龚家方4号斜坡涌浪数值模拟分析

对于库区滑坡来说，不能只考虑滑坡体本身造成的灾害，还要考虑滑坡体引起的涌浪灾害，为了研究滑坡涌浪的传播、衰减规律，在Geo-wave软件的技术上，二次开发形成FAST软件。以三峡库区龚家方4号斜坡为研究对象，分别在175、156、145 m的库水位条件下，在长约23 km、宽约10.4 km的区域内进行涌浪数值模拟，获得涌浪传播模拟数据。经过模拟软件数据处理模块的计算分析，形成了分析涌浪传播规律的一系列图件。对不同水位下涌浪模拟的计算结果进行对比分析发现，随着库水位的下降，滑坡产生的最大涌浪值和在对岸的爬高值都有增长的趋势，但其对航道存在威胁的时间逐渐变短。模拟区各位置的最大波高空间分布形态具有中间内凹、两翼沿岸坡延伸的特征。涌浪传播的急剧衰减区基本分布在涌浪源附近1 km的范围内，涌浪源处的波高越大，单位距离内的涌浪下降高度也越大。由于涌浪在岸边有叠加、壅高现象，建议航道内船只经过地质灾害点附近时应沿江中心快速通行。

Numerical simulation of tsunami due to slope failure at Gongjiafang on Three Gorges reservoir

For slope failures on reservoir, we can’t only see the damage from their deformation and failure, but also think about the disaster from the tsunami caused by them. This paper attempts to obtain the law about spread and attenuation of the reservoir tsunami caused by slope failure. It uses the software of FAST (Fast Assessing System for Tsunami) and GEO-WAVE to numerically simulate such tsunami. It selects the slope #4 at Gongjiafang on the Three Gorges reservoir as the actual case. The simulation area is about 23 km long and 10.4 km wide and the reservoir water levers are 175 m, 156 m and 145 m respectively. Figures about the tsunami are gained with the numerical simulation. The pictures of wave probes are charted with calculation and analysis of data processing module. Comparative analyses of simulation results under the three water levers are given. As water lever decreases, the largest wave height and the largest climbing height have an increasing tendency, but the time of wave damaging the passage gets shorter. The largest wave height has a distribution rule that the shape in middle of river is concave and the shapes on both sides of river are protuberant. The rapid attenuation area of impulse wave distributes in the region at a distance of 1 km from the source point. The higher is the wave height of source point, the more is the drop height of impulse wave in unit length. Because the waves can be superposed near bank, it is suggested that boats must speed through along the middle of the reservoir river immediately when they are near the slope #4.