EFFECT OF CYCLIC LOADING DIRECTION ON SANDY SLOPE LIQUEFACTION

This article investigates the effect of cyclic shear loading direction, produced by earthquake on liquefaction resistance of a sandy carbonate slope (material obtained from Hormuz Island). Presence of slopes produces initial static shear stress which may have different orientations with cyclic earthquake loading. In this paper, an experimental study performed cyclic undrained constant volume bidirectional simple shear test accomplished on reconstituting cylindrical specimen prepared by the dry pluvial deposition method. Results published by Lee & Seed (1967), Vaid & Chern (1985) and Andersen & Hoeg (1992) showed that the cyclic resistance of the sands could decrease or increase in slopes based on the amount of the initial static shear value and specimen density. Yang & Sze (2011) studied the three factors of density, vertical stress and initial static shear on liquefaction behavior of silica sands independently and showed that in a constant relative density the value of static shear plays a considerable role in the dynamic behavior of sands. Li et al. (2016) examined the effect of initial static shear produced by slopes on the monotonic behavior of silica sands under different conditions of stress and density; they found out that the monotonic behavior of sands varies based on the angle between monotonic loading direction and the initial static shear stress direction. Besides, Boulanger & Seed (1995) and Kammerer (2002) examined the effect of initial static shear on cyclic behavior of silica sands and concluded changing direction affects the liquefaction resistance and its behavior.

Keywords:

Multidirectional loading , Simple shear , Liquefaction , Carbonate sand