JP6804121B2 - Support strength test equipment and strength determination method for rocks around a certain (mine) tunnel - Google Patents

Description

The present invention relates to a technical field of rock support around a tunnel.

China's coal mines are mainly underground mining, and many tunnels need to be dug underground. The use of mine support to keep the mine in good condition and to maintain the stability of the surrounding rocks is very important for the construction and production of the coal mining industry. The mine support works reduce the movement of surrounding rocks and prevent the cross section of the mine from becoming too small, preventing the surrounding rocks and other scattered rocks from falling. The effect of mine support is determined not only by the nature of the support itself, but also by a series of factors such as the nature of the surrounding rocks and the method of contact between the support and the surrounding rocks.

The design of "support strength" is an important parameter in the design of the tunnel support, and it is important to fully demonstrate the superiority of the tunnel support method and ensure the safety of the tunnel. If the support strength is too high, the support material will be wasted, the cost will increase, and the progress of excavation will be affected. If the supporting strength is not sufficient, the deformation of the surrounding rocks cannot be effectively controlled, and disasters such as the collapse of the side wall of the tunnel and the collapse of the crown may occur. Choosing the right bearing strength can effectively control the deformation of the surrounding rocks while maintaining the integrity of the rocks around the tunnel, avoiding loosening of the surrounding rocks and damage to the support due to impact fracture.

Currently, engineering analogy and theoretical calculation methods are mainly used to determine the bearing strength of the tunnel. The engineering analogy is based on the existing tunnel and is a method of proposing support strength parameters for new construction through analogy. However, since this method mainly depends on the successful experience of the existing design, the actual situation of the tunnel is different, and it can be seen that the support strength obtained by this method is not optimal. The theoretical calculation method is based on several support theories such as suspension theory, synthetic beam theory, and enhanced arch theory, and the support parameters are calculated to determine the support strength. In many cases, theoretically calculated design results are used as a reference only, as existing support theories have many limitations and specific conditions of use that make it difficult to accurately and reliably determine the required parameters. ..

The rocks around the mine are frequently damaged and anxious during their service period, especially in a complex (dynamic-static) complex stress environment, as the dynamic load caused by rock rupture and fault collapse in deep coal mines increases significantly. It causes qualitativeness and is difficult to support and control. Currently, no suitable theory has been established for calculating bearing strength. Engineering analogies always provide excess support, and there is no way to obtain the supporting strength of surrounding rocks in a (dynamic-static) complex stress environment. Therefore, it is considered necessary to break through the existing technology.

The present invention mainly provides a high-precision support strength test device for rocks around a tunnel by improving operability by solving technical problems existing in the prior art.

The present invention simultaneously provides the presented test apparatus and support strength determination method.

The above technical problems of the present invention are mainly solved by the following technical methods:

The rock bearing strength test device around the tunnel provided by the present invention includes the following parts:

A load-bearing frame unit consisting of a base, vertical columns, and a beam. The presented columns are placed vertically on both sides of the top surface of the base and the beam is fixed horizontally on top of the columns;

The axial pressure loader is fixed in the center of the top surface of the base and is used to apply bottom-up axial pressure to the specimen;

The impact loader is fixed to the beam and is used to apply a top-down axial impact load to the specimen;

A confinement pressure loader is provided between the axial pressure loader and the impact loader, and there are also lateral and longitudinal confinement pressure loaders, which are used to apply confinement pressure to the specimen in a horizontal plane;

The load control unit controls and loads the presented axial pressure load device, impact load device and confinement pressure load device.

The monitoring unit monitors the status of receiving the force of the presented specimen during the loading process;

The data analysis unit is connected to the load control unit and receives and analyzes the data from the monitoring unit.

The presented axial pressure load unit then includes an axial pressure load oil cylinder, an axial pressure load oil tank, and a downward push head. Here, the axial pressure load cylinder is fixed to the presented base, the axial pressure load oil tank is connected to the axial pressure load oil cylinder, one end of the downward push head is connected to the axial pressure load oil cylinder, The other end extends vertically into the confinement pressure loading device and is in contact with the underside of the specimen.

The presented axial pressure load oil cylinders then include an axial pressure load oil cylinder body, an axial pressure load piston, and an axial pressure load piston rod. There is an oil cavity inside the axial pressure load oil cylinder body, and the axial pressure load piston is slidably connected to the axial pressure load oil cylinder body. One end of the axial pressure load piston rod extends into the oil cavity via the axial pressure load piston. The other end of the axial pressure load piston rod is connected to one end of the downward push head, and one end of the axial pressure load piston rod is curved.

Next, the presented impact load device includes an impact load oil cylinder, an impact load oil tank, a push pressure head and a column that receives pressure. The impact load oil cylinder is fixedly connected to the beam and the impact load oil cylinder is connected to the impact load oil tank. One end of the pressure-bearing column is connected to the piston rod of the impact load oil cylinder, the other end is connected to the top of the above-presented upward pressure head, and the bottom of the upward pressure head is on the top surface of the specimen. Are in contact.

Next, the presented confinement pressure load device is a pressure chamber (small hollow part), two confinement pressure load oil cylinders, a confinement pressure load oil tank, and two first side pressure heads and two second side pressure heads. Is equipped with. The specimen is placed in a pressure chamber and the confinement pressure load oil tank is connected to two confinement pressure load cylinders. The piston rod of the confined pressure load oil cylinder is connected to the first side pressure head, and the two first side pressure heads are located outside the adjacent sides of the pressure chamber, respectively. It then extends horizontally into the pressure chamber and then contacts the two adjacent sidewalls of the specimen. Grooves are provided in each of the two side walls on the opposite side of the first side pressure head in the pressure chamber, the second side pressure head is installed in the two grooves, and the two second side pressure heads are tested. In contact with the other two adjacent sidewalls of the body

The presented monitoring unit then includes a pressure sensor and signal collector connected to each other. This pressure sensor is placed between the pressure receiving column and the upward push head, respectively, and the signal collector is connected to the data analysis unit between the second side pressure head and the test piece.

The method for testing the supporting strength of rocks around a tunnel provided by the present invention has the following steps:

Step 1: The static stress state of the rock around the tunnel has been measured using the stress relaxation method.

Step 2: Obtain dynamic load characteristics near rocks around the tunnel using a micro-vibration system and reversely estimate the strength and frequency of impact loads from the test.

Step 3: Make a standard test piece from the rock around the tunnel.

Step 4: Load test

Step 4.1: Place the test piece on the test piece, adjust the position of each pressure head of the tester, and apply a constant pressure to the test piece first.

Step 4.2: Simulate the tunnel confinement pressure using a lateral confinement pressure loading device according to the static stress state of the rock around the tunnel measured in step 1. After that, a fixed pressure in the X direction is applied to the test piece. The axial pressure loader applies continuously increasing Z-direction (ie, axial) pressure to the specimen, and the longitudinal confinement pressure loader applies Y-direction bearing capacity to the specimen, with a minimum bearing capacity of 0. Is set to.

Step 4.3: When the minimum bearing capacity is applied to the specimen, the impact load is applied to the specimen according to the strength and frequency of the impact load according to step 2, and the destruction status of the specimen is observed after the impact load is completed. To do.

Step 4.4: Replace the specimen and keep the pressure in the X direction and the pressure in the Z direction unchanged to increase the bearing capacity in the Y direction. Repeat steps 4.1-4.3 to load test the replaced specimen. Similarly, each time the specimen is replaced, the bearing capacity increases. Every time the bearing capacity increases, the fracture condition of the test piece is observed again after the load test. Search for a bearing capacity that does not destroy the test piece, and estimate the bearing capacity from this bearing capacity. The supporting strength here is the supporting strength required for rocks around the tunnel.

The positive effect of the present invention is to set various bearing strength values for the deformation fracture test of the rock, using the actual static load stress and dynamic load impact characteristics of the rock around the tunnel as the load stress. Consider both the effects of static load stress and dynamic load stress and the combined effects of the two. It can be well anastomosed with the actual stress state of the rock around the tunnel at the site, and the supporting strength obtained can maintain the safety and stability of the surrounding rock. Furthermore, high-precision, simple and convenient test operations can be performed more reliably.

In order to more clearly explain the actual construction example of the present invention or the technical solution in the prior art, the drawings used in the actual construction example or the description of the prior art will be briefly described below. Of course, this is a particular embodiment of the invention, and for those skilled in the art no creative labor, other drawings can be obtained by the following drawings.

Assembly structure diagram of the support strength test device for rocks around the tunnel of the present invention Structural drawing of the confinement pressure load device of the support strength test device for rocks around the tunnel of the present invention Structural drawing of the axial pressure load oil cylinder of the supporting strength test device for rocks around the tunnel of the present invention. Explanatory drawing of the magnitude and direction of the pressure applied to the specimen by the axial pressure load device

Excellent examples of the present invention will then be described in detail with reference to the accompanying drawings, and the advantages and features of the present invention may be more easily understood by those skilled in the art. Therefore, the scope of protection of the present invention is more clearly defined.

As shown in Fig. 1-3, in the support strength test device for rocks around the tunnel of the present invention:

The load-bearing frame unit 1 includes a base 11, a vertical column 12, and a beam 13. The presented columns 12 are placed vertically on both sides of the top surface of the base 11, and the beam 13 is fixed horizontally on top of the columns 12;

The axial pressure loading device 2 is fixed in the center position on the upper surface of the base 11 and is used to apply bottom-up axial pressure to the specimen 8.

The impact load device 3 is fixed to the beam 13 and is used to apply a top-down axial impact load to the specimen 8.

A confinement pressure loader 4 is provided between the axial pressure loader 2 and the impact loader 3, and the confinement pressure loader 4 is used to apply confinement pressure to the specimen in a horizontal plane;

The load control unit 5 controls and loads the presented axial pressure load device 2, impact load device 3, and confined pressure load device 4 in a misaligned manner;

Monitoring unit 6 monitors the situation under the force of specimen 8 during the loading process;

The data analysis unit 7 is connected to the load control unit 5 and is used to receive and analyze the data from the monitoring unit 6.

Specifically, the axial pressure load device 2 includes an axial pressure load oil cylinder 21, an axial pressure load oil tank 22, and a downward push head 23. The axial pressure load cylinder 21 is fixed to the base 11, the axial pressure load oil tank 22 is connected to the axial pressure load oil cylinder 21, and one end of the downward push head 23 is connected to the axial pressure load oil cylinder 21. The other end extends vertically into the confinement pressure loading device 4 and is in contact with the lower surface of the specimen 8. In the present invention, the downward push head 23 is moved upward by the drive from the axial pressure load cylinder 21, and the axial pressure can be applied to the test body 8.

In an embodiment of the present invention, the axial pressure load oil cylinder 21 includes an axial pressure load oil cylinder body 211, an axial pressure load piston 212, and an axial pressure load piston rod 213. There is an oil cavity 214 in the axial pressure load oil cylinder body 211, and the axial pressure load piston 212 is slidably connected to the axial pressure load oil cylinder body 211. One end of the axial pressure load piston rod 213 extends into the oil cavity 214 via the axial pressure load piston 212. The other end of the axial pressure load piston rod 213 is connected to one end of the downward push head 23, and one end of the axial pressure load piston rod 213 is a curved surface 215. In the present invention, one end of the axial pressure load piston rod 213 changes the uniform load applied to the test piece 8 by the curved surface 215 into a continuously increasing load. Therefore, we have simulated the actual force components of the test piece 8 in the field to make the research results more accurate.

In the embodiment of the present invention, the impact load device 3 includes an impact load oil cylinder 31, an impact load oil tank 32, a push pressure head 33, and a column 34 that receives pressure. The impact load oil cylinder 31 is fixedly connected to the beam 13, the impact load oil cylinder 31 is connected to the impact load oil tank 32, and one end of the pressure receiving column 34 is connected to the piston rod of the impact load oil cylinder 31. .. The other end is connected to the top of the previously presented push pressure head 33, and the bottom of the push pressure head 33 is in contact with the top surface of the specimen. In the present invention, an impact load can be applied to the test piece 8 by the impact load oil cylinder 31.

Looking at FIG. 2, the confinement pressure load device 4 has a pressure chamber 41 (small hollow part), a confinement pressure load oil tank 43, a lateral confinement pressure load oil cylinder 42a, a vertical confinement pressure load oil cylinder 42b, and a vertical first. The pressure head 44b, the second vertical pressure head 46b, and the test piece 8 are installed in the pressure chamber 41. The confinement pressure load oil tank 43 is connected to the lateral confinement pressure load cylinder 42a and the longitudinal confinement pressure load cylinder 42b, and the piston rod of the lateral confinement pressure load oil cylinder 42a is connected to the lateral first pressure head 44a. The piston rod of the longitudinal confined pressure load oil cylinder 42b is connected to the longitudinal first pressure head 44b. The lateral first pressure head 44a and the longitudinal first pressure head 44b are respectively arranged outside the adjacent side surfaces of the pressure chamber 41. The two pressure heads then extend horizontally into the pressure chamber 41 and contact the two adjacent side walls of the specimen 8. A first groove 45a and a second groove 45b are provided on two side walls on the opposite side of the first horizontal pressure head 44a and the first vertical pressure head 44b in the pressure chamber 41, respectively, and the first groove 45a is inside the first groove 45a. A lateral second pressure head 46a is attached. A longitudinal second pressure head 46b is mounted in the second groove 45b, and the two second pressure heads are in contact with the other two adjacent side walls of the specimen. In the present invention, the horizontal and vertical confinement pressures in the horizontal plane are generated by the cooperation of the horizontal first pressure head 44a and the horizontal second pressure head 46a, and the vertical first pressure head 44b and the vertical second pressure head 46b. It is added to the test body 8. Here, a better method is to provide fastening bolts on both sides of the lateral second pressure head 46a and the longitudinal second pressure head 46b, which can be fixed in the groove by the fastening bolts.

The monitoring unit 6 of the present invention includes a pressure sensor 62 and a signal collector 61 connected to each other. The pressure sensor 62 is arranged between the column 34 receiving the pressure and the upward pressure head 33, between the lateral second pressure head 46a and the test piece, and between the vertical second pressure head 46b and the test piece 8. , The signal collector 61 is connected to the data analysis unit 7. The signal collector 61 collects the correlation pressure data and sends it to the data analysis unit 7. The data analysis unit 7 analyzes these data.

As shown in Figure 1-3, the method of determining the supporting strength of rocks around the tunnel of the present invention has the following steps:

Step 1, measure the stress state of the surrounding rocks. The stress states here include static stress states and dynamic impact features. Specifically, the stress relaxation method is used to measure the static stress state of the rock around the tunnel, and the micro-vibration system is used to obtain the dynamic load characteristics near the rock around the tunnel. In this example, a hole is drilled in the tunnel in the working direction using a specialized rig, a micro-vibration probe is placed in the hole, a seismic wave pickup is connected, and a micro-vibration monitoring system is connected to form a complete monitoring network. To do. Using the micro-vibration monitoring system, the amount of micro-vibration energy is acquired during the mining process, and the intensity and frequency of the impact load are estimated in reverse (dynamic impact characteristics).

Step 2, place the prepared test piece 8 in the pressure chamber 41, adjust the positions of the upward pressing pressure head 33, the downward pressing pressure head 23, the lateral first pressure head 44a and the lateral second pressure head 46a, and then adjust the positions. Apply a constant pressure to the specimen 8.

Step 3, Depending on the static stress state, a fixed X-direction pressure is applied to the specimen 8 using the lateral first pressure head 44a and the lateral second pressure head 46a. The axial pressure load device 2 applies a continuously increasing Z-direction pressure to the specimen 8, and the longitudinal first pressure head 44b and the longitudinal second pressure head 46b apply a bearing force in the Y direction to the specimen 8. However, the minimum bearing capacity is required to be 0 before impacting. Based on conventional experience, the minimum bearing capacity in the Y direction is set to 0MPa, and the gradual increase value is set to 2MPa.

Step 4, According to the dynamic impact characteristics, under the condition that the bearing capacity in the Y direction is 0 MPa, an impact load is applied to the specimen 8 using the impact load device 3, and the destruction status of the specimen is checked after the test is completed. Observe.

Step 5, Replace the specimen, keep the X-direction pressure and the axial pressure unchanged, and increase the Y-direction bearing capacity to 2MPa. Repeat steps 2-4 to perform a load test. Similarly, each time the test piece is replaced, the bearing capacity of 2MPa is increased, and each time the bearing capacity is increased, the state of destruction of the test piece is observed again after the load test. Search for a bearing capacity that does not destroy the test piece, and estimate the bearing capacity from this bearing capacity. This support strength is the support strength required for rocks around the tunnel.

In summary, in the present invention, the actual static load stress and dynamic load impact characteristics of the rock around the tunnel are used as the test load stress, and different support strengths are set to perform the rock deformation fracture test. Consider both the effects of static load stress and dynamic load stress and the combined effects of the two. It can be well anastomosed with the actual stress state of the rock around the tunnel at the site, and the supporting strength obtained can maintain the safety and stability of the surrounding rock. Furthermore, high-precision, simple and convenient test operations can be performed more reliably.

Although the above are specific examples of the present invention, the scope of protection of the present invention is not limited to the specific examples, creative work and design are omitted, and any modification or substitution is also within the scope of the present invention. included. Therefore, the scope of protection of the present invention is determined by the criteria defined by the scope of the claim.

1-Load-bearing frame unit, 11-Base (bottom seat), 12-Vertical column, 13-Beam;
2-Axial pressure load device, 21-Axial pressure load oil cylinder, 211-Axial pressure load oil cylinder body, 212-Axial pressure load piston, 213-Axial pressure load piston rod, 214-Oil cavity, 215-Cylinder, 22-Impact load oil tank, 23-Downward push head;
3-Impact load device, 31-Impact load oil cylinder, 32-Impact load oil tank, 33-Upward pressure head, 34-Pillar receiving pressure;
4-Confinement pressure load device, 41-Pressure chamber, 42a-Horizontal confinement pressure load oil cylinder, 42b-Vertical confinement pressure load oil cylinder, 43-Confinement pressure load oil tank, 44a-Horizontal first pressure head, 44b -Vertical 1st pressure head, 45a-1st groove, 45b-2nd groove, 46a-Horizontal 2nd pressure head, 46b-Vertical 2nd pressure head;
5-Load control unit;
6-Monitoring unit, 61-Signal collector, 62-Pressure sensor;
7-Data analysis unit
8-Test specimen

Claims (7)

It is a support strength test device for rocks around the mine tunnel.
The load-bearing frame unit consists of a base, vertical columns, and beams, the columns are arranged vertically on both sides of the top surface of the base, and the beams are fixed horizontally on top of the columns;
The axial pressure loading device is fixed in the center position on the top surface of the base and is used to apply bottom-up axial pressure to the specimen;
The impact loader is fixed to the beam and is used to apply a top-down axial impact load to the specimen;
A confinement pressure loader is provided between the axial pressure loader and the impact loader, and there are also lateral and longitudinal confinement pressure loaders, used to apply confinement pressure to the specimen in a horizontal plane;
The load control unit controls and loads the presented axial pressure load device, impact load device and confinement pressure load device, respectively;
The monitoring unit receives the force of the test piece presented during the loading process and monitors its condition;
The data analysis unit is connected to the load control unit and is a support strength tester for rocks around the tunnel, which is characterized by receiving and analyzing data from the monitoring unit. Axial pressure load devices include an axial pressure load oil cylinder, an axial pressure load oil tank, and a downward push head, the axial pressure load cylinder is secured to the presented base, and the axial pressure load oil tank is Connected to the axial pressure load oil cylinder, one end of the downward push head is connected to the axial pressure load oil cylinder and the other end extends vertically into the confinement pressure load device and contacts the underside of the specimen. The support strength test device for rocks around a tunnel according to claim 1. Axial pressure load oil cylinders include an axial pressure load oil cylinder body, an axial pressure load piston, and an axial pressure load piston rod, with an oil cavity inside the axial pressure load oil cylinder body and axial. The pressure load piston is slidably connected to the axial pressure load oil cylinder body, one end of the axial pressure load piston rod extends into the oil cavity via the axial pressure load piston, and the axial pressure load piston rod The support strength test device for rocks around a tunnel according to claim 2, wherein the other end is connected to one end of the downward push head and one end of the axial pressure load piston rod is a curved surface. The impact load device includes an impact load oil cylinder, an impact load oil tank, a push pressure head and a column that receives pressure, the impact load oil cylinder is fixedly connected to the beam, and the impact load oil cylinder is an impact load oil. One end of the column that connects to the tank and receives pressure is connected to the piston rod of the impact load oil cylinder, the other end is connected to the top of the previously presented upward pressure head, and the bottom of the upward pressure head The support strength test device for rocks around a tunnel according to claim 1, which is in contact with the upper surface of a test piece. The confinement pressure load device is equipped with a pressure chamber (small hollow part), two confinement pressure load oil cylinders, a confinement pressure load oil tank, and two first side pressure heads and two second side pressure heads. Located in the pressure chamber, the confinement pressure load oil tank is connected to two confinement pressure load cylinders, the piston rod of the confinement pressure load oil cylinder is connected to the first side pressure head, and the two first side pressure heads Located on the outside of the adjacent sides of the pressure chamber, respectively, extend horizontally into the pressure chamber, contact the two adjacent side walls of the specimen, and inside the pressure chamber, the two side walls on the relative side of the first side pressure head. A second side pressure head is mounted in each of the two grooves, and the two second side pressure heads are in contact with the other two adjacent side walls of the specimen. Support strength test device for rocks around the tunnel described in. The monitoring unit includes a pressure sensor and a signal collector connected to each other, and the pressure sensor here is placed between the pressure receiving column and the push head, respectively, and signals between the second side pressure head and the specimen. The support strength test device for rocks around a tunnel according to claim 5, wherein the collector is connected to a data analysis unit. The method for determining the strength of the rock around the tunnel according to any one of claims 1 to 6 by the support strength test device.
Step 1: Measure the static stress state of the rock around the tunnel using stress relaxation and
Step 2: Use a micro-vibration system to obtain dynamic load characteristics near rocks around the tunnel and reversely estimate the strength and frequency of impact loads from the test.
Step 3: Make a standard test piece from the rock around the tunnel as a raw material.
Step 4: About load test
Step 4.1: Place the test piece on the tester, adjust the position of each pressure head of the tester, and apply a constant pressure to the test piece first.
Step 4.2: According to the static stress state of the rock around the tunnel measured in step 1, the confinement pressure of the tunnel is simulated using the lateral confinement pressure loading device, and the X direction fixed to the specimen. The axial pressure loader applies a continuously increasing Z-direction pressure to the specimen, and the longitudinal confinement pressure loader applies a Y-direction bearing capacity to the specimen, where the minimum support is achieved. Set the force to 0,
Step 4.3: When the minimum bearing capacity is applied to the test piece, the test piece is subjected to an impact load according to the strength and frequency of the impact load according to step 2, and the destruction state of the test piece is observed after the impact load is completed. And
Step 4.4: Replace the specimen, keep the pressure in the X direction and the pressure in the Z direction unchanged, increase the bearing capacity in the Y direction, and repeat steps 4.1-4.3 to the replaced specimen. A load test is performed, and similarly, the bearing capacity is increased each time the specimen is replaced, and each time the bearing capacity is increased, the destruction status of the specimen is observed again after the load test, and the bearing capacity that does not destroy the specimen is observed. This method is characterized in that the bearing capacity is estimated by the bearing capacity, and the bearing capacity at this time is the required bearing capacity of the rocks around the tunnel.

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