Study On Stability And Support Technology Of Roadway Surrounding Rocks In A Dense Mineral Areas Of A Tungsten Mine In South Jiangxi

The deformation and destruction of the roadway surrounding rock is one of the key research objects in the safety of mine safety.It will not only affect the progress of mine production,but also bring a series of safety hazard accidents.There is an area of dense mineral veins in the 378 section of a tungsten mine in southern Jiangxi,and most of mineral veins are distributed in parallel,with irregular spacing and similar occurrence.This area passes through a section of roadway which contains a main transportation roadway and a tramcar yard of inclined shaft mouth in the north-south direction.As the mining of the veins will form a dense stope area around this section of roadway,the disturbance caused by these vein mining will have some effect on the stability of the surrounding rock in the roadway.In view of this situation,on-site investigation,theoretical analysis,numerical simulation and on-site monitoring are used to analyze the stability of the surrounding rock of this section of tunnel and optimize the support parameters.The details and conclusions are as follows:（1）Through on-site investigation and mine geological data,understand the geological conditions,mine veins and roadway distribution in the area.（2）Rock samples are taken from the mine site,processed into rock cores,measured for density,Brazil split test,shear test,uniaxial strength pressure test to obtain the mechanical parameters related to the rock,and then the relevant mechanical parameters of the rock were subtracted by the Hook Brown criterion,and the corresponding physical parameters of the rock were calculated..（4）The FLAC^3D software is used to simulate the mining of vein,and the distribution law of surrounding rock stress,displacement and plastic area in the process of mining is analyzed.The results show that with the mining of the vein,the stress in the roof of the main roadway and the intersection of the main roadway and the roadway along the vein are relatively concentrated,and there is the possibility of tensile failure.And the roof of the roadway has a downward displacement trend,in which the displacement of the transportation roadway roof is the most obvious,while the displacement of the two sides of the roadway surrounding rock is not obvious.（5）Through the analysis of the rock loose zone theory,it is concluded that the main transportation roadway at the vein intensive areas is the key support area,and the loosening zone type is typeⅠandⅡ,which can be supported by shotcrete and rock bolt.Based on the numerical simulation of the study on the stress and displacement law of surrounding rock,the FLAC^3D software is used to optimize the mortar bolt support parameters of the main transportation roadway,a key supporting area,and the technically economically feasible support parameter is the bolt length 2.0m,anchoring length 1.0m,pre-tensioning force 40kN and Top angle anchor angle75°.（6）The stability of the surrounding rock of the transportation roadway and the underground mine yard roadway was monitored by the photoelastic stress gauge and the convergence instrument.The monitoring results showed that with the stress concentration at the center of the main transportation roadway,the tramcar yard of inclined shaft mouth was relatively stable.The displacement of roadway section has an increasing trend.The maximum convergence value of transportation roadway is 9.12mm,the displacement of roof is large,and the displacement of two sides is not obvious.