Prediction of shrinkage behavior of soft soil using ramp loading consolidation theory

Abstract

Soft soil is a highly saturated soil and its low shear strength undermines the reliability for construction. Hence, to reclaim soft soil for construction, more research is required to improve our understanding on the changes in soft soil properties with ongoing dewatering. Shrinkage behavior of soft soil is studied in this paper. Some of the previous studies focused on the simulation of soil volume change and matric suction change while neglecting the soft soil settlement during fully saturated stage of shrinkage. The aim of this research is to predict the settlement of soft soil at the stage where soil is fully saturated and moisture content is high. During this stage, suction of soil is assumed to be zero and the decreased pore water pressure induced by evaporation is taken as the main reason for settlement. With the soil shrinkage happening, the pore water pressure decreases due to water loss and effective stress increases, being the mechanical reason for soil settlement. To predict the settlement during fully saturated stage of soil shrinkage, the ramp loading consolidation theory is applied. The shrinkage test of saturated kaolin with initial moisture content of 150% has been conducted in laboratory and vertical settlement was recorded. Ramp loading consolidation simulation method is applied to soft soil settlement estimation and the prediction fits well with the experiment.