Shear Modulus and Damping Ratio of a Calcite Cemented Gravelly Sand

This paper presents results of a comprehensive study on the dynamic behavior of a calcite cemented gravelly sand. The focus of this study is on the shear modulus and damping ratio, as two of the most commonly used parameters in dynamic analysis of soil behavior, and the effect of calcite cementation on their variations. The effects of cementation on dynamic response of cemented gravelly sands are not readily apparent to touch and may be variable due to varying cement contents and bonding between the particles. This is specifically observed in gravelly sands where owing to the particulate nature, applied loads are mainly carried through resistance at interparticle contacts. The experimental program which was implemented in this study included a total of 113 undrained cyclic triaxial tests on specimens of gravelly sand with different levels of calcite content under different confining and deviator stresses. From the results of this study, it was concluded that the dynamic properties of cemented gravelly sands may vary depending on the magnitude of applied confining stress and the level of cementation. The dynamic properties of uncemented and lightly cemented gravelly sands were found to be quite similar, both highly affected by the confining stress implying a frictional behavior. On the contrary, due to the governing effect of inter-particle bonds, cemented soils behaved in a more cohesive manner at low to medium levels of strain. In this case, the rate of shear modulus degradation was found to be greater and the damping ratio was less dependent on the magnitude of shear strain. Finally, a set of correlations were presented to estimate the shear modulus degradation and damping ratio curves for variously cemented gravelly sands.Author names: Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 1 Given name: [Mohammad Reza], Last name: [Shakeri]. Author 2 Given name: [S. Mohsen], Last name: [Haeri]. Author 3 Given name: [M. Mahdi], Last name: [Shahrabi].I confirm the author names have been accurately presented and are in the correct sequence.