Small Strain Shear Modulus of Undisturbed Gravelly Soils During Undrained Cyclic Triaxial Tests (original) (raw)

Dynamic Properties of Gravelly Materials

2010

This paper studies the dynamic characteristics (i.e. shear modulus and damping ratio) of modeled gravelly soils used as construction materials in some rock-fill dams in Iran by conducting large-scale triaxial testing. Tested specimens were compacted to more than 95% maximum dry density, according to Modi ed Proctor, and tested according to ASTM D 3999. Accurate monitoring of strains by means of non-contact type displacement transducers to infinitesimal strains as small as 0.0001% enabled us to obtain Gmax with some extrapolation. Based on the available experimental results the ranges for G=Gmax ???? and D ???? are defined for materials with > 30% fine content and materials with < 15% fine content. The results clearly indicate the need for modification in previously proposed G=Gmax ???? curves, particularly for gravels with > 30% fine content. Also, the suggested D ???? curves lay out of the bounds of data reported by previous researchers, which may be due to the effects of ...

Stress–dilatancy of gravel for triaxial compression tests

Annals of Warsaw University of Life Sciences – SGGW. Land Reclamation, 2018

The stress–plastic dilatancy relationships for gravel are analyzed based on drained triaxial tests experiments described in literature. For this, Frictional State Theory is used. The characteristic points and stages of shearing may be defined from the analysis of η–Dp relationship. The characteristic points and stages of shearing cannot be identified from ordinary stress–strain, volumetric strain–shear strain relationships that are shown in literature.

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.