Modified Mesri creep modelling of soft clays in the coastal area of Tianjin (China)

Abstract

The nonlinear creep characteristics of typical clays in the coastal area of Tianjin were studied by consolidated-undrained triaxial creep tests. The tests were performed via the stepwise loading method, and the creep curves of the soft clays under different stress states were obtained from the raw data processed by Chen and Kang’s method. The experiments showed that the long-term deformation of soft clays can be divided into two stages, that is, the deformation produced by increasing stress and the deformation produced by a constant load. By analysing the test data, a modified Mesri model was established based on the classical Mesri creep model, which treated the final strain of the first-stage soil deformation as the initial strain and described the second-stage soil deformation using a combination of a stress-strain hyperbolic function and strain-time hyperbolic function. The modified model contains four parameters; all of the parameters have clear physical significance and can be determined by experiment. Verification indicated that the calculated results were in good agreement with the experimental ones. For further verification, the model was applied to the calculation of the long-term settlement in the coastal area of Tianjin. The results showed that the modified model can predict the long-term creep deformation of soft clays with a satisfactory accuracy.

Keywords

• coastal area of Tianjin
• modified Mesri model
• soft clay
• creep
• triaxial creep test