Observed and Predicted Behavior of Maipo River Sand

At present, finite-element methods are frequently used in the analysis of geotechnical engineering problems. The selection of an appropriate constitutive law primarily involves balancing simplicity with accuracy. Given that many practitioners still use the hyperbolic model, the adequacy of a modified version of this simplified stress-strain relation-ship to predict the nonlinear behavior of granular soils, is herein examined. Drained triaxial tests were performed on specimens composed of Maipo River sand at different relative densities. These specimens were subjected to different stress-paths in order to an extensive comparison of the measured strains and the predicted values. In addition, laboratory plate-load tests were conducted on rough, circular and strip, surface footings, which were 100-mm in diameter and 60-mm wide, respectively. The testing box, with dimensions 1.05 m × 1.05 m × 0.65 m, was filled with air-dried sand by using a raining apparatus. A field plate-load test performed on dense sandy gravel was also analyzed. From the good agreement achieved between the empirical observations and both the calculated strains and load-settlement relationships, it is concluded that the proposed hyperbolic model predicts with sufficient accuracy the nonlinear response of granular soils in most practical cases, as long as the soil mass is not close to failure.