Importance of Nonlinearity in Finite Element Analysis of a Braced Excavation in Soft Soils

F. Cai, K. Ugai
Dept. of Civil and Environmental Engineering, Gunma University, Kiryu, Japan
A. Nakamura
Forum 8 Co., Ltd., Tokyo, Japan

Keywords:
Finite element, braced excavation, nonlinearity, GeoFEAS

ABSTRACT:
It recently becomes highly necessary to predict the deformations of retaining walls and neighbouring structures induced by deep excavations. For such a purpose, the finite element analysis is an effective approach; however, they are important to verify selected constitutive models for soils including how to select the parameters
of the constitutive models, and to improve analysis precisions for various grounds. This paper uses a twodimensional finite element elastoplastic geotechnical analysis software GeoFEAS to calculate a historical case of retained excavation 8m deep in soft ground using elastic model and Duncan-Chang’s nonlinear elastic model.
The calculated wall deflection was consistent with the observations for the last excavation stage if Young’s modulus was determined via an empirical equation using the N-value of SPT for sands and undrained shear strength of unconfined compression test for clayey soils. Elastic back analysis shows that Young’s modulus had
to be decreased stage by stage of excavation to let the calculated maximum wall deflection equal to the observations. Nonlinear elastic analysis indicates that the wall deflection and surface settlement was consistent with the observations for every excavation stage.

Importance of Nonlinearity in Finite Element Analysis of a Braced Excavation in Soft Soils 2011-04-14T05:05:00-07:00 Rating: 4.5 Diposkan Oleh: Andre S