Coral sand is the only material for island land reclamation. Due to its special marine biogenesis and porosity structure

coral sand particles are easily crushed at normal level of engineering stress. In this study

drained triaxial shear tests were carried out on coral sand retrieved from a reclamation reef in the South China Sea to study the evolution law of the strength

deformation and particle breakage properties of coral sand with different levels of density and confining pressure. The comparative analysis of shear strength index is made between current study and previous investigations. The results show that strain softening and dilatation tendency of coral sand gradually weaken with an increase in confining pressure and decrease in compactness. Within the normal confining pressure range

the values of the peak and critical state frictional angles of coral sand were 33o?58o and 28o?47o

respectively

both of which decreased with an increase in the confining pressure. The relationship among the secant modulus E50

relative density and effective confining pressure for coral sand was established. The relationship between the peak friction angle of coral sand and the modified relative breakage index (Br*) can be fitted by a power function equation with a negative index. When the extent of particle breakage is large

the decreasing trend of peak friction angle with an increase in the modified relative breakage index slows down. The correlation between the modified relative breakage index and plastic work for coral sand could be simulated using hyperbolic curve

and it is hardly affected by density. The research results can provide useful reference and technical support for island reclamation and infrastructure construction in the South China Sea.