Applicability of small strain stiffness parameters for pile settlement calculation

Abstract

This study presents the importance of using advanced constitutive soil models in numerical modelling as a daily geotechnical practice. Back-calculated stiffness from observations of the soil deformations in-situ very often are greater than those used for the geotechnical design. Design is often too conservative, because of insufficient soil investigation data, in terms of applied material models and simplification in analytical or numerical design [2,3,4,10,14]. Hence, there are highlighted advanced soil testing techniques and consecutive soil material models in this study, which could help to estimate pile settlements in PLAXIS 3D AE02 numerical code. Pile loading test is simulated for different pile diameters and interface constrains at the specific site, where residential building is designed on piles. Bender element tests were conducted at laboratory for subglacial till as the end-bearing soil layer for the project, and Hardening Soil Small (HSSmall) soil material model applied in the numerical analysis. The presented approach gives initial pile bearing capacity estimation for different pile diameters and interface constrains, so designer can decide the most technically and economically substantiation technology. Insitu pile loading test data essentially would help to calibrate initial model for the designed pile, finally adjusting the geotechnical design.