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ABSTRACT

Electrical Resistivity (ER) is a non-destructive geophysical method for geotechnical and geo-environmental investigation. This technique is promising in producing soil moisture map and obtaining subsoil profile information. Additionally, the saturated and unsaturated soil parameters can be evaluated through the electrical resistivity method. The saturated and unsaturated soil properties are critical parameters for earthen infrastructure design, especially the landfill bottom liners and top covers, whereas the soil hydraulic properties play a significant role in the overall performance. On the other hand, Soil water characteristic curve (SWCC) determination is the primary step in the landfill alternative cover design providing values of field capacity (θFC) and wilting point (θWP), water storage capacity, hydraulic conductivity, etc., However, the existing methods for obtaining SWCC have limitations in efficacy. Consequently, the design parameters for landfill top cap may have certain degrees of inadequacies. Thus, this study attempts to use electrical resistivity method as an alternative to determine the essential unsaturated design parameters (θFC and θWP) of landfill alternative cover. In this study, the quantitative relationships between resistivity-moisture content and resistivity-suction were constructed using field data followed by the van Genuchten model. These relationships among the resistivity-suctionmoisture content were used to estimate the θFC and θWP. The magnitude of θFC and θWP was found slightly underestimated than the actual design values. However, the methodology developed in this study to estimate the design parameters of landfill cover proved to be a viable alternative method. An analytical approach was also introduced to compute water storage capacity of alternative cover system using resistivity data.