Abstract: In order to investigate the creep behaviors of soft soil in Pearl River Delta, a series of laboratory drained and undrained triaxial creep tests were performed. The test results show that in drained condition, soft soil has large initial deformation but small creep deformation. While in undrained condition, creep effect is significant. It indicates that enhancing the drainage ability of soft soil foundation can reduce the probability of creep rupture. By introducing Singh-Mitchell creep equation, the drained and undrained creep models of soft soil are proposed, in which exponential function is adopted for stress-strain relationship and power function for strain-time relationship. Predicted results are in good agreement with the experimental results. The values of model parameters change a lot with the variation of drainage condition, which results from the dependence of strain-time and stress-strain relationships on drainage condition.

Key words: soft soil, creep, drainage condition, Singh-Mitchell creep equation, stress-strain-time relationship