考虑地质模型不确定性的渐进式滑坡变形演化机理研究

The deformation evolution of the progressive landslide, an important topic in the prevention and mitigation of landslide hazards, has been widely studied around the world. The geological model, which is referred to herein as the spatial distributions of the stratum type and the geotechnical parameters at the geological site of concern, is the fundamental input parameter to the analysis of the deformation evolution of the landslide; however, owing to the deposit histories, tectonic activities and human activities, both the stratum type and the geotechnical parameters could be spatially varied. In such circumstances, the purpose of this research is to study uncertainty of the geological model at the comprehensive field test site in Huangtupo Landslides, and then to study the deformation evolution of the progressive landslide considering geological model uncertainty. Within the framework of this project, an uncertain geological model, which could simultaneously consider the spatial variations of the stratum type and the geotechnical parameters, will be established; in which, the spatial variations of the stratum type and the geotechnical parameters will be modelled with the Markov chain model and the conditional random field model, respectively. And then, a refined numerical model, which could simulate the complete evolution process of the progressive landslide deformation, will be built; in which, the continuum mechanics and the discontinuum mechanics of the sliding materials will be modelled with the numerical program FLAC3D and PFC3D, respectively. With the established geological model and the refined numerical model, Monte Carlo simulation will readily be employed to simulate the uncertainty of the geological model at the landslide site, as such the influence of the geological model uncertainty on the deformation evolution of the progressive landslide could be studied; based upon which, the deformation evolution of the progressive landslide, under the scenario of the uncertain geological model will be revealed. It is worthwhile noting that the field data regarding both the geological model and the landslide defamation, involved in this research, will be collected from the comprehensive field test site in Huangtupo Landslides. This research is expected to provide theoretical and technical supports for both the evaluation and the mitigation of the progressive landslide hazards in China; and, this research is expected to have a broad positive impact on both the theoretical development and engineering application.

渐进式滑坡变形演化机理是滑坡地质灾害防灾减灾研究的重要课题。地质模型是滑坡变形演化机理研究的重要输入参数，然而受沉积历史、构造活动及工程活动等影响，工程场地地层类型与岩土参数均存在空间随机分布特性。本项目以巴东黄土坡滑坡野外大型综合试验场为现场研究基地，在研究黄土坡滑坡工程场地地质模型不确定性的基础上，开展地质模型不确定性条件下渐进式滑坡变形演化机理研究。运用马尔科夫链与条件随机场分别模拟地层类型与岩土参数空间随机分布，建立工程场地不确定性地质模型；运用FLAC3D与PFC3D分别模拟滑坡体连续介质与非连续介质力学性态，建立渐进式滑坡变形演化过程精细数值模型；运用蒙特卡洛抽样方法对滑坡地质模型进行抽样模拟，研究地质模型不确定性对渐进式滑坡变形演化过程的影响，揭示地质模型不确定性条件下渐进式滑坡变形演化机理。项目的实施可为我国渐进式滑坡地质灾害评价与防治提供理论与技术支撑。

开展考虑地质模型不确定性的渐进式滑坡变形演化机理研究具有重要意义。本项目以巴东黄土坡滑坡野外大型综合试验场和秭归马家沟滑坡野外综合试验场为现场研究基地，在研究典型滑坡工程场地地质模型不确定性的基础上，开展了地质模型不确定性条件下渐进式滑坡变形演化机理研究。基于条件随机场与马尔科夫理论，提出了工程场地不确定性地层建模方法，构建了马家沟滑坡不确定性地层模型，揭示了地层不确定性对马家沟滑坡稳定性与滑动面位置的影响；基于条件随机场理论，构建了典型滑坡案例岩土参数空间分布不确定性模型，研究了岩土参数不确定性对滑坡稳定性的影响；基于上述地层与岩土参数不确定性建模方法，提出了地层不确定性与参数不确定性耦合建模方法，研究了地层不确定性与参数不确定性耦合作用对工程地质问题性能响应的影响。采用有限元分析软件COMSOL，研究揭示了库水位波动对库岸边坡稳定性的影响规律；采用离散元分析软件PFC，建立了渐进式滑坡变形破坏过程精细数值模型；运用离散参数随机组合表征滑坡变形破坏过程数值建模参数不确定性，提出了考虑建模参数不确定性的渐进式滑坡变形破坏及运动过程不确定性分析方法；以深圳市光明新区红坳弃土场滑坡和重庆市武隆区铁矿乡鸡尾山滑坡为例，开展了考虑建模参数不确定性的滑坡变形破坏及运动过程模拟；结合典型滑坡现场调查与数值模拟，初步完成了不同场地条件作用下滑坡运动速度、运动距离与堆积形态等的室内滑坡运动过程物理模型试验装置设计与可行性验证工作。依托该项目发表中文核心及以上论文11篇，其中SCI论文9篇（包括第一作者5篇、通讯作者4篇）；邀请国内外学者来访讲学6人次，参加国内外学术会议20次（包括5次分会场主席、3次分会场主持人、2次大会特邀报告、3次大会邀请报告、4次大会分会场报告）。各项指标均超额完成。项目研究成果可为滑坡地质灾害评价与防治提供理论与技术支撑，具有重要的科学理论意义和工程应用价值。