Preliminary experimental investigation on the inundating-induced collapse in collapsible soils improved by encased sand column

Abstract

ABSTRACT The present research aims to explore experimentally the performance and modes of failure of the wetting-induced collapse of fully penetrating reinforced and unreinforced models of a short single sand column in a collapsible soil subjected to partial inundation through a series of model tests under high constant total stress of more than 200 kPa. A specific loading frame and a test container were designed to apply vertical pressure and measure vertical movements of the columns . The experimental test results demonstrated that providing only sand columns in collapsing soil have no significant contribution in reducing the large volume change and sudden collapse when wet. In contrast, geosynthetic-encased columns prevented the occurrence of wetting-induced collapse and highly reduced the sudden vertical movements to a gradual process under relatively high applied pressure. Additionally, a slight change in the dry density of the soil had a dramatic influence on the behaviour of the wetting-induced collapse and modes of failure. In this study, the experimental test results and theoretical results from different analytical approaches in the literature have confirmed that it is practically possible to apply high total stress of more than 300 kPa on a single footing on collapsible soils subjected to wetting condition.