Cyclic failure characteristics of silty sands with the presence of initial shear stress

Abstract

Liquefaction of silty sands remains an outstanding issue since it continues to lead to catastrophic consequences in recent earthquake events. The cyclic characteristics, such as cyclic failure pattern and cyclic resistance, are the fundamental aspects of liquefaction analysis. The difficulty and uncertainty of characterization and evaluation of cyclic behavior and liquefaction resistance of silty sand mainly come from the complicated interactions of various influencing factors, such as packing density, confining pressure, initial shear stress, cyclic loading amplitude, soil properties, and soil fabric. This study presents a series of laboratory testing results to identify the cyclic failure patterns of silty sands considering different soil states, fines contents, initial static shear stress, etc. It is found that the failure patterns are related to the states of soils and the cyclic loading characteristics, i.e., the combination of initial shear stress and cyclic loading amplitude for silty sands with similar soil fabric, and that the cyclic resistance of silty sands is also a function of soil states and initial static shear stress for similar soil fabric. Critical state soil mechanics is implemented to characterize the cyclic failure patterns and cyclic resistance. Implications of the present study to the existing liquefaction assessment methods are also discussed.