GRAVITY-DRIVEN GROUNDWATER-FLOW AND SLOPE FAILURE POTENTIAL .1. ELASTIC EFFECTIVE-STRESS MODEL
GRAVITY-DRIVEN GROUNDWATER-FLOW AND SLOPE FAILURE POTENTIAL .1. ELASTIC EFFECTIVE-STRESS MODEL
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DOI：
10.1029/91wr02694
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发表时间：
1992-03-01
影响因子：
5.4
通讯作者：
REID, ME
中科院分区：
文献类型：
--
作者：
IVERSON, RM;REID, ME
丘陵或山地地形影响重力驱动的地下水流动及其在浅层地下环境中有效应力的分布。有效应力反过来又影响边坡破坏的可能性。为了评估这些影响，我们建立了一个二维稳态孔隙弹性模型。控制方程将地下水效应作为体力，表明空间均匀孔隙压力变化不影响有效应力。我们使用两个有限元代码来实现模型。作为一个例子，我们计算了一个直的、均匀的山坡上的地下水流场、总力场和有效应力场。总体力和有效应力场表明，地下水流动不仅会影响有效正应力，还会影响剪应力。在大部分边坡中，地下水的流动显著增加了库仑破坏电位PHI，我们将其定义为最大剪应力与平均有效正应力之比。地下水流动也使最大破坏电位的位置向坡脚移动。然而，地下水流动对破坏潜力的影响并不像基于简单的一维极限平衡分析所预测的那样明显。这是二维流场和应力场的连续性、兼容性和边界约束的结果，它指出了我们的弹性连续体模型和通常用于评估边坡稳定性的极限平衡模型之间的重要区别。
Hilly or mountainous topography influences gravity-driven groundwater flow and the consequent distribution of effective stress in shallow subsurface environments. Effective stress, in turn, influences the potential for slope failure. To evaluate these influences, we formulate a two-dimensional, steady state, poroelastic model. The governing equations incorporate groundwater effects as body forces, and they demonstrate that spatially uniform pore pressure changes do not influence effective stresses. We implement the model using two finite element codes. As an illustrative case, we calculate the groundwater flow field, total body force field, and effective stress field in a straight, homogeneous hillslope. The total body force and effective stress fields show that groundwater flow can influence shear stresses as well as effective normal stresses. In most parts of the hillslope, groundwater flow significantly increases the Coulomb failure potential PHI, which we define as the ratio of maximum shear stress to mean effective normal stress. Groundwater flow also shifts the locus of greatest failure potential toward the slope toe. However, the effects of groundwater flow on failure potential are less pronounced than might be anticipated on the basis of a simpler, one-dimensional, limit equilibrium analysis. This is a consequence of continuity, compatibility, and boundary constraints on the two-dimensional flow and stress fields, and it points to important differences between our elastic continuum model and limit equilibrium models commonly used to assess slope stability.