Study on shear characteristics of calcareous sand with different particle size distribution

For the island and reef project formed by filling calcareous sand, problems of wide particle size distribution (PSD) complex mechanical properties have to be faced. Therefore, in order provide basic parameters for construction project, triaxial shear tests were carried out on sands with five different typical PSDs. The results showed that as gradation became narrower, axial strain corresponding strain-softening point all a decreasing trend their differences gradually decreased; confining pressure has significant impact volumetric deformation modulus sand PSD. cohesion positive correlation non-uniformity curvature coefficients, while variation an internal friction angle parabolic law; also changes parabola change fine contents. Furthermore, establishing PFC3D discrete element model, it was found numerical simulation good agreement test results, which verifies feasibility rationality mesoscopic parameter calibration. It discovered wider range, greater critical coordination number; sample narrow interval more likely present rotating displacement field form penetrating band. This study can design stability analysis high steep slopes sites.