This paper presents the derivation of a generalized nonlinear softening load-transfer model to analyze the load-settlement response for a single pile subjected to axial loading. The model requires the calculation of a single parameter, n, so that the number of field trial tests can be reduced significantly compared with other empirical solutions with multiple parameters. Variations in n can provide approximations for different soil–pile interaction systems. The model explicitly considers both the hardening and degradation behavior of skin friction with shear displacement. The effectiveness of the proposed method was verified through comparison of the evaluations with field measurements and other analysis results. A hyperbolic load-settlement model of pile-point resistance was incorporated with the load-transfer function for skin friction to develop an efficient computer program for settlement analysis of axially loaded piles. A comparison was made between the current approach and other analyses. Satisfactory performance was obtained for the new calculation framework, where the estimated settlement differed within 13%. In this paper, the softening effect of load-settlement response of a pile is also illustrated in a worked example.

A rigid nonyielding retaining structure needs to be dimensioned to have adequate stiffness, such that it can resist mobilized lateral earth pressures. This corresponds to the at-rest condition, as there are, in general, negligible lateral deformations in the backfill. Measures that can mobilize higher soil shear strength and reduce lateral thrust are therefore sought to provide a more efficient design. The present study investigates the possibility of inserting compressible geofoam panels against rigid walls using physical model testing. Controlled yielding is allowed in the backfill with the occurrence of deformations in the geofoam. The mobilized earth pressures vary from the maximum at rest, to the intermediate, and finally to the minimum full active state depending on the magnitude of displacement. The effects of geofoam thickness and stiffness on lateral earth pressure reduction are explored. The measured pressure and displacement distributions form a comprehensive reference for use in calibr...