Moving type of key strata and its influence on ground pressure in fully mechanized mining face with large mining height

To master the structure pattern and moving type of key strata is the basis of analyzing mine pressure in a fully mechanized mining face with large mining height. With the theoretical analysis applied,two structure patterns and six moving types of key strata were put forward,and the forming conditions of structure patterns and moving types were given. The two structure patterns include “ cantilever” structure morphology in the caved zone and stable “ hinged” structure morphology in the fractured caved zone. The six moving types include “cantilever” directly baggy fall type, “cantilever” bi-directional rotation baggy fall type,“cantilever” quadratic rotation baggy fall type,“cantilever-hinge” alternating movement type,“ voussoir beam” moving type and “ short voussoir beam” moving type. The six moving types of key strata in caved zone were verified by the UDEC numerical simulation method,and the different influence laws of the six moving types of key strata in caved zone on the mine pressure were revealed,which were also verified by the measured data.