A Semi-empirical Approach-Based Model for Swell Characterization of Expansive Clays

Expansive soils often pose as a potential geo-hazard for structures built on them due to the volumetric changes associated with moisture variation. Soil water characteristic curve (SWCC) is a direct representation of the pore and grain distribution of clays while the variation of in situ soil matric suction governs the hydration processes. In the present research, five natural expansive clays were studied at their 95% of maximum dry unit weight. Swell behavioral evaluations are conducted using standard test procedures. Both desorption and adsorption SWCC’s were determined using pressure cell apparatus and filter paper method. Adsorption paths are utilized for analysis study as swelling behavior is the main scope of the research. A novel path traversed by the soil specimen on the void ratio-moisture content-log (soil suction) plot, and the corresponding slope, namely the modified specific moisture capacity, ‘α’, is identified as the main influential parameter. This modified specific moisture capacity exhibited direct relationship to swelling strains and swelling pressure of all five natural clays. A simple model for predicting one dimensional swell strain and swell pressure was established based on reliable predictions obtained using the modified specific moisture capacity of clays.