Zhangji Coal Mine Group A 14131 High Mining Face Study On The Law Of Mine Pressure Manifestation

The group A coal face of Zhangji Coal Mine has features such as thick coal seam,low hardness of coal,direct coverage of sandstone,and large gas.In order to achieve high production and high efficiency of the mine,the first mining face 14131 adopts full-height,full-thickness mining.In this paper,theoretical analysis,numerical simulation and field measurement methods are used to study the overburden failure rule,support work resistance,and the behavior of mine pressure in the high mining height of Zhangji Coal Mine.The study found that the increase in the length of the working face led to an increase in the influence range of roof overburden rock mining,the movement of the rock strata,and more complete destruction,so that the face support equipment bears an increase in load,combined with the analysis of the roof overlying stratum structure and the bearing force,to determine the work No more than 200m in length.With the increase of mining height,the roof displacement and vertical stress are also increased,the stability of the coal wall is reduced,and the overall performance of the support is required to be higher when using the one-time mining full height for mining.According to the specific geological conditions,the theoretical and numerical simulation analysis of the work surface supports shows that the 14131 working face uses the ZZ18000/30/65D hydraulic support to control the stope roof.Field measurement shows that the initial pressure step of the industrial test surface 14131 is 30m to 35m,and the average is 31m;the step pressure step is 11m to 19m,and the average is 13.3m;the entire working face is not synchronized and the pressure sequence Is the middle-lower-upper,from the middle to both ends of the development.For the selected stent,the distribution of working resistance and end resistance frequency is in a normal distribution.The average resistance of the stent is 17.2 MPa,which is 42%of the rated value of 40.4 MPa;the ratio of the end-to-end resistance of the stent is less than 35 MPa is approximately 90%,and the average end-resistance of the stent is 23.1 MPa,which is 57%of the rated value.During the entire period of operation,the operating state of the bracket is sTab.and meets the requirements for support.