Analysis on roof movement behavior workface during rotational adjustment in Daizhuang mine

Based on the pressure monitoring of the support in Daizhuang Mine's 1341-workface during the rotational adjustment,the abutting jointing time of the mechanized mining equipment without coal pillar and the normal recovery time,behavior of the roof movement is researched in two aspects which are the longitudinal and advance direction.The results show that:the periodic weighting step of main roof during the recovery is 11.5m long;the roof weighting step is 8m long during the first rotation,6m long during the second rotation,the weighting step of immediate roof is 5.6m during abutting jointing without coal pillar,which is shorter than the periodic weighting step during the recovery,but the pressure are greater in the workface;and the lateral fracture span of the roof is 10.52m whose impact is not obvious to the pressure because of the periodic pressure.Due to the pressure in the different parts of workface is different during the rotational adjustment,the roof fall first in the top face,then in the center and last in the bottom.the results provide a scientific guidance to the supporting and the design of the roof control.