Research on lateral strata pressure characteristic in goaf of top coal caving in extra thick coal seam and its application

Abstract：By using the online intrinsic-safe mining pressure monitoring system, two observations regarding the lateral pressure were made to one solid coal side of goaf at the working face 3801 （where the fully-mechanized top-caving method FMTC was used） at Shuiliandong Mine,with the results are as follows：（1） The characteristics of movement of the overlying rock, force borne by the supports, and the lateral supporting pressure in the tunnel were obtained, the fact that pace of the periodical lateral pressure equals to that of the periodical strike pressure was revealed, and a model for the lateral overlying rock structure was established based on the stabilized roofing, the upper roof＇ s structure （16- 24 m above the coal seams） and the rock-beam structure for the main roof in the tunnel of goal. （2） The conclusion was drawn that the property of the separating wall of the tunnel can suit the movement of the overlying rock resulted from the calculation by establishing the model of force-beating of the separating wall of the tunnels in goaf in combination with the stress-strain relation. （3） The dominance of the overlying rock movement on pressure was determined on the basis of the features of the force bearing of the advanced support due to the lateral periodical pressure and the lateral supporting pressure, which will be used to study the theory by which the rock formation＇ s movement controls the mine＇ s pressure. The result was applied to optimize the width of the coal pillar between 3802 transport level and 3801 working face to 8 m, reduced by 22 m compared with the previous one so that the former meets the expectation afterconstruction.