Influence factors of overlying coal strata falling and mine pressure behaviours in western coal mines

In the western mines,the deformation,movement and breakage of overlying strata induced by high intensity mining are the root causes of geological hazards (e. g. large area roof falling,water and sand inrush) and environment damage (e. g. water and soil loss). Incorporated with numerical simulation,in-site micro-seismic monitoring and theo- retical analysis,the paper study on influence factors of overlying coal strata falling and mine pressure behaviours. Tak- ing Xiaojihan Coal Mine as an example,the deformation,breakage,falling and “ three zones” formation are well dis- cussed,the ground pressure behaviours at different mining speed are also investigated in detail,and the influence rules of different mining height and excavation speed on failure of coal strata are finally clarified. Results of in-site micro seismic monitoring show that,different mining rates of working face causes different range and completion degree of ground stress adjustment. Through comprehensive analysis,the caving characteristics of overlying coal strata and the law of “three zones” origination and evolution are systematically revealed,which will provide scientific basis for estab- lishing failure law and stability criterion of overlying strata in high intensity mining.