In recent years there has been a steady increase in geo-environmental engineering projects requiring enhancement in the site characterization techniques. This paper presents results of a site characterization program carried out in a deactivated sanitary landfill in Brazil. The program included traditional drilling, sampling and laboratory tests and electrical resistivity tests. The advantage of using geophysical methods for guiding the use of the geotechnical in situ testing is discussed. Moreover, the necessity of additional research to adjust modern technologies for using in site characterization of tropical soils is commented.
Geo-environmental characterization refers to the surficial and subsurficial representation that approximates the actual in situ conditions. This representation is typically developed by both surface and subsurface characterization (Campanella et al, 1998). In situ testing methods often provide the best possible information at selected locations for groundwater contamination problems where stratigraphic, geotechnical, hydrogeological and some specific environmental parameters are required on a specific and/or screening basis (Campanella et al, 1994). Combining geophysical and geotechnical in situ techniques is the best way to get all the information required in a good site characterization program. This paper presents results of a site characterization program carried out in a deactivated sanitary landfill area in Ribeirão Preto, São Paulo State, Brazil where 600.000 m3 of domestic waste was inappropriately disposed. The site characterization included a geo-electrical survey and traditional drilling, sampling, and laboratory tests. The results shows that selecting an appropriate geophysical technique and elaborating a rational planning make it possible to assess the volume of waste, the flow paths and to evaluate the impact caused by the waste disposal. The major advantage of using a surficial geo-electrical method is to guide the drilling and sampling program as well as to define the location of monitoring wells.