基于大型数据库的堰塞坝特征统计分析与溃决参数快速评估模型

STATISTICAL ANALYSIS AND EFFICIENT DAM BURST MODELLING OF LANDSLIDE DAMS BASED ON A LARGE-SCALE DATABASE

21世纪以来地质灾害频发形成大量堰塞坝。然而由于缺乏详细的资料,现在对堰塞坝特征和溃决等方面的研究受到很大的制约。同时,绝大部分堰塞坝寿命极短且勘察条件恶劣,很难在短时间内获取详细的坝体参数,因此急需基于有限的可用数据进行堰塞坝溃决参数快速评估。收集国内外1 298例堰塞坝案例,对堰塞坝的分布、诱因、寿命、溃决模式、坝高、库容、成因等特征进行统计分析。通过对41例具有详细溃决信息的案例进行分析,建立坝体溃决参数(峰值流量、溃口尺寸、溃决时长)的快速评估模型,并将模型应用于唐家山堰塞坝的溃决分析。最后,基于大量案例数据进行堰塞坝模型和人工土石坝模型应用的对比分析,发现将人工坝模型用于堰塞坝会得到偏危险的结果,进而可能导致非常保守的决策和不必要的经济损失。该研究对于全面了解堰塞坝特征,尤其是对堰塞坝溃决参数评估和应急管控有一定的理论和实际价值。

Serious geological disasters occurred worldwide at an alarming rate resulting in large number of landslide dams. Owing to lack of the detailed data,the studies of the characteristics and the burst of the landslide dams have been rather limited. Moreover,it is often very difficult to obtain the detailed data of landslide dams,since the life spans of landslide dams are rather short and the survey of landslide dams is normally arduous. Therefore,an efficient model of dam burst with limited parameters is urgently demanded for the risk assessment and the mitigation of landslide dams. A database with 1 298 landslide dams from all over the world was compiled. The characteristics of landslide dams including the locations,the triggers,the life spans,the failure modes,the dam heights,the lake volumes and the causes of landslide dams were analyzed based on the database. A dam burst model was established to estimate the burst parameters（the peak discharge,the burst size and burst time） based on 41 cases with the detailed information in the database. The model was applied to Tangjiashan landslide dam. Finally,comparison was made between the model for landslide dams and the one for man-made earth and rockfill dams and finding was made that using the models for man-made earth and rockfill dams to assess the landslide dams would over estimated the danger and resulted in a very conservative decision leading to unnecessary high economic cost.