Rock dynamic impact test system and test method

Abstract

The present invention discloses a rock dynamic impact test system in the field of underground rock engineering mechanics, including a detection platform, a control system and a plurality of impact components arranged around the detection platform, wherein the impact components include an inflatable device, a high-pressure steel pipe, an impact bullet and an incident rod, wherein the high-pressure steel pipe is fixedly installed by a telescopic rotating bracket, the inlet end of the high-pressure steel pipe is connected to the inflatable device through a high-pressure hose, and a solenoid valve is provided at a position near the inlet end of the high-pressure steel pipe, and the outlet end is slidably connected with the incident rod, and the impact bullet can be slidably installed between the inlet end and the solenoid valve in the high-pressure steel pipe, and the control system is electrically connected to the inflatable device and the solenoid valve, and can control the start and stop thereof according to the timing. The test system can simulate the dynamic mechanical characteristics of rocks in high-stress areas under different impact directions, impact angles and impact timing combinations, which is conducive to analyzing the dynamic mechanical properties of rocks under complex stress paths.

Description

Technical Field

[0001] The invention relates to the field of underground rock engineering mechanics, and in particular to a rock dynamic impact test system and a test method. Background Art

[0002] As underground projects continue to move deeper into complex areas, the instability of surrounding rocks caused by high geostress phenomena is becoming more frequent, especially for large underground caverns. Geological disasters such as rock bursts and rock bursts are closely related to high geostress. The deformation and failure characteristics of rocks under dynamic impact have become the focus of engineering attention, and have important guiding significance for guiding the excavation and support of subsequent caverns. In the past, when studying the dynamic mechanical properties of rocks, test devices such as drop hammers and unidirectional Hopkinson bars were mostly used to carry out related research, mainly focusing on the dynamic impact of rocks in a single direction. However, in actual engineering, rocks are mostly in a three-dimensional stress state. Therefore, under a more complex state of geostress, rocks may be subjected to impact loads from different directions, including a single impact from only one direction, or a combined impact from multiple directions.

[0003] In addition, the time when the rock is subjected to impact will change dynamically with the stress adjustment. The limitation of previous experiments is mainly reflected in the lack of a complete set of equipment that can be used to simulate the rock subjected to multi-directional combined impact and different impact timings.

[0004] During the excavation of underground caverns, the directions of the three-dimensional stresses will not always be fixed. Therefore, in different areas where rockbursts or rock bursts may occur, the direction of the impact load on the rock may present different angles with the horizontal line, that is, eccentric impact may occur. The previous related test equipment mainly focused on the impact load on rock specimens in the horizontal direction, and eccentric impact research was rarely carried out. For the surrounding rock of caverns in high-ground stress areas, the dynamic mechanical properties of rocks are an important basis for optimizing design measures and improving construction processes. Therefore, it is particularly important to study the dynamic mechanical properties of rocks in high-ground stress areas under different impact directions, impact angles and impact sequence combinations, but there are currently no relevant test devices and methods. Summary of the invention

[0005] In order to overcome the above-mentioned deficiencies of the existing rock impact test, the technical problem to be solved by the present invention is to provide a rock dynamic impact test system and test method which can simulate underground surrounding rocks being subjected to different directions, angles and time sequences.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] The rock dynamic impact test system comprises a detection platform, a control system and a plurality of impact components arranged around the detection platform, wherein the impact components comprise an inflatable device, a high-pressure steel pipe, an impact bullet and an incident rod, wherein the high-pressure steel pipe is fixedly installed by a telescopic rotating bracket so that its direction and angle relative to the detection platform are adjustable, the inlet end of the high-pressure steel pipe is connected to the inflatable device through a high-pressure hose, and a solenoid valve is provided at a position near the inlet end of the high-pressure steel pipe, and the outlet end is slidably connected with the incident rod, the impact bullet can be slidably installed between the inlet end of the high-pressure steel pipe and the solenoid valve, the control system is electrically connected to the inflatable device and the solenoid valve, and can control their start and stop according to a timing sequence.

[0008] Furthermore, the impact components include four components, which are respectively arranged in the front, back, left and right directions of the detection platform, and the impact points are respectively aimed at the central areas of the four surfaces of the rock specimen located on the detection platform.

[0009] Furthermore, the inflation device is a nitrogen cylinder, a control valve is provided at the connection between the high-pressure hose and the nitrogen cylinder, and an exhaust valve and a pressure gauge are provided at the inlet end of the high-pressure steel pipe.

[0010] Furthermore, the control valve, the exhaust valve and the pressure gauge are electrically connected to the control system.

[0011] Furthermore, a fixed boss is provided on the inner wall between the inlet end of the high-pressure steel pipe and the solenoid valve, and the impact bullet is placed on the fixed boss.

[0012] Furthermore, the detection platform includes a fixed platform, a dynamic resistance meter and a transmission rod. The transmission rod includes multiple rods, which are arranged around the fixed platform. The outer ends of the transmission rods are fixedly connected to the fixed platform, and the inner ends are abutted against the surface of the rock specimen placed on the fixed platform. The transmission rod is provided with a transmission rod strain gauge, and the incident rod is provided with an incident rod strain gauge. The transmission rod strain gauge and the incident rod strain gauge are electrically connected to the dynamic resistance meter through wires respectively.

[0013] Furthermore, the outer end of the transmission rod is threadedly connected to the fixing platform via a bolt.

[0014] Furthermore, at least two transmission rods are provided on one surface of the rock specimen and are arranged at intervals.

[0015] Furthermore, a support frame is provided on the top of the fixed platform, and a high-speed camera is provided on the support frame.

[0016] The method for conducting rock testing using the rock dynamic impact test system comprises the following steps:

[0017] a. Obtain rock specimens that require mechanical testing and process them into appropriate sizes according to the requirements of the testing platform;

[0018] b. Place the rock specimen on a fixed platform and install the transmission rod around it so that the inner end of the transmission rod contacts the surface of the rock specimen;

[0019] c. Arrange the impact assembly according to the test requirements, and adjust the direction and angle of the impact assembly so that the inner end of the incident rod contacts the surface of the rock specimen and a part of the outer end is located in the high-pressure steel pipe to ensure that the incident rod is stable;

[0020] d. Set the incident rod strain gauge and the transmission rod strain gauge on the incident rod and the transmission rod respectively, and connect them to the dynamic resistance meter with wires;

[0021] e. Use the control system to set the impact force and impact interval of the impact component, then start the equipment to impact the rock specimen, and finally collect the test data to analyze the dynamic mechanical properties of the rock.

[0022] The beneficial effects of the present invention are as follows: by arranging a plurality of impact components around the detection platform as the power source for the dynamic impact of the rock, multi-directional impact is achieved, and multi-angle impact can be achieved by adjusting the angle of the high-pressure steel pipe. At the same time, by controlling the impact sequence of each impact component, multi-time sequence impact can be achieved, thereby more accurately simulating the dynamic mechanical characteristics of the rock in the high ground stress zone under different impact directions, impact angles and impact sequence combinations, which is conducive to analyzing the dynamic mechanical properties of the rock under complex stress paths. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the test system of the present invention.

[0024] Marked in the figure are, 1-detection platform, 2-control system, 3-impact assembly, 4-rock specimen, 5-telescopic rotating bracket, 6-solenoid valve, 10-transmission rod strain gauge, 11-fixed platform, 12-dynamic resistor, 13-transmission rod, 14-wire, 15-bolt, 16-support frame, 17-high-speed camera, 30-incident rod strain gauge, 31-inflating equipment, 32-high-pressure steel pipe, 33-impact bullet block, 34-incident rod, 35-high-pressure hose, 36-control valve, 37-exhaust valve, 38-pressure gauge, 39-fixed boss. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings.

[0026] like Figure 1As shown, the rock dynamic impact test system of the present invention includes a detection platform 1, a control system 2 and a plurality of impact components 3 arranged around the detection platform 1, the impact component 3 includes an inflation device 31, a high-pressure steel pipe 32, an impact bullet 33 and an incident rod 34, the high-pressure steel pipe 32 is fixedly installed by a telescopic rotating bracket 5, so that its direction and angle relative to the detection platform 1 are adjustable, the inlet end of the high-pressure steel pipe 32 is connected to the inflation device 31 through a high-pressure hose 35, and a solenoid valve 6 is provided at a position near the inlet end of the high-pressure steel pipe 32, and the outlet end is slidably connected with the incident rod 34, the impact bullet 33 can be slidably installed between the inlet end of the high-pressure steel pipe 32 and the solenoid valve 6, the control system 2 is electrically connected to the inflation device 31 and the solenoid valve 6, and can control their start and stop according to a timing sequence.

[0027] Compared with the existing rock detection system, the main improvement of the present invention is that multiple impact components 3 are added, and the angle of the high-pressure steel pipe 32 can be changed by adjusting the telescopic rotating bracket 5, so as to realize impact tests at different angles. The impact process of the impact component 3 is: first, the solenoid valve 6 is closed, the impact bullet 33 is put in from the inlet end of the high-pressure steel pipe 32, and the high-pressure hose 35 is connected, and then the high-pressure steel pipe 32 is inflated by the inflation device 31, and the impact bullet 33 is pushed on the solenoid valve 6 by the gas. After the pressure reaches the set requirement, the solenoid valve 6 is opened, and the high-pressure gas ejects the impact bullet 33 and hits the incident rod 34. The incident rod 34 then transmits the force to the rock specimen 4 on the detection platform 1, realizing the impact effect on the rock specimen 4.

[0028] Considering the test requirements and the limitation of the arrangement structure, the impact components 3 preferably include four, which are respectively arranged in the four directions of the front, back, left, and right of the detection platform 1, and the corresponding rock specimen 4 is preferably arranged in a cubic shape, so that the impact point of the impact component 3 is respectively aligned with the central area of ​​the four faces of the rock specimen 4, so as to improve the accuracy of the test. The impact in four directions can basically simulate the impact condition of the rock mass in actual conditions.

[0029] For the inflating device 31 of the impact assembly 3, a high-pressure air pump which is relatively common on the market can be used, which can adjust the air pressure. However, it is generally used for continuous punching operations, and a single rock impact test generally only needs one impact. Therefore, in order to simplify the structure and reduce costs, the inflating device 31 can use a nitrogen bottle, and a control valve 36 is provided at the connection between the high-pressure hose 35 and the nitrogen bottle, and an exhaust valve 37 and a pressure gauge 38 are provided at the inlet end of the high-pressure steel pipe 32. The process of using a nitrogen bottle for impact is: first, the solenoid valve 6 is closed, the impact bullet 33 is put in from the inlet end of the high-pressure steel pipe 32, and the high-pressure hose 35 is connected, and then the control valve 36 is opened, the exhaust valve 37 is closed, and the high-pressure steel pipe 32 is inflated. After the pressure gauge 38 shows that the pressure value reaches the set value, the control valve 36 is closed, and finally the solenoid valve 6 is opened to realize the ejection of the impact bullet 33. After the impact is completed, the exhaust valve 37 is opened to discharge the remaining gas to facilitate subsequent tests.

[0030] Furthermore, in order to realize automatic control, the control valve 36, the exhaust valve 37 and the pressure gauge 38 are all electrically connected to the control system 2. The control system 2 also controls the control valve 36 and the exhaust valve 37 according to the above process.

[0031] For the impact bullet 33, in order to avoid being blocked by the electromagnetic valve 6 and the friction resistance with the high-pressure steel pipe 32 during the impact process, thereby reducing the impact force, a fixed boss 39 is provided on the inner wall between the inlet end of the high-pressure steel pipe 32 and the electromagnetic valve 6, and the impact bullet 33 is placed on the fixed boss 39. The provision of the fixed boss can make the size of the impact bullet smaller than the size of the high-pressure steel pipe, and ensure that the impact bullet 33 is located at the center of the high-pressure steel pipe 32, and will not contact the edge of the high-pressure steel pipe 32 and the electromagnetic valve 6 during the ejection process, thereby ensuring the accuracy of the impact force.

[0032] For the detection platform 1, the solution provided by the present application is that the detection platform 1 includes a fixed platform 11, a dynamic resistor 12 and a transmission rod 13. The transmission rod 13 includes a plurality of rods, which are arranged around the fixed platform 11, and the outer ends thereof are fixedly connected to the fixed platform 11, and the inner ends thereof are abutted against the surface of the rock specimen 4 placed on the fixed platform 11. The transmission rod 13 is provided with a transmission rod strain gauge 10, and the incident rod 34 is also provided with an incident rod strain gauge 30. The transmission rod strain gauge 10 and the incident rod strain gauge 30 are respectively electrically connected to the dynamic resistor 12 through a wire 14. When arranging the transmission rod 13, its axial direction should be parallel to the corresponding impact direction, so that it can stably receive and sense the impact load.

[0033] Since the transmission rod 13 is also used as a fixing member of the rock specimen 4, in order to facilitate the transmission rod 14 to fix the rock specimen 4, the outer end of the transmission rod 14 is threadedly connected to the fixing platform 11 through a bolt 15. By rotating the bolt 15, the length of the transmission rod 13 can be adjusted, thereby ensuring that the inner end of the transmission rod 13 can stably contact the rock specimen 4, and the function of the transmission rod 13 itself can be achieved while fixing the rock specimen 4.

[0034] In order to improve the accuracy of the test, at least two transmission rods 13 are installed on one surface of the rock specimen 4 and arranged at intervals, which is conducive to force balance and improves the detection accuracy.

[0035] In addition, in order to facilitate observation of the deformation and crushing of the rock specimen during the test, a support frame 16 is provided on the top of the fixed platform 11 , and a high-speed camera 17 is provided on the support frame 16 .

[0036] The method for conducting rock testing using the rock dynamic impact test system comprises the following steps:

[0037] a. Obtain the rock specimen 4 that needs to be subjected to mechanical testing, and process it into an appropriate size according to the requirements of the testing platform;

[0038] b. Place the rock specimen 4 on the fixed platform 11 and install the transmission rod 13 around it so that the inner end of the transmission rod 13 contacts the surface of the rock specimen 4;

[0039] c. Arrange the impact assembly 3 according to the detection requirements, and adjust the direction and angle of the impact assembly 3 so that the inner end of the incident rod 34 contacts the surface of the rock specimen 4, and a part of the outer end is located in the high-pressure steel pipe 32, and the incident rod 34 is ensured to be stable;

[0040] d. Install the incident rod strain gauge 30 and the transmission rod strain gauge 10 on the incident rod 34 and the transmission rod 13 respectively, and connect them to the dynamic resistance meter 12 through the wire 14;

[0041] e. Use the control system 2 to set the impact force and impact interval of the impact component 3, then start the equipment to impact the rock specimen 4, and finally collect the test data to analyze the dynamic mechanical properties of the rock.

[0042] Compared with traditional rock mass tests, this test method can simulate the dynamic impact of underground surrounding rocks in different directions, angles and time sequences. It can provide a more complete way to study the dynamic characteristics of rocks in deep high-stress areas, breaking through the limitations of previous unidirectional or one-dimensional impacts. It has the advantages of easy operation and variable combination forms, and is more conducive to studying the dynamic mechanical properties of rocks under complex stress paths.

Claims

1. Rock dynamic impact test system, characterized by: The invention comprises a detection platform (1), a control system (2) and a plurality of impact assemblies (3) arranged around the detection platform (1), wherein the impact assemblies (3) comprise an inflatable device (31), a high-pressure steel pipe (32), an impact bullet (33) and an incident rod (34), wherein the high-pressure steel pipe (32) is fixedly installed by a telescopic rotating bracket (5) so that its direction and angle relative to the detection platform (1) are adjustable, the inlet end of the high-pressure steel pipe (32) is connected to the inflatable device (31) by a high-pressure hose (35), and a solenoid valve (6) is provided at a position near the inlet end of the high-pressure steel pipe (32), and the outlet end is slidably connected to the incident rod (34), the impact bullet (33) can be slidably installed between the inlet end of the high-pressure steel pipe (32) and the solenoid valve (6), the control system (2) is electrically connected to the inflatable device (31) and the solenoid valve (6), and can be adjusted according to the control system (2). The start and stop of the rock test piece (4) are controlled by timing; the impact components (3) include four components, which are respectively arranged in the four directions of front, back, left, right and left of the detection platform (1), and the impact points are respectively aligned with the central areas of the four surfaces of the rock test piece (4) located on the detection platform (1); the detection platform (1) includes a fixed platform (11), a dynamic resistance meter (12) and a transmission rod (13); the transmission rod (13) includes a plurality of components, which are arranged around the fixed platform (11), the outer ends of which are fixedly connected to the fixed platform (11), and the inner ends of which are abutted against the surface of the rock test piece (4) placed on the fixed platform (11); the transmission rod strain gauge (10) is provided on the transmission rod (13), and the incident rod strain gauge (30) is provided on the incident rod (34); the transmission rod strain gauge (10) and the incident rod strain gauge (30) are respectively electrically connected to the dynamic resistance meter (12) through a wire (14).

2. The rock dynamic impact test system according to claim 1, characterized in that: The inflation device (31) is a nitrogen bottle, a control valve (36) is provided at the connection between the high-pressure hose (35) and the nitrogen bottle, and an exhaust valve (37) and a pressure gauge (38) are provided at the inlet end of the high-pressure steel pipe (32).

3. The rock dynamic impact test system according to claim 2, characterized in that: The control valve (36), the exhaust valve (37) and the pressure gauge (38) are electrically connected to the control system (2).

4. The rock dynamic impact test system according to claim 1, characterized in that: A fixed boss (39) is provided on the inner wall between the inlet end of the high-pressure steel pipe (32) and the electromagnetic valve (6), and the impact bullet (33) is placed on the fixed boss (39).

5. The rock dynamic impact test system according to claim 1, characterized in that: The outer end of the transmission rod (13) is threadedly connected to the fixed platform (11) via a bolt (15).

6. The rock dynamic impact test system according to claim 1, characterized in that: At least two transmission rods (13) are provided on one surface of the rock mass specimen (4) and are arranged at intervals.

7. The rock dynamic impact test system according to claim 1, characterized in that: A support frame (16) is also provided on the top of the fixed platform (11), and a high-speed camera (17) is provided on the support frame (16).

8. The test method of the rock dynamic impact test system according to claim 1 is characterized by: The following steps are involved: a. Obtain rock specimens that require mechanical testing and process them into appropriate sizes according to the requirements of the testing platform; b. placing the rock specimen (4) on a fixed platform (11), and installing a transmission rod (13) around the fixed platform so that the inner end of the transmission rod (13) is in contact with the surface of the rock specimen (4); c. Arrange the impact assembly (3) according to the detection requirements, and adjust the direction and angle of the impact assembly (3) so that the inner end of the incident rod (34) contacts the surface of the rock specimen (4) and a part of the outer end is located in the high-pressure steel pipe (32), and the incident rod (34) is ensured to be stable; d. Arrange the incident rod strain gauge (30) and the transmission rod strain gauge (10) on the incident rod (34) and the transmission rod (13) respectively, and connect them to the dynamic resistance meter (12) through the wire (14); e. Using the control system (2), the impact force and impact interval of the impact assembly (3) are set, and then the equipment is started to impact the rock specimen (4). Finally, the test data is collected to analyze the dynamic mechanical properties of the rock.

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