Abstract: Focused on the special physical properties, a series of triaxial consolidated undrained shear test of different relative density of coral sand samples were performed to analyze the influence of the different relative density on the stress-strain relationship. Throughout the analysis of test results, it is concluded that the density has a significant influence on the stress-strain relationship of the coral sand. With the relative density increase, the peak deviator stress of the sample gradually increases; the secant modulus, E₁, increases with the increase of the confining pressure and the relative density , E₁ has a good linear relationship with the change of the confining pressure; as the density increases, the strength indices, c and φ values, both increase with the increase of the density, and the density has a greater impact on the cohesion of the coral sand sample and has little effect on the angle of internal friction. 

Key words: coral sand, triaxial shear test, relative density, stress-strain, strength