Study of the Hydromechanical Behavior of Collapsible Soils in The Ghardaïa Region, Algeria

Abstract

The rapid growth of the population has resulted in extensive land use and a notable expansion of construction activities on problematic soils. Arid and semi-arid regions in southern Algeria have witnessed significant urbanization and infrastructure development. These areas are generally characterized by unsaturated surface deposits and deep groundwater levels, allowing soils to remain unsaturated to considerable depths for long periods. Under the influence of climatic cycles and repeated wetting–drying processes, soils progressively develop their microstructure, hydraulic characteristics, and consequently their physical and mechanical properties.Recent studies have shown that soil-water retention curves (SWRC) are effective tools for characterizing the stress state of unsaturated soils, describing their hydromechanical behavior, and estimating their strength parameters. The aim of this research is to characterize these soils and examine the additional shear strength resulting from suction variations, as well as the influence of soil compaction on the collapse mechanism. Soil samples were collected from the Metlili Valley, an arid region located southwest of Ghardaïa. The findings reveal significant volumetric changes caused by suction reduction. Furthermore, an increase in suction enhances shear strength, mainly due to the rise in apparent cohesion associated with capillary effects.