A NEW NONLINEAR HYSTERETIC RULE FOR WINKLER TYPE SOIL-PILE INTERACTION SPRINGS THAT CONSIDERS LOADING PATTERN DEPENDENCY

摘要

We propose a new hysteretic rule for p-y curves to be used in the dynamic analysis of deep foundations. We first examine the results of past lateral cyclic pile load experiments to clarify the characteristics that are to be modeled in the load transfer hystereses in p-y curves. We then undertake an analytical study of soil element behavior when subject to cyclic passive (compressive) and active (extensile) deformation. We found that the soil resistance intensity to piles varies with different cyclic loading patterns, as the stress-dilatancy behavior in soil varies with cyclic loading patterns. We developed a new hysteretic rule that satisfies the observed dominant characteristics. Although the proposed hysteretic rule has its background in the peak-oriented rule, it is further extended to be a function of the loading pattern. Numerical tests using the proposed model showed that the model is capable of reproducing observed differences in the behavior of piles subjected to fully-reversed cyclic loading and one-sided cyclic loading, even though the typical peak-oriented rules are unable to predict these outcomes.