Date of Graduation
Master of Science in Civil Engineering (MSCE)
Second Committee Member
Electrical, Resistivity, Soil
The purpose of this research is to explore the applicability of Capacitively-Coupled Resistivity (CCR) as an improvement on traditional drilling and sampling methods for subsurface soil investigations. The CCR method could be used to identify critical locations for drilling and sampling such as expansive clay layers and anomalies (sinkholes, unknown landfills, etc.) rather than uniformly sampling across a site. CCR surveys were performed at Alpena, Arkansas along a highway expansion project changing US 62 from a two lane to four lane highway, and at Alton, Illinois along the Mel Price Levee, a 5.2 mile levee along a portion of the Mississippi River. A geometrics OhmMapper was used to acquire the CCR resistivity data with emphasis placed on investigating the near surface material properties (0-5 meters). The Alpena site was comprised of silt, clay and suspected bedrock with a deep water table, while the Alton site was comprised of clay and sand with a shallow water table. The survey was performed at both sides of the highway at Alpena and along the landside and riverside of the levee at Alton. The resulting resistivity plots revealed continuous subsurface soil information and emphases the impact of water level when interpreting the resistivity results as significant changes in the resistivity ranges for fine and coarse grain soils are possible for different moisture conditions. The measured soil resistivity values at the Alpena site with a deep water table were much higher than the values at the Alton site with the shallow water table. The accuracy of the CCR method was assessed by identifying the number of locations where the soil type predicted by CCR matched the existing boring and CPT logs. Resistivity from CCR was able to distinguish between areas of predominantly fine-grained material and coarse-grained material but limitations exist in separating soils with similar grain sizes (silts and clays).
Coker, F. (2018). Geophysical Assessment of Subsurface Soil Conditions Using Capacitively Coupled Resistivity. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/2848