To reproduce in an accurate way by artificial methods the real behaviour of the soil is extremely complicated, given the intrinsic heterogeneity of the soil and the innumerable external factors that affect its mechanical-hydraulic response. At present, there are several constitutive models, both traditional and modern, that attempt to simulate the possible stress paths that a geomaterial can undergoes. Within the practical engineering the most used model has been Mohr-Coulomb, which shows an elastic-perfectly plastic response. However, the soil is far from exhibiting a behaviour similar to that shown in this model. Modern constitutive laws can simulate in a more appropriate way the non-linear behaviour of the soil. However, they use several parameters that increase the complexity of the models. The objective of these constitutive models is none other than to extrapolate its mathematical formulation to the global behaviour of geotechnical structures. Before adjusting the parameters that should be used in the numerical modelling of real geotechnical problems, it is necessary to understand the behaviour at the elementary level (experimental) of the constitutive model. Normally this process is called calibration of parameters. In this work, the numerical results of triaxial compression tests for a typical normally consolidated soil are shown. Various constitutive models are used, which reveal different stress paths, for which the dispersion in the obtained results is considered.