Year of Publication

2018

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Arts and Sciences

Department

Earth and Environmental Sciences (Geology)

First Advisor

Dr. L. Sebastian Bryson

Second Advisor

Dr. Edward W. Woolery

Abstract

Landslide characterization and hazard assessments require multidisciplinary approaches that connect geologic processes with geotechnical parameters. Field monitoring of hydrologic variables such as water content and water potential, coupled with geoelectrical measurements that can establish relationships used for geotechnical and landslide hazard investigations is deficient.

This study brings together different techniques to develop a methodology that connects geoelectrical measurements and shear strength. A field-based framework was established that includes (1) analysis of long-term soil moisture fluctuations within different landslides (2) establishment of constitutive and new equations that test the use of electrical conductivity to predict soil-water relationships and shear strength (3) using electrical resistivity tomography (ERT) to support and facilitate the prediction of shear strength in a slope.

Hydrologic conditions including volumetric water content, water potential, and electrical conductivity in the soil were measured at three active landslides in Kentucky. The in-situ electrical conductivity used within the framework is valid as a predictor of suction stress and shear strength. The ERT supports interpretations of landslide failure zones, landslide type, lithologic boundaries, and changes in moisture conditions, but also is able to utilize the methodology to calculate shear strength, and provide a spatial view of shear strength in the slope. The practical application of this framework is to support landslide hazard assessment and further understand the long-term influence of moisture conditions in hillslope soils. These parameters are pertinent to investigating the stability of landslides that are often triggered or reactivated by rainfall.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2018.393

Funding Information

This research was supported by Terracon, Inc. and the Terracon Foundation grant. the U.S. Geological Survey Landslide Hazards Program, and the Kentucky Geological Survey.

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