基于结构面力学特性的嵌岩桩侧摩阻力分布分析

现有嵌岩桩桩-岩结构面力学特性研究中很少考虑胶结力作用，在考虑桩-岩界面胶结作用的基础上，提出了完整的嵌岩桩桩-岩界面剪切机理，即包括胶结破坏、滑动剪胀及剪切滑移3部分，且嵌岩桩侧摩阻力主要由胶结力和摩擦力构成。根据桩-岩界面剪切不同阶段的力学特性，建立完整的桩-岩界面剪切本构函数，并推导出其荷载传递方程。基于所获得的解答，深入探讨桩侧摩阻力和桩身轴力随深度变化的分布规律，并从理论上解释桩侧摩阻力单、双峰值分布现象。分析结果表明，桩侧摩阻力峰值沿桩身分布并不存在传统观点认为的0.15l及0.75l固定分布位置，且侧摩阻力双峰值沿桩身分布位置均随桩顶荷载增大而向下移动，当荷载超过某一临界值后，表现为单峰值分布。工程实测数据与理论计算结果的对比分析进一步阐述了理论解的合理性和可行性。

Distribution of shaft resistance of rock-socketed piles based on mechanical properties of pile-rock interface

Considering the bond strength of pile-rock interface, a full shear mechanism of rock-concrete interface of rock-socketed piles is proposed, which includes bond damage, sliding dilatancy and shear slipping, and pile shaft resistance mainly consists of bond strength and friction. According to the mechanical properties of joints at different shear stages, the function of a complete constitutive model for rock-concrete interface is founded, and its load transfer equation is explored as well. On the basis of its analytic solution, the distributions of frictional resistance and axial force along the pile length are discussed, which can theoretically explain the distribution law that has single or double-peak shaft resistance value. The analysis results indicate that the traditional distribution location, such as 0.15l or 0.75l does not exist, and that the position of the double-peak shaft resistance values moves down gradually along the pile with the increase of the load, and that the form of single-peak appears when the load exceeds its critical value. The results of comparing the theoretical analysis with the engineering case show that the analytic solution is reasonable and feasible.