基于土体非均匀性表征和THM耦合分析的滑坡机理及风险评估研究

Landslide is a commonly encountered geological disaster, and it poses a huge threat to the safety of human life and property. The mechanism of slope instability, prediction of slope deformation and risk assessment of landslide have been consistently attracting attentions in geological disaster research. This project investigates the mechanism and risk of landslide based on multi-field coupling theory by considering soil non-uniformity. Characterization of spatial variability of soil parameters by 3D non-Gaussian random fields is put forward. Coupled thermal-hydro-mechanical (THM) analysis on slope stability is conducted, and approaches of identify the sliding surface of a slope with non-uniform soil is proposed. A theoretical method for landslide mechanism is proposed based on soil non-uniformity and coupled THM analysis. Meanwhile, the influence of spatial variability of soil parameters, rapid change of seepage field and thermal effect on the slope stability are addressed extensively. An advanced calculation method for estimating the failure probability and quantitatively assessing for landslide hazard is established, resulting in a comprehensive and efficient simulation platform for evaluating the landslide risk. The research is aimed to advance current understanding of soil slope stability analysis, by providing theoretical basis and technical support for forecasting landslide deformation, quantitatively assessing landslide risk and reducing landslide disaster.

滑坡是最常见的地质灾害之一,对人类的生命财产安全构成重大威胁。厘清滑坡滑动机理、预测滑坡变形、减轻滑坡灾害一直是地质灾害领域研究的热点问题。本项目针对土体非均匀性和多场耦合分析的滑坡机理及风险评估问题开展研究，重点研究土体参数空间变异性非正态三维随机场表征方法、基于热-流-固（THM）耦合分析的滑坡机理、考虑空间变异性的滑坡关键滑动面识别方法。提出基于土体非均匀性和THM耦合分析的滑坡机理分析方法，阐明土性参数空间变异性、渗流场急变和温度效应等因素对边坡失稳的影响机制。将提出考虑土体非均匀性和THM耦合作用下边坡失效概率计算方法以及滑坡灾害后果定量评估方法，建立一种基于高效数值模拟的滑坡风险综合评估方法。研究成果将为预测滑坡变形、定量评估滑坡风险、减轻滑坡灾害提供理论依据和技术支撑。

边坡稳定性评价和失效后果分析一直以来都是水工岩土工程领域重要的研究课题。由于受到复杂地质演化的影响，天然岩土体参数通常具有明显的非均质性，显著影响边坡稳定性评价结果。因此，如何表征土体参数的非均质性以及量化其对于边坡稳定性的影响是一个值得探究的问题。本课题通过理论研究、数值分析和试验研究相结合的方法，围绕土体非均匀性和THM耦合效应对边坡稳定性影响机制及相应风险评估方法展开研究。针对土体强度、复杂渗流边界和滑面热效应在滑坡过程中的影响机制进行了系统梳理。研究结果表明：相对非均质多层土坡而言，基于均质边坡模型得到的边坡稳定安全系数易高估边坡整体的稳定性，导致偏于不保守的估计；边坡失稳后滑面上因土体摩擦生热使得温度升高，热膨胀产生的超孔压在短时间内来不及消散，导致土体有效应力降低，土体参数的热-水-力耦合作用明显，影响滑动土体的运动特征。此外，在蒙特卡洛模拟和滑坡涌浪形成机理的框架下，提出了一种考虑土体非均匀性的三维滑坡涌浪风险定量评估方法，可为预测滑坡变形、定量评估滑坡风险、减轻滑坡灾害提供理论依据和技术支撑。项目执行期间发表论文35篇，其中SCI论文20篇，中文核心3篇，国际会议论文11篇；起草参编地方标准1本；获批国家发明专利5项，软件著作权1件，其中软件著作权实现了成果转化。项目负责人入选全球前2%顶尖科学家“2022年度科学影响力排行榜”。