Effect of pore fluid pH on the collapse behaviour and microstructural evolution of a loess

Abstract

This study investigated the role of pore fluid pH in governing the microstructural characteristics of loess soil and its ultimate effect on collapse mechanisms. A series of standard oedometer tests was conducted to evaluate the impact of acidic and alkaline pore fluid pH on the collapse behaviour of loess. The microstructural characterisation of soil exposed to different values of pore fluid pH was done by performing microscopic analysis of specimens before and after oedometer tests. In addition, the obtained micrographs were processed using an image analysis tool in order to interpret the influence of different pore fluid pH interactions on the evolution of soil pore-size distribution characteristics. The results obtained in this study indicated that the pore fluid pH has significant effect on the structural stability of loess and on the evolution of pore-size distribution during consolidation and consequently, on its wetting-induced collapse behaviour.