ABSTRACT
Engineered landfills are considered to be the most economical form of waste disposal system for low-level radioactive and municipal solid wastes. The most important elements in containing waste within engineered landfills are the lining systems. To achieve complete encapsulation of waste, an impervious layer with hydraulic conductivity ≤10−9 m/s is provided in lining systems. This impervious barrier can be composed of naturally available clayrich soil or amended soil or by synthetic materials such as geomembrane or geosynthetic clay liner. When clay-rich soil is abundantly available near the landfill site, then it is desirable to use this material as an impervious barrier. One of the predominant failures of soil barrier is the occurrence of desiccation cracking due to moisture fluctuation and cracking due to the differential settlement formed mainly due to the decomposition of waste and/or subgrade over which the containment system is laid. Keck & Seitz (2002) found nearly 160 subsidence cases in the Radioactive Waste Management Complex-Subsurface Area Disposal sites from 1983 to 2002. The observed maximum and average subsidence depth values were 3.7 m and 0.6 m respectively; with a distortion level ranging from 0.066 to as high as 0.888. Distortion level (a/l) is defined as the ratio of central settlement a at any stage of deformation to the influence length l within which differential settlements are induced. Qian et al. (2002) categorized differential settlements of landfill covers as being large craters with localized depressions. Large
the allowable payload is 0.625 t. With the help of an on-board central processing unit (CPU), LAN connections and embedded signal conditioning and filter cards, data can be continuously acquired. The detailed specifications of the centrifuge hardware are discussed by Chandrasekaran (2001).
