Stability control method of surrounding rock supported by double pressure relief and constant resistance support in gob-side excavation of small coal pillars

Abstract

The invention relates to the technical field of coal mining, in particular to a stability controlling method of double-pressure-relief constant resistance supporting surrounding rock for a small coalpillar gob-side driving entry. The stability controlling method comprises the steps that in the stoping process of a coal body to be stoped in a section, a stoping working face of the section is constructed in advance, a roof of a return airway is subjected to roof-cutting pressure relief blasting, and a blasthole is located in the middle position of the return airway to form a first cutting slit;gob-side entry driving of a track roadway of a coal body to be stoped of a next section is performed, and a roof is supported through a constant resistance large deformation anchor cable; and in thestoping process of the coal body to be stoped of the next section, the stoping working face of the next section is constructed in advance and roof-cutting pressure relief blasting is performed, and asecond cutting slit is formed. The roof-cutting blasting is carried out in the return airway, the influence of stoping of the working face of the section and the dynamic pressure generated after stoping on a track roadway of the working face of the next section is reduced, and the effect of relieving the pressure is achieved; and the cutting slits are formed in the middle positions of the roadwayto form two shorter short cantilever structures, and more security is achieved. The track roadways are subjected to reinforcement support and roof-cutting blasting to perform secondary pressure relief.

Description

technical field [0001] The application relates to the technical field of coal mining, and in particular to a method for controlling the stability of surrounding rock with double pressure relief and constant resistance support for small coal pillar gob-side entry. Background technique [0002] In the longwall mining method of underground coal mining, at least two mining roadways need to be arranged in one mining face. After coal mining, the upper roof of the mining face and the two roadways collapses to form a goaf, and the roof sinking of the goaf will affect the surrounding area. The pressure generated by the coal and rock mass forms a higher pressure peak in the area around the goaf. In the advancing direction of the working face, the pressure on the leading working face is called the leading abutment pressure, and the pressure on both sides of the working face is called the lateral abutment pressure. Not only that, during the coal mining process, due to stress accumulati...

AI Technical Summary

Problems solved by technology

However, the existing anchor steel strand anchor cable is a support material with small deformation. During the support process, the anchor bar and anchor cable have sufficient rigidity but small deformation, and cannot produce large elongation while ensuring the support strength. Deformation, due to its small deformation, a part of the effective elongation is consumed while applying a large prestress. When the surrounding rock is deformed, the ordinary bolt cannot provide a larger deformation, and thus it is broken. Therefore, The anchor cable cannot be applied with a large prestress during use, which greatly reduces its support effect as an active support form

Using truss or U-steel for mining roadway support The process of installing truss or U-shaped steel is complicated, the excavation efficiency is low, and the recycling process is complicated and the workload is large. Even if it is not recycled, a large amount of steel is wasted and the support cost is increased.

Images