Abstract: Taking the determination of high cutting fully mechanized coal mining face and district sublevel coal pillar in the second panel of Tingnan Coal Mine as the engineering background, Theoretical calculation and field measurement had been used to analysis elastic central zone of district sublevel small coal pillar and failure scope, and the influencing scope of lateral abutment pressure of the gob and variation range of plastic area of 4 different coal pillar widths were obtained by numerical simulation. The results showed that the destruction of a coal pillar was greatly affected by mining; in the range of 0~3 m far from the edge of coal pillar was crushing zone. And the scope that different degrees of failure occurred at edge of coal pillar was 3~6 m, and in this scope it has certain capacity. The low lateral abutment pressure scope near the gob was about 20 m; there was a certain limit of stable region in the middle of the coal pillar when its width was 10-12 m. Finally, the reasonable width of district sublevel small coal pillar suitable for Tingnan coal mine was determined as 10~12 m.

Key words: high cutting coal mining, district sublevel small coal pillar, crushing zone, plastic failure