Centrifuge Model Test Study on Failure Behavior of Soil Slopes Overlying the Bedrock

Abstract

A number of landslides occurred in the soil slopes deposited on the bedrock. The bedrock significantly influenced the failure behavior of the overlying slope, which should be reasonably captured in the slope stability analysis. To elucidate the deformation and failure mechanism of slopes overlying the bedrock, a series of centrifuge model tests were conducted to simulate different shapes and roughnesses of the bedrocks, together with a pure soil slope without any bedrock for comparison. The failure mode of the slope could be categorized to three types: sliding along the bedrock, failing inside the soil, and their combination. The steep and smooth bedrock decreased the safety limit of a slope and served as a weak surface so that the soil slope slid along it. The gentle or rough bedrock increased the safety limit of a slope and changed the failure behavior of the slope. The bedrock also changed the direction and magnitude of the slope displacement, and the extent of variation depended on the properties of the bedrock. The slope exhibited significant coupling of deformation localization and failure. This could be used to explain the influencing mechanism of the bedrock on the failure behavior of slope. The bedrock significantly changed deformation behavior of the slope, accordingly changed the location and development process of the deformation localization, and finally affect the shape of the slip surface and stability level of the slope.