海洋工程中现行的桩-土界面剪切强度设计方法一般有两种:(1)根据工程经验与规范进行判断;(2)根据土层地质勘查报告中的土体强度参数进行判断。对于海洋桩基而言,合理地确定土-结构物界面的剪切强度尤为重要。界面剪切强度将直接影响桩基承载力的大小,过高或过低地估算桩基承载力都可能会造成严重工程事故发生。为了研究沉桩过程中桩-土界面特性,本文通过自制大型直剪仪对不同粒径的土样进行了直剪试验分析,提出“抗剪糙度”概念,研究了砂土的内摩擦角、相对密度和抗剪糙度三者之间的关系和粘土的抗剪糙度与不排水强度间的关系。研究表明,土与钢板界面的抗剪糙度并非常数,砂土抗剪糙度的变化规律性较强,而软粘土的抗剪糙度受固结程度、扰动程度、土体强度等因素影响而呈现较大变化。最后,对“抗剪糙度”在实际工程中的运用提出了一定的建议。 There are two general design methods for the shear strength of the pile-soil interface in marine engineering: (1) Judgment based on engineering experience and specifications; (2) Judgment based on the soil strength parameters in the soil geological survey report. For marine pile foundations, it is particularly important to determine the shear strength of the soil-structure interface reasonably. The interfacial shear strength will directly affect the bearing capacity of the pile. To estimate the bearing capacity of the pile too high or too low may cause serious engineering accidents. In order to study the pile-soil interfacial characteristics during pile-sinking process, the direct shear tests on different sizes of soil samples were carried out by using self-made large direct shear tester. The concept of “anti-shear roughness” was put forward and the internal friction angle , Relative density and shear resistance of the relationship between the three and the relationship between clay anti-shear roughness and undrained strength. The results show that the shear resistance of the interface between soil and steel is not constant, and the regularity of the shear resistance of the sand is strong. However, the shear resistance of the soft clay is affected by the degree of consolidation, the degree of disturbance and the soil strength Influence and show a greater change. Finally, some suggestions are put forward for the application of “anti-shear roughness” in practical engineering.