Seepage Weakening Mechanism Of Soft Rock Roadway In Fissured Development Coal Mine

Rock with bedding,joint and fractured is often accompanied by abundant groundwater, and the effect of groundwater will cause serious deterioration of rock formation. The rock weakening generated in the construction of the the roadway that often cause a serious accident such as roofing. Therefore, this paper studies on these roadway with groundwater, so as to find a suitable new technology support,reinforcement, repair and other aspects of the unstable roadway,which is very necessary.This paper is focus on the seepage sandstone, the powdery sandstone and the mudstone,studing their mineral composition, microstructure form, water chemical failure mechanism and the description of its destruction mechanism. And the analysis of the seepage of the mudstone roadway, the classification of the roof, the stability of the surrounding rock and the elasto-plastic theory analysis of the seepage tunnel are also studied on. The main points can be summarized as follows:(1) The mudstone mineral composition and its natural intricate joint pore microstructure is the main cause of rock damage in Sandstone, powdery sandstone and mudstone roadway. The water environment and the physical and chemical reactions of water are extremely harmful to the rock of the powdery sandstone and mudstone.(2) In practice, It can be evaluate and classify the seepage condition according to the roof of the roadway, which is different from the traditional water enrichment coefficient and mine water quality evaluation method.The weak layer, the old top water-bearing sandstone and the early support are all the risk factors that can restrict the stability of the roadway.(3) The stress and displacement of the elasto - plastic zone before and after the application of the support body are calculated and answered. It can be use a porosity function to express the damage value of the physical and chemical reactions of water.(4) Based on the examples of several roadway in Pengzhuang coal mine and the numerical simulation method, the support methods of two typical seepage sandstone roadway are discussed, and the corresponding effective support scheme is found.