Study on Similar Material Simulation of Fully Mechanized Top Coal Caving Mining in Ultra Thick Seam with Watery Overburden Strata

In order to study on the failure features of the watery overburden strata above the fully mechanized top coal caving face under the condition of the different mining height,taking No. 401101 coal mining face of the first coal mining face in Hujiahe Mine as the engineering background,a physical similar simulation experiment method was applied to three mining experiments with different mining heights( 10m,8m and 6m). When the coal mining face was pushed forward to 180m,the overburden strata would be in failure status under the different mining height. Whether the height of the water flowing cracking zone would reach at the water bearing stratum or not,based on the circumstances,the periodical failure and the cracking development process of the mining strata were analyzed and the variation of the roof support pressure distribution was analyzed. The analysis conclusion would provide the references to the reliable mining height of the first coal mining face in Hujiahe Mine in order to the avoid the roof water permeable disaster.