库岸堆积层滑坡入水过程的能量耗散机理与转化规律研究

The energy dissipation and conversion of the collusive landslide is a bottleneck problem because of big porosity, loose construction and complicated interaction between slide mass and water body when reservoir landslide moves into water, and it restricts the development of landslide movement and water wave disaster. The material composition of typical colluvial landslides and fluvial morphology in the Three Gorges Reservoir area, is analyzed to establish the landslide model and river model of physical simulations in laboratory. In this proposal, an experiment system was designed to simulate the process of landslide moving into the water, and to analyze the effect of grain composition on accumulation features of the landslide after failure. Another experiment system was designed to measure viscous resistance of submerged blocks, to discuss the correlation between viscous resistance and porosity. The energy dissipation mechanism of the colluvial landslide will be analyzed by combining with the landslide dynamics, the hydrodynamic and the energy balance theory. Experiments of landslide-generated water waves and the numerical simulation method are used to simulate the movement of landslide into the water and the generation of water waves, and to analyze influencing factors of wave energy. An energy transformation model will be established for the correlation between water wave energy and viscous resistance dissipation of landslide energy. The velocity of the Xintan landslide and landslide-generated water wave are employed to verify or amend the energy transformation model. The research has important scientific significance for the development of reservoir landslide dynamic theory, the improvement in prediction methods of landslide-generated water waves and establishment of disaster prevention and reduction plan for landslide disaster chain system.

库岸堆积层滑坡孔隙率大、结构松散，固液间相互作用复杂，其入水过程的能量耗散与转化已成为制约滑坡运动与涌浪灾害研究的瓶颈问题。本项目在综合分析三峡库区典型堆积层滑坡的结构特征和河道特征的基础上，构建室内物理模拟的滑体模型和河道模型，开展滑体入水过程的模型实验，分析颗粒级配对堆积特征的影响；基于水下运动滑块模型的阻力实验，探究粘滞阻力与滑体孔隙率的关系；结合滑坡动力学、流体力学和能量平衡理论，分析库岸堆积层滑坡入水过程的能量耗散机理；采用室内实验和数值方法，模拟滑坡入水和涌浪产生的连续过程，分析涌浪波能量的影响因素，研究滑坡能量的粘滞阻力耗散量和涌浪波能量的关系，建立滑坡入水过程的能量转化模型；结合新滩滑坡的运动速度和涌浪特征，对滑坡能量转化模型的有效性进行检验和修正。本课题的研究对于发展水库滑坡运动学理论、完善滑坡涌浪预测方法和制定滑坡灾害链系统的防灾减灾预案具有重要的科学意义。

库岸堆积层滑坡是水库运行过程中重要的地质灾害类型，失稳后堵塞江河、激起涌浪而造成损失的例子屡见不鲜。库岸堆积层滑坡孔隙率大、结构松散，固液间相互作用复杂，其入水过程的能量耗散与转化已成为制约滑坡运动与涌浪灾害研究的瓶颈问题。本项目在综合分析三峡库区堆积层滑坡的结构特征和河道特征的基础上，提出三峡库区典型堆积层滑坡的地质模型和三种典型的河道模型；选取万州区典型堆积层滑坡2805个基底摩擦力参数为统计样本，提出了堆积层滑坡滑带基底摩擦参数的最优概率分布模型；开展了水下运动滑块模型的阻力试验，得出了滑体运动时压强水头增量与滑体的速度平方成正比的关系，分析了滑体孔隙率对粘滞阻力的影响，建立了考虑粘滞阻力的涉水滑坡入水过程中的运动速度计算模型，探究了库岸堆积层滑坡入水过程的能量的基底摩擦耗散机理和粘滞耗散机理；基于Tsunami Squares数值方法，以三峡库区典型滑坡新滩滑坡和红岩子滑坡为例，分析了堆积层滑坡从启滑到最终入水的全过程，研究了堆积层滑坡的运动及堆积特征，分析滑坡涌浪特征及其传播规律；构建了室内物理模拟的滑体模型和河道模型，开展散体滑体入水和涌浪产生的模型实验，分析了散体试块的渗透系数对涌浪波特征参数和能量转化率的影响。研究成果表明：如果散体滑块的渗透系数大于冲击速度时，当滑体冲击入水时，水会瞬间渗透到滑体中，导致排开水的体积减小，从而导致激起的涌浪波幅相对较小，滑体入水后能量的转化率相对较低；当渗透系数小于冲击速度时，滑体入水时不会在波浪产生的过程中瞬间被水渗透，滑体冲击入水激起的涌浪波波幅较大，同时滑体入水后能量的转化率较高。本课题的研究对于发展水库滑坡运动学理论、完善滑坡涌浪预测方法和制定滑坡灾害链系统的防灾减灾预案具有重要的科学意义。