基于流变理论的滑坡海啸数值模拟研究

Numerical Study of Submarine Landslide Tsunami Based on Rheological Theory

基于Herschel-Bulkley流变理论建立表征粘塑性泥石流滑坡过程的数学模型,利用有限体积法求解非剪切层与剪切层的质量和动量平衡过程,计算滑体失稳与滑动过程中不同时刻滑坡体厚度的变化特性.在传统的非线性浅水波方程中计及底面运动边界条件,发展可用于模拟海底滑坡激发海啸的生成、传播和爬高淹没过程的数值模型.复演了1998年巴布亚新几内亚滑坡海啸,结合实测数据验证该模型的可靠性.针对我国南海的白云滑坡和文莱滑坡可能存在的大规模滑坡,分别模拟计算了白云滑坡体积为50km^3和100km^3、文莱滑坡体积为1200km^3的滑坡演化过程,及其引起的滑坡海啸.根据计算得到的南海滑坡海啸的最大波幅分布和近岸的波面时间序列,分析了南海潜在的滑坡海啸传播演化规律和对我国近岸的灾害性影响特征.

Based on the Herschel-Bulkley rheological theory, the governing equation describing the viscoplastic debris flow has been solved by finite volume method, which can model the landslide process. The landslide model is coupled with the nonlinear shallow water equation model including the moving bottom boundary conditions to constitute landslide tsunami model. The generation, propagation, run up and inundation of landslide tsunami can be computed numerically. The 1998 Papua New Guinea landslide tsunami was simulated to validate the numerical model by comparing with measurements firstly. To distinguish the potential landslide tsunami hazard in South China Sea, the scenarios of the landslides with volume of 50 andl00 km^3 in Baiyun Slide and 1200 km^3 in Brunei Slide were computed and discussed. The characteristics of the propagation of landslide tsunami in South China Sea and coastal hazards were analyzed.