Fender pressure relief method for mechanically cutting tight roof at intervals

Abstract

The invention discloses a fender pressure relief method for mechanically cutting a tight roof at intervals. The method comprises the following steps that a walking part of a rock cutting machine is adjusted, so that a cutting tool is parallel to a roadway; an inclination adjusting mechanism of the cutting tool is adjusted, so that the cutting tool deflects towards a coal pillar, and an acute anglealpha is formed by the cutting tool and a tunnel roof; the cutting tool is started to be attached to the surface of the side wall of the coal pillar, the cutting tool is adjusted to deflect upwards,and the deflection angle is beta; the walking part of the rock cutting machine is driven, so that the walking part moves the rock cutting machine towards the other end of a roadway by the distance S1at the speed V, and a cutting joint is formed; a row of anchor cables is driven in at the position S2 away from the coal wall within the range of the cutting joint, the re-driving length of the anchorcables is L, the pre-tightening force of the anchor cables is P, and the interval between the anchor cables is S3; the cutting tool is withdrawn to the initial position, and the rock cutting machinemoves along the roadway by the distance S4; and the above content is executed, and the process is stopped after the whole mining roadway roof is cut. By means of the arrangement, the effect reducing loads borne by the coal pillar is achieved.

Description

technical field [0001] The invention relates to the technical field of coal mining, in particular to a pressure relief method for small coal pillars by mechanically cutting a hard roof at intervals. Background technique [0002] In coal mining, in order to avoid mutual interference between adjacent working faces, coal pillars with a certain width are generally reserved to isolate adjacent mined-out areas. However, the retention of coal pillars will cause a waste of mine resources and reduce the service life of the mine. In order to reduce coal loss and increase recovery rate, scholars at home and abroad have proposed small coal pillar mining technology. The small coal pillar mining technology reduces the protective coal pillar of the adjacent working face from the original 20-40m to 3-6m. Small coal pillar mining not only increases the resource recovery rate, but also the roadway is located in the surrounding rock stress reduction area, which is easy to maintain, so it is ...

AI Technical Summary

Problems solved by technology

However, when there is a hard roof on the working face, the hard roof will form a triangular suspension plate or cantilever beam on the side of the roadway, which will squeeze the coal pillar and cause serious deformation and damage to the roadway.

In this case, downhole hydraulic fracturing is usually used to cut the hard roof. However, hydraulic fracturing is difficult to control the expansion of hydraulic fractures. Therefore, an accurate and efficient method of roof cutting and pressure relief for small coal pillars is urgently needed.

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