岩土工程中的土钉、锚杆(索)、桩基的承载力计算中需要用到一个重要参数—土的摩阻力。设计一般依据勘察报告或者现行的规范的经验数据取值,但不同条件下土的摩阻力差别较大,勘察报告往往又不能全面地提供,有时甚至应用混乱。该文通过对土的摩阻力发生的机理、影响因素等方面理论和研究成果的梳理,辨析其中的差别。分析表明土的类别和物理力学性质是影响土的摩阻力的最主要因素,应力状态、桩土相对位移、成孔工艺以及尺寸效应也有较大影响,锚杆(索)与桩基的破坏模式不同是二者摩阻力有差异的根本原因,在粘性土中锚杆(索)的摩阻力小于桩基的侧阻力,粉土及砂土中二者相差不大,碎石类土和岩石中则锚杆(索)的摩阻力要大得多。 Geotechnical engineering in the nail, anchor (cable), pile bearing capacity calculation requires the use of an important parameter - soil friction. The design is generally based on the survey data or the empirical data of the current norms. However, the frictional resistance of the soil varies greatly under different conditions, and the survey reports often can not be provided in an all-round way and are sometimes used in confusion. This paper analyzes the mechanism and influencing factors of soil friction resistance and the combing of the research results, and analyzes the differences among them. The analysis shows that the type and physical-mechanical properties of soil are the most important factors that affect soil resistance. The stress state, the relative displacement of pile-soil, pore-forming process and size effect also have significant effects. The failure modes of anchor (cable) and pile foundation The difference is the fundamental reason for the difference in friction between the two. The frictional resistance of anchor (cable) in the cohesive soil is less than the lateral resistance of the pile foundation. The difference between the silt and sand is small, The bolt (cable) friction is much larger.