【摘要】 为了研究采空区覆岩采动裂隙形成过程中的演化规律,基于煤岩细观破裂力学特性的数值模拟方法,结合非线性的分形几何理论,研究了覆岩采动裂隙演化过程并定量地描述了其时空分布特征,结果表明:采动下覆岩不断劣化,其内部细观损伤积累最终引起覆岩破坏.采动裂隙演化过程中的声发射具有自相似性的分形特征,加载后其分维值首先小幅度的升高,随后急剧下降,尤其是在破坏前降到最低,该特性可作为评价覆岩破坏的有效指标.上述结果能很好地解释覆岩采动裂隙的演化机制,并指导灾害发生前覆岩稳定性发展趋势的预测预报等防治实践.更多还原

【Abstract】 In order to study the mining crack evolution process of the overlying strata in goaf,based on the numerical method for meso rupture mechanics characteristics of coal rock,combined with nonlinear fractal geometry theory,the evolution process of mining crack and quantitative description of the spatial and temporal characteristics were researched.The results show that the overlying strata deteriorated continuously under mining,simultaneously,the internal meso damage accumulation of rock eventually cause the overlying strata failure.The acoustic emission in the cracks evolution process is with self-similarity.The fractal dimension increases firstly with a small amplitude after loading,and then sharp declines,especially decreases to a minimum value before damage.It is considered to be a effective indicator in evaluation of overburden damage.By means of the overlying results,the overburden fractured evolutionary mechanisms are explained perfectly,and it is able to guide forecasting and control practice of rock stability before disasters.更多还原