Numerical Testing of Narrow Coal Pillar Width Identified With Large Section Roadway Driving Along Next Goaf

Aiming at the problem of narrow coal pillar width identified with large section roadway driving along next goaf in fully mechanized caving face, the different widths of narrow coal pillar deformation and stress distribution were studied by using numerical test method in the paper, the reasonable narrow coal pillar width was determined and successfully applied to engineering practice. Some conclusions can be drawn as follows: when the width of coal pillar was 3 m, 4 m, 5 m, 6 m, 8 m and 10 m, the non-yield destruction coal pillar width was 0 m, 0 m, 1 m, 2.6 m, 4.8 m and 7 m; the stress distribution of narrower coal pillar is approximate triangular, and the little bigger coal pillar is approximate trapezoidal distribution; the triangular distribution are overlapping results of both sides vertical stress peak. The middle stress of trapezoidal distribution is lower, because of mining and tunneling influence smaller; the displacement of the coal pillar to the roadway was increased with pillar width, then from big to small when it was up to a certain extent, finally tended to be stable; the 5 m coal pillar was chosen as the pillar's better stress condition, and the necessary strengthen supporting measures can meet the needs of engineering.