Downward movement of sliding soil mass in earthquake-induced earth slopes may gradually improve the system's stability. Hence, significant change in critical (or yield) acceleration of the slope is anticipated. The existing simplified coupled procedures, however, assume a constant critical acceleration in stick-slip sliding analysis. Fully coupled sliding block analyses with continuously increased critical acceleration were conducted to estimate earthquake-induced permanent displacement of earth slopes. The sliding mass was assumed as a flexible chain moving along the planes with gradually gentler inclinations. The measured data of a slope failure test in a shaking table were used to validate performance of the model. The proposed approach was compared with the previous procedures, which ignored critical acceleration changes due to downward movement of the sliding mass. Accordingly, earth slopes with smaller slip length were more influenced by the downward movement modification, especially in sma...

This paper represents multivariate fragility functions (MFFs) based on sliding displacement of soil slopes for landslide hazard assessment. The MFFs correlate the sliding displacement probability of slopes to earthquake intensity measures (IMs). Conditional distributions are employed to develop MFFs for failure probability analysis of slopes by considering scalar and vector IMs in the absence of any predetermined predictive model for sliding displacement of slopes. Three sliding displacement-based damage states are defined herein as the low, moderate, and high levels of landslide hazard. The results demonstrate that the probability of exceedance from a given damage state strongly depends on the type and the number of IMs chosen for the fragility analysis whereas the predicted failure probabilities resulted from the scalar and multivariate analyses can vary up to three times. Results of this study indicates that the multivariate fragility analyses can lead to landslide damage estimation in more reliable manner, compared with the scalar-valued fragility curves which are commonly used to predict the seismic hazard of earth slopes.

Pore-water pressure buildup strongly affects seismic permanent displacement of the slopes constituted from saturated soils. Previous attempts simulating the generation of excess pore pressures (or decrease in soil strength) have been applied in the sliding block models, but the models assumed a rigid block. In the present study, a simplified procedure is presented to account for this effect in sliding block analysis. A correlation between excess pore pressure ratio and cumulative absolute velocity is obtained through the fully coupled solid-fluid effective stress analysis of level ground. The effect of pore-water pressure variation on critical acceleration is investigated in this paper, and the available Newmarkian sliding block methods, such as the rigid block, decoupled, and coupled approaches, are modified to estimate seismic permanent displacement in the presence of excess pore pressure buildup. The present study is original because the method not only simulates the generation of excess pore pressures but also considers the coupled procedure. In addition, centrifuge test results of lateral spreading in the infinite sloping ground are used to demonstrate that the proposed modification considerably improves prediction of seismic sliding displacement. The results clearly demonstrate that ignored pore-water pressure buildup in sliding block procedures can lead to unconservative estimates of seismic permanent displacements during seismic loading.