in-place anchor pullout test that achieves a confining pressure loading according to claim 6, wherein, The data measurement system includes a load sensor, a displacement sensor, a data acquisition instrument and a data analyzer, the load sensor is fixed to the lower surface of the moving cross beam, the bottom end of the pull rod penetrates the load sensor, the lower surface of the load sensor is in contact with the top of the pad plate, the displacement sensor is arranged on the moving cross beam, the load sensor and the displacement sensor are both connected with the data acquisition instrument, the data acquisition instrument collects monitoring data and transmits the monitoring data to the data analyzer, and the data analyzer outputs the load and displacement in the simulation pulling process.

8. The apparatus for performing a jacked-in-place anchor pullout test that achieves a confining pressure loading according to claim 7, wherein, An L-shaped limiting stop pin connected with a limiting switch is arranged on the moving cross beam, and a limiting piece is arranged on the upper part and the lower part of one side of the outer frame.

9. A test method for a device for performing a test for a pull-out of an anchor rod, which implements a hierarchical confining pressure loading according to claim 8, characterized by, The steps are as follows: A. Preparation of anchoring body test piece According to the rock mechanics performance of the coal mine roadway site, a rock sample is prepared, an anchoring drill hole is drilled in the center of the rock sample, and the hole is cleaned, then the anchor rod is placed in the anchoring drill hole, and the anchoring agent is placed, to obtain an anchoring body test piece, the size of the anchoring body test piece is determined according to the size of the confining pressure loading mechanism; B. Pressure chamber and anchoring body test piece installation Start the lifting motor and move the moving cross beam upwards to reserve the pressure chamber position, install the pressure chamber base, bottom layer pressure chamber, middle layer pressure chamber, top layer pressure chamber, anchoring body test piece, pad and pressure chamber cover in the rack in turn, adjust the position of the moving cross beam, fix the anchor rod in the T-shaped opening in the cylindrical clamp, and adjust the position of the pulling nut to make it tightly adhere to the hollow oil cylinder pressure head; C. Pressurize the pressure chamber to simulate the stress state of the rock mass Connect the liquid inlet valve and the liquid outlet valve in the pressure chamber to the oil pump in turn, then control the oil pump through the servo controller to pressurize the pressure chamber to the preset value, apply different pressures to the top layer pressure chamber, middle layer pressure chamber and bottom layer pressure chamber to realize graded confining pressure loading, and restore the real stress environment of the anchoring body; D. Perform pull-out test and record test data After the confining pressure tends to be stable, oil is fed into the pulling oil cylinder base, force is applied to the pull rod through the hollow oil cylinder pressure head and the pulling nut, and then static load is applied to the anchoring body test piece to simulate the pull-out load of the surrounding rock in deep roadway, then the experimental data measured by the load sensor and displacement sensor are recorded and saved; E. Disassemble the test device First, release the residual stress of the pull rod and anchor rod, then control the oil pump through the servo controller to unload the confining pressure, open the oil outlet valve to release the pressure, raise the moving cross beam, and then remove the pressure chamber cover, pad, anchoring body test piece, top layer pressure chamber, middle layer pressure chamber, bottom layer pressure chamber and pressure chamber base in turn.

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