Dynamics of creeping landslides controlled by inelastic hydro-mechanical couplings
Dynamics of creeping landslides controlled by inelastic hydro-mechanical couplings
复制标题
非弹性水力耦合控制的蠕变滑坡动力学
DOI：
10.1016/j.enggeo.2023.107078
复制
发表时间：
2023
影响因子：
7.4
通讯作者：
Buscarnera, Giuseppe
中科院分区：
文献类型：
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作者：
Li, Xiang;Chen, Yanni;Handwerger, Alexander L.;Buscarnera, Giuseppe
缓慢移动的山体滑坡会影响附近的基础设施和社区，常常造成广泛的经济损失。虽然许多山体滑坡在数十年或更长时间内表现出缓慢且间歇性的滑动，但有时它们会迅速加速并导致灾难性的失败。尽管众所周知滑坡动力学是由流体力学过程控制的，但很少有分析模型能够通用地结合剪切带材料的非弹性行为，从而阻碍了对其特性如何调节耦合流体流动和滑坡运动的幅度和速率的准确量化。为了解决这个问题，我们开发了一个模拟框架，其中包含活动滑坡底部降雨引起的、变形介导的孔隙水压力瞬变。该框架涉及两个连续扩散过程的计算，一个在上部刚性多孔滑坡块内，另一个在非弹性剪切带内。尽管该框架可以与任何弹塑性本构定律联系起来，但在这里我们通过完美弹塑性摩擦模型来模拟滑坡运动，这使我们能够考虑土体材料的标准属性，例如弹性模量、摩擦角、膨胀角和导水率。与加州海岸山脉缓慢移动的山体滑坡相关的数值案例研究表明，所提出的公式捕捉了降水引起的不同时间运动模式。在每种情况下，我们通过结合正膨胀系数，实现了数据和模拟之间相对准确的匹配，这导致负超孔隙水压力和自我调节运动的自发产生。相反，没有膨胀的模拟（因此反映了临界状态的逼近）会产生急剧的加速度，这是典型的灾难性失控加速度。我们的研究结果鼓励将所提出的框架与针对特定地点的地质材料特性和数据可用性量身定制的本构法结合使用，从而有利于对自然界中观察到的各种爬行滑坡趋势的通用表示。
Slow-moving landslides affect proximal infrastructures and communities, often causing extensive economic loss. While many of these landslides exhibit slow and episodic sliding for decades or more, they sometimes accelerate rapidly and fail catastrophically. Although it is known that the landslide dynamics are controlled by hydro-mechanical processes, few analytical models enable a versatile incorporation of the inelastic behavior of the shear zone materials, thus hindering an accurate quantification of how their properties modulate the magnitude and rate of coupled fluid flow and landslide motion. To address this problem, we develop a simulation framework incorporating rainfall-induced, deformation-mediated pore-water pressure transients at the base of active landslides. The framework involves the computation of two sequential diffusion processes, one within an upper rigid-porous landslide block, and another within the inelastic shear zone. Although the framework can be linked to any elastoplastic constitutive laws, here we model landslide motion through an elastic-perfectly plastic frictional model, which enables us to account for standard properties of earthen materials such as elastic moduli, friction angle, dilation angle, and hydraulic conductivity. Numerical case studies relevant to slow-moving landslides in the California Coast Ranges show that the proposed formulation captures different temporal patterns of movement induced by precipitation. In each of the case, we achieved a relatively accurate match between data and simulations by incorporating positive dilation coefficients, which leads to spontaneous generation of negative excess pore-water pressure and self-regulating motion. Conversely, simulations with no dilation (hence, reflecting the approach of critical state) produce sharp acceleration, typical of catastrophic runaway acceleration. Our findings encourage the use of the proposed framework in conjunction with constitutive laws tailored to site-specific geomaterial properties and data availability, thus favoring a versatile representation of the variety of creeping landslide trends observed in nature.