厚硬顶板预裂弱化后应力场及裂隙场演化特征数值模拟研究

Numerical Simulation Study on Evolution Characteristics of Stress Field and Fracture Field after Hard Roof Pre-Cracking and Weakening

工作面上覆厚硬顶板,开采过程中,若不经过弱化处理,易引起大面积悬顶,造成采场周围应力集中,工作面前方形成高强荷载源;工作面后方形成瓦斯存储库,顶板一旦垮塌易造成冲击地压及瓦斯异常涌出灾害的发生。因此,对于厚硬顶板要经过超前弱化处理,而摸清弱化前后采场周围应力场、裂隙场分布及演化特征是工作面灾害防治的基础和关键。通过UDEC数值模拟,结合矿井实际地质资料及相关煤岩力学参数,建立了平面数值模型。通过模拟计算,得出顶板弱化前后应力场、裂隙场分布特征。通过现场验证,模拟结果与现场实际吻合。这为顶板弱化及高位钻孔措施优化调整提供了理论依据。

The working face is covered with a thick hard roof. In the mining process, if the roof is not weakened, it will easily lead to a large area of suspended roof, resulting in stress concentration around the stope and the formation of high-strength load source in front of the working face. Gas storage is formed at the rear of the working face. Therefore, the thick hard roof should be treated with advanced weakening, and the distribution and evolution characteristics of stress field and fracture field around the stope before and after weakening are the basis and key to the disaster prevention of the working face. Through UDEC numerical simulation, combined with the actual geological data of the mine and related mechanical parameters of coal and rock, the plane numerical model is established. Through the simulation calculation, the distribution characteristics of stress field and crack field before and after roof weakening are obtained. Through field verification, the simulation results are in good agreement with the field practice. This provides a theoretical basis for the weakening of roof and the optimization and adjustment of high drilling measures.