Observations on the response of natural fine-grained soils with respect to particle fabric

Fine-grained silty soils with high levels of saturation are commonly found in natural river deposits, and experience from recent earthquakes suggests that such soils have the potential for earthquake-induced softening and strength reduction. In spite of significant research, only limited work has been undertaken to study the effects of soil particle fabric/microstructure on the mechanical behavior of natural silts. With this background, a systematic laboratory program involving monotonic and cyclic shear tests conducted on natural fine-grained soils was undertaken, and the results from this work are drawn to illustrate the importance of soil particle fabric/microstructure in governing the response of silt in addition to the traditionally considered effects from the void ratio (density) and confining stress. The void ratio (density) and particle fabric seem to compete in governing the mechanical performance (e.g., shear stiffness and strength), and the lack of accounting for soil particle fabric seem to impede comprehensive definition of soil behavior