Research on deformation characteristics of surrounding rocks in irregular roadway of inclined thick coal seams and asymmetric support technology

To study the large deformation and mine pressure behaviors of irregular roadway in inclined thick coal seam, an asymmetric support technology of irregular roadways based on anchor cables reinforcing coal pillar at high side and large diameter drilling pressure relief at low side is proposed. As a filed investigation, the transport roadway and ventilation roadway of the working face in Wulan Mulun Coal Mine are divided into three regions and the stresses and displacements of the irregular roadways in these regions are analyzed. The key parameters of the asymmetric support technology based on anchor cables reinforcing coal pillar at high side and large diameter drilling pressure relief at low side are determined. The results show that the stresses of the advanced transport roadway are the most complex. The bearing stress of the high side is higher than that of the low side, which shows asymmetric state. The deformation of the coal pillars is the main reason for the slipping deformation of the surrounding rock at the high side, while the stress concentration in the rock leads to the deformation of the surrounding rock at the low side. The coal pillar at the high side is reinforced by the anchor cables effectively and the stress concentration in the rock at the low side is transferred to distant field by the large diameter drillings holes. Verified by the field application, the asymmetric support technology based on anchor cables reinforcing coal pillars at high side and large diameter drillings releasing bearing pressure at low side can obviously reduce the deformation of the irregular roadway and effectively suppress the roof bed separation.