Overburden Pressures Exerted on Clay Liners

Abstract

The range of overburden pressures induced on compacted clay liners beneath landfills, surface impoundments, and waste piles is documented, and loading pressures for consolidometer hydraulic conductivity testing of a compacted clay sample is suggested. Results indicate maximum overburden pressures for hazardous waste landfill facilities across the nation vary considerably, but are generally in the range of 3,300–7,400 lbs/sq ft (160 to 360 kPa). Land disposal of waste materials is typically achieved in one of three types of facilities: landfill, waste pile, or surface impoundment; the type selected for various waste streams depends on the physical and chemical properties of the materials. Leachates from all facilities, however, are often a potential source of groundwater contamination. Research is currently underway to evaluate the response for selected clay soils exposed to non‐water waste chemicals, but the focus is in fixed‐ and flexible‐wall test permeameters. This paper documents overburden pressures experienced under field conditions; these results can be included in laboratory permeability tests which use consolidation devices.