Study On The Section Pillar Stability Of The Fully Mechanized Top-Coal Caving Mining Face In Dongpo Mine

The fully mechanized top-coal caving mining is one of the main methods for mining thick coal seams in China.But,it has the disadvantage with wasting large amount of resources, and the loss of section coal pillar has accounted for 36.7%.Study on the section pillar stability and reasonable width of pillar has the vital significance for the stability of roadway and improving the recovery rate of coal resources.In this thesis, the No. 4 coal seam face geological condition in the Dongpo coal mine as the background, research methods of observation, rock mechanics test, physical simulation, numerical simulation and theoretical calculation, study on the reasonable width of coal pillar. Through the observation and rock mechanics test, get the rock mechanics parameters of coal and overburden movements 404 face in the Dongpo mine, providing the basis for reasonable width of pillar.Using the limit equilibrium theory of rock mass have get the coal pillar width of plastic zone,and if the elastic kernel width is 2 times the height of pillar,then the minimum width of coal pillar is 17.57 M. Using FLAC3 D, get the different coal pillar width of the deformation and the abutment pressures distribution, analyses the stability and reasonable width of pillar. Through physical simulation of different l pillar width, according to the deformation, damage state and abutment pressure distribution, concluded that the coal pillar width shall be not less than 18 M.Based on the above research results, the pressure arch theory, effective area theory and Wilson theory, in accordance with the subsidence basin, have divided into three kinds of state of the coal pillars, set up the dynamic load model of pillar. The first is the first section coal pillar "arch" structure model, that coal pillar supports the "arch" structure load; The second is multi face of subcritical subsidence basin model, supporting the "arch" structure for multi pillar. With the span increasing, pillar load increases. the formula of the pillar load is corrected above the first model based on high arch; The third is critical subsidence basin model, that pillar supports the control zone overburden weight. On the basis of pillar dynamic load model, combined with the Obert-Dwvall/Wang strength theory of rock mass, and the calculation formula of section coal pillar width is given.The research results of this thesis provide a theoretical basis for the width of section pillar for full-mechanized top-coal caving face in Dongpo mine, and under similar conditions of coal pillar size design has the certain reference value.