Performance of Isolated, Cemented Stone Columns in Clayey Soils: Fid-Bau Portal

Performance of Isolated, Cemented Stone Columns in Clayey Soils

Santos, Anibal E. / Bernhardt-Barry, Michelle L. / Stuedlein, Armin W.

Experimental studies have demonstrated that the stiffness and bearing capacity of conventional stone columns can be significantly increased by using cement-coated aggregate. However, there are still uncertainties regarding the global performance, load transfer mechanisms, and design of cemented stone columns under various field conditions. Results of full-scale footing loading tests conducted to investigate the effects of cemented aggregate on the load-displacement responses of isolated cemented stone columns are presented. Field calibrated three-dimensional discrete element method (DEM) simulations were used to examine the behavior of the cemented stone columns. The cemented aggregates were modeled using discrete-deformable blocks in conjunction with a strain-softening constitutive model that was calibrated using laboratory triaxial test data to improve simulation of the nonlinear response. The DEM models demonstrated several important behavior mechanisms for cemented stone columns that ultimately improve understanding of the effects of cemented granular material on performance and design. At low cement contents (5% by dry weight herein), the stone column exhibits a bulging-type failure mechanism similar to conventional uncemented stone columns. At higher cement contents (10% in this study), bulging is not observed, and the behavior resembles that of a concrete pile. Bearing capacity improvement factors ranging from 2 to 4 were obtained from columns simulated with 5% and 10%, cement contents (i.e., CC) respectively, at serviceability and ultimate limit states.