Some Factors Affecting the Predictions of Ground Movements Around an Excavation in Stiff Clay
The paper describes a sensitivity study of predictions of excavation behaviour in a heavily overconsolidated clay using a non-linear cross-anisotropic elastic model for the soil. The model is experimentally based and is capable of including non-linearity of stress-strain behaviour, dependence of stiffness on both stress level and stress path direction, and changes in stiffness caused by changes in the stress path direction. Analyses are reported of an instrumented full-scale trial excavation and computed displacements are compared with the observed behaviour. Firstly, the effect of including anisotropy is quantified, by comparing analyses with isotropic and anisotropic soil models. The effects of modelling the recent stress history and changes in the stress path direction during excavation are then investigated. Finally, analyses with linear and non-linear stress-strain behaviour are compared to isolate the effect of including a strain-dependent stiffness.
KeywordsGround Movement Stress Path Instrumentation Data Back Analysis Ground Response
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- Hird, C.C. and Pierpoint, N.D. (1994). A non-linear anisotropic elastic model for overconsolidated clay based on strain energy. Proc. 3rd European Conference on Numerical Methods in Geotechnical Engineering, Manchester, UK. Published by Balkema, Rotterdam: 67–74.Google Scholar
- Jardine, R.J., Potts, D.M., St. John H.D. and Hight, D.W. (1991). Some practical applications of a non-linear ground model. Proc. 10th ECSMFE, ‘Deformation of Soils and Displacements of Structures’, Florence 1: 223–228.Google Scholar
- Pierpoint (1996), The prediction and back analysis of excavation behaviour in Oxford Clay. Ph.D. Thesis, University of Sheffield, UK.Google Scholar
- Wroth, C.P. and Houlsby, G.T. (1985). Soil mechanics — property characterisation and analysis procedures. Proc. 11th International Conference on Soil Mechanics and Foundation Engineering, San Francisco, USA, 1: 1–55.Google Scholar