A modified creep index and its application to viscoplastic modelling of soft clays*

摘要

Conventional consolidation tests on reconstituted specimens of numerous natural soft clays show a decreasing of creep index Cαe with increasing soil density. Based on all selected and conducted experimental results, a modified creep index Cαe* defined in double logarithmic plane lge-lgt, was plotted for various clays, from which Cαe* can be assumed as a constant for different soil densities. Then, the modified creep index was applied to a newly developed elastic viscoplastic model. In this way, the modified creep index Cαe* can naturally take into account the nonlinear Cαe revealing the influence of soil density in the soil assemblies without additional parameters. Finally, the enhanced model was incorporated into the finite element code ABAQUS and used to simulate a consolidation test and a test embankment. The improvement of simulations by the modified creep index was highlighted by comparing simulations using the conventional creep index Cαe.