Study On Stability Control Technology Of Overburden Rock During Strip Paste Filling Mining In Bailu Coal Mine

The Yulin area in northern Shaanxi is a key planned large-scale coal construction base in China.In the early stages of development,the house pillar mining method was basically used,resulting in a large number of leftover coal pillars,wasting coal resources.At the same time,unreasonable mining methods have damaged groundwater resources,causing serious soil erosion,and the long-term bearing capacity of coal pillars is prone to instability,leading to large-scale roof pressure and frequent occurrence of mining earthquakes.This article proposes a strip paste filling coal mining method to protect groundwater resources and avoid the generation of residual coal pillars and large-scale weighting.Based on the control of overlying rock with paste filling in Bailu Coal Mine,the thesis calculates and analyzes the limit span L=13.85 m for the control of overlying rock with strip paste using a fixed beam mechanical model;Based on Wilson’s strength theory,a mechanical model for the cooperative loading of strip paste backfill and coal pillar was established,and the filling process parameters and strength of the backfill were determined to be 4.05MPa;Based on the equivalent mining height theory,it is obtained that the maximum height of the water conducting fracture zone in paste filling mining is 27 m.Using FLAC3 D simulation,the influence of filling ratio,filling body strength,and filling width on overlying rock deformation and the development height of water conducting fracture zone was studied,as well as the primary and secondary relationships.The research results have been implemented in the CT701 working face of the seventh mining area,and the filling process parameters are: the filling rate is 98%,the filling body strength is 5MPa,and the strip width is 8m;Through the measurement of the strength of the filling body,the displacement of the roadway roof and floor,and the height of the water conducting fracture zone,the control effect of strip paste filling mining on the overburden damage is good,which provides a reference for the mining of coal resources under similar geological conditions,and is also of great significance for the recovery of the remaining coal pillars in the entire northern Shaanxi region.