三峡库区黑石板滑坡涌浪分析

自三峡工程建设以来,库区范围内发生多起滑坡涌浪,为了正确预防和制定涌浪减灾方案,需要预测滑坡涌浪所波及的范围、涌浪的高度、传播的速度、以及波浪爬高。为此,结合三峡库区秭归县水田坝乡黑石板滑坡实例,采用基于水波动力理论FAST模拟软件进行涌浪计算分析及预测。结果显示:175 m水位下,滑坡体滑移入江速度约5.56 m/s,最大涌浪高度为37.2 m,对岸最大爬高为36 m;涌浪主要危害区为吒溪河内,传播至长江及其他支流后涌浪高度最大不超过0.6 m;在滑坡河段2 km范围内泓深线附近涌浪从约12 m下降至3 m,该急剧衰减区是滑坡涌浪急剧作用区,对应位置为水田坝乡。研究表明,涌浪传播、衰减、浪高、爬高与水域深浅、沟谷微地形密切相关,因此根据海啸预警划分方法和涌浪计算结果,得到黑石板滑坡涌浪预警分区;尤其是通过淹没线与遥感影像叠加,得到了水田坝乡受直接威胁的建筑分布。

Analysis of surge induced by Heishiban Landslide in Three Gorges Reservoir Area

Since the construction of the Three Gorges Project，several landslide surges occurred in the area of Three Gorges Reservoir. In order to correctly prevent the landslide and make the landslide surge and disaster reduction scheme，it is necessary to predict the influencing range of the landslide surge as well as the height，propagation speed and run-up of the surge. Combined with the actual case of Heishiban Landslide occurred in the area of Three Gorges Reservoir，the landslide surge is calculated and predicted by means of the theory of wave dynamics-based FAST software. The result shows that under the water level of 175m， the slipping speed of the landslide body into the river is about 5. 56 m/ s with the maximum surge height of 37. 2 m and the maximum run-up of 36 m at the other side of the river. The main endangered area of the landslide surge is within Zhaxi River，while the maximum height of the surge when it spreads to the Yangtze River and its other tributaries is not beyond 0. 6m. The height of the landslide surge is decreased from about 12 m to 3 m near the thalweg within a range of 2 km at the landslide river reach， while the sharp attenuation region of the surge is just its serious effecting area，for which the corresponding location is Shuitianba Town. The study result indicates that the propagation，attenuation and run-up of the landslide surge are closely related to the depth of water area and the micro-topography of valleys therein，thus the early-warning zoning of the surge induced by Heishiban landslide is obtained in accordance with the relevant tsunami early-warning zoning method and the calculation result of the landslide surge，especially the distribution of buildings directly threatened in Shuitianba Town is obtained through overlapping the inundation line with the remote sensing images concerned.