Effect of Geosynthetics on Swell Reduction During an Extreme Rainfall Event

Expansive (reactive) soils can swell during rainfall causing damage to engineering structures. This paper seeks to investigate the effect of geosynthetic material on the swell reduction of such soils. A series of large-scale long-term soil column experiments were conducted on a very high plasticity reactive soil under simulated rainfall conditions. Non-woven geosynthetics combined with geogrid and woven geosynthetics were used as primary geosynthetic material to provide reinforcement and drainage for the soil mass. The obtained results revealed that these geosynthetics did not improve the California Bearing Ratio values of the soil. However, when placed in the soil mass, the geosynthetic materials greatly reduced the total swell of the soil. Visual observations and the experimental data on water content, suction, and vertical displacements indicated that the geosynthetics provided better drainage of the soil mass. This limited the time of water–soil interaction, thus reducing the total swell of the soil.