Strength Characteristics of Reef Limestone for Different Cementation Types

Abstract

The strength of reef limestone is an important parameter for conducting the bearing capacity designing of coral reef foundation. Therefore, it is important to obtain the strength index of reef limestone to ensure the strength and stability of reef foundation. In this paper, reef limestone of three different cementation types [gravelly calcareous sandstone (A); calcareous conglomerate (B); coral limestone (C)] were tested by field point load test. Then, the uniaxial compression test was carried out indoors by using the rock samples of corresponding cementation type, and the relationship between the two strengths was discussed. The results show that: ① the point load strength and uniaxial compressive strength of gravelly calcareous sandstone (A) are similar to that of calcareous conglomerate (B), and are significantly lower than that of coral limestone (C); the point load strength is about 1/3 to 1/2 of that of coral limestone and the uniaxial compressive strength is less than 50% of that of coral limestone. ② The uniaxial compressive strength of reef limestone is generally greater than the point load strength, which is due to the brittle nature of the reef limestone, and the different mechanism of action of point load test and uniaxial compression test. ③ There is a positive correlation between the point load strength and uniaxial compressive strength of reef limestone. The difference between the two strengths varies with the cementation type. The quantitative research on relationship between the two strengths of reef limestone must take into account the cementation type.