Seismic fragility assessment of slopes with scalar-valued and vector-valued earthquake intensity measures

Seismic fragility assessment provides the conditional probabilities of an engineering system exceeding some limit states under various seismic intensities, which is the indispensable component in probabilistic seismic risk analysis framework. To extent this method to slope engineering, a framework for the elaborated slope seismic fragility assessment with scalar- and vector-valued seismic intensity measures (IMs) is presented. 20 seismic IMs are firstly chosen to perform optimal analysis and identify appropriate IMs for slope seismic fragility assessment. Seismic fragility functions of a slope with optimal scalar IM are then developed for seismic fragility assessment. Considering that single-IM parameter cannot fully reflect ground motions characteristics, the vector-valued IMs (two IM parameters)-based fragility surfaces of the slope are also constructed for improved and efficient slope seismic fragility assessment. The seismic failure probability of the slope can consequently be predicted by two different IMs. Finally, the results of fragility curves and surfaces are also compared, which indicates slope failure probability may be underestimated or overestimated by scalar-valued fragility functions. The results obtained in this study show that vector-valued earthquake IMs can obtain more robust slope seismic fragility functions and are better able to characterize earthquake damage potential on slopes.