Site characterization of five hazardous waste landfills

Geotechnical characterization of hazardous waste sites is a challenge, mostly due to the health and safety concerns associated with drilling and sampling work at the site. Therefore, non-intrusive soundings, such as geophysical measurements (e.g., Spectral Analysis of Surface Waves, SASW; Ground Penetrating Radar, GPR), are preferable. Some intrusive methods, however, like Cone Penetration Test (CPT) and trenching might be acceptable provided that adequate worker protection and equipment decontamination is provided. This paper documents a case history of geotechnical characterization of a hazardous waste site. The site consisted of five hazardous waste landfills, each containing different waste. The characterization was done by conducting non-intrusive (SASW and GPR) soundings and intrusive (CPT; trenching and drilling) exploration. To compensate for a lack of sampling and laboratory testing, the results of non-intrusive and intrusive investigations were mutually compared and evaluated using established correlations. Application of the findings in composite landfill cover system design is also discussed in this paper.