Ensaios triaxiais dinâmicos de solos argilosos

Abstract

Drained triaxial dynamic test were performed with non saturated compacted samples of four clay residual soils form subgrade and improved subgrade layers. The soil samples were taken from pavements at federal highways BR-040/RJ, BR-116/ MG, and BR-277/PR. Testing aimed at two objectives: to study the effect of applied stresses and compaction conditions on the resilient modulus, and to verify the effects of stress magnitude, compaction moisture, and delay between compaction and testing (thixotropy), on the correlation between deformations - recoverable and permanent - and the number of load applications. Bi-linear and linear correlations between resilient modulus and the deviator stress were obtained. Confining pressure has little influence on the modulus. Mathematical expressions were estabilished between permanent and resilient axial deformations and the number of load applications. Those referring to permanent cumulated deformations permit us to calculate the contribution of each layer to the total permanent deformation of the pavement structure (rutting at wheel paths). A relation was found between the permanent axial deformation and the CBR value, which is common to the four soils tested at different compaction conditions. This research is part of a project on mechanics of pavements sponsored by the Road Research Institute, which also gives the necessary support for all the field work.