Mechanical and volumetric responses of biocemented coral sand at different relative densities

Abstract

This study investigates the influence of relative density on the mechanical response and stress–dilatancy behavior of biocemented coral sand through consolidated drained triaxial compression tests. Specimens were prepared at three relative densities (D_r = 20%, 50%, 80%) and tested under three effective confining pressures ({\sigma }_3^{\prime } = 100, 200, 400 kPa). The results show that the strength and dilatancy behaviors of coral sand are significantly influenced by biocementation treatment, relative density, and effective confining pressure. Both the initial stiffness and peak strength of biocemented specimens are significantly enhanced compared with their untreated counterparts. However, biocemented coral sand shows a strong tendency toward dilation, which becomes more pronounced at higher D_r or lower {\sigma }_3^{\prime }. Empirical relationships are subsequently proposed to predict the peak stress ratio (η_f) and the failure dilatancy ratio (d_f) as functions of D_r and {\sigma }_3^{\prime }. These relationships provide a practical criterion for evaluating the dilatancy potential of biocemented coral sand, providing valuable direct implications for the design of biocemented coral sand foundations.

Graphical abstract

Keywords

biotreatment / coral sand / dilatancy / relative density / stress ratio

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