长期干旱背景下降雨型松散堆积体滑坡机理及预测方法研究

Loose deposits slopes are widely distributed in China. Rainfall is one of the important triggering factors for loose deposits landslides. Therefore, the study of rainfall-induced loose deposits landslides can reduce the damage of life and property caused by landslides, and has a very important theoretical significance and social value.. In recent years, under the environment of global warming, extreme weather occurs frequently, especially the prolonged drought alternates with heavy rainfall. The study will be carried out aiming at the loose deposits slopes under the extreme weather occurred in Yunnan, Guizhou, and Sichuan in recent years. First, degradation effects of the loose deposits under prolonged drought will be investigated by laboratory tests. Second, the influence of prolonged drought - heavy rainfall on loose deposits slope will be investigated by the combination of model tests, field observations and numerical analyses, revealing its failure mechanism caused by rainfall. Finally, based on the failure mechanism, comprehensive meteorological drought index (CI) will be used to reflect the degradation effects caused by prolonged drought. A landslide prediction model will be developed using CI together with the dynamic rainfall threshold for the loose deposits slope that experiences prolonged drought. The study results will not only offer guidance for the design and disaster prevention of loose deposits slopes affected by the construction, but also have far-reaching impact on promoting technological progress.

松散堆积体边坡在我国分布广泛，降雨是松散堆积体滑坡最主要的触发因素之一。开展降雨诱发松散堆积体滑坡的研究，对减少滑坡造成的生命和财产损失，具有十分重要的理论意义和社会价值。. 近年来在全球变暖的大环境下，极端气候频发，我国很多地区长期干旱和强降雨交替出现。本项目针对近年来我国云贵川地区极端气候下的松散堆积体边坡展开研究。首先通过试验研究长期干旱背景下的松散堆积体边坡岩土体性质的劣化效应。进而通过模型试验、现场观测和数值分析研究长期干旱－强降雨交替作用对松散堆积体边坡的影响，揭示其降雨致滑机理。最后，基于松散堆积体边坡降雨致滑机理，在滑坡预测模型中引入综合气象干旱指数反映长期干旱对松散堆积体边坡造成的不利影响，结合动态降雨量阀值，建立长期干旱背景下的松散堆积体滑坡预测模型。该研究成果不仅对工程建设影响范围内的松散堆积体边坡的设计和灾害防治具有指导意义，而且对推动行业技术进步具有深远影响。

近年来在全球变暖的大环境下，极端气候频发，我国很多地区长期干旱和强降雨交替出现。针对这一特殊研究背景，结合高速公路建设中广泛存在的松散堆积体边坡稳定性问题，本项目首先通过试验研究了长期干旱背景下的松散堆积体边坡岩土体性质的劣化效应。设计了边坡物理模型试验装置，设计了降雨模拟系统和多物理量监测系统，开展了边坡降雨致滑物理模拟，对经历过长期干旱和未经历长期干旱的松散体边坡的降雨影响进行了对比研究。根据现场观测资料，基于数值分析研究了长期干旱－强降雨交替作用对松散堆积体边坡的影响规律，揭示其降雨致滑机理。基于松散堆积体边坡降雨致滑机理，结合滑坡和降雨条件的统计分析结果，在滑坡预测模型中引入综合气象干旱指数反映长期干旱对松散堆积体边坡造成的不利影响，建立长期干旱背景下的松散堆积体滑坡预测模型，模型可回归为传统的滑坡预测模型。研究成果不仅对工程建设影响范围内的松散堆积体边坡的设计和灾害防治具有指导意义，而且对推动行业技术进步具有一定影响。