考虑桩-土摩阻效应的桥梁桩基水平承载特性研究

Research on Horizontal Bearing Characteristics of Bridge Pile Foundations Considering Pile⁃soil Friction Effect

为研究桥梁大直径桩基在水平荷载作用下,桩-土效应对其力学特性的影响程度,结合新建重庆至昆明高速铁路毛家村水库特大桥大直径桩基项目,运用理论解析方法,基于弹性地基梁模型和p-y曲线法求解桩基水平承载力,考虑桩-土摩阻效应,比较理论值与现场实测值,并研究桩-土界面摩擦角和桩直径敏感参数。结果表明,桩顶水平承载力和桩身最大弯矩在κ=06φ时的计算值与实测值对比效果良好。随着桩-土界面摩擦角增加,桩侧摩阻力、桩身附加轴力和桩身附加弯矩不断增加,随着桩直径增加,桩顶位移折减比和桩身最大弯矩折减比均呈线性减小。

In order to study the influence of pile-soil effect on the mechanical properties of bridge large-diameter piles under horizontal load,this paper combined with the project of large-diameter pile foundation of Maojiacun Reservoir Bridge on the newly-built Chongqing-Kunming High-speed Railway,uses the theoretical analysis method,based on the elastic foundation beam model and p-y curve method to solve the horizontal bearing capacity of the pile foundation,and takes the effect of pile-soil friction into account,compared theoretical values with on-site measured values,studied parameters of the friction angle at the pile-soil interface and the pile diameter.The results indicate that,the horizontal bearing capacity of the pile top and the maximum bending moment of the pile body are considered,when considering the pile-soil friction effect(κ=06φ),the comparison between the calculated value and the measured value is good.As the friction angle between the pile-soil interface increases,the pile side friction resistance,additional axial force on the pile body,and additional bending moment on the pile body also continue to increase,as the pile diameter increases,the pile top displacement reduction ratio and the maximum bending moment reduction ratio of the pile body both linearly decrease.