Effective Young's Modulus for a Footing on a Spatially Variable Soil Mass
Journal
Geotechnical Special Publication
Journal Issue
GSP 284
Pages
360-369
Date Issued
2017
Author(s)
Abstract
This study investigates the possibility of representing the effective Young’s modulus for a footing problem using a suitable spatial average. The effective Young’s modulus (Eeff) of the spatial variable soil mass is defined as the Young’s modulus actual “felt” by the footing and is simulated by a homogenization procedure that match the responses between a random finite element analysis (RFEA) and a homogeneous finite element analysis. The spatially variable Young’s modulus is simulated by a stationary lognormal random field. It is found that the traditional spatial averaging model that treats all soil regions equally important cannot satisfactorily represent the Eeff for the footing problem. Further numerical evidences show that the concept of “mobilization” is essential: highly mobilized soil regions are more important than non-mobilized regions. For the footing problem, the soil regions close to the footing are highly mobilized, so a spatial averaging model with non-uniform weights should be adopted. Moreover, the non-uniform weights are prescribed (not depending on random field realization). The “prescribed mobilization” for the spatially variable Young’s modulus is in high contrast with the “emergent mobilization” for the spatially variable shear strength. The difference may be due to the localization of the shear failure and the non-localization of the elastic deformation.
Type
conference paper