Hyperbolic Constitutive Model For Tropical Residual Soils

Transcript

The stress-strain response of natural soils depends on soil state, stress history and drainage conditions. Many constitutive models are available for describing the stress-strain relationship for different soil types. It is desirable to have a comprehensive model, based on sound principles of continuum mechanics, capable of describing the soil behaviour under any type of loading. The model parameters involved in such models most often, require elaborate experimental procedures to evaluate them. There are many instances when a problem posed to an engineer may not necessarily require such a complex material model. For example, a simple undrained analysis may be sufficient for the immediate or end of construction (this will be always critical condition) of structures on clayey soils. Depending on specific field situation, it may be possible to analyze the problem with much simpler model. Therefore, there is a need to develop a realistic and simple model whose parameters can be determined easily with simple procedures. The cardinal aim of the present paper is to develop a simple constitutive relationship using hyperbolic approach, based on analysis of test results on five different types of soils. Combination of stress ratio and mean principal stress is identified to capture the strain softening behaviour of residual soils. The model developed is applied to predict the stress-strain response for other soils found in literature. The model predictions are quite comparable and model parameters are easily determinable.