基于改进的FAST模型的千将坪滑坡涌浪研究

千将坪滑坡是三峡库区支流浅水区滑坡产生涌浪的典型案例,但对大范围、长距离的水动力过程和涌浪灾害分析研究成果较少.基于浅水区滑坡涌浪物理实验的推导公式,更新了FA ST 涌浪计算系统,构建了相应的涌浪源数值模型,在已有的滑坡涌浪灾害快速评价系统程序中新构建了浅水区滑坡涌浪源数值模型,开展了千将坪滑坡涌浪研究.数值计算区域为18.6 km×11.8 km,包括千将坪滑坡附近的长江干流及支流.计算结果显示,千将坪滑坡产生的最大浪高为38.8 m,最大爬高为36.7 m.最大涌浪空间分布显示大于1 m 涌浪的河道长约10.5 km,大于2m 涌浪的河道长约9.3 km,大于3 m 涌浪的河道长约8 km.大于1 m 的波浪影响范围主要集中在青干河和锣鼓洞河,涌浪在河道中传播受地形影响而有快速衰减或放大效应.与多源数据对比表明,涌浪爬高数值相差为±2 m,相关性系数达0.97.建立的涌浪数值模型具有消耗计算资源少、计算速度快、计算结果精度较好等优点.基于水波动力学的浅水区滑坡涌浪源模型将可用于水库区支流或干流浅水区滑坡产生的涌浪问题研究,为大范围长距离滑坡涌浪灾害预测预警提供重要技术支撑.

Study on impulse wave generated by Qian-jiangping landslide based on improved FAST model

Qianjiangping landslide is a typical impulse wave example generated by landslide in shallow water area in Three Gorges Reservoir,but there are seldom water dynamic process and impulse wave research progress, especially focusing on waterway in range of big region and long distance. Based on the formulae derived from physical experiments on impulse wave generated in shallow water,numerical model of landslide-induced impulse wave in shallow water is built in the former Code named Forecasting Analysis System for Tsunami generated by landslides, and study on impulse wave generated by Qianjiangping landslide is carried out, updating the FAST landslide impulse wave calculation system and establishing the corresponding wave source model.The numerical calculating region is 18.6 km×11.8 km,including the Yangtze River and its branch around Qianjiangping land-slide.The calculating results show that the maximum of impulse wave is about 38.8 m and the maximum run-up is about 36.7 m.The spatial distribution of impulse wave presents that there are about 10.5 km long waterway with impulse wave above 1 m-height,there are about 9.3 km long waterway with impulse wave above 2 m-height,and there are about 8 km long waterway with impulse wave above 3 m-height.The waterway with impulse wave above 1 m-height concentrated distribute in Qinggan river and Luogudong River.There exist rapid decay and enlarge-ment effect when impulse wave propagate in waterway encountering various topographical.Comparing with multi-source data,the run-up values are differ in about ±2 m with the correlation coefficient of 0.97.The established impulse wave numerical model has the advantages of less computation resource consumption, fast calculating speed and better accuracy numerical results.This numerical model of landslide-induced impulse wave in shallow water is beneficial to the research on impulse wave problem in branch or shallow water in reservoir, which can give important technical support for forecasting and prewarning on landslide-induced impulse wave in huge re-gion and long distance.