Materials Project Summary

Hardin County Landfill
Hardin County Landfill
Project Name: Hardin County Landfill – Phase 2B
Location: Hardin County, Kentucky
Facility Type: Government / Landfill
GEM Services: Geotechnical / Construction Materials

Project Description:

The landfill is located in terrain characterized by deep hollows formed primarily by surface water runoff. The remnant ridge tops are capped with a thin layer of plastic clays and limestone. Progressing down the slopes, the rock transitions to siltstone, then to shale. Most of the existing slopes are steep (on the order of 1.5H:1V) with minimal soil cover, making access difficult. The shale weathers to form weak fissile, highly jointed, low durability shale and silty clay soils that commonly experience landslides if exposed on slopes. The slopes on this unit are covered by narrow landslide blocks, as indicated by fresh scarps and/or tilted trees. Slope failures are common. Landslides in the shale member occur naturally as colluvium moves down the slope or as toe areas are undercut by erosion. Frequently, the slope failures are precipitated by man-made changes, such as crest or slope fills, toe cuts, or altering groundwater seepage patterns, all which occur during construction. The purpose of our geotechnical exploration was to obtain and evaluate subsurface information in order to assess slope stability, identify geotechnical concerns that may affect the proposed construction, and develop design and construction recommendations for site preparation and fill construction. GEM designed the soil and rock cuts for the landfill to minimize disturbance and construction costs. GEM also conducted construction material testing during construction of the landfill. These services included subgrade evaluation, density testing, visual observation of shot-rock/soil fill, geosynthetic liner observation and testing, and laboratory testing.