CN103471914A - Triaxial impact ground pressure true simulation test system - Google Patents

Abstract

The invention discloses a three-axis simulation test system for impact ground compaction, which is characterized in that it includes a flexible loading unit, a confining pressure loading unit and an impact loading unit; The vertical pressure is applied to the specimen, and the confining pressure loading unit makes the specimen under the triaxial stress condition, and the impact load is applied to the specimen through the impact loading system, and the specimen is damaged under the condition of high stress and impact disturbance, its strength decreases and certain displacement, in this process, the reaction force steel strand in the flexible loading unit quickly supplements the loading of the specimen, simulating the further extrusion work of the external surrounding rock on the coal and rock mass; the present invention better simulates the rock burst conditions, and the triaxial loading condition is especially suitable for simulating the gravity-type rock burst in the mining roadway.

Description

Real triaxial simulation test system for ground bump compaction

technical field

The invention relates to the research on the law of rock burst occurrence in deep engineering, in particular to a true triaxial simulation test system for rock burst.

Background technique

Rockburst refers to the fact that the coal rock mass under high ground stress is damaged by the roof fracture or blasting disturbance around the coal mine roadway or mining face, and is further and rapidly squeezed by the surrounding rock during the destruction process, and is released instantaneously. A mine dynamic phenomenon in which huge energy causes destruction. It is often accompanied by loud noises, coal and rock mass being thrown into the mining space and air waves, etc., causing damage to the support equipment in the mining space and deformation of the mining space, causing casualties and damage to the mine and roadway in severe cases, and even causing surface subsidence cause local earthquakes.

Rock burst is an important problem faced by the mining industry, which seriously affects the safe production of mines. Especially in the process of deep mining, the surrounding rock is under high stress conditions, and is disturbed by the fracture of the overlying strata in the stope, and the mining roadway is prone to occurrence Rockburst disaster. To study the occurrence law of rock burst, it is necessary not only to conduct theoretical analysis, but also to explore its essential law through indoor simulation experiments.

通过加载，使煤岩体处于高应力状态下；

对高应力条件下的煤岩体施加冲击荷载，以模拟采空区覆岩断裂导致的应力波对巷道的冲击；

在煤岩体破坏的过程中迅速进行补充加载，即补充能量，以模拟外部围岩对煤岩体的进一步挤压做功。但是，目前还没有设备能够同时满足上述三个条件，实验室模拟成为冲击地压的研究的瓶颈。 According to field observations and theoretical analysis, in order to simulate rock burst indoors, the following three necessary conditions must be met:

By loading, the coal and rock mass is placed in a state of high stress;

The impact load is applied to the coal and rock mass under high stress conditions to simulate the impact of the stress wave on the roadway caused by the fracture of the overlying rock in the goaf;

In the process of coal rock mass failure, supplementary loading is carried out quickly, that is, energy is added to simulate the further extrusion work of the external surrounding rock on the coal rock mass. However, there is no equipment that can meet the above three conditions at the same time, and laboratory simulation has become the bottleneck of rock burst research.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art, and provide a kind of impact ground compaction triaxial simulation that can make the test piece bear the impact load under the triaxial high stress condition, and quickly replenish energy during the test piece destruction process test system.

To achieve the above object, the present invention adopts the following technical solutions:

A true triaxial simulation test system for ground shock compaction, characterized in that it includes a flexible loading unit, a confining pressure loading unit and an impact loading unit;

The flexible loading unit includes a base, a loading oil cylinder, a servo oil source, a loading backing plate, a reaction force plate, and a reaction force steel strand; one end of the loading oil cylinder is supported on the base, and the other end applies an axial load to the specimen; The left and right sides of the force plate are respectively provided with through holes for connecting the reaction force steel strands; The force plate exerts a reaction force, and when the reaction force plate is impacted, it will not produce a support effect. When the specimen is damaged, it will shrink instantly under the action of elasticity, and quickly supplement the load on the specimen;

The confining pressure loading unit includes a loading frame, a loading pad, a loading cylinder, and a servo oil source. The loading cylinder is fixed on the four inner sides of the loading frame, and the loading cylinder exerts pressure on the test piece driven by the servo oil source. ;

The impact loading unit is used to apply a vertical impact load to the rock sample, including an impact weight, a boom, a lifting device and a guiding device, the weight and height of the impact weight can be adjusted, and the lifting device is fixed It is used to lift the impact weight on the boom, and the surface of the guide device is marked with a scale, which is used to measure the height of the impact weight and prevent the impact weight from deflecting when it falls;

The test piece is in the shape of a cube with a horizontal through hole or a half hole in the middle, and the surface of the test piece is coated with lubricant to reduce the frictional force it receives during deformation.

The present invention may also include a measurement and control system, the measurement and control system is used to measure and control the load applied by the loading oil cylinder and the displacement that occurs, including a load and displacement measurement unit and a servo control unit; the load and displacement measurement unit includes three The stress sensor and LVDT displacement gauge on the loading mechanism in each direction are used to measure the load and displacement of different boundaries of the test piece, and transmit the measurement results to the servo control system unit; the servo control system unit includes 3 independent numerical control units , respectively controlling the load and displacement in three directions according to the measurement results of the load and displacement measurement and control unit.

Principle of the present invention is:

The flexible loading unit of the present invention exerts vertical pressure on the test piece through the loading cylinder and the reaction force steel strand. During this process, the reaction force steel strand has a certain elastic elongation, and then the test piece is placed under triaxial stress through the confining pressure loading unit. Under the conditions; through the impact loading system, the impact load is applied to the specimen to simulate the impact of the stress wave on the roadway caused by the fracture of the overlying rock in the goaf. Since the reaction force steel strand is a flexible material, it will not impact the impact like a conventional rigid column. The impact of the load (support effect) has achieved the goal of allowing the specimen to further withstand the impact load under specific triaxial load conditions for the first time; the specimen is damaged under high stress and impact disturbance conditions, and its strength is reduced and a certain displacement occurs. During this process, the reaction steel strand in the flexible loading unit shrinks instantaneously, and the specimen is quickly supplemented with loading, that is, energy is supplemented, simulating the further extrusion work of the external surrounding rock on the coal and rock mass;

The invention can better simulate the occurrence condition of rock burst, and the triaxial loading condition is especially suitable for simulating the gravity type rock burst in mining roadway.

Description of drawings

Below in conjunction with accompanying drawing and specific embodiment the present invention will be further described:

Accompanying drawing 1 is the top view schematic diagram of the main structure of the present invention before installation of counter force plate and counter force steel strand;

Figure 2 is a schematic front view of the main structure of the flexible loading unit of the present invention.

Detailed ways

With reference to accompanying drawings 1 and 2, a ground shock compaction triaxial simulation test system is characterized in that it includes a flexible loading unit, a confining pressure loading unit and an impact loading unit.

The flexible loading unit includes a base 1, a loading cylinder 2, a servo oil source, a loading backing plate 3, a reaction plate 4, and a reaction steel strand 5; one end of the loading cylinder 2 is supported on the base 1, and the other end is on the test Part 6 applies an axial load; the left and right sides of the reaction force plate 4 are respectively provided with through holes for connecting the reaction force steel strands 5; there are multiple reaction force steel strands 5, and one end of any one is fixed on the base, It is fixed on the counter force plate and is used to exert counter force on the counter force plate, and it will not produce a supporting effect when the counter force plate 4 is impacted. When the test piece 6 is damaged, it will shrink instantly under the action of elasticity, and it will quickly affect the test piece. Supplementary loading; the test piece 6 is cube-shaped, with a horizontal through hole or a half hole in the middle, and the surface of the test piece is coated with lubricant to reduce the friction force it receives during deformation.

The confining pressure loading unit includes a loading frame 7, a loading backing plate 8, a loading oil cylinder 9, and a servo oil source. The loading oil cylinder 9 is fixed on the four inner sides of the loading frame 7, and is tested under the drive of the servo oil source. Piece 6 applies pressure.

The impact loading system is used to apply a vertical impact load to the rock sample, including an impact weight, a boom, a lifting device and a guiding device, the weight and height of the impact weight can be adjusted, and the lifting device is fixed It is used to lift the impact weight on the boom, and the surface of the guide device is marked with a scale, which is used to measure the height of the impact weight and prevent the impact weight from deflecting when it falls.

The present invention may also include a measurement and control system, the measurement and control system is used to measure and control the load applied by the loading oil cylinder and the displacement that occurs, including a load and displacement measurement unit and a servo control unit; the load and displacement measurement unit includes three The stress sensor and LVDT displacement gauge on the loading mechanism in each direction are used to measure the load and displacement of different boundaries of the test piece, and transmit the measurement results to the servo control system unit; the servo control system unit includes 3 independent numerical control units , respectively controlling the load and displacement in three directions according to the measurement results of the load and displacement measurement and control unit.

The above-described embodiments are only one of the more preferred specific implementation modes of the present invention, and the usual changes and replacements performed by those skilled in the art within the scope of the technical solutions of the present invention shall be included in the protection scope of the present invention.

Claims (3)

1. A true triaxial simulation test system for ground shock compaction, comprising a flexible loading unit, a confining pressure loading unit and an impact loading unit; The flexible loading unit includes a base, a loading oil cylinder, a servo oil source, a loading backing plate, a reaction force plate, and a reaction force steel strand; one end of the loading oil cylinder is supported on the base, and the other end applies an axial load to the test piece; The left and right sides of the force plate are respectively provided with through holes; there are multiple reaction force steel strands, one end of which is fixed on the base, and the other end is fixed on the reaction force plate; The confining pressure loading unit includes a loading frame, a loading pad, a loading cylinder, and a servo oil source, and the loading cylinder is fixed on the four inner surfaces of the loading frame; The impact loading unit is used to apply a vertical impact load to the rock sample, including an impact weight, a boom, a lifting device and a guiding device, the weight and height of the impact weight can be adjusted, and the lifting device is fixed Used to lift the impact weight on the boom, the surface of the guide is marked with a scale. 2. A kind of rockburst true triaxial simulation test system according to claim 1, characterized in that, said test piece is in the shape of a cube with a horizontal through hole or a half hole in the middle, and the surface of the test piece is coated with lubricating agent. 3. The ground shock compaction triaxial simulation test system according to claim 1, characterized in that it comprises a measurement and control system, and the measurement and control system includes a load and displacement measurement unit, a servo control unit, and the load and displacement measurement The unit includes stress sensors and LVDT displacement gauges arranged on the loading mechanism in three directions, and the servo control system unit includes 3 independent numerical control units.

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