多向荷载下高承台群桩基础分析方法及应用研究

发布时间：2018-11-12 13:03

【摘要】：跨海大桥、海上石油平台、跨海输电塔、测风塔等近海大型结构服役环境复杂,高承台群桩基础受到自身重力、风力、水流甚至船舶撞击力等多种荷载作用,极易引起基础倾斜倒塌。由多向荷载作用下引起的群桩基础破坏失效屡有报道。目前国内外对于多向荷载下群桩基础计算分析方法研究较少,亟需开展相应研究工作。本文针对高承台群桩基础多向共同受荷问题,建立了由刚性承台—弹性梁—土非线性弹簧组成的群桩计算模型。采用水平p-y曲线法、竖向荷载传递法、扭转τ-y曲线法,计算基桩在各自由度上的非线性刚度。模型考虑了群桩效应和基桩推扭耦合效应；水平受荷群桩效应通过设置p乘子实现；基桩推扭耦合效应则通过引入修正单桩分析模型实现。采用牛顿迭代法对计算模型进行求解。对受推力和扭矩共同作用的大尺寸物理模型试验3×3群桩基础进行了分析,分析结果与试验结果基本吻合,表明该计算方法可靠性良好。通过采用多组p乘子对比分析发现,小偏心水平荷载下水平群桩效应更接近于群桩水平单独受荷,大偏心水平荷载下水平群桩效应更接近于群桩扭转单独受荷。通过参数分析发现,在水平和扭转荷载共同作用下,群桩中各基桩桩头剪力分配不均匀性十分显著；获得了不同桩间距和不同承台高度时群桩中基桩轴力变化规律,为复杂荷载下群桩设计提供依据。本文结合工程资料和试桩结果,采用多向荷载下高承台群桩计算方法,实现了对有斜桩的输电线路海中铁塔基础的计算分析,获得了其在多向荷载作用下内力分配规律和变形情况,指导了该工程的设计。
[Abstract]:Cross-sea bridges, offshore oil platforms, transoceanic transmission towers, wind towers, and other offshore large-scale structures are in complex service environments, and pile groups with high caps are subjected to various loads such as their own gravity, wind, water flow and even ship impact force. It is easy to cause the foundation to collapse. The failure of pile group foundation caused by multi-directional load has been reported frequently. At present, there are few researches on the calculation and analysis of pile group foundation under multi-direction load, so it is necessary to carry out corresponding research work. In this paper, a calculation model of pile group composed of rigid cap, elastic beam and soil nonlinear spring is established to solve the problem of multi-direction common loading of pile group foundation with high cap. The horizontal p-y curve method, vertical load transfer method and torsion 蟿 -y curve method are used to calculate the nonlinear stiffness of foundation pile on various degrees of freedom. The coupling effect of pile group and pile pushing and torsion is considered in the model. The horizontal pile group effect is realized by setting p multiplier and the coupling effect of pile pushing and torsion is realized by introducing the modified single pile analysis model. Newton iteration method is used to solve the calculation model. The large scale physical model test 3 脳 3 pile group foundation subjected to the combined force and torque is analyzed. The results are in good agreement with the experimental results, which show that the calculation method is reliable. Through the comparative analysis of multiple p multipliers, it is found that the effect of horizontal pile group under small eccentricity horizontal load is closer to that of pile group under horizontal load alone, and the effect of horizontal pile group under large eccentricity horizontal load is closer to that of pile group under torsional load. Through parameter analysis, it is found that under the combined action of horizontal and torsional loads, the uneven distribution of shear force at the pile head of pile group is very significant. The variation law of axial force of pile group in different pile spacing and pile cap height is obtained, which provides the basis for pile group design under complex load. Combined with engineering data and pile test results, the calculation method of pile group with high cap under multi-direction load is adopted in this paper, and the calculation and analysis of the sea tower foundation of transmission line with inclined piles are realized. The law of internal force distribution and deformation under multi-direction load are obtained, and the design of the project is guided.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU473.1

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