Secondary compression characteristics and settlement calculation of soft clay under overloading-unloading and reloading

A series of 1-D consolidation tests are carried out for soft remolded clay under overloading-unloading and reloading.It is found that the primary consolidation time is greatly reduced than that of the original compression.The secondary consolidation coefficient is not related to time of sustained loads,and it becomes larger as the reloading pressure increases and becomes less with the pre-consolidation pressure.The regular relationship between the secondary consolidation coefficient and OPR(over pressure ratio) can be simulated by the simplified hyperbolic model.Based on the model,the secondary compression settlement formula is established,which reflects the influence of soft clay characteristics,pre-consolidation pressure and reloading pressure.Comparison between calculated values of the engineering example and post-construction measured data shows that the results by the secondary compression settlement formula are reliable.The present method is more reasonable than the traditional methods,while the results by the traditional methods are much larger than the true results.