Ultimate limit state design using an advanced ‘Brick' model in the finite-element method

Abstract

The increasing use of the finite-element method in geotechnical design has raised the question of the compliance of this design approach with Eurocode requirements for the ultimate limit state conditions, especially when a more complex soil constitutive model has been used. Past authors have identified several important issues relating to the application of the finite-element method in ultimate limit state design, including the effects of initial stresses, effects of stress history, choice of soil model, significance of the failure of structural member and the timing when the partial factor of safety is applied during the design assessment. In this paper, an advanced 'Brick' soil model has been used to demonstrate its application in the design of different geotechnical structures and the effects of the design assumptions used in the design of these structures. The paper also demonstrates the versatility of the Brick soil model in the derivation of the new set of input parameters when the necessary partial factor is applied to the strength of the soil as required in the Eurocode design approach.

Editorial

“…Such improvements have the potential for reduced tunnel settlement and greater safety of the workforce during construction. The link with the next paper is that the advanced Brick model for finite-element analysis (FEA) introduced by Yeow (2014) was originally developed for the prediction of ground and structural movements during tunnelling and large excavation formation. The model was originally derived for use in heavily over consolidated London Clay but has also been used successfully in soft, normally consolidated Bangkok Clay and marine clay in Singapore to assist in the design of many large underground urban developments.…”

“…The model was originally derived for use in heavily over consolidated London Clay but has also been used successfully in soft, normally consolidated Bangkok Clay and marine clay in Singapore to assist in the design of many large underground urban developments. In this paper Yeow (2014) is particularly interested in how the requirements of Eurocode 7 can be incorporated in FEA using the Brick model and demonstrates the versatility of the model in deriving new input parameters when the necessary partial factor is applied in a specific design approach. London Clay is used as the basis for material parameter generation and several simple hypothetical cases are used to test the findings.…”