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.

摘要

为了检查珊瑚礁石灰岩-混凝土剪切破坏特性，我们进行了大规模的直接剪切试验，研究了五种类型的界面：平面、倾斜、弧形、阶梯和三角形。此外，在三种界面连接类型下检查了剪切破坏特性和剪切强度变化：光滑、泥浆填充和胶结。结果表明，珊瑚礁石灰岩与混凝土之间光滑、充满泥浆的界面处的剪切现象以界面滑移破坏模式为特征。界面处的泥浆起到良好的润滑剂作用，大大降低了剪切强度。对于珊瑚礁石灰岩与混凝土的胶结连接，其抗剪强度随着剪切位移的增加而迅速增加。当抗剪强度达到一定值时，急剧下降后趋于平稳，在界面的珊瑚礁灰岩侧发生剪切破坏。在所研究的试件中，最大剪切强度从高到低依次为：阶梯界面、三角形界面、弧形界面、倾斜界面和平面界面，而相应的剪切位移依次增加。本研究结果可为珊瑚礁灰岩地层桩基施工提供参考。而相应的剪切位移按此顺序增加。本研究结果可为珊瑚礁灰岩地层桩基施工提供参考。而相应的剪切位移按此顺序增加。本研究结果可为珊瑚礁灰岩地层桩基施工提供参考。