Identifying unsaturated suction variations of Highway Embankments using coupled Electrical Resistivity Imaging (ERI) and Field Instrumentation: Fid-Bau Portal

Identifying unsaturated suction variations of Highway Embankments using coupled Electrical Resistivity Imaging (ERI) and Field Instrumentation

Nobahar, Masoud / Salunke, Rakesh / Chia, Henry Kini / La-Cour, Ian / Khan, Sadik / Amini, Farshad

Abstract

In Highway Embankments (HE) constructed on Expansive Yazoo Clay Soil (EYCS), in situ moisture and matric suction variations are environmentally driven variables that can significantly impact the safety of the constructed slope. The collected moisture content and suction data are localized and have low spatial resolution on embankments with point borehole monitoring systems with sensor instrumentation. On the other hand, Electrical Resistivity Imaging (ERI) allows high spatial resolution monitoring and is a proven method of mapping the subsurface geologic setting. Multiple studies have proven a correlation between resistivity and soil moisture. The comparison between resistivity and matric suction, on the other hand, has been rarely attempted, much less for EYCS through field-based investigation. The objective of the current study is to compare the field-sensor-based matric suction and soil moisture data with resistivity data. This localized comparison informed the capability of the ERI data to extrapolate the moisture content and suction parameters globally or to other areas of the slope where the instrumentation isn’t available. Comparing ERI, matric suction, and volumetric soil moisture content is critical to embankments reliable predictive models. This study’s findings can improve performance monitoring requirements for susceptible HE.