Abstract:

In this study, we measured compressive strength in coral samples from Weizhou Island, northern South China Sea, and the Meiji Reef, the Nansha Islands, southern South China Sea, using uniaxial compressive strength experiments. Differences in coral skeletal structure were revealed using these data, coral reef geological and ecological methods, and the engineering mechanics. The results showed that the uniaxial compressive strength of Meiji corals is approximately three times higher than that of Weizhou corals, indicating that Weizhou corals’ carrying capacity is relatively low. The mechanical properties of Nansha corals showed a character of elastic curve, with a short stage of yield and good ductility. On the contrary, the compressive strength of Weizhou corals has an irregular changing elastic curve character, with multiple compression processes. Based on the observations on the broken samples after compressive experiments, Weizhou samples were not broken on the growth direction of the axis, but in the area of small holes and low density. Increased bioerosion caused changes in the structure of Weizhou coral skeletons, and subsequently poor compressive strength, low bearing capacity, and chaotic mechanical properties. This work demonstrates the effect of water pollution on coral skeletal structure. We suggest that priority should be given to seawater quality protection and control before reef project and coral ecological restoration.

Key words: compressive strength, coral, skeletal structure, bioerosion, South China Sea