含复杂裂隙网络岩质边坡三维稳定性计算方法

Three-dimensional Stability Calculation Method of Rock Slope with Complex Fracture Network

岩质边坡稳定性主要受控于结构面的空间组合关系,二维稳定性计算结果往往忽略结构面切割的空间效应,无法准确反映其真实稳定性情况。基于离散裂隙网络模型(DFN)提出了考虑复杂裂隙网络分布的岩质边坡三维稳定性计算方法,该模拟方法假定岩体由岩块和裂隙面组成,分别采用实体单元和无厚度摩擦接触界面单元模拟,基于有限元强度折减法求得岩质边坡的潜在滑动面及安全系数。结果表明,该方法可有效分析含多条裂隙面三维边坡稳定性;二维平面应变模型无法准确反映真实三维边坡失稳问题,忽略三维效应的边坡稳定性分析易出现过于保守设计的情况;在保证精度的前提下,所提方法可有效减小前处理网格剖分难度,对于解决含复杂裂隙网络岩质边坡三维数值模拟问题具有优势。

The stability of rock slopes is mainly controlled by the spatial combination of structural planes.The calculation results of two-dimensional slope stability often ignore the spatial effect of structural plane cutting,and cannot accurately reflect its true stability situation.A three-dimensional stability analysis scheme for rock slopes considering the distribution of complex fracture networks is proposed based on the discrete fracture network model(DFN).It is assumed that the rock slope is composed of rock block and discrete fractures,which are simulated by solid elements and zero-thickness frictional contact interface elements,respectively.The potential sliding surface and factor of safety of the rock slope are obtained based on the finite element strength reduction technique.The results show that the proposed approach can effectively analyze the three-dimensional stability of slopes containing multiple discrete fractures.The two-dimensional model cannot adequately solve the three-dimensional slope instability problem,and slope stability analysis that ignores the three-dimensional effect is prone to overly conservative design.On the premise of ensuring accuracy,the adopted approach can effectively reduce the difficulty of preprocessing mesh generation,which has advantages in solving three-dimensional numerical simulation problems of rock slopes with complex fracture networks.