The Scheme Optimization Of Staggered Distance Mining And Law Of Influence On Overburden Of Multiseam In Xiaobaodang No.2 Coal Mine

Northern Shaanxi is the main production area of in China coal resources,but the short of water resources,ecologically fragile and environmental problems such as surface cracks and groundwater leakage caused by coal mining in the region have become increasingly enormous.Therefore,how to attain safe and efficient coal mining while minimizing environmental damage to ecologically fragile areas and achieving coordinated development of coal resource development and ecological environmental protection is the main goal at the moment.In order to fundamentally reveal the influence mechanism on overburden of staggered distance mining in multiseam,the development law of water-conducting fissure zone and the stress transfer law of the staggered distance mining under repeated mining was been systematically studied in this paper.First,the coal pillar staggered distance mining in multiseam was consided.The theoretical analysis,numerical simulation and similar material simulation were comprehensively used to analyze the reduction damage mechanical mechanism of the staggered distance mining.And the staggered distance mining plans were optimized by the engineering background of the Xiaobaodang No.2 coal mine.The results are as follows:Subsequence,the staggered distance mining model of the multiseam was generalized and a reasonable staggered distance range was derived.A reasonable range of staggered distance mining was calculated coupled with the of Xiaobaodang No.2 Coal Mine geological condition.The σzz curve showed a "peak" shape and the principal stress peak value appeared in the center of the coal pillar.The Z displacement curve domenstrated a "Л" shape and the smallest settlement value illustrated in the center of the coal pillar.The optimal of stress distribution,the optimal of peak stress,and the optimal of Z displacement appeared in the same scheme.The optimal staggered distance value was 40 m,and the most unfavorable(worst)distance value was 0 m,in staggered distance mining of double seams.The optimal staggered distance value was 40 m,and the most unfavorable(worst)distance value was 0 m,under the condition of keeping the optimal staggered distance value of the double seams(40m),in staggered distance mining of multiseam.The most unfavorable staggered distance mining scheme had a maximum development height of 210 m in the water-conducting fissure zone,which was 1.1 times that of the optimal scheme.There was six fractured in the overburden conduct to the ground,which was 1.5 times the optimal scheme.The maximum width of surface cracks was 0.75 m,which was 1.67 times that of the optimal scheme,and the maximum vertical displacement of surface cracks was 1.2 m,which was 20 times that of the optimal scheme.The surface subsidence curve had two sudden changes,and the surface had three obvious cracks and heave areas.The optimal scheme of reduction damage staggered distance mining in multiseam could effectively reduce the development height of water-conducting fissure zone in the overburden,sligten the development intensity of surface cracks,and fully realize water conservation and reduction damage mining.The research results could provide a certain theoretical basis and reference for the reduction damage mining of multiseam in northern Shaanxi.