A two stage model for moisture-induced deformations in expansive soils

Abstract

Moisture-induced suction changes in expansive soils due to infiltration and evaporation result in failure of civil infrastructure. The objective of this paper was to develop a two stage deformation model by simultaneously calculating soil suction and stress state. The model predictions were validated using a one-year field monitoring data.Background: Moisture-induced suction changes in expansive soils due to infiltration and evaporation result in failure of civil infrastructure. The objective of this paper was to develop a two stage deformation model by simultaneously calculating soil suction and stress state. The model predictions were validated using a one-year field monitoring data. Results: Deformations in expansive soils closely match cyclical suction changes corresponding to seasonal weather variations. Volume changes fluctuated close to the ground surface and gradually decreased with depth (overburden pressure) due to isolation from meteorological effects. The top 2 m depth was found to be the active zone susceptible to moisture variations. Conclusions: The model agreed well with the monitoring data trends with deviations attributed to analytical assumptions in the equations, ineffective capture of antecedent soil conditions, possible soil heterogeneity and anisotropy, and hysteresis in soil saturation and desaturation.