Study on shear behavior of coral reef limestone–concrete interface

摘要

Abstract To examine the coral reef limestone–concrete shear failure characteristics, we conducted large-scale direct shear tests to study five types of interfaces: planar, sloped, arc shaped, stepped, and triangular. Furthermore, the shear failure characteristics and shear strength variations were examined under three interface connection types: smooth, mud filled, and cemented. The results show that the shear phenomena at the smooth and mud-filled interfaces between the coral reef limestone and concrete were characterized by the interface slip failure mode. The mud at the interface acted as a good lubricant and greatly reduced the shear strength. For the cemented connection between the coral reef limestone and concrete, the shear strength increased rapidly with the shear displacement. When the shear strength reached a certain value, it abruptly decreased and then tended to level off, and shear failure occurred at the coral reef limestone side of the interface. Among the studied specimens, the maximum shear strengths were in the following order from highest to lowest: stepped interface, triangular interface, arc-shaped interface, sloped interface, and planar interface, while the corresponding shear displacements increased in that order. The results of this study can serve as a reference for the construction of pile foundations on coral reef limestone strata.