Similar simulation study on mine pressure behavior law of 8.5 m high mining face

In order to determine the mine pressure law of the extra-thick coal seam overburden and the change of the working resistance of the support,according to the geological conditions of the coal seam,and the similar three theorem,the laboratory plane similar simulation method was used to study the overburden breaking,the pressure stepping distance,the support resistance as well as the periodic pressure law of the working face under the conditions of fully-mechanized mining in large mining height with shallow overburden strata.The results show that when the coal is cut normally,the initial caving distance of immediate roof is 23 m,the initial caving distance of the main roof is 38 m,and the periodic caving distance is 17 m.When the mining pressure of the working face is strong,the maximum working resistance of the support is about 24 000 kN,and the overburden collapse will form a rock pillar with a width of 12～20 m.The maximum resistance occurs when the key layer is unstable,and the maximum pressure occurs during the fourth and fifth periodic periods,and the stagnation of the working face leads to a significant increase in the resistance.The research provides technical reference for improving the technical level of the supporting technology of the extra-thick coal seam.