Dynamic Properties of Gravelly Materials
نویسندگان
1 Department of Civil Engineering,University of Tehran
2 Department of Civil Engineering,Iran University of Science and Technology
3 Department of Civil Engineering,Iran University of Science and Technology
4 Department of Geomatics Engineering,Building and Housing Research Center
doi
چکیده
This paper studies the dynamic characteristics (i.e. shear modulus and damping ratio) of modeled gravelly soils used as construction materials in some rock-fill dams in Iran by conducting large-scale triaxial testing. Tested specimens were compacted to more than 95% maximum dry density, according to Modi ed Proctor, and tested according to ASTM D 3999. Accurate monitoring of strains by means of non-contact type displacement transducers to infinitesimal strains as small as 0.0001% enabled us to obtain Gmax with some extrapolation. Based on the available experimental results the ranges for G=Gmax ???? and D ???? are defined for materials with > 30% fine content and materials with < 15% fine content. The results clearly indicate the need for modification in previously proposed G=Gmax ???? curves, particularly for gravels with > 30% fine content. Also, the suggested D ???? curves lay out of the bounds of data reported by previous researchers, which may be due to the effects of testing frequency, fine content, and confining pressure. In addition, a predictive hyperbolic model for estimating normalized shear modulus (G=Gmax) versus shear strain ( ) is presented. Effects of the number of cyclic loadings over the shear modulus and damping ratio are also investigated.
