Drained shear behavior of coral sand-diatom mixtures

Diatom and coral sand are widely distributed in tropical and subtropical areas, and their mixtures from natural marine sediments may show various engineering properties. A series of triaxial drained shear tests were conducted to analyze the influences of diatom content and effective confining pressure on the shear characteristics of coral sand-diatom mixtures. The test results indicate that the maximum friction angle and the brittleness index of coral sand-diatom mixtures decrease with the increase in confining pressure. The relationships of the maximum friction angle, secant modulus, and brittleness index with diatom content exhibit distinct tendencies under different effective confining pressures. Moreover, Bolton’s stress-dilatancy equation for the coral sand-diatom mixture is examined, where the slope and intercept are found to be independent of the diatom content.