Abstract: Using FLAC3D numerical simulation as the main method, the influence of plastic zone development characteristics,stress distribution characteristics and deformation characteristics of surrounding rock in the surrounding rocks of the straight wall of thick coal seam with different buried depth and different lateral pressure coefficients is analyzed.The results show that with the increase of buried depth,the deformation of surrounding rock of roadway increases linearly,the damage depth of surrounding rock is larger and the plastic region is surrounded by shape,and the lateral pressure coefficient has a great influence on the failure form of roadway,and when the lateral pressure coefficient is 0.5,the distribution of plastic zone shows "butterfly Wing shape 1 o'clock",the plastic zone distribution is "sailing shape",the distribution is more uniform,and the lateral pressure coefficient continues to increase,the roadway gradually becomes "narrow high shape" and finally develops into "hourglass shape".The support scheme of the return air lane of the fish truck mine is optimized,the joint support of the anchor net cable is used,and the surface of the roadway is sprayed,the roof sinking is 35 mm after the roadway is stabilized,and the shift of the help area is 50mm,which satisfies the need of normal safe production.

Key words: Thick coal seam, Straight wall semi-circular arch, Plastic zone distribution, Surrounding rock failure