Caracterização preliminar geotécnica do subsolo do Campo Experimental de Geotecnia e de Fundações da Universidade Federal do Ceará (CEGEF – UFC)

Abstract

This work aims to characterize, from the realization of geotechnical laboratory and field tests, the subsoil of the Experimental Field of Geotechnics and Foundations of the Federal University of Ceará (CEGEF - UFC), with the objective of subsidizing future geotechnical work. The methodology initially consists in extracting deformed and undeformed samples at different depths in the subsoil. Then, the following tests are performed for physical characterization: natural humidity, sieving and sedimentation granulometry, real density, liquidity limit (wL), plasticity limit (wP), and compaction, in the Normal Proctor energy. In addition, special geotechnical tests are performed, such as the triaxial densified and drained (CD), the densification and direct shear tests, as well as percussion surveys (SPT). For a better characterization of the subsoil layers under study, as well as their properties, Georadar (GPR) is also used as a mechanism to perform a non destructive test. Based on these results, the subsoil analyzed presents open granulometry, i.e., poorly graded, non-plastic, and is classified as a granular soil of the sandy-silt type, of the SM group, according to the Unified Soil Classification System (SUCS). The Oedometer tests made it possible to observe an increase in soil stiffness with depth, until the depth tested with this test, which was 2 m. The determinations of the effective friction angle (') of the soil from the triaxial and direct shear tests were convergent, with maximum variations of 2º. The cohesive intercept, although low, varied up to about 40 kPa.