Discussion on powered supports jammed by strata pressure in coal mining face of Qidong Mine

According to the water table variation in the deep measuring borehole and the water inrush in the coal mining face before and after the powered support jammed by the strata pressure,the paper held that the mining fissures had affected to the No.4 soft pressurized water beating zone in combination with the strata pressure measuring results.At high water pressure,the water in the pressurized zone would flow to the coal mining face with the mining fissures.At this cireumstance,a model on main roof period breaking and the powered support mutual function under the No.4 soft pressurized water bearing zone was established.A mechanics analysis was conducted with the model.The analysis showed that the even conducted features of the No.4 water bearing zone could make the even distributed constant loading above the basic roof to have periodical uneven strong pressure,which the present support technique of the coal face could not meet the requirements.