Response of Piles in Multilayers of Soil under Uplift Forces

Abstract

A new methodology is introduced to determine the mobilized pile response under axial tension forces in a soil profile with multilayers of sand and/or clay. The proposed model allows the assessment of the load transfer (t–z) and pile-head load versus displacement (Q–Z) curves based on the mobilized pile skin resistance as induced by the vertical displacement at the soil–pile interface. The methodology provides a t–z model for sand and two alternative t–z models for clay, which are a function of soil and pile properties. The load transfer (t–z) curve is evaluated based on the soil–pile interaction and stress–strain relationship of soil up to failure. The suggested method is validated by using a number of case studies with different types of piles and multilayered soil profiles (i.e., sand and clay deposits). The reasonable and good agreements between the results from full-scale load tests and predictions from the suggested models highlight the capabilities of the presented technique. Results from current practice and numerical analysis are also presented.