Development of t–z curve for piles in sands under uplift force

Abstract

A methodology is developed to assess the load transfer (t–z) curves of piles in sandy soils under uplift/tension force based on soil–pile interaction. Compared to current practice, the proposed approach accounts for soil and pile properties and contributes to the improvement in the construction of a nonlinear (springs) t–z curve in sandy soil which can be utilized with other computer codes to model the soil–pile response under tension forces (i.e., seismic events). The technique determines the mobilized shear stress/strain in soil associated with pile upward displacement at the soil–pile interface under progressing tension forces. A nonlinear soil constitutive model is employed to evaluate the variation of soil shear stress/strain at the soil–pile interface up to failure. The presented approach accounts for the influence of the pile length and diameter on the predicted t–z curve and has been validated through a number of comparisons with measured pile-head response and t–z curves.