Collaborative Research: Multi-Dimensional and Multi-Physics Analysis of Rainfall-Induced Landslides and Runout

合作研究：降雨引起的滑坡和径流的多维和多物理分析

• 批准号: 1561764
• 负责人: Ning Lu
• 金额: $ 27.93万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-15 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1561764&HistoricalAwards=false
• 关键词: Collaborative; Research; Multi; Dimensional; Physics

Landslides are continual natural hazards that can damage infrastructure and cause significant loss of life as occurred in the Oso Landslide (March 22, 2014) in Snohomish County, Washington. Some landslides are rapid and exhibit large runout over few minutes, whereas others are intermittent and move only small distances in a given year. Both of these hazards are usually triggered by precipitation. The main objective of this research project is to develop a three-dimensional (3D) slope stability framework that incorporates unsaturated soil hydraulic properties, effective stresses, and shear strengths to better predict the location, shape, and depth of rainfall-induced landslides, such as the recent Oso Landslide near Seattle and the La Conchita Landslides (1995 and 2005) near Los Angeles. The proposed 3D model will be used to simulate time-dependent variations in saturation from water infiltration, impact of surface vegetation and timbering, and rises in hydrostatic pore-water pressures from runoff that will be used to predict the runout distance based on the calculated factor of safety, slope angle, and pore-water pressures after triggering. The key product of this research will be a new validated framework for slope stability analyses and landslide risk assessment. This 3D variably-saturated stability analysis framework is important because it accounts for the following factors that are not incorporated in traditional two-dimensional (2D) limit equilibrium slope stability analyses: (1) effective stresses under both saturated and unsaturated conditions, (2) stress-dependent unsaturated and saturated strength envelopes, (3) 3D slide mass geometry, volume, shear forces, and boundary conditions, (4) spatial variation and depth of the unsaturated zone and hydrostatic pore-water pressures across the slide mass, and (5) variation in unsaturated and saturated soil shear strength across the slide mass. Current limitations with 2D analyses affect the calculated limit equilibrium factor of safety and thus the ability to predict the occurrence, shape, volume, and runout distance of the potential slide mass. For example, a 2D analysis does not provide an estimate of the 3D shape and volume, which is key to predicting slide mass volume, pore-water pressures, and runout distance. The results of this project will improve landslide detection, prediction, hazard mapping, land-use planning, and property rights policy decisions. For new subdivisions the geotechnical concerns can be identified and zoning adjusted to manage the risk with the proposed 3D analysis.

山体滑坡是一种持续性的自然灾害，可能会损坏基础设施并造成重大人员伤亡，正如华盛顿州斯诺霍米什县发生的奥索山体滑坡（2014 年 3 月 22 日）那样。 有些山体滑坡速度很快，在几分钟内就会出现较大的滑移，而另一些滑坡则是间歇性的，在一年内仅移动很小的距离。 这两种危害通常都是由降水引发的。 该研究项目的主要目标是开发一个三维 (3D) 边坡稳定性框架，该框架结合了非饱和土水力特性、有效应力和剪切强度，以更好地预测降雨引起的滑坡的位置、形状和深度，例如例如最近西雅图附近的奥索山体滑坡和洛杉矶附近的拉孔奇塔山体滑坡（1995 年和 2005 年）。 所提出的 3D 模型将用于模拟水渗透引起的饱和度随时间的变化、地表植被和木材的影响以及径流引起的静水孔隙水压力的上升，这将用于根据计算的因子预测径流距离触发后的安全性、坡度角和孔隙水压力。这项研究的关键产品将是一个经过验证的新框架，用于边坡稳定性分析和滑坡风险评估。 这种 3D 可变饱和稳定性分析框架很重要，因为它考虑了传统二维 (2D) 极限平衡边坡稳定性分析中未纳入的以下因素：(1) 饱和和非饱和条件下的有效应力，(2)与应力相关的不饱和和饱和强度包络线，(3) 3D 滑动体几何形状、体积、剪切力和边界条件，(4) 不饱和区的空间变化和深度以及滑动体上的静水孔隙水压力，以及(5) 滑坡体上非饱和和饱和土体抗剪强度的变化。 当前二维分析的局限性会影响计算的极限平衡安全系数，从而影响预测潜在滑动质量的出现、形状、体积和跳动距离的能力。 例如，2D 分析不提供 3D 形状和体积的估计，而这对于预测滑动质量体积、孔隙水压力和跳动距离至关重要。 该项目的成果将改善滑坡检测、预测、灾害测绘、土地利用规划和产权政策决策。 对于新的细分，可以识别岩土工程问题并调整分区，以通过建议的 3D 分析来管理风险。