Yield Strength Ratio and Liquefaction Analysis of Slopes and Embankments

A procedure is proposed to evaluate the triggering of liquefaction in ground subjected to a static shear stress, i.e., sloping ground, using the yield strength ratio, su(yield)/(sigma)ʹv0. Thirty liquefaction flow failures were back analyzed to evaluate shear strengths and strength ratios mobilized at the triggering of liquefaction. Strength ratios mobilized during the static liquefaction flow failures ranged from approximately 0.24 to 0.30 and are correlated to corrected cone and standard penetration resistances. These yield strength ratios and previously published liquefied strength ratios are used to develop a comprehensive liquefaction analysis for ground subjected to a static shear stress. This analysis addresses: (1) liquefaction susceptibility; (2) liquefaction triggering; and (3) post-triggering/flow failure stability. In particular, step (2) uses the yield strength ratio backcalculated from flow failure case histories and the cyclic stress method to incorporate seismic loading.