Volume 31, Issue 1 (January 2008)
Characterization of Glyben for Seismic Applications
Glyben is artificial clay that is prepared by mixing sodium bentonite powder and glycerin. It is used for laboratory tests and scale modeling for geotechnical applications. The mechanical properties of glyben depend on the bentonite and glycerin mix proportions. The shear strength, dynamic shear modulus, damping ratio, and Poisson’s ratio were evaluated for glyben samples prepared with different glycerin/bentonite ratios. Vane shear tests, T-bar tests, hammer tests, and resonant column tests were conducted on glyben specimens and the shear strength and dynamic properties were evaluated considering a wide range of strain values and confining pressure. The measured glyben properties were compared with properties of natural cohesive soils to verify the range of applicability of glyben as a test bed material. It was found that glyben has the same range of strength and dynamic properties as soft to medium stiff clay. The trend of variation of the shear modulus and damping ratios of glyben is similar to that of natural clays. It is noted, however, that the damping ratio of glyben is higher than that of natural clays for shear strains below 0.01%. It was concluded that glyben can reasonably model the nonlinear behavior of natural soil under strong dynamic excitation.