Non-linear and linear models in design of retaining walls

This paper compares non-linear and linear elasto-plastic models in the numerical analyses of a retaining wall in stiff clay. The paper aims to be applicable to routine design, where often a non-linear elasto-plastic model is not available and instead a linear elasto-plastic model is used. Current guidelines suggest deriving the appropriate linear elastic stiffness from the non-linear soil behaviour, on the basis of the expected straining in the ground. However, it is not always straightforward to choose a representative strain level. The paper presents profiles of linear elastic stiffness, back-calculated to match the maximum wall deflection of the non-linear analyses in the short term. On the basis of the non-linear soil stiffness–strain curve, the paper then derives a corresponding strain level for each linear elastic stiffness profile. Three different support systems are examined: a single-propped wall, a double-propped wall, and a top-down construction. A number of non-linear stiffness–strain curves are considered for the stiff clay and two K₀ profiles are examined.