采动覆岩破坏演化特征研究对煤炭安全开采具有重要指导意义。以新疆哈密大南湖一矿1303工作面为研究对象,根据开采技术条件,构建采动覆岩破坏演化特征实验模型;分析覆岩运移特征与声发射监测信息,揭示了采动覆岩单次破裂及来压过程中多次破裂的能量耗散与演化特征,其历程分别为"释放-积聚-释放"与"裂隙扩展-破裂-垮落"。借助钻孔电视判定覆岩破坏演化高度,结果表明:工作面开挖后,覆岩破坏高度随模型开采持续增加,但受下方煤岩体碎胀效应影响,覆岩破坏高度增幅随来压次数增加而逐渐降低。工作面推进至246.4 m时,破裂岩块间形成稳定的挤压平衡结构,工作面达到充分采动状态,采动覆岩破坏高度峰值为96.0 m.相关研究成果为指导工程实践提供了定量依据。
Analysis on failure evolution characteristics of mining overburden strata is significant to the safe coal production. According to the technological settings of No. 1303 caving face,a physical simulation model has been built. Analyzing experimental phenomenon and acoustic emission monitoring information,energy dissipation and evolution mechanism were revealed during single stage and weighting period,that is "discharge-accumulation-discharge "and "fissure expansion failure caving ". Judging the height of overburden strata failure by borehole TV,relevant result revealed that the height of overburden strata failure continues to increase along with the mining model advancing; on the contrary,because of the bulking effect,each growth of overburden strata fracture is decreasing with periodic weighting. When the working face advances to 246. 4 meters,the failure rocks form stable extrusion equilibrium structure,and the working face turns into sufficient mining phase. Besides,peak value of overburden strata failure height is 96. 0 meters. All research achievements provide a quantitative basis to guide the engineering practice.