Geoelectric characterization for implantation a landfill in simões filho, Bahia, Brazil

Abstract

The present study brings the results from the integration of applying a geoelectrical method and direct investigation methods in the qualitative and quantitative characterization of the geological-geotechnical environment. The purpose was to establish a local hydrostratigraphic model, in order to survey information that would aid in the implementation of cells for the final destination of urban solid waste over the sediments of the São Sebastião Formation, in Simões Filho, Bahia, Brazil. Twelve vertical electrical soundings, two SPT soundings and one geological sounding composed the quantitative surveys and techniques used. Unidimensional inversions presented mean error of 4.1%. Bidimensional inversions presented 5.7% mean error. Lower-value geoelectrical facies (< 1,000 Ohm.m) were attributed to occurrences between the silt and clay fraction, while higher-value facies (> 1,000 Ohm.m) corresponded to occurrence between the silt and sand fraction. The hydrostratigraphic model included a confined aquifer, represented by a succession of alternating sandy and clay-rich layers with subhorizontal contact, often laterally truncated, with at least two thick layers of clay occupying the first 100 m in depth. Moreover, water occurred in permeable porous layers, between depths of 40 and 50 m, approximately. Regarding the degree of compactness, in the first 100 m in depth, soils were classified as medium to hard.