Towards a better understanding of the mechanics of soil liquefaction

Abstract

Liquefaction is essentially a phenomenon in which saturated granular soil loses much of its strength and stiffness under cyclic or monotonic loading. Largely because of the complexity and uncertainty of the phenomenon, soil liquefaction remains an area of great difficulty in soil mechanics and geotechnical engineering, and the worldwide practice in liquefaction evaluation remains to be highly empirical. In this paper, we present some new developments in understanding the mechanics of soil liquefaction, which are firmly based on specifically designed experimental programs involving both clean and silty sands at a broad range of initial states. The key issues examined include the role of initial static shear stress on cyclic behavior and liquefaction resistance of sand, the fabric effects, the role of non-plastic fines in altering the potential for liquefaction, and the role of particle grading. We propose some new perspectives on these issues in a sound theoretical framework, and suggest several important implications for engineering practice.