Study On The Relevant Technology Of Ultral-Close Thin Coal Seams Mining Under Complex Surrounding Rock Condition

This thesis, by means of situ measurement, theoretical analysis, numerical and physical simulation, studies the relevant technologies on the ultra-close thin coal seam mining, bringing forward the controlling models and ways of roof and floor of the close thin coal seams under the complex mining, and eventually obtaining the reasonable parameter of the arrangement of the middle seam roadway when the upper coal seam is still up and the lower seam has been mined as well as the means to control the surrounding rocks. These methods are applied to the mining practice. The specific work is as follows:First of all, by the application of elastic-plastic mechanics, this thesis makes researches on the pressure and deformation of surrounding rock while mining the ultra-close coal seams, and figures out the regulation of surrounding rock stress and deformation of the middle seam.Secondly, the thorough researches of the stress state and moving regularity of the upper coal floor, the relation between the depth of destroyed upper coal floor and mining height, the overburden failure height and moving regularity of the lower coal roof are made by using Flac3D modeling. Meanwhile, through the physical simulation, the basic conditions of mining ultra-close seams are analyzed and proved from the perspective of deformation.Thirdly, the types of roof and floor under the complex joint mining situation are classified; the controlling models of surrounding rock are established by comprehensive analysis.Finally, on the basis of situ measurement as well as the previous researches, the factors influencing the roadway arrangement are analyzed; the reasonable space parameter of roadway of the ultra-close thin seams mining is proposed; and controlling plan of the surrounding rocks are determined and applied to mining practice.This paper is of great practical and theoretical significance in the ultra-close seams mining, solving the practical problems of the ultra-close seams mining and providing valuable experience for mining under similar conditions.