Cyclic Strength and Settlement Behaviors of High Compacted Saturated Gravelly Soils

This paper presents the undrained cyclic strength and settlememt behaviors of high compacted saturated gravelly soils using large-scale triaxial equipment. Based on the results, the failure critera for dense gravel materials in 15-50 loading cycles may be adopted, considering the fine content and cyclic shear stress due to earthquake shaking, as follows: (a) inducing 2% permanent accumulated axial strain (PAAS) for ru<0.8 (i.e. ratio of maximum excess pore-water pressure to effective confining pressure), for the specimen with fine content higher than 14%, (b) inducing 2% double amplitude axial strain (DAAS) for ru≥1 for isotropic consolidated dense gravelly specimen containing fine grain smaller than 4% under very high stress ratio as much as 0.45 and higher. For high copmpacted gravelly specimen, when in the first cycle of loading, ru and DAAS are higher than 0.20-0.25% and 0.4-0.5%, respectively, the initial liquefaction (ru>1) or failure may be occurred in less than 50 cycles by inducing PAAS or DAAS for about 2%. Cyclic strength of gravelly materials containing fine contain higher than 14% are smaller than that of the specimen containing fine grain smaller than 4%.