The Research On The Reasonable Size Of Coal Pillar With Fully Mechanized Caving In Deep Mines

With the continuous mining, and now the focus is transferred to deep coal seam mining, the geological hosting condition and stress environment of deep coal seam are significantly different from shallow coal seam. In order to ensure the exploitation of coal resources safely and efficiently,it is particularly important to study the reasonable coal pillar design relevant to deep coal seam mining. Based on the geological data and production practice of Lu’an western mining district,in order to provide the certain reference value of reasonable coal Pillar dimension of full-mechanized top-coal caving face in deep mines,this paper achieved a number of results by means of theoretical resolution, numerical simulation and site investigation.(1) Based on the research of overlying rock’fault structure upon section coal pillar of the full-mechanized top-coal caving face、section coal pillar strength、load-、plastic zone and stress distribution, this paper analyze equilibrium conditions for the fault structure to maintain the stability and the major influencing factors of the coal pillar stability. (2) Under the guide of the basic principles of deep mining section coal pillar’s width, On the geological condition of No.3coal seam in Lu’an western mining district, and on the basis of the fundamental theoretical research, through ways of theoretical analysis, basic assumptions, model-building and mechanics calculating, theoretical Calculation formula B≥Z+αd(x0+x1) is deduced to determine width of section coal pillar.Using the orthogonal experiment, with orthogonalty combination design with five factors and five levels is conducted to study the effects of the coal pillar’ width, height, thickness, coal seam buried depth, Protodrakonov scale of hardness on the coal pillar nuclear area rate. Numerical simulation tool FLAC3D software is used to simulate the25orthogonal test scheme, finally the paper Obtaine the coal pillar nuclear area’ ratelinear equation and section coal pillar width’numerical simulation formula.(3) According to the actual conditions of Tunliu coal mine of Lu’an western mining district, through applying theoretical formula and numerical simulation formula proposed by this paper, the reasonable width of section coal pillar for Tunliu coal mine full-mechanized top-coal mining face is obtained. The numerical simulation and mine pressure observation are used to analysis the width of section coal pillar Whether it is reasonable or not. The result show the correctness of the theory research is verified preliminarily. The research results of this paper provide a train of thought of coal pillar size design for the rest coal mines of Lu’an western mining district.