Influence of Swell Pressure from Expansive Fill on Retaining Wall Stability

Retaining wall designs most always specify use of drainable granular backfill. However, in actual practice, onsite soils are sometimes used as a cost-saving measure. In North Texas these onsite soils are often expansive cohesive materials. Traditional design using non-expansive cohesive backfill is well established. However, these methods do not consider the lateral swelling pressures that expansive soils exert upon wetting. This paper offers a method for estimating the magnitude of lateral swell pressure that may be exerted on such structures when these materials are used as backfills. In addition, stability analyses results depicting the impact of swell pressures of these materials on calculated Factors of Safety (FS) values for external stability are presented.