岩石裂隙中水流脉动压力传播的数值模拟

Numerical simulation on propagation of fluctuating pressure of flow within rock fractures

为了分析网络结构对裂隙水体内脉动压力传播规律的影响,引入蒙特卡罗模拟方法,通过数值模拟得到与天然裂隙网络在统计上相似的仿真裂隙网络,以此作为裂隙水的赋存空间,建立一维瞬变流模型,对脉动压力在裂隙网络中的传播进行数值模拟,得出裂隙水中脉动压力传播的非定常时间过程,以及裂隙网络中压力脉动强度的空间分布云图。模拟结果表明,岩体裂隙网络中脉动压力的传播具有显著的各向异性,裂隙中各点的瞬时脉动压力是由该点所衔接(尤其是直接衔接)的裂隙线元的水力瞬变作用以及裂隙入口干扰源、裂隙末端反射源三者共同作用的结果。

We used the Monte-Carlo method to analyze the influence of network structure on the propagation law of fluctuating pressure of flow within fractures. A replica of the fracture network was created by numerical simulation, which has resembled statistical characteristics with natural fracture network. Taking the replica of fracture network as main space of fissure water, a one-dimensional transient flow model was established to numerically simulate the propagation of fluctuating pressure. And then, the unsteady time process of fluctuating pressure＆#39;s propagation of fissure water and the spatial distribution nephogram of fluctuating intensity were generated. We concluded that the propagation of fluctuating pressure in rock fracture network has significant anisotropy. And the transient fluctuating pressure at any node within fractures is determined by the combination of three factors： the hydro-transient effect of fracture line elements connected with the node（ especially of those directly connected with the node） , the interfering source at fracture entrances, and the reflection source at fracture ends.