深部巷道围岩蠕变分析与离散元模拟

将顶管法应用于深部煤矿地质条件下深部岩体施工中,会遇到因岩石流变等大变形导致顶管机的卡停甚至抱死,因此充分考虑岩石的流变特性,对顶管法在高地应力区的应用十分重要。以张集矿北区1413A高抽巷为例,利用离散元PFC3D(particle flow code 3D)程序对巷道蠕变特性进行了系统的研究。首先,调用伯格斯模型,通过虚拟蠕变试验对巷道所处粉砂岩层的微观参数进行标定,并与室内试验数据对比,从而验证离散元方法用于岩石蠕变问题分析的可行性。然后,建立巷道的平面应变离散元模型,设置多个测量球,得到了巷道围岩的应力应变在时间和空间上的分布情况,并与理论解对比,发现两者吻合较好,可为后续巷道围岩蠕变的深入研究提供有益的参考。

Discrete Element Method Analysis of Surrounding Rock Creep in Deep Mining Roadway

In the construction of pipe jacking method, because of the large deformation such as rock rheology, it will lead to the jamming or even locking of the pipe jacking machine. Therefore, taking full account of the rheological properties of rock, it is very important for the application of pipe jacking method in ground stress area. In this paper, a case study of the 1413A high-pumping tunnel in the north of Zhangji mine is carried out. Creep characteristics of the roadway are systematically studied by the discrete element method. Burgers contact model is invoked, and the microscopic parameters of the siltstone are calibrated through virtual creep test. To verify that discrete element method can be used to solve problem of rock creep problem, the result of numerical simulation and laboratory test were compared. Moreover, by establishing the plane strain discrete element model of the roadway and setting a series measuring balls, stress and strain distribution of the surrounding rock are obtained. It is found that result of numerical simulation can be in agreement on the theoretical solution, and this can provide useful reference for in-depth study of surrounding rock creep.