库岸牵引式滑坡演化过程能量耗散-变形破坏特征与判据研究

For large water conservancy and hydropower project, evolution process simulation and prediction of the reservoir bank landslide is the key scientific problem. The aim of this project is to analyse the energy dissipation-deformation failure characteristics and criterions on the evolution process of tractive landslide. Baishuihe Landslide and Sanzhouxi Landslide are studied as the cases by considering the significant cyclical fluctuations of water and rainfall conditions in Three Gorges Reservoir. By using the field survey and monitoring, centrifugal simulation test and numerical simulation, multi-field characteristic information in each feature part on the evolution process of typical landslide are obtained for extracting deformation failure characteristics of landslide and conversion-dissipation characteristics of energy. Based on the Fractal Theory and State Space Reconstruction Theory, the macro deformation temporal evolution model of landslide is researched. And System Dynamics Theory and Strain Equivalence Principle are used to study the evolution of landslide energy dissipation. In order to implement grade warning of typical tractive landslide on reservoir bank under the condition of reservoir running, Limit Analysis Method and Multi-Information are heterogeneously integrated to establish the energy-deformation characteristic criterion of landslide in different evolution stages. The achievement of the project could provide theoretical support to explore the evolution process of reservoir bank landslide, to evaluate its long-term stability reasonably and to effectively control bank landslide.

针对水利水电工程中库岸滑坡演化过程模拟与预测研究的关键科学问题，本项目以三峡库区白水河和三舟溪滑坡为例，围绕库水周期性大幅涨落和降雨条件下牵引式滑坡的演化过程能量耗散-变形破坏特征与判据开展以下研究：通过现场调查与监测、离心模拟试验及数值模拟等技术手段，获取滑坡在演化过程中各特征部位的多场特征信息，提炼出滑坡变形破坏及能量转换与耗散的特征；基于分形理论和状态空间重构理论，进行滑坡宏观变形时空演化模式的研究；基于系统动力学和应变等效原理开展滑坡能量耗散演化的研究，以此揭示在动态渗透压与应力耦合作用下滑坡不同演化阶段的能量-变形动态响应规律，建立滑坡演化变形破坏和能量耗散状态方程；基于极限分析和多源信息异类融合，提出滑坡不同演化阶段的能量-变形特征判据，实现典型库岸牵引式滑坡在水库运行条件下的分级预警。为探究库岸滑坡的演化过程、合理进行库岸滑坡长期安全性评价、有效进行库岸滑坡防治提供理论支撑。

作为世界上最大的水力发电枢纽，三峡水库政治、经济和社会地位重大，而库区滑坡地质灾害频发。因此，开展三峡库区滑坡的演化阶段判识研究具有重要意义。针对水利水电工程中库岸滑坡演化过程模拟与预测研究的关键科学问题，本项目以三峡库区典型滑坡为例（凉水井滑坡、白水河滑坡等），围绕库水周期性大幅涨落和降雨条件下牵引式滑坡的演化过程能量耗散-变形破坏特征与判据开展以下研究：1）通过开展库水位升降条件下凉水井滑坡离心模型试验研究，揭示了三峡库区云阳县凉水井滑坡在库水位升降条件下的变形破坏机理与演化模式。2）开展了降雨联合库水位升降条件下凉水井滑坡离心模型试验，实现了降雨联合库水位升降工况在土工离心试验中的控制，揭示了三峡库区云阳县凉水井滑坡在降雨联合库水位升降条件下的变形破坏机理与演化模式。3）基于有限元数值模拟开展了凉水井滑坡演化过程中能量耗散研究，探究了重力势能、动能、摩擦耗能以及外荷载做功之间相互转化关系，提出了滑坡的滑动系数-能量概率熵变化率判据。4）分别从点位移、区间位移的角度开展了三峡库区阶跃式滑坡位移预测研究，解决了传统阶跃型滑坡位移预测模型研究中存在的突变状态预测结果滞后和结果可靠性不明确等典型问题，提升了模型对滑坡变形状态的判识和预测的精准性与可靠性。5）开展了库岸滑坡饱和渗透系数与滑带土强度的空间变异性研究，建立了非平稳随机场模型，从不确定性的角度探究了库岸滑坡的时变可靠度。6）针对目前滑坡演化阶段划分研究中判据种类繁多、划分结果不统一的问题，提出了反距离加权联合期望的多判据综合判识模型，实现了库岸滑坡演化阶段的综合判识。项目研究成果为探究库岸滑坡的演化过程、合理进行库岸滑坡长期安全性评价、有效进行库岸滑坡防治提供理论支撑。