Effect of rockfill berm on the stability of large geotextile mat dikes on soft clay

Abstract

This paper investigates the effect of rockfill berms on the stability of large geotextile mat dikes filled with sand built upon soft clay. Finite element analyses were conducted aiming to provide insight into the design of large geotextile mat dikes by using rockfill berms reinforcement. The FE results were validated against previously published data, with good agreement obtained. A parametrical study was then carried out to explore the failure mechanism, limiting stack height and geotextile tension distribution of the dikes. Based on the FE results, two failure mechanisms, i.e. the so-called global and local failure mechanisms, were observed. A formula was proposed to predict the critical width of the base of the dike to differentiate the two mechanisms. It is found that rockfill berm can increase the limiting stack height and safety factor of the dike, and the shape of rockfill berms has a significant influence on the stability of large geotextile mat dikes. Finally, a general design method was proposed to evaluate the required dike height and factor of safety for the design of the large basal-reinforced geotextile mat dikes, which can provide a guidance for practical application.