Effect of lateral boundary condition on confined - reinforced earth subjected to differential settlement

Abstract

A new method, the confined-reinforced earth (CRE) method, has been suggested to strengthen the subgrade layer, at the bottom of road pavement. The method uses granular soil, geogrids and confining tie rods. It is intended to reduce the damage from the large differential settlement between bridges or culverts and their approaches due to major earthquakes, and to make it possible for vehicles, especially emergency vehicles to pass the resulting unevenness. This study presents model tests designed to investigate the effects of the length of confined-reinforced earth by examining how lateral boundary conditions affect the consequences of differential settlement. Tests with two lateral boundary conditions, i.e. fixed-fixed (both ends of the geogrids are laterally fixed) and fixed-free (one end of the geogrid is laterally fixed and the other end is free) of the CRE method were performed and the effect of differential settlement was compared. The results show that the lateral boundary condition significantly affects the CRE behavior and the deformation in the fixed-fixed boundary condition is smaller than that in the fixed-free boundary condition.