MONITORING AND CHARACTERIZATION OF THE MEADOWVIEW LANDSLIDE, BOYD COUNTY, KENTUCKY: PRELIMINARY RESULTS

The Kentucky Geological Survey is conducting a landslide monitoring project in Boyd County, Ky, located in the northeastern part of the Eastern Kentucky Coal Field, part of the larger Appalachian Basin. The Meadowview Landslide is a shallow, rototranslational slide with upper rotation morphing into a translational flow toward the toe. The slide was caused by a complex interaction between slope modification, geology, soils, and slope morphology, and was triggered by heavy rainfall in late April 2011. The length and width of the displaced mass is 40 m and 67 m, respectively. Approximate depth of the displaced mass is 3 m, and the volume of material is approximately 3,816 m³. This landslide is representative of many that occur over the region.

The purpose of this study is to determine depth, shape, and velocity of the sliding mass using various tools for a full site characterization. Six soil test borings, along with the installation of two open standpipe piezometers to measure long-term groundwater levels and two inclinometer casings to monitor slope movement and development of the probable failure surface were installed. Slotted PVC pipe was installed at the remaining two boring locations in order to conduct downhole electrical resistivity (ER) testing. A rain gage and water-level transducer have also been installed. Preliminary results show a failure surface approximately 3 m deep near the head scarp and approximately 1.2 m deep toward the toe. Cumulative movement measured by both inclinometers yields an average of 7.6 mm of displacement. A recent increase in displacement rate measured by both inclinometers correlates to an increase in measured rainfall at the site (July 2013).

The obtained samples were tested in the laboratory, including triaxial shear, unconfined compression, determination of density, natural moisture determination, and Atterberg limits testing. In addition, a correlation between geotechnical and geological data from traditional field exploration methods and the less invasive and nondestructive geophysical testing (i.e., ER testing) will be pursued. As the study continues, slope stability analysis will be conducted and the results will be compared to failure planes predicted by ER testing.