Progressive Failure of Unsaturated Fill Slope Caused by Cumulative Damage Under Seepage Surface

Abstract

Seepage surface position of fill slope can fluctuate owing to rainfall and groundwater supply from behind the slope. Therefore, in this study, shaking-table tests of an unsaturated fill slope were conducted to examine the influence of the seepage surface position on the fill slope stability by comparing with previous results in the fully saturated condition. An acceleration amplification factor was used to evaluate the stability. If the embankment was in an unsaturated condition, a slip plane was formed along the seepage surface. With ongoing increase of input acceleration, the slip progressed to behind the slope. Comparison of the unsaturated and saturated results showed that although the failure mechanism in which the slip surface was formed by the reduction in rigidity was common, the input acceleration at failure and deformation mode were different. When the slip surface was formed and failure occurred, the input acceleration in the unsaturated fill slope was more massive, and the deformation at the same excitation stage was small. These results imply that the unsaturated fill slope has a higher earthquake resistance than the saturated fill slope. Moreover, it is shown that the progress of plastic deformation inside the embankment and the formation process of the slip plane can be estimated from the change in the acceleration amplification factor regardless of seepage surface position.

A Systematic Review of Physical Modelling Techniques, Developments and Applications in Slope Stability Analyses

“…For example, Linfang et al [96] proposed a novel method for estimating slope seismic stability analysis using the Yushu Airport Road 3# landslide as a case study. Similarly, Murao et al [97] used shaking table tests to examine the progressive failure of unsaturated slopes in investigating the influence of seepage surface conditions on the fill slope. Likewise, Sun et al [98] proposed a new limit equilibrium method for evaluating the stability of cable-reinforced high bedding rock slopes in relation to rotational bi-planar failure using tilt equipment.…”