Abstract: Coral sand is widely distributed in the South China Sea, and its mechanical properties are very different from terrigenous sand. To study the effect of average particle size and water content on the shear strength of coral sand, triaxial shear tests were carried out on coral sand samples under different working conditions by using laboratory triaxial tests. On this basis, the influence of the ultimate bearing capacity of foundation on coral sand samples was studied. The test results show that the coral sand exhibits obvious dilatancy and stress softening under low pressure. The peak shear strength and the peak strain increase with the increase of average particle size. With the change of the water content, the cohesion of the soil sample increases first and then decreases and the internal friction angle decreases. Through the analysis and the comparison of the ultimate bearing capacity, the main difference of the bearing capacity coefficient is concentrated in Nγ, in that the coefficient of Terzaghi formula is significantly larger than the other three formulas. The influence of the cohesion on the bearing capacity of Maislav formula is higher than other formulas.

Key words:  , Shear, Average Particle Size, Water Content, Ultimate Bearing Capacity Comparison