Pullout of Geosynthetic Reinforcement with In-plane Drainage Capability

While there are significant economic reasons for relaxing the currently stringent specifications for backfill material in reinforced soil structures, it is also true that failure of these structures have often involved inadequate drainage and use of low quality, fine-grained soils. However, geosynthetic inclusions can be used within fine-grained soils if they can provide not only reinforcement, but also lateral drainage. While using reinforcement with in-plane drainage capability is conceptually enticing, transmissivity requirements for such application have not been properly quantified. This study presents preliminary results of an ongoing experimental testing program involving geogrid pullout tests conducted in wet, fine-grained soils. Pairs of tests were conducted using geogrids with the same tensile strength but with and without in-plane drainage channels. The beneficial effect of lateral drainage is being quantified.