Moisture Migration Under Mat Foundations in Nicosia Marl

The paper investigates the moisture changes occurring due to rainfall and evaporation under a mat foundation in an expansive soil of Cyprus called Nicosia marl. For this purpose, laboratory experiments were performed on samples of Nicosia marl for the determination of the hydraulic and water retention characteristics. A field water infiltration experiment was performed at a site where pairs of volumetric water content and matric suction sensors were installed at two different depths, in order to back-calculate the in situ hydraulic characteristics. Based on the experimental data and back-calculation results, finite element analysis of moisture migration underneath a mat foundation over the course of a hydrological year were performed using rainfall and evaporation input boundary conditions at the free ground surface consistent with Nicosia climatic data. Series of parametric analyses are performed varying the values of foundation embedment depth, the van Genuchten model parameters, and the vertical and horizontal hydraulic conductivities. The parametric study sheds light also on the effectiveness of two ground improvement approaches that are frequently used as remedies in the case of expansive clays, namely prewetting and soil replacement by gravel fill.