Abstract: The detrimental effect of expansive soils to slope stability is commonly observed and remains a great challenge in geotechnical engineering. Due to the poor understanding of the failure mechanism, the engineering solution could be sometimes less effective. This paper summarized two (2) typical slope failure modes upon structural evaluations of expansive soil strata based on two full scale insitu tests combining with other reported failure examples in real engineering practices. The two observed failure types are: surficial failure due to the sliding of the expansive soils; and, mid fissural failure circle. This study further investigated the mechanisms and factors controlling the slope failure and provided recommendations for potential engineering solutions. These findings would provide helpful information to understand slope failures due to the presence of expansive soils.

Key words: Expansive soils, Channel Slopes, Failure Mechanism, Engineering Solutions