开采保护层覆岩裂隙演化规律模拟

Simulation study on fracture evolution law of overlying strata when mining protective layer

为提高瓦斯抽采率和揭示保护层采动覆岩裂隙演化规律以及定量分析保护层卸压增透范围,将覆岩裂隙定义为具有开裂损伤功能的粘结单元,利用ABAQUS开发了粘结单元本构关系,建立了采动覆岩砌体结构内聚力模型,进行了粘结单元表征下的保护层采动裂隙演化数值模拟,通过粘结单元损伤程度分析采动裂隙发育状态,根据裂纹的连通状态界定采场覆岩损伤破坏区域,并得到了采动卸压范围及渗透率分布规律,采动裂隙演化规律模拟结果与实验一致,验证了覆岩砌体结构内聚力模型的精准性.

In order to improve the efficiency of gas drainage and study on the law of fracture evolution under the influence of mining, and determine the pressure relief ranges, this paper defined the fracture of overlying strata as a kind of stickiness which has the function of simulating cracks, used ABAQUS to develop the constitutive response of cohesive element, and built the model masonry construction with cohesion of overlying strata. Cohesive element was applied to the simulation of mining a protection layer, fracture development situations of overlying strata can be analyzed according to the damage degree of cohesive elements, and the typical regions of overlying strata can be defined according to the fissure connectivity. With the method of numerical simulation, the law of fracatre evolution and the area ranges of pressure relief are found, and the simulation results of fracture evolution are in accord with experimental results, which proves that the model masonry construction with cohesion can accurately characterize the fracture evolution.