Impact of remolded soil fabric on the volumetric deformation behavior of clayey soils

Abstract

The volumetric deformation of clayey soils, leading to a reduction in the bearing capacity and serviceability of pavements and building structures, is a major concern during their design, construction, and maintenance. Several approaches are often followed to mitigate the volume expansion and concomitant damage, including removal and replacement, moisture treatment with appropriate compaction protocols, and chemical treatment. During these treatment processes, the in-situ fabric is altered as the natural undisturbed soils are remolded and compacted. Hence, it is crucial to understand the effect of remolding on the volumetric characteristics of clayey soils. To investigate this effect, coefficient of linear extensibility (COLE) tests were conducted on both natural and remolded soil samples. The objective was to evaluate the impact of soil fabric modification on volumetric characteristics such as suction compressibility index (γh) and soil water-retention characteristics, i.e., the soil–water characteristic curve (SWCC) of clayey soils. Our findings indicated that remolded soils had approximately 10% to 30 % higher γh-values than those of unaltered soils, which can be attributed to changes in porosity. Two distinct mechanistic models were developed using the packing theory concept to link the γh-value and SWCC of remolded and natural soils. Finally, an analysis was conducted to compare the potential vertical movement (PVM) of natural and remolded clay soils. This analysis revealed that the remolded soil fabric substantially increased the PVM values, particularly for high-plasticity clay soils. This effect should be considered when assessing the impact of treatment that requires remolding, which substantially alters the soil structure and fabric.