Numerical assessment of the effect of reinforcement on the performance of reinforced soil dikes

A reinforced soil dike with geogrids and metallic bar mats has been proposed as a new construction method to satisfy the environmental conservation of rivers. With this method, it is possible to not only reduce construction period and cost, but also retain or reestablish native vegetation as much as possible on the dike slope. The behavior of the reinforced soil dike, however, has not been investigated extensively. An assessment is therefore needed of the effectiveness of various reinforcement designs for the river dike with geogrids and metallic bar mats. In this paper, the background and objective of this study are first outlined. Then, a numerical method and the analysis procedure are briefly described. Based on a full-scale test, the method is used to examine the effectiveness of proposed reinforcement strategies for a soil river dike. The numerical series include: (1) an unreinforced case, (2) use of metallic bar mats, (3) use of geogrids, and (4) use of both geogrids and metallic bar mats. Analyses are carried out using an elastoplastic finite element method, in which the behavior of sands is described by means of an elastoplastic constitutive model previously developed within the framework of the Matsuoka-Nakai failure criterion. Finally, the effectiveness of the reinforcement for the soil river dike is discussed based on the numerical results.