Regulation of landslide motion by dilatancy and pore pressure feedback
Regulation of landslide motion by dilatancy and pore pressure feedback
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DOI：
10.1029/2004jf000268
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发表时间：
2004-12
影响因子：
--
通讯作者：
R. M. Iverson
中科院分区：
文献类型：
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作者：
R. M. Iverson
[1]一个新的数学模型阐明了如何不同的风格和速率的滑坡运动可以导致库仑摩擦的调节水饱和的基底剪切带的扩张或收缩。模型方程的归一化表明，由于滑坡运动、剪切带体积变化和孔隙压力变化之间的耦合而产生的反馈取决于单一的无量纲参数α，而无量纲参数α又取决于双折射角θ和孔隙压力产生和消散的内在时间尺度。如果剪切带土壤在边坡破坏过程中收缩，则α 0和负反馈允许缓慢、稳定的滑坡运动发生，而正孔隙压力由雨水渗透提供。稳态滑动速度v0服从v0 = −（K/ψ）p*e，其中K是水力传导系数，p*e是由膨胀产生的归一化（无量纲）负孔隙压力。然而，如果雨水渗透和随之而来的孔隙压力增长继续有增无减，它们的影响最终会抵消负p*e的稳定影响。然后，无限的滑坡加速发生，加剧了不稳定的发展，如果随着滑坡运动的进行而减少。尽管如此，模型方程的数值解表明，缓慢，近稳定的运动的粘土丰富的滑坡可能会持续数月的负孔隙压力反馈，调节基础库仑摩擦的结果。类似的稳定运动是不太可能发生在砂丰富的滑坡，其特点是较弱的负反馈。
[1] A new mathematical model clarifies how diverse styles and rates of landslide motion can result from regulation of Coulomb friction by dilation or contraction of water-saturated basal shear zones. Normalization of the model equations shows that feedback due to coupling between landslide motion, shear zone volume change, and pore pressure change depends on a single dimensionless parameter α, which, in turn, depends on the dilatancy angle ψ and the intrinsic timescales for pore pressure generation and dissipation. If shear zone soil contracts during slope failure, then α 0, and negative feedback permits slow, steady landslide motion to occur while positive pore pressure is supplied by rain infiltration. Steady state slip velocities v0 obey v0 = −(K/ψ) p*e, where K is the hydraulic conductivity and p*e is the normalized (dimensionless) negative pore pressure generated by dilation. If rain infiltration and attendant pore pressure growth continue unabated, however, their influence ultimately overwhelms the stabilizing influence of negative p*e. Then, unbounded landslide acceleration occurs, accentuated by an instability that develops if ψ diminishes as landslide motion proceeds. Nonetheless, numerical solutions of the model equations show that slow, nearly steady motion of a clay-rich landslide may persist for many months as a result of negative pore pressure feedback that regulates basal Coulomb friction. Similarly stabilized motion is less likely to occur in sand-rich landslides that are characterized by weaker negative feedback.