Unconfined compression tests and Brazilian tests were performed on dry and wet specimens in order to investigate the relation between microstructure and fracture strength in weathered coral skeletons. In particular, we theoretically considered the distribution of internal stress in coral skeletons by introducing pore-pressure in coral skeletons. As the result of experimental and theoretical consideration, we determined that the strength of coral skeletons strongly depend on pore-size and pore-pressure. Furthermore, we described that the coral skeletons show a marked tendency to a fracture localization, and the size effect was not observed in any experiments. With these experimental phenomena, we showed that the pores distribution is closely related.
