降雨诱发土质滑坡大变形破坏机制分析与致灾范围预测

By considering the influences of both the soil heterogeneity and different rainfall patterns, the project is proposed to determine the sliding areas of rainfall induced slope failures, with particular emphasis on the slope post-failure stage, trying to under the underlying slope failure mechanism and its evolution process. Through a series of in-door slope failure experiments, considering the influences of different rainfall durations, intensities, etc., the slope failure processes will be observed. Combing with the numerical simulations using the material point method (MPM), the slope failure mechanism is to be illustrated, and also, a failure criterion is to be proposed. Different failure modes will be categorized as well. Finally, a method to determine the failure impact zones will be obtained, and applied to the Yangbaoding landslide in Shenzhen city, due to a strong rainfall. The project is expected to provide a reasonable and reliable tool for the assessment of the sliding areas of soil landslides.

围绕我国土质滑坡灾害应急处置中关于致灾范围确定的关键科学问题，基于岩土体材料物理力学参数分布的不均匀性、不确定性，以及不同的降雨模式影响，研究土质边坡的变形破坏机制和演化规律，着重考虑边坡失稳破坏后（失稳、垮塌直至形成最终平衡状态）产生大变形运动过程的变形机制以及致灾范围预测。开展不同的降雨强度、降雨历时等外界水力条件下边坡变形破坏全过程的室内试验，发展完善基于随机物质点法的新型数值模拟技术，阐明边坡失稳破坏机制，提出边坡失稳判据，揭示边坡破坏后的变形演化规律，分类不同的边坡破坏模式，形成降雨条件下土质边坡破坏影响范围的确定方法，并应用于深圳市羊宝地滑坡等典型降雨诱发土质边坡滑坡致灾范围的分析与预测。项目成果以期为降雨条件下土质边坡的安全性评估及致灾范围预测提供科学的理论依据及计算方法。

边(滑)坡灾害防治是保障国家重大工程安全与发展战略实施的迫切需要，如何针对滑坡灾害全过程进行防灾减灾和风险调控是目前所面临的重大工程难题，同时也具有重大的战略意义与现实意义。本项目围绕边（滑）坡灾害的全过程变形机制，搭建了降雨诱发滑坡的室内模型试验系统，考虑了不同的颗粒级配以及降雨诱发条件，揭示了边坡变形破坏的全过程，构建了基于速度格式的流固耦合物质点计算模型，定量确定了边（滑）坡灾害的致灾范围，发展了基于径向基点插值法的积分优化算法，有效降低了应力震荡现象，并最大程度上减弱了背景网格的影响，最后建立了一种基于代表性滑面和响应面的考虑土体空间变异性的改进边坡可靠度分析方法，大幅度提高了计算效率，为大规模的边坡风险评估提供了新的途径。本项目有望为降雨条件下边坡的安全性评估及致灾范围预测提供科学的理论依据及计算方法。