Theoretical study on roof movement and abutment pressure distribution of longwall panel with 8. 5 m mining height

After analyzed comprehensively,it is found that some better economic and social benefits will be ob-tained if the longwall panel is extracted with mining height at 8. 5 m (the highest mining height in the world). However,the in- crease of mining height may result in a strong overburden pressure which will impact the safe and efficient production seriously. Therefore,in order to overcome this problem,after analyzing the mining pressure changes induced by differ- ent mining heights, engineering analogy, theoretical analysis and similar material simu-lation are used to study the movement of overburden strata and the distribution of abutment pressure. In order to consider the influence of interme- diate principal stress on the yield function,Lode parameter is introduced to modify the traditional formula based on the D-P criterion. Regression analysis method is used to predict the dynamic load coefficient of the longwall face. The re- sults show that the thickness of roof is 22. 68 m. The first and periodic weighting lengths are 56 m and 21 m. During some normal mining activities, the ground pressure strength is 1. 51 MPa determined by quantitative analysis and 1.69 MPa determined by estimation method. The position of peak point of the abutment pressure is 13 m with influ- ence scope of 60 m. The research findings lay a solid theoretical foundation for the selection and design of shields,the safe and efficient production of fully mechanized mining face.