【作者】 叶元芬；

【导师】 王成；

【作者基本信息】 重庆交通大学 ， 桥梁与隧道工程， 2008， 硕士

【摘要】 桩基在历次强、大地震中均出现大量破坏现象。由于破坏的隐蔽性,桩基灾后维修工作极为复杂且耗资巨大。对地震作用下超长桩-土-桥梁结构动力相互作用进行研究具有重要的学术意义和工程实用价值。在对桩-土-结构相互作用的理论研究现状,桩基震害及其破坏机制等进行系统总结的基础上,对目前超长桩-土-桥梁结构动力相互作用的理论研究与实际运用之间存在的问题,主要开展了以下几个方面的研究:○1利用单桩-土-结构动力相互作用的模型及分析方法,探讨了动力影响深度与桩长的关系,并对有限长桩、超长桩及无限长桩在水平简谐荷载作用下的动力响应进行研究,为超长桩的简化计算提供理论依据。○2以液化场地桩-土-桥梁结构振动台模型试验为基础,建立有限元数值模型。并通过调整桩土材料参数、桩土界面参数、边界条件及地震波形式等实现振动台试验的计算机模拟分析。○3探讨判断有限元模型液化的判断标准。除直接引用液化估算经验公式外,可考虑采用近似孔压比来进行判断。通过设置两个工况数值分析的总应力之差来实现。○4针对强震区的桥梁桩基,建立超长桩-土-桥梁结构相互作用的有限元模型,进行有限元静力分析,将分析所得的桩顶水平位移和竖向位移与试验测得的相应值进行比较,以判断有限元模型的正确性。建立考虑桥梁上部结构与不考虑桥梁上部结构时的有限元模型,分析两者的区别,提出相关结论。更多还原

【Abstract】 Pile foundations were damaged seriously during the past major earthquakes. Large amount of cost have been paid for the remedy of pile foundations after earthquakes because they are concealed projects. So to study super-long pile-soil-bridge structure dynamic interaction under earthquake is of significant academic meaning and great practical value.On the basis of systematical summarization of the current state of research on pile-soil-structure interaction, the damages of pile caused by earthquake and the mechanisms of piles failure, aiming at current problems between theoretical researches and practical situation of super-long pile-soil-bridge structure dynamic interaction, the researches are made as follows:○1 Making the use of models and analytic methods for single pile-soil-structure, the relationship between dynamic influence depth and pile length is discussed. The dynamic response of finite pile, super-long pile and infinitely-long pile under horizontal harmonic loads is studied and it provides theoretical evidence to the simplifying calculation for super-long pile.○2 Based on the shaking table model test of the soil-pile-structure interaction in liquefied ground, finite element numerical model is modeling. After the debugging of pile and soil material references, pile-soil interface references, boundary conditions, earthquake waves, and so on, to reliaze the better simulation of numerical analysis.○3 The judgment standard of liquefaction in finite element is also been discussed. Besides experienced equation, the approximate pore pressure ratio is put forward in this paper. After setting two different cases in numerical analysis, the subtracting of total stresses is applied to liquefaction judgment.○4 According to piles in macro seismic area, modeling super-long pile-soil-bridge structure dynamic interaction finite element model. The comparison of the horizontal and vertical displacement of pile-cap in static numerical analysis with the corresponding value in tests can be the correction judgment of the finite element model. After that, model super-long pile-soil-bridge structure dynamic interaction models to consider the effect of the superstructure of bridge to dynamic response.更多还原