Reasonable Parameter Selection Of Drilling Pressure Relief In Deep Roadway With Different Lithology

It is difficult to maintain the stability of deep roadway surrounding rock only by increasing the support strength.Transferring and reducing the stress of surrounding rock is the key to realize the stability control of roadway surrounding rock.Due to the advantages of simple process,convenient construction and small engineering quantity,the technology of borehole pressure relief in roadway is widely used at present.However,the scheme and parameter design of borehole pressure relief in practical engineering mainly rely on engineering experience,and the reasonable parameter selection of borehole pressure relief in different lithology is particularly important.This paper focuses on the selection of reasonable parameters for drilling pressure relief in mudstone,sandy mudstone and siltstone,which are common in deep roadways of Huainan and Huaibei mining areas in Anhui Province.Using the numerical simulation method under the guidance of theoretical analysis,the maximum principal stress distribution in five typical directions of the side is analyzed by FLAC3 D numerical simulation software,and the reasonable position of drilling pressure relief is determined.The reasonable parameters of drilling pressure relief in mudstone,sandy mudstone and siltstone are determined by analyzing and comparing the maximum principal stress σ,cohesion c and g G displacement u of roadway f F,h H direction in different pressure relief drilling diameters(50mm,80 mm,100mm,150 mm,200mm),different pressure relief drilling lengths(3m,6m,8m,10 m,15m,18 m,20m)and different row spacing arrangement(single row hole,row spacing is 1.5m×1.5m,1m × 1m,0.5m × 0.5m).The reasonable parameters of borehole pressure relief are applied to the engineering practice of three-level water sump roadway in Zhuxianzhuang of Huaibei Mining Group,and combined with multi-point displacement meter for measurement,good results have been achieved.The following conclusions are drawn :(1)When drilling and depressurizing the roadway which is mainly subjected to self-weight stress,the drilling should be selected as far as possible between the ac position of the roadway side,and the pressure relief drilling should be drilled as soon as possible after the excavation of the roadway.(2)For three different lithology,respectively,within a certain range of appropriate increase in borehole diameter d,borehole length L and reduce the row spacing between boreholes a×b is conducive to the control of roadway surrounding rock stability.(3)When the lithology of roadway surrounding rock is mudstone,the reasonable parameters of borehole pressure relief are : diameter d=100mm,length L=15m,row spacing a×b=1m×1m;when the lithology of roadway surrounding rock is sandy mudstone,the reasonable parameters of borehole pressure relief are : diameter d=100mm,length L=10m,row spacing a×b=1m×1m;when the lithology of roadway surrounding rock is siltstone,the reasonable parameters of borehole pressure relief are :diameter d=150mm,length L=8m,and row spacing a×b=1m×1m.(4)Based on the engineering practice of Zhuxianzhuang three-level sump roadway in Huaibei Mining Group,the numerical calculation model of borehole pressure relief in Zhuxianzhuang three-level sump roadway is established.The borehole pressure relief test is carried out and the engineering measurement is carried out.The measured results are basically consistent with the simulated results.Figure [61],table [7],reference [60]...