Rheological characteristics and one-dimensional isotache modelling of marine soft clays

This paper presents a novel elasto-viscoplastic constitutive formulation based on the isotache concepts and the Nishihara model. Incorporating a novel viscoelastic body to include the delay elastic deformation of marine soft clays under the external load, the proposed model is used to evaluate the theories of consolidation-creep coupling, strain rate dependency and stress relaxation of saturated marine soft clays, and hence, the methodology used to determine the parameters of the model is discussed. Ningbo marine soft clay is selected as an example to interpret the determination of the model parameters on a field scale. A series of conventional oedometer tests are conducted as well. Eventually, we utilize the model to simulate several kinds of rheological tests, including one-dimensional (1-D) long-term compression tests on Ningbo marine soft clays, 1-D constant rate of strain (CRS) tests on Batiscan clays and 1-D stress relaxation tests on Hong Kong marine deposits. These findings indicate good agreement between the computational and experimental results, suggesting the given model can provide reliable forecasts for the rheological characteristics of marine soft clays.