Drained and Undrained Behavior of an Aeolian Sand from Natal, Brazil

Abstract

The behavior of sands subjected to diverse loading conditions has been the object of many studies in recent decades. Constitutive models that are able to simulate the behavior of sands have been developed based on critical state theory. Researchers have shown that the defining parameters of the critical state line (CSL) can be obtained by performing drained and undrained tests on samples with different initial densities. This work aims to verify the drained and undrained behavior of aeolian sand from Natal, Brazil, based on critical state soil mechanics. Drained and undrained tests were performed on samples with initial void ratios equal to 0.7 and 0.8, which correspond to loose and medium-dense relative densities, respectively. Samples with both void ratios were subjected to confining stresses equal to 50, 100, 200 and 300 kPa. The results show that the critical state line can be defined from the drained and undrained tests performed on samples with loose and medium-dense initial relative densities. The parameters from the critical state theory were obtained using projections on the planes p'- q and lnp' - v. The critical state friction angle is equal to 31.5 degrees, and it is compatible with clean and uniformly graded sands with angular to subangular features and composed mostly of quartz. The obtained M, Gamma and lambda values are equal to 1.26, 1.863 and 0.03, respectively. The obtained parameters will be used in analyses and numerical simulations of the geotechnical structures built on aeolian dune deposits from the city of Natal, Brazil.