Experimental cyclic P-Y curves for saturated loose sand

A study on cyclic p-y curves that relate soil resistance to pile deflection in cohesionless soils near ground surface is the subject of this paper. Well-established p-y curve generation procedures are necessary for satisfactory estimation of the response of pile foundations in cohesionless soils under dynamic loads. Nonlinear p-y curves for seismic loads can be quite different from the ones based on the American Petroleum Institute (API) code. Several factors affect p-y curves. Effects of loading rate and excess pore-water pressure due to soil pile interaction are reported in this study. Previous parametric studies have shown degradation effects of excess pore-water pressure development due to pile movements relative to the free-field soils on the stiffness and strength of the supporting soils (Kagawa and Kraft, 1981; Martin et al., 1980). However, experimental evidence was not available for the influence of excess pore-water pressure on p-y curves. Rate of loading has long been recognized as an important factor on the behavior of pile foundations in cohesive soils (Briaud and Garland, 1985). Its influence on p-y curves in cohesionless soils has not been studied extensively. Recent experimental studies have demonstrated effects of the rate of loading in cohesionless soils (Ozden, 1999).