Modeling the cumulative impact of river curvature on landslide-induced surge waves: refinement based on the Pan Jiazheng model

Abstract The river curvature ( κ ) has a significant impact on the magnitude of the landslide induced surge waves (LISW). To overcome limitations of a widely used empirical relation, referred to as Pan’s model, in estimating the surge wave magnitude for engineering design, and disaster prevention and mitigation, improvements in Pan’s model are made in the paper. A method widely used in topography is adopted to quantify the rive curvature and accordingly a database is established that cover 71 dams in various rivers across China. Thereafter, a commercial computational fluid dynamic numerical code (FLOW-3D) is used to quantify the impact of the river curvature. Based on FLOW-3D numerical results, a new variable, the comprehensive computation length ( S ’), is introduced to consistently capture the geometrical features of the upstream of the river from the location of the landslide to the engineering structures built in the river. Numerical results indicated that the effect of curvature on surge wave propagation stabilized for κ greater than 1.05, while the attenuation rate of surge wave height increases significantly with increasing curvature for κ below 1.05. Then, it is demonstrated that once the newly defined length that considers the river curvature replaces the length in Pan’s model, the new model leads to a significant improvement in accuracy of estimating the surge waves magnitude. Two field cases are described to further demonstrate that. The first field case involves a landslide occurred Jinsha River in 2013. Due to the limited availability of surveillance data, FLOW-3D was used to estimate the surge wave magnitude. In the second field case, a landslide occurred in Qingjiang River in 2007. In contrast to the first field case, however, a wealth of surveillance data is available to identify the surge wave’s magnitude. In both cases, the new model’s predictions are consistent with FLOW-3D estimate or well recorded data.