Fissuras no pavimento da rodovia ERS-149 - Geofísica aplicada como auxílio na caracterização do terreno

Geophysics is widely recognized tool in indirect subsurface and non-invasive investigation. It is applied in different near-surface and geotechnical studies. As an example, we can mention ground investigations for structures, cables, fractures, cavities and water infiltration. In geotechnics, lithologies heterogeneities, fault/joints and basement rocks soil (altered zone) investigations have been producing significant results with low costs, less time and simple logistics. This study proposes the use of direct current resistivity profiles to detect and characterize altered rocks layers limits (regolith), water saturated areas and depth as an auxiliary aid to characterize a collapsed asphalt paved road (ERS-149). The area is located between Faxinal do Soturno and Nova Palma cities, Rio Grande do Sul State, Brazil. Locally, on the road side, several cracks occurred due the ground instability leading to an asphalt and material below collapse. We performed two DC-resistivity profiles perpendicular to the road integrated with a high-resolution digital elevation model. The results presented a large amount of unconsolidated material (soil and rocks fragments) and a significant inpore water filling zones. These features, associated with the gravitational action in the area are interpreted as the main sliding, cracking and collapsing causes. The use of geophysics in this context was a valuable and effective method as an aid to conduct and locate direct subsurface investigations as detail geological and soil mapping and drill-holes to better describes the lithology/materials refining the subsurface modeling.