Engineering Practice for Roof Caving Treatment in Multi-structure Soft Rock Face

In order to solve the technical problem of easy roof caving due to the multi-structure in front of soft rock mining face, taking 110603 working face in Wenjiaba Coal Mine as the research object, using the method of field investigation and data analysis, the main reasons of roof caving in working face are obtained. First, the overall fragmentation of coal is caused by a large number of fault structures and it is not stable. Second, the rock formation is mainly soft clay with a high degree of muddy clay. When the rock is swollen with water, it causes the bottom of the support to be drilled and cannot contact with the roof. The support resistance would not be effectively utilized. Third, the two supporting surfaces of the working face are not strong enough during the excavation so that the overall carrying capacity of the surrounding rock cannot be effectively utilized. Fourth, the advance of working face is slow, and the affected height of “three belts” also increases correspondingly, resulting in the overall destruction of surrounding rock in working face being accelerated. In this paper, according to the reasons of the above-mentioned roof collapse, the comprehensive reinforcement method of the advanced grouting of working face, grouting of coal wall and grouting in front of top-coal caving region zone, is used to grout and consolidate the coal-rock mass to enhance the overall carrying capacity of surrounding rock. Then, carry out the local anchor rope reinforcement support for the existing support of the two lanes can guarantee the safe mining of working face.