Influence of soil suction on runoff during whiplash events

Abstract

The influence of soil suction on rainfall-runoff during whiplash events is explored. A series of 600 finite element simulations were completed using PLAXIS LE Groundwater. A model 2D soil profile was developed in the software to simulate a fat clay soil native to Oklahoma. Rainfall intensity, initial soil suction, and surface slope elevation were treated as log normally distributed random variables. Desiccation cracking was explicitly included in the model as a function of initial soil suction. The depth of the desiccation cracking was determined according to the soil’s tension capacity. the results indicate that rainfall-runoff is greatly influenced by soil suction. For a given rainfall intensity, the portion of the rain that becomes runoff varies according to soil suction; however, this relationship is not strongly correlated. The simulation results exhibit significant variability, which emphasize the complexity of this relationship. The occurrence of desiccation cracking reduced but did not eliminate the potential for rainfall-runoff for desiccation crack depths less than 5 m for the soil in this study.