In order to obtain the characteristics of strata movement during the mining operations at II-31 coal face in Chaoyang coal mine,the interaction between surrounding rock and supports,the distribution of abutment pressure caused by mining,the paper proposes a method for determining the parameters,properties and bolting effects of supports.The field observation and measurement at II-31 coal face was conducted to find the distance of initial pressure and period pressure for the coal seam investigated,supports' ...