【摘要】 为了判定采场隔水关键层和计算导水裂隙带高度,进行了覆岩采动导水裂隙分布特征的相似模拟实验和力学分析.提出了破断裂隙贯通度的概念和计算公式.试验结果表明,采场覆岩裂隙带上位岩层的回转变形空间较小,且由于岩层刚度和厚度的差异,薄岩层会完全破断;但坚硬厚岩层破断裂隙未贯通,没有形成竖向"导水、导气"裂隙.为了描述岩层的破断程度及破断裂隙导水能力的强弱岩层破断裂隙的贯通度随其下自由空间的增大而增大,且存在自由空间阀值,大于其阀值时则增加缓慢并趋于1;随岩层厚度增大,起裂时岩层破断裂缝的张开角度减小;岩层破断裂隙的贯通度随裂纹尖端临界张开位移的增大而呈线性减小,随岩层周期破断距的增大也呈近似线性减小.更多还原

【Abstract】 Simulation and mechanical analysis were used to study the distribution of water conducting fissures induced in overlying strata by mining.The concept of degrees of fracture-fissure is presented.The results show thin strata completely fracture but hard,thick strata fracture incompletely.Incompletely fractured strata are not capable of vertically passing water or gas.Different stiffness and thickness of the upper strata affect the deformation in the fracture zone.The degree of fracture-fissure increases as the free space in the fracture zone increases.There is a gradual increase that tends to one as the free space exceeds some threshold value.As the strata thickness increases the open angle of the starting fracture-fissure decreases.The degree of fracture-fissure is linearly reduced along the crack tip at the critical opening displacement.It is also approximately linearly decreasing with an increase in the periodic fracture distance in the strata.更多还原