Failure characteristics and stress transfer rule of overburden under multiple mining in contiguous coal seams
The failure characteristics of overburden in contiguous coal seams mining are different from those in single seam mining,and there are problems of interlayer influence.Taking the 11#,14-2#and 14-3#coal seam in Yanzishan Coal Mine of Jinneng Holding Coal Industry Group as the research object,through the physical similarity simulation experiment and numerical simulation calculation,the overburden failure characteristics and stress transfer rule of the surrounding rock of the roof and floor during the contiguous coal seams mining were studied and analyzed.The research results show that with the increase of mining frequency,the lateral crack development and vertical crack penetration effect of the roof are more obvious,the caving block degree decreases obviously,and the pressure law is not obvious.The mining-induced stress peak value of coal seam roof overburden decreases with the increase of mining frequency.Under the influence of the first mining,the overburden stress after the stabilization is obviously smaller than that of the virgin rock,while the overburden stress after repeated mining stabilization is similar to that before the mining.Under the influence of multiple mining movements,the overlying strata are destroyed more thoroughly,forming a stepped cut.The research results can provide reference for the control of surrounding rock,water accumulation and gas control in goaf in contiguous coal seams with similar conditions.
contiguous coal seamsmultiple miningoverburden failure characteristicsstress transfer law
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