Abstract:In order to explore the influence of mining heights on the three-dimensional stress distribution of coal-seam in unsymmetrical disposal and fully-mechanized top-coal caving,based on unsymmetrical disposal characteristics,the analyses of numerical simulation and in-situ observation are synthetically applied according to the geological and technical conditions of the working face 1151(3) in Xieqiao Mine. The characteristics of 3D stress distribution of coal-seam and its thickness effects are obtained. The results show that the seam stress on working face represents unsymmetrical distribution in unsymmetrical disposal;and the abutment pressure peak value and its distance to face and stress-relaxed area are maximum at the side of coal pillar. The coal-seam thickness effects behave that the stress peak value and 3D stress distribution of coal-seam are changed with mining height changing. The seam-stress peak value decreases with the increasing of mining height,but the distance between peak value location and coal-seam wall augments and the abutment pressure shift to further coal-seam wit the increasing of the mining height. The study will provide lots of theoretic references to reasonable preservation of coal pillar,layout of gateway,stability control of surrounding rock,increment of the recovery ratio and efficiency of caving,etc..