Test study on secondary consolidation behavior of soft soil under different loading paths

Abstract

Based on a series of one-dimensional consolidation tests for undisturbed samples in Guangzhou Nansha, the relationship between secondary consolidation properties and the stress history, load ratios and overload pre-pressure had been researched. The results show that the division of primary and secondary consolidation of soft soil is not only associated with the consolidation pressure, but also with loading ration, soil compression process and soil permeability decreased, etc factors. The main factors to affect the secondary consolidation coefficient are the loading ratio, pre-consolidation pressure, load duration, pre-consolidation pressure pc etc. Cα presents different regularities. For example, the larger the ratio is, the greater the influence of the coefficient of secondary consolidation is; secondary consolidation coefficient has a peak value when consolidation pressure equal to the pre-consolidation pressure;the longer duration of the front load, the smaller secondary consolidation coefficient of the later load. After preloading, the secondary consolidation ratio Cα and compression index Cc is a constant: Cα/Cc≈0.03. The test results indicate that preloading processing is a good way to reduce post-construction settlement: the secondary consolidation coefficient is small when the soil is over-consolidated state, and it can greatly reduce the amount of secondary consolidation deformation.