Erosion processes on dike slopes

Abstract

Erosion processes are divided in two parts, whereas first process is detachment process and second process is transport of detached soil. The main function of grass cover is to avoid detachment. Therefore certain strength is necessary to execute this assignment. Resistance of grass covers are affected by several parameters. The influencing parameters are density of canopy cover, root depth as well as tensile and shear strength of roots. Also the mentioned parameters are influenced by grassland management which has no engineering background, but management changes growing habit and determines strength of turf. In the present, models to evaluate strength as well as loads are concerned with the effecting parameters. Models of CIRIA (Construction Industry Research and Information Association) deal with general slopes in landscapes and loads caused by rainfall and running down of rainwater. Another model which is directly concerned with dikes is VTV 2004 (Voorschrift Toetsen op Veiligheid). VTV 2004 has disposed concepts to evaluate strength of grass covers and loads caused by waves. The most current model is EPM (Erosiegevoelige Plekken Model), which is a graduation report. This report is custom-built at the TU Delft and deals with spots susceptible to erosion on dike slopes. EPM describes those spots with help of scouring models. All those models evaluate strength and load separate.