Study on similar simulation of the roof strata movement laws of the large mining height workface in shallow coal seam

Based on the condition of No.1-2 coal seam of Shang Wan Coal Mine Shendong mining area, the movement of the overlying strata of the 7.0m large mining height workface have been studied by similar simulation test, which geometric similarity ratio is 1:50. The results show that: the immediate roof strata caves stratified to loose blocks, and the goaf can't be filled with these loose blocks; the basic roof strata caves stratified too, the lower slice caves to loose blocks, it evolves into the immediate roof and widen the immediate roof; there is the periodic weighting phenomenon of size alternating in the large mining height workface of No.1-2 coal seam; the immediate roof and the basic roof and the overlying strata of basic roof have different characteristics of caving; the large mining height workface has a greater sphere of supporting pressure than the traditional small height workfacc, the peak supporting pressure of the large mining height workface is more depth to the coalwall than the average mining height workface, and this led to workface roof strata fracture further ahead.