Static and cyclic behavior of North Coast calcareous sand in Egypt

• Static and cyclic behavior of calcareous sand at North Coast of Egypt is studied.
• Effects of density, confining pressure, and cyclic stress ratio are investigated.
• North Coast Dabaa calcareous sand has higher cyclic strength than other siliceous sands.
• Cyclic resistance ratio-confining pressure–density relationship is developed.

This research studies the behavior of calcareous sand located in the North Coast of Egypt, Dabaa area, under static and cyclic loading. The study is performed through a series of monotonic and cyclic undrained triaxial tests conducted on two relative densities and different effective confining pressures. The cyclic tests were carried out at different cyclic stress ratios. Failure under cyclic loading was found to be governed by the gradual development of excess pore water pressure until liquefaction is reached, rather than cumulative development of axial strain (cyclic mobility). The cyclic strength of the tested sand is compared with other calcareous and siliceous sands reported in the literature. The test results indicate that loose Dabaa calcareous sand has higher cyclic strength compared to other siliceous sands, probably due to the existence of different shapes of calcareous sand particles within the tested soil. Relationship between cyclic resistance ratio, effective confining pressure, and relative density was developed for the tested sand.