Distribution characteristics analysis of pressure-arch in horizontal stratified rocks under coal mining conditions

摘要

The criteria of separation and dislocation of the layered roof in mining are put forward through the simplified mechanical model with weak inter-layers. Considering five different variables, namely the number of layers, the distance from the weak inter-layers to the mine opening, the thickness of the weak inter-layers, the lateral pressure coefficient and the spacing of the bedding planes, the distribution characteristics of the pressure-arch in the horizontal stratified rocks are analyzed during coal mining using FLAC3D. The results show that the newly appeared pressure-arch is composed of the original pressure-arch in each layer and the pressure-arch shape being affected by the weak layer in the surrounding rock of the mine opening. As the distance between the inter-layers and the coal seam increases, the effect on the pressure-arch is reduced gradually. The thinner inter-layers produce greater impact on the pressure-arch. The lateral pressure coefficient has a great influence on the pressure-arch and a stable pressure-arch could only be formed when the lateral pressure coefficient is in a suitable range.