International Journal of Ocean System Engineering 2(4) (2012) 200-208 SPH Modeling of Surge Overflow over RCC Strengthened Levee Lin Li 1 , Farshad Amini 1* , Xin Rao 2 and Hongwu Tang 2 1 Department of Civil and Environmental Engineering, Jackson State University, Jackson, Mississippi, 39217, USA 2 State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, China, 210098 (Manuscript Received October 4 2012; Revised November 2, 2012; Accepted November 29, 2012) Abstract Surge overflow may cause damage on earthen levees. Levee strengthened on the levee crest and landward-side slope can provide protection against the erosion damage induced by surge overflow. In this paper, surge overflow of a roller compacted concrete RCC strengthened levee was studied in a purely Lagrangian and meshless ap- proach, the smoothed particle hydrodynamics (SPH) method. After verifying the developed model with analytical solution and comparing the results with full-scale experimental data, the roughness and erosion parameters were calibrated. The water thickness, flow velocity, and erosion depth at crest, landward-side slope and toe were calcu- lated. The characteristics of flow hydraulics and erosion on the RCC strengthened levee are given. The results indicate that the RCC strengthened levee can resist erosion damage for a long period. Keywords: SPH method, Surge Overflow, Roller compacted concrete, Levee, Erosion 1. Introduction Earthen levees are used extensively in the United States to protect populations and infrastructure from periodic floods and high water due to storm surges. When the surge level exceeds the levee crest eleva- tion without accompanying wave action, surge only overflow/overtopping occurs and produces fast- flowing water on the landward-side slope that can damage the protective covering and expose the under- lying soil to erosion. Post-Katrina investigations showed that during overtopping, the landward-side of levees was exposed to significantly higher velocities and much greater erosive forces than the flood side [1]. Protecting earthen levees from erosion by surge overflow is necessary to assure a viable and safe levee system [2]. Roller compacted concrete (RCC) is one of the levee strengthening methods to resist erosion damage [3,4]. RCC is a combination of sand and gravel having a controlled gradation to which cementing materials such as cement and pozzolan are added. The con- trolled-gradation stone aggregate contains the nomi- nal maximum size aggregate averaging about 38 mm. The materials are blended with water to damp con- sistency that can be hauled in vehicles or delivered with a conveyor, spread with earth-moving equipment in layers, and compacted with a steel-drum vibratory roller [5]. Due to its simplicity, RCC has been used in dam construction and modification and has potential applications for use in protection against overtopping of levees [6,7]. A full-scale study on surge overflow and combined wave and surge overtopping of a levee strengthened with RCC was conducted in the Large Wave Flume. The hydraulic data (discharge, water velocity and flow thickness) and erosion depth were obtained. Based on the measured flow thickness and flow ve- locity on the crest and the landward-side slope, new equations were developed to estimate the distribution of instantaneous discharge, flow parameters on the * Corresponding author. Tel.: +1 601 9793913, Fax.: +1 60109793238, E-mail address: famini@jsums.edu Copyright © KSOE 2012.