Experiments of creep rate for over-consolidated clay under plain strain condition and a simple correlation

Abstract

Soft foundations of high embankments exhibit significant time-dependent effect on deformation in decades after construction, and there is a lack of simple method for predicting the creep rate of over-consolidated soft clay under plain strain condition. In this paper, laboratory creep tests under plain strain consolidation with different principal stress ratio were shown. The variation of stress in zero strain direction (σy) under different degree of consolidation was analysed. Linear relationship between (σy) and the applied principal stress σx (or σz) was found. And then, the creep rate of volumetric strain (Cα) and vertical strain (β) were calculated and linked to volumetric stress defined ratio of over-consolidation (OCRp) and stress ratio (K). Finally, the new parameter K∙OCRp was found to have a good correlation with the creep rate (Cα or β).

Keywords

• over-consolidation
• plain strain
• creep
• stress ratio