ABSTRACT:

The vertical stress, failure patterns and deformation of roadway surrounding rock under different coal pillar width are studied by using FLAC3D software. The results show that with the increase in the width of coal pillar, stress concentration range and factor in pillar decreases, gradually showed uniform bearing form, at the same time, the displacement of roadway and plastic zones in pillar gradually decrease. With the increase of the width of coal pillar, the range of elastic core is larger, indicating that the more stable the roadway coal pillar is, the more safety will be. Taking into account that large coal pillar width would result in the waste of resources, the reasonable coal pillar width is between 14–16 m.

1 INTRODUCTION

According to numerous studies on the rational section coal pillar, many effective methods to determine the reasonable size of coal pillars can be categorized as follows (Cui et al. 2012, Tu et al. 2011, Zhang & Shi 2004, Chen 2014, Shao et al. 2014): 1) Mathematical statistics, a large number of measured results give rise to inductive reasoning that unstable surrounding rock conditions of coal pillar size; 2) Application of mine pressure regularity with various coal pillar and empirical formula to analyze the reasonable size of the coal pillar; 3) The reasonable coal pillar width range determined based on measured pillar abutment pressure distribution method analysis of coal seam; 4) According to the limit equilibrium theory to derive the coal hold steady when the width formula; 5) The estimation formula of three dimensional plastic zone width of coal pillar stress. The numerical simulation of roadway surrounding rock is performed to analyze the width of coal pillar under different stress and movement for working face 222203 in Shuangxin Mining Co. coal mine, Inner Mongolia.

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