Theoretical Analysis on Reduction of Load-Induced Excess Pore-Water Pressures in Roads with Geogrids

Abstract

Geogrids used in roads can not only stabilize granular bases on weak subgrade but also have the potential to reduce excess pore-water pressures and deformations in road layers under traffic loading. In this paper, the solution for the geogrid-stabilized two-layered saturated soil system was derived according to the layered elastic theory and the Biot consolidation theory, and considering the benefits of geogrids. In the derivation, the lateral confinement and tensioned membrane effects of the geogrid were expressed as external stresses applied at the interface as continuity conditions. The effect of the geogrid on suppressing excess pore-water pressures in roads was characterized along the depth. Due to the generation of pore-water pressure, the instant total vertical and radial stresses were higher than those calculated by the Burmister solution without considering pore-water pressure, while the instant vertical strains/displacements were lower than those calculated by the Burmister solution due to the reduction of the effective stresses. The inclusion of the geogrid reduced the pore-water pressure so that the deterioration of the road could be mitigated. The calculations using the proposed solution also showed that the reduction of the pore-water pressure was significant near the location of the geogrid.