堆积层滑坡地表变形裂缝的水力性质及降雨入渗规律研究

The mechanism of rainfall-induced landslide is a long-standing scientific problem, and it has been paid close attention to for a long time. The colluvial landslide induced by rainfall is the most widespread and most serious landslide hazard in the world. The ground surface fissure occurred during the deformation stage of the colluvial landslide may change the natural relatively uniform infiltration pattern. The preferential flow in the open and interconnected fissures lead to the rapid change of hydraulic conditions in the deep part of the landslide, and the process cannot be characterized by the traditional uniform infiltration model. Therefore, based on the analysis of the deformation law and the mechanical properties of the fissure set of colluvial landslide, through the typical landslide investigation, laboratory experiment and numerical analysis, the relationship between the mechanical properties and morphological parameters such as the opening, the depth and the length of the fissures in various landslide deformation stages is going to be studied. Then the hydraulic properties of the fissure can be determined by the morphological parameters. Based on the percolation theory of pore and fissure medium, the double model for the uniform infiltration and the preferential infiltration along the fissure at the deformation stage of the colluvial landslide will be established. According to the typical rainfall process during the flood season in the southern China, the infiltration law of the typical colluvial landslide in different deformation stages and its influence on the stability will be analyzed to propose a prediction model for landslide deformation and failure. The results are of great scientific significance to the development of landslide hydraulic theory and the guide of landslide prediction and forecasting.

降雨型滑坡机理是由来已久且持续被关注的科学问题，由降雨引发的堆积层滑坡是世界范围内最普遍、且危害最严重的滑坡灾害类型。堆积层滑坡在变形阶段形成地表裂缝将改变原本相对均匀的入渗模式，张开贯通的裂缝中优先流入渗的存在，使滑坡深部的水力条件被快速改变，这一过程不能通过传统的均匀入渗模型刻画。为此，本项目基于堆积层滑坡变形规律和配套裂缝力学属性分析，通过典型滑坡调查、室内实验和数值分析，研究滑坡变形各阶段裂缝力学属性与张开度、深度、长度等形态参数的关系，继而，根据裂缝形态参数判断裂缝的水力学性质。基于孔隙和裂隙介质的渗流理论，建立堆积层滑坡变形阶段裂缝优先流入渗和均匀入渗的双重模型。根据我国南方汛期典型降雨过程，分析典型堆积层滑坡在不同变形阶段的入渗规律及其对稳定性的影响，提出滑坡变形破坏的预测模型。成果对发展滑坡水力学理论，指导滑坡预测预报具有重要科学意义。

降雨引发的堆积层滑坡是世界范围内最普遍、且危害最严重的滑坡灾害类型。堆积层滑坡的物质组成、边界条件的不均一性和渗流场及应力场等因素的多变性决定了该类边坡的失稳规模、滑移形式和滑面形成特征等方面的复杂性。项目在分析滑坡地表裂缝发育的时空特征和影响因素关系的基础上，建立了地表宏观变形现象和滑坡力学成因之间的关系，揭示了滑坡系统的演化模式和渐变破坏过程。通过现场测试和室内试验，测定了滑坡岩土体的渗透特性和不同含水率条件下滑带土的抗剪强度变化规律。基于典型滑坡的调查结果，建立了室内物理实验模型，模拟不同裂缝发育条件下堆积层滑坡的降雨入渗过程。以三峡库区万州区堆积体滑坡为研究对象，结合库岸滑坡动态监测资料，分析了了降雨和库水位波动过程中地下水的响应规律。采用机器学习算法进行滑坡多源信息融合，构建了多种算法耦合的预测预报模型，建立了地质条件、诱发因素为一体的滑坡综合预警预报判据。该项目研究的降雨条件下堆积层滑坡的变形破坏模型，对该类滑坡的防灾减灾和预警预报具有重要的科学理论意义和实际应用价值。