滑坡体溃决洪水数学模型研究  

Numerical modeling of breach of landslide dams

作　　者：岳志远[1] 曹志先[1] 闫军[1] 

机构地区：[1]武汉大学水资源与水电工程科学国家重点实验室,湖北武汉430072

出　　处：《水动力学研究与进展（A辑）》2008年第5期492-500,共9页Chinese Journal of Hydrodynamics

基　　金：国家重点基础研究发展(973)计划(2007CB714106);国家自然科学基金(50459001)资助

摘　　要：滑坡体溃决过程中泥沙运动非常活跃、滑坡体变形速度快,且与水流之间存在着强烈的相互作用。现有水沙数学模型为非耦合模型,在一定程度上忽略了其基本力学特征,难以准确地描述这类物理问题。本文建立二维水沙耦合数学模型,并采用修正的上扬通量公式来描述泥沙运动和滑坡体溃决过程。运用该模型研究了试验条件下上游水流漫顶和淹没过程中滑坡体溃决诱发的水沙变化规律,数值解与水槽试验数据基本一致。研究表明:现有基于恒定均匀条件的泥沙上扬通量公式并不直接适用于复杂水流条件下滑坡体溃决过程,需要进行更深入的研究;滑坡体溃决能够引发强非恒定流甚至激波,传统的对渐变流的数值计算方法难以准确地捕捉该现象,必须采用高性能数值格式:现有经验方法难以准确地计算坝址处流量过程,以此作为边界条件的传统溃坝洪水数学模型未必能够获得准确、可靠的结果。Breach of landslide dams may induce intense sediment transport and rapid bed evolution under high flow regime, for which traditional Aecoupled mathematical river models based on simplified conservation equations are not applicable. A two-dimensional coupled mathematical river model is presented which is generally applicable to the processes with either intense or weak sediment transport. The model is applied to the pilot study of the flooding due to overtopping break of landslide dams. The model is tested against experimental data, with reasonably good agreement between numerical results and measurements. It is found that existing sediment entrainment formulations based on steady and uniform flow may not be directly applicable for the breach process of landslide dams due to highly unsteady and non-uniform flows, which necessitates the further study. The flow due to breach of landslide dams are seen to be highly non-uniform and even feature shock waves such that traditional numerical schemes for gradual varied flow are not applicable, and high-performance numerical schemes are critical. Traditional mathematical models for dam-break floods need to be reformulated since it is hard to appropriately estimate the discharge hydrograph at the dam-site using existing empirical relationships.

关 键 词：数学模型 水沙耦合 滑坡体溢流侵蚀溃决 上扬通量 激波 

分 类 号：TV122.4[水利工程—水文学及水资源]