Research On Surrounding Rock Control Technology Of Driving Roadways Along Goaf In Sitai Coal Mine

Using the on-site research, numerical simulation, theoretical analysis and on-siteindustrial tests and so on，the surrounding rock control technique of driving roadwaysalong goaf under two hard conditions is studied and analyzed with the background ofSitai coal mine81215face tailgate. This paper has important significance for miningefficiently and safely with driving roadways along goaf under two hard conditions.The main conclusions of the study are given below:(1) Based on the theory of dominant stratum, a mechanical model of overburdenstructure of driving roadways along goaf under two hard conditions is established. Inorder to provide theoretical basis for studying how to effectively control the roadwaydeformation on the roadway along gob with bolting under two hard conditions，thestability of the overburden on the roadways along goaf after exploiting the roadwayand during mining the working face were analyzed.(2) The reasonable minimum pillar width was calculated with limit equilibriumtheory and elastic-plastic theory. The stress and displacement of coal pillar fordifferent width after drilling the roadway and during mining No.81215face by usingFLAC-3Dnumerical methods were analyzed. It is found that the pillar vertical stressincreases with the increase of the coal pillar width, while the roadway deformationwith the coal pillar width gradually reduces first, then increases and finally balances.With the analysis on the rule about the internal stress variation of pillar coal underdifferent width and roadway deformation of the No.81215face, it is found thatretaining6m pillar can meet stability of surrounding rock in stope.(3) Based on mechanical parameters of No.81215face rock measured inlaboratory, theoretical calculations on the surrounding rock stress, deformation anddamage ranges for the roadway along goab were carried out. By analyzing the impacton stability of the roadway in different supporting parameters using numericalsimulation analysis, the bolting parameters of the roadway are optimized design andselecting reasonable support parameters.(4) A industrial test on site was carried out. After drifting the tailgate ofNo.81215working face, the relativesurrounding rock deformation of tunnel walls arecloser to the amount of37mm, the rock deformation of the side along the gob is closerto15mm, the rock deformation of the side along the working face is closer to22mm.The largest deformation amount of the roof to floor reaches23mm, which roofsubsidence is8mm, the floor heave is15mm. Taking the roadway overall deformation into consideration, the deformation of surrounding rock can be effectively controlled,the safety and stability of roadway is ensured in the use of period, and the surroundingrock control technique of driving roadways along goaf under the two hard conditionsis further improved. It has important significance for the driving roadways along goafretaining design scientific and coal mine safety and high efficiency production.