Resistência transversal de dar zarrouk e índice de resistência à penetração do solo: novas equações e correlações para o latossolo amazônico

Abstract

The soil is commonly used in civil construction and investigated by geotechnics for the suitability and installation of civil works foundations. The most common soil investigation method performed by geotechnics is the Standard Penetration Test (SPT), as this test allows us to obtain the soil’s consistency and compaction through the SPT N-value (Nspt). However, this method is limited in terms of investigation depth due to the impossibility of auger penetration in saprolites or the bedrock itself, assigning a certain resistance to a given material only concerning how much it withstands the penetration of the standard sampler in the test. In addition to SPT, the electrical resistivity method also maps the subsurface by estimating electrical resistivity values calculated after injecting an electrical current into the subsoil. The combined application of these two methods increases the accuracy in interpreting soil lithology and compaction by correlating the Dar Zarrouk´s Transverse Resistance (T), derived from resistivity, with the Nspt values in a linear relationship. This study proposes new correlations between T and Nspt for specific coordinates in Manaus-AM by estimating vertical and lateral resistivity and using Nspt information from drilling reports. The study utilized data from five Vertical Electrical Soundings and two Electrical Resistivity Tomography surveys to calculate T, along with five SPT reports from the central-south, west, and north zones of the city. The results showed strong correlations in some neighborhoods and weak correlations in others, indicating variations in lithology and soil compaction across different locations. These correlations allowed us to establish novel linear relationships between T and Nspt for each investigated region of the city, forming a reference framework of equations for future geotechnical works in these areas.