裂隙岩体中的渗流–应力耦合作用是岩质边坡失稳的重要因素之一。离散裂隙网络(DFN)模型用于研究裂隙岩体渗流,具有概念简单、效率高、适用性强的优点,是研究裂隙岩体渗流问题最为有效的手段之一。非连续变形分析(DDA)方法是专门针对裂隙岩体的非连续特性提出的一种变形场求解方法,能够更加真实地刻画工程岩体。将DFN模拟和DDA方法结合起来,提出基于DDA-DFN的渗流–应力耦合模型,给出考虑裂隙渗流情况下岩体块体系统的瞬时平衡方程,用于研究裂隙岩体变形对渗流的影响和渗流–应力耦合作用下裂隙岩体的变形破坏特征。利用该耦合模型,对一大型水利水电工程边坡稳定性进行分析。结果表明,水库蓄水后,地下水大幅度抬升,渗流–应力耦合作用加剧,导致边坡裂隙岩体中的关键部位发生大变形甚至破坏,进而触发边坡的进一步失稳。实例分析验证了这种方法用于边坡稳定性分析的有效性。
Hydro-mechanical coupling in fractured rock mass is one of the key factors controlling rock slope stability.In this paper,discrete fracture network(DFN) model is used to study fluid flow in fractured rock mass.The DFN has a simple concept with high efficiency and applicability,and it is one of the most effective means to study the fracture seepage problem.Discontinuous deformation analysis(DDA),proposed specifically for the discontinuous nature of the fractured rock mass deformation calculations,is applicable to more realistic characterization of engineering rock mass.Combining DFN simulation and DDA,the hydro-mechanical coupling model is proposed;and instantaneous equilibrium equations of rock block system considering fracture seepage,which are used to research the effects of fractured rock mass deformation on fracture seepage and the failure characteristics of rock mass under hydro-mechanical coupling,are presented.By the proposed coupling model,stability of a slope near a large water reservoir is analyzed.Simulated results show that groundwater uplifts greatly with the reservoir impoundment;and hydro-mechanical coupling is intensified,which leads to some key parts of the fractured rock slope present large deformation or even damage,further triggering the failure of the slope.The case study verifies the effectiveness of the coupling model applied for slope stability analysis.