Shear Localization Due to Liquefaction-Induced Void Redistribution in a Layered Infinite Slope (original) (raw)

SHEAR STRAIN DEVELOPMENT IN LIQUEFIABLE SOIL UNDER BI-DIRECTIONAL LOADING CONDITIONS

A comprehensive testing database composed of modeling-quality multi-directional cyclic simple shear testing on medium to high relative density, fully-saturated samples of Monterey 0/30 sand has recently been developed. This testing program incorporated a variety of multi-directional stress paths, including a large number of stress paths never before examined. Results from these tests have proven useful for enhancing current understanding of liquefaction behavior by allowing for a more complete theory to emerge. This new 3-dimensional theory greatly expands current understanding of liquefaction behavior and elucidates some areas in which current theory—which has been based principally on uni-directional laboratory testing—can be misleading or unconservative. Of particular interest are the topics of pore pressure generation and softening, the relationship between pore pressure and strain capacity, and the dilational lock-up in medium density sands that acts to limit large free-flow type deformations. Insight has also been gained on the complex effects caused by an initial static shear stress such as would be imposed by sloping ground conditions or the presence of a structure.

Effect of the Spatial Variation of the Shear Modulus on Soil Liquefaction Potential

Soil liquefaction is at the origin of major damage caused by an earthquake, both human lives lost as well as material losses. Several authors have studied soil liquefaction using deterministic and probabilistic methods. In this paper we study the effect of variation of the shear modulus on soil response defined by the excess pore pressure ratio (r u). Shear modulus is modeled by a log-normal random field, while discretization of the field is done using Karhunen Loève method. Finn deterministic model of liquefaction is modeled using the finite difference software Flac 3D. The results show that the spatial variation of soil properties has a significant impact on the excess pore pressure ratio.