Analysis of A Braced Excavation In Soft Soils Considering The Consolidation Effect

Abstract

The studies of excavations in soft clayey soils are normally based on undrained total stress analyses. A better approach consists of taking into account the effects of consolidation during the excavation-bracing process and after the completion of the construction by means of coupled finite element analyses in effective stresses. In this paper, the geotechnical behaviour of a braced excavation in the soft soils of San Francisco (USA) is analysed, both during and after the construction period. Numerical analyses are performed with a finite element program, which incorporates the Biot consolidation theory (coupled formulation of the water flow and equilibrium equations) and soil constitutive relations simulated by the p-q-h critical state model. Numerical results are compared with field results.

Cut Slopes in Clayey Soils: Consolidation and Overall Stability by Finite Element Method

“…Only some quantitative differences were observed in the horizontal displacements, despite an overall qualitative similarity. Using the program, very good agreements of numerical and field results were also observed both in an embankment on soft soils incorporating stone columns (Domingues 2006) and in an braced excavation in very soft ground (Costa 2005). …”

“…The accuracy of the finite element program has been assessed in several ground structures involving consolidation (Borges 1995(Borges , 2004Borges andCardoso 2001, 2002;Costa 2005;Domingues 2006) by comparing numerical results to field measurements. For instance, with regard to embankments on soft ground, Borges (1995) compared results of two geosynthetic-reinforced embankments, one constructed up to failure (Quaresma 1992) and the other observed until the end of consolidation (Yeo 1986;Basset 1986a, b).…”

Bi-Layer Diaphragm Walls: Structural and Sectional Analysis

“…On the other hand, fewer studies (e.g. : (Carrubba, Colonna 2000;Costa et al 2007;Ou, Lai 1994)) have evaluated the forces and stresses produced on the walls.…”

Embankments on Soft Soil Reinforced with Stone Columns: Numerical Analysis and Proposal of a New Design Method

“…The finite element program used in this study has been applied in several ground structures involving consolidation (Borges 1995(Borges , 2004Cardoso 2001, 2002;Costa 2005;Domingues 2006) and assessed by comparing numerical results to field measurements. For instance, with regard to embankments on soft ground, Borges (1995) compared results of two geosynthetic-reinforced embankments, one constructed up to failure (Quaresma 1992) and the other observed until the end of consolidation (Yeo 1986;Basset 1986a, b).…”