Reinforced Soil Structures with Poorly Draining Backfills. Part I: Reinforcement Interactions and Functions

In this and a companion paper (Mitchell and Zornberg 1994), the use and performance of reinforced soil structures constructed with poorly draining and/or cohesive backfills is evaluated. This evaluation shows that proper design and construction can result in stable, durable, and economical earth structures. Permeable reinforcements may be especially useful for soil structures with poorly draining backfills because the drainage capabilities of the geosynthetic can dissipate excess pore water pressures, thus enhancing stability. Consequently, the design of a safe and economical structure should address two aspects specific to poorly draining backfills: the cohesive soil-reinforcement interaction and the reinforcement drainage characteristics. The present paper focuses on experimental and analytical studies undertaken to evaluate these issues. Tensile strength, durability, and creep response of geosynthetics embedded in marginal soils are also addressed. There is strong experimental evidence that permeable inclusions can effectively reinforce clay structures.