Research On Strata Behavior Regularity Of No.11213 Fully Mechanized Face In Xiaojihan Coal Mine

In recent years, large mining height technology which is the main mining method in Shanbei mine and Dongsheng mine has been widely used in Chinese large mineral zone.However,height roof structure and mining pressure mechanism of large mining is still not unified.Especially there has a few the roof structure and high pressure mechanism research on thick overlying bedrock and double key stratum in large mining height longwall face of the North of Shaanxi.It has important theoretical and practical significance that mastering roof structure of large mining and revealing ground pressure mechanism.According to Xiaojihan coal mine geology and mining conditions of the No.11213 fully mechanized working face combined with the mineral pressure observation first weighting interval is 54 m and periodic weighting length is 16 m. Some supports are pushed down result from fierce strata behaviors during first and periodic weightingWe take numerical simulation to study the rupture process of roof key stratum, structure characteristics, stability and the mining height’s effect on the overlying strata movement in large mining height face.By establishing the mechanical model, the main influencing factors are mining height, the roof structure size,he loading layer thickness, the position of the hinge points(thickness and filling of immediate roof) on the analysis of the stability of key stratum structure.Finally, the mechanism of small periodic weighting in large mining height face is the sliding instability, of lower key stratum structure.The mechanism of great periodic weighting is the additive effectof the instability of upper key stratum structure resulting in the sliding instability of lower key stratum structure.