A Modified Drucker-Prager Cap Plasticity Model for Triaxial Simulation of Residual Soils

Resumo

A large area of Brazil, even as the world, is covered by residual soils. These soils arise as the result of
the weathering process of the intact rock and are characterized by the permanence of fragmented elements at the
site of formation. The accuracy of a numerical simulation depends on the adequacy of the model and its parameters
to the soil behavior. In this context, this research aims to numerically evaluate triaxial tests of residual soils to
assess the influence of the model parameters on the stress-strain-volumetric response. The analysis was performed
using ABAQUS software, in which an elastic-plastic model with Drucker-Prager failure criteria and CAP plasticity
was used. The numerical response was compared with a laboratory test in which confining stresses of 20 kPa, 35
kPa, and 50 kPa were employed. A sensitivity analysis of the parameters of the model was performed. The results
indicated that the studied model showed a satisfactory prediction of stress-strain-volumetric behavior of the
residual soil. In the sensitivity analysis, the cohesion, friction angle, cap eccentricity, and hydrostatic yield stress
parameters presented more impact in the numerical response.