嵌岩桩及较破碎岩石桩基影响系数探讨

纵观以往对嵌岩桩的研究,主要是针对嵌岩桩(嵌入完整、较完整岩石)的承载性状的研究,而对端阻、侧阻影响系数和综合影响系数的研究较少。国内外笔者通过256根嵌岩桩静载试验资料,对嵌岩桩的3个影响系数进行统计分析,并对其影响因素进行探讨,得到3个影响系数与抗压强度和深径比的关系。在贵阳地区分布有大量较破碎岩石,然而目前对于嵌入较破碎岩石上桩的影响系数的研究尚缺乏,这给桩的设计带来一定的问题。由14根嵌入较破碎岩石中桩体的静载试验,本文对桩端阻、侧阻影响系数以及综合影响系数进行了探讨,为在较破碎岩石上设计的桩体提供一定的参考。最后结合相关规范、科研成果和本文试验数据,将端阻、侧阻影响系数和综合影响系数进行较为全面、详细的划分,并给出一张同时考虑岩性和完整性的影响系数建议取值的表格。

Study on Coefficients for Rock-socketed Piles and Less-fragmentized Rock Pile Foundation

There are many scholars studying the bearing capacity of rock-socketed pile, while few researches study on pile’s coefficient. 256 rock-socketed pile static load testes are collected to study the shaft resistance, tip resistance and comprehensive coefficient and the influence factors, drawing a conclusion that the three coefficients are related to saturated uniaxial compression strength of rock and embedded depth-diameter ratio. Many less-fragmentized rocks are found in Guiyang area, and the research on less-fragmentized rock pile foundation is lacking, which provides a difficult issue for designers. According to the 14 pile static load testes that embed in less-fragmentized rock, three coefficients will be discussed to provide an example for local engineers. The recommended values of shaft resistance, tip resistance and comprehensive coefficient will be given according to the degree of integrity and hardness of rock, code, research and the tests result.