Study On The Failure Law Of Overlying Rock In The Narrow Strip Paste Filling Mining Of Bailu Coal Mine

For a long time,the mining method of knife pillar or room pillar has been widely used in Yulin area of Shaanxi Province,which results in a very low rate of coal resources extraction and a large amount of coal resources waste.Therefore,this paper studies and puts forward a new mining method--narrow strip paste filling mining,that is,a mining method that divides the working face into several narrow strip working faces and rounds?in this paper,four rounds are taken as an example?to successively mine and carry out paste filling in the goaf.Based on the engineering background of mining under water pressure in Bailu coal mine in Yulin,this paper puts forward the method of filling mining with narrow strip of paste,expounds the mining filling process of filling with narrow strip of paste,simulates and studies the characteristics of the movement and damage of overlying rock in each stage of the round mining process,and analyzes the geology that affects the filling mining with narrow strip of paste to control the movement and damage of overlying rock and the development height of water conducting fracture zone Mining factors and filling factors;The direct roof and supporting pillars on both sides after strip coal pillar mining are simplified as fixed support beam model,and the ultimate span of direct roof in Bailu coal mine is calculated to be 14.58m,which provides basis for the selection of strip coal pillar width;The mining process of narrow strip paste filling is analyzed,and the mechanical model of roof movement in narrow strip filling mining is established based on elastic foundation beam theory,The deflection equation of roof rock beam is derived,the subsidence value of roof rock beam under different factors of mining filling strip is calculated by using Maple software,and the movement and failure of overlying strata are analyzed.The main and secondary relations of factors influencing the movement and failure rule of overlying strata in narrow strip paste filling mining are the underconnected amount of filling body,the width of narrow strip and the strength of filling body.The equivalent mining height principle based on paste filling mining is obtained On the basis of theoretical calculation,it is concluded that the development height of the water conducting fracture zone in the overlying strata of the narrow strip paste filling mining in Bailu coal mine is 30m,which can ensure the safety of the narrow strip paste filling mining under the water body;The FLAC^3Dnumerical simulation model of the narrow strip paste filling mining face in Bailu coal mine is established,and the effects of the filling rate,the strength of the filling body and the width of the narrow strip paste filling on the opening of the narrow strip paste filling are studied Under different filling rate,filling strength and narrow strip width,the influence of overburden movement and failure,development of water conducting fracture zone and surface movement and deformation law in the working face.The research results provide a reference for the engineering practice of filling mining under the water body of Bailu coal mine.This paper are 42 Figures,7 tables and 78 references.