Analysis Stability Influence Of Different Stress Of Thin-layer Complex Roof

Ground stress and section coal pillars in upper coal layer have a huge effect on thestability of the thin-layer complex roof mining gateway. The thin-layer complex roof wasresearched according to Dongrong2nd colliery’s geological condition, adapted syntheticallytheoretical analysis, numerical simulation analysis, field measurement and industrial test toresearch the mechanism of the roof damage,theoretical analysis, numerical simulationanalysis, field measurement and industrial test was adapted synthetically on it. Researchfindings and conclusions are as follows:(1) With the coefficient of lateral pressure λ increasing, roadway’s sides zone of plasticityreduce relatively, roof and floor’s plastic zone increases comparatively, shear failure wherehappen turn from roadway’s sides to roof and floor.(2) When the roadway is located in the hangingwall of the fault, the breaking of roadwaywhich distances from the fault10-20m range tensile failure and shear failure, the failure areaof roadway which distances from the fault15m is the biggest, failure depth of the roof istwice the roadway’s sides’; When the roadway is located in the footwall of the fault, thedamage to roof and the left side of roadway by the fault tectonic stress is bigger, roadwaysurrounding rock damage distance from fault0~10m area damage is the largest.(3) With distance between roadway and coal pillar of the No16coal seam increasing,displacement of roadway surrounding rock reduces quickly, especially, roof displacement;plastic zone area of roadway reduces, particularly, plastic zone area of roadway’s sides; sitewhich it damaged turn from roof and floor to roadway’s sides.(4) When coal pillar of the No.16coal seam is located in the footwall of the fault, asdistance between roadway and fault increasing, plastic zone area of roadway surrounding rockincreases, roof destructive manner is tensile-shear damage, the damaged site turns from the deep place to the superficial place; destructive manner of roadway’s sides is shear damaging,the damaged site is relatively shallow. when coal pillar of the No.16coal seam is located inthe hangingwall of the fault, shear damaged area of roadway’s sides is big, the damaged site isrelatively shallow, damaged area of roof and floor is little, the damaged site is relatively deep.(5) Anchor bolt with high pre-tightening force, reinforcement supported with pre-stressedanchorage cable and grouting surrounding rock strengthening etc. technology measures areused to enhance global stability of thin-layer complex roof mining gateway, the applicationeffect show that it meet requirements of workface mining, has achieved satisfactory economiceffect.