不同强度动载叠加下巷道围岩力学特征数值模拟研究

Numerical Simulation on Mechanical Characteristics of Roadway Surrounding Rock Under Superimposed Dynamic Load with Different Strengths

为研究不同强度叠加动载作用下底板巷道围岩力学特性,以朱仙庄煤矿Ⅱ5采区879瓦斯抽采巷道为工程背景,运用数值模拟软件FLAC3D对不同强度叠加动载作用下,巷道围岩应力、位移及塑性区分布规律进行研究。结果表明:巷道应力集中系数随扰动强度增加以不规则简谐运动波形形式增加,巷道顶底板及两帮应力集中程度加剧,峰值位置朝围岩深部转移;巷道顶板及两帮变形量随着扰动强度增加呈增加—下降—增加的变化趋势,其中右帮变化速率最大,顶板次之,左帮最小;巷道在剪切破坏的主导作用下产生破坏,且当扰动强度小于40 MPa时,巷道围岩塑性屈服网格数增量每兆帕0.2个,强度超过40 MPa时,塑性屈服网格数平均增量为每兆帕0.6个。

In order to study the mechanical characteristics of floor roadway surrounding rock under superimposed dynamic load with different strengths, taking 879 gas drainage roadway in Ⅱ5 mining area of Zhuxianzhuang Coal Mine as the engineering background, numerical simulation software FLAC3 D was used to study the stress, displacement and plastic distribution of roadway surrounding rock under superimposed dynamic load with different strengths. The results show that: the stress concentration coefficient of roadway increases in the form of irregular harmonic motion waveform with the increase of disturbance intensity, the stress concentration degree of roadway roof, floor and two sides is aggravated, and the peak position shifts to the deep surrounding rock. The deformation of roadway roof and two sides presents increase-decrease-increase trend with the increase of disturbance intensity, and the change rate of right side is the largest, followed by roof, and the left side is the smallest. The roadway is damaged under the leading action of shear failure, when the disturbance strength is less than 40 MPa, the increment of plastic yield mesh number of surrounding rock is 0.2 per MPa, and when the strength exceeds 40 MPa, the increment of plastic yield mesh number is 0.6 per MPa.