Numerical Study on Reasonable Width of Creep Pillar in Coal-rock Interbedded Thin-roof Section of Deep-well and High-stress

In order to determine the reasonable width of section coal pillars in the working face of coal-rock interbedded thin-roof under the influence of deep-well and high-stress and creep failure, the method of field measurement, theoretical analysis and numerical simulation were adopted to carry out the research, through field peep and stress test, the roof type of the working face was determined to be the thin interbed roof of coal and rock; the width of section coal pillar was determined as 29.56 m by elastic core formula; numerical simulation showed that when the coal pillar width was 20 m, 25 m and 30 m, the elastic core area width was 4 m, 15 m and 22 m respectively, accounting for 20.0%, 60.0% and 73.3% of the coal pillar width. The research results show that 30 m coal pillar can ensure the stable use of roadway, and roof structure, high stress, creep failure and the influence of dynamic pressure are the main reasons of roadway deformation. With the influence of roadway tunneling and mining on creep calculation, the displacement curve can be divided into four areas, namely Ⅰ initial creep zone, Ⅱ decay creep zone, Ⅲ stable creep zone, Ⅳ mining acceleration creep zone, the corresponding curve shapes of coal pillar stress are solitary peak type, platform type and saddle type.