THE DYNAMIC CHARACTERISTICS OF SATURATED DENSE CORAL SAND SAMPLES

Constructions placed on coral sand foundations on offshore islands are often subjected to wave and wind loads, which are cyclic dynamic loads. Therefore, a study on the behavior of coral sand under the effect of cyclic dynamic loads is necessary to evaluate the bearing capacity of the structures. This study is devoted to determining dense coral sand's dynamic parameters using Controls dynamic triaxial compression testing device under large deformation and different confining pressure conditions. Parameters analyzed in the present work include excess pore pressure, damping ratio, dynamic elastic modulus and dynamic shear modulus. In addition, to evaluate the correlation between static and dynamic elastic modulus of coral sand, the study conducted additional static triaxial compression experiments according to the consolidated undrained condition. The results showed that an increase in pore water pressure and a decrease in dynamic shear modulus as shear strain increases, while the damping ratio also increases. As the shear strain is less than 0.1%, the damping ratio showed minimal variation. The dynamic elastic modulus of the coral sand is approximately 1.5 times greater than its static elastic modulus.