Effect of Rainfall Infiltration on the Stability of Compacted Embankments

Abstract

Rainfall infiltration causes the collapse of unsaturated embankments due to loss of suction. In this paper, the Barcelona Basic Model (BBM), a constitutive model developed for unsaturated soils, was implemented in Fast Lagrangian Analysis of Continua (FLAC) for simulating the effect of varying rainfall intensities on compacted embankments. It was observed that large vertical deformations occur and considerably high positive pore-water pressures get developed, accounting for the collapse of an embankment. The results also show that rainfall intensity and duration affect the slope stability. A comparison was made between the results obtained using the Mohr–Coulomb model and BBM. It was found that the soil undergoes larger deformations when modeled using BBM as BBM accurately models the loss of suction upon saturation. Reliability analysis of embankment shows that probabilistic analysis provides a better assessment of slope stability rather than the factor of safety and shows that suction and hydraulic conductivity are critical parameters influencing slope reliability for unsaturated soil slope embankments.