Effects of temperatures and fines content on the shear properties of calcareous sand

Calcareous sand is regarded as one of the special marine deposits and widely adopted as dredged hydraulic filling materials for island reclamation. The deposited foundation probably contains a large amount of fine-grained sand due to hydraulic transportation. In offshore regions, the construction of geothermal infrastructures, such as oil pumps and platforms, is urgently needed in reclamation island regions. Therefore, the effects of temperature and fines content on the shear properties of calcareous sand requires further investigation. In this study, a series of temperature-controlled drained triaxial shear tests were carried out on calcareous sands containing various fines content. The measured results show that increasing temperature promotes the micro-expansion of particles and intensifies the amount of particle crushing. Increasing fines content leads to marked decrement in shear strength, suppressing the dilatancy behavior. The fine-grained particles play a lubricating role between neighboring grains and greatly change the effective contact mode. It is noted that both internal friction angle and the cohesion of calcareous sand-fines mixture also decrease with increasing temperature and fines content. A good relationship between peak mobilized friction angle\(\:\:{\:\phi\:}_{peak\:}\)and effective confining pressure \(\:{\sigma\:}_{c}^{{\prime\:}}\) for calcareous sand under different thermal loading paths is noticed. An emprical equation to estimate the peak mobilized friction angle \(\:{\:\phi\:}_{peak\:}\)for calcareous sand considering the combined influences of temperature, fines content and confining stress has been proposed. The predicted performance of the established model is satisfactory.