Gravity‐driven groundwater flow and slope failure potential: 2. Effects of slope morphology, material properties, and hydraulic heterogeneity
Gravity‐driven groundwater flow and slope failure potential: 2. Effects of slope morphology, material properties, and hydraulic heterogeneity
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DOI：
10.1029/91wr02695
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发表时间：
1992-03
影响因子：
5.4
通讯作者：
M. Reid;R. M. Iverson
中科院分区：
文献类型：
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作者：
M. Reid;R. M. Iverson
山坡形态，材料特性和水力异质性影响地下水流的作用，挑起边坡不稳定。我们定量评估这些影响，采用弹性有效应力模型和库仑破坏潜力的概念，在我们的同伴文件（艾弗森和里德，这个问题）。敏感性分析表明，控制模型结果的四个无量纲量（即，泊松比、孔隙度、地形剖面和导水率对比）、边坡剖面和导水率对比对地下水渗透力、有效应力和边坡破坏潜力具有最显著和最多样的影响。重力驱动的地下水流强烈地影响平衡山坡的形状，我们将其定义为具有均匀近地表破坏潜力的山坡。对于无地下水流的均质边坡，平衡坡面剖面是平直的;但对于重力驱动的水流，平衡剖面是凹的或凹凸的，并且最大的破坏潜力存在于凸形边坡的底部附近。在非均质边坡中，小于1个数量级的相对较小的渗透系数差异显著影响渗透力场和边坡破坏潜力。最大的影响发生时，如果电导率对比度是四个数量级或更多，大的水力梯度通常会导致特别大的故障潜力，从低电导率层相交的地面。
Hillslope morphology, material properties, and hydraulic heterogeneities influence the role of groundwater flow in provoking slope instability. We evaluate these influences quantitatively by employing the elastic effective stress model and Coulomb failure potential concept described in our companion paper (Iverson and Reid, this issue). Sensitivity analyses show that of four dimensionless quantities that control model results (i.e., Poisson's ratio, porosity, topographic profile, and hydraulic conductivity contrast), slope profiles and hydraulic conductivity contrasts have the most pronounced and diverse effects on groundwater seepage forces, effective stresses, and slope failure potentials. Gravity-driven groundwater flow strongly influences the shape of equilibrium hillslopes, which we define as those with uniform near-surface failure potentials. For homogeneous slopes with no groundwater flow, equilibrium hillslope profiles are straight; but with gravity-driven flow, equilibrium profiles are concave or convex-concave, and the largest failure potentials exist near the bases of convex slopes. In heterogeneous slopes, relatively slight hydraulic conductivity contrasts of less than 1 order of magnitude markedly affect the seepage force field and slope failure potential. Maximum effects occur if conductivity contrasts are of four orders of magnitude or more, and large hydraulic gradients commonly result in particularly large failure potentials just upslope from where low-conductivity layers intersect the ground surface.