Abstract
The stress-strain relationships for soils and soft rocks have been studied in triaxial and plane-strain compression tests for a wide range of strain levels by Tatsuoka and Shibuya (1991), who demonstrated that the hyperbolic model does not satisfactorily predict the overall stress-strain behaviours of various geotechnical engineering materials. A new simple non-linear model is proposed by the Authors which requires three materials parameters, all of which are easily determined from laboratory tests and some of which are from in-situ shear wave velocity measurements. Calculated performance is in excellent agreement with precise laboratory measurements of stress-strain behaviour over a wide range of strains. This new model is used to study the problem of an axisymmetric excavation. It is demonstrated that the problem of stress redistribution is critically dependent on the assumed stress-strain behaviour, particularly at small strains.
