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目的:研究大直径桩横向惯性效应对其动力响应的影响以及与土体径向非均质性的关系。创新点:1.采用Rayleigh-Love杆模型模拟大直径桩,考虑其横向惯性效应;2.所建立的桩土相互作用模型能同时考虑土体的竖向成层性和径向非均质性。方法:1.采用Rayleigh-Love杆模型模拟大直径桩,建立桩土体系纵向振动控制方程(公式(1)和(4));2.通过求解方程,得到桩顶纵向振动频域响应解析解(公式(15))和时域响应半解析解(公式(16));3.通过参数分析的方法,研究横向惯性效应对桩顶响应的影响以及与桩身参数和桩周土径向非均质性的关系(图2~9);4.通过与工程实例的对比,证明本文解的合理性(图11)。结论:1.考虑横向惯性效应时,桩底反射信号后移,导致桩的计算长度大于其实际值;2.横向惯性效应的影响程度随着桩身半径、泊松比、桩周土软化范围和软化程度的增大而增强,随着桩身混凝土强度等级、桩周土硬化范围和硬化程度的增大而减弱;3.考虑横向惯性效应时的计算曲线与实测曲线更为吻合。
Objective: To study the influence of transverse inertia effect of large diameter pile on its dynamic response and its relationship with the radial heterogeneity of soil. Innovative points: 1. Use Rayleigh-Love rod model to simulate large diameter pile, considering its transverse inertia effect; 2. The established model of pile-soil interaction can consider both vertical stratification and radial heterogeneity . (1) and (4)); 2. By solving the equations, the analytic solution of frequency response in the longitudinal vibration of pile top is obtained (Formula (15)) and the semi-analytical solution of time domain response (formula (16)). 3. By means of parametric analysis, the influence of transverse inertia effect on pile top response and the influence of pile- Homogeneity (Figure 2 ~ 9); 4. By comparing with the engineering example, prove the rationality of the solution (Figure 11). When the lateral inertia effect is considered, the reflected signal of the bottom of the pile is shifted backward, which leads to the calculated length of the pile is greater than its actual value.2. The influence degree of the transverse inertia effect varies with the radius of the pile body, Poisson’s ratio, And the degree of softening increases with the strength of the pile concrete, hardening of the soil around the pile and the degree of hardening and weakened; 3. The calculation of the curve considering the horizontal inertia effect more in line with the measured curve.