Soil Water Retention Curves for Residual Soils Using Traditional Methods and MIP

This paper presents the pore size distribution and the soil water retention curves (SWRC) for an undisturbed residual soil obtained using traditional methods and using mercury intrusion porosimeter (MIP). The specimens were obtained from two residual soil profiles of the Serra do Mar, SP, Brazil. The results obtained allowed the evaluation of the pore size distribution along the soil profile and its relation to the water retention characteristics of the soil profile. The SWRC obtained using traditional methods, such as suction plate, pressure plate and filter paper method, is compared with the soil water retention curve inferred from the MIP. The results indicated that the amount of meso and macropores tends to increase with depth, while the amount of micropores tends to decrease. The comparison between the SWRC obtained using the MIP technique and the traditional procedures suggested that the former overestimates the water retention capacity for lower suctions.