【作者】 李荣庆；

【导师】 贡金鑫；

【作者基本信息】 大连理工大学 ， 结构工程， 2009， 博士

【摘要】 港口工程板桩结构和桩基在其设计使用年限内应具有足够的可靠度,保证其可靠度要做到对结构进行合理的设计、施工和使用,而合理的设计在一定程度上反映在设计规范规定的安全水平上。所以,从某个角度讲,设计规范的合理性和先进性是结构可靠性的基础。本文以工程应用为目标,结合港口工程板桩设计规范和桩基规范修订的需要,对板桩结构和桩基可靠度进行了研究,主要研究内容如下:(1)提出了一种板桩结构计算的新方法,本法不需对板桩进行离散,借助简支梁的挠度计算公式,根据板桩与土的变形协调条件和结构的静力平衡条件即可解得板桩的内力、位移及拉杆拉力,与ANSYS计算结果进行了对比,结果符合较好;(2)对影响板桩结构可靠度的因素进行了研究,对板桩码头结构设计中变量的统计特性进行了分析,针对板桩墙内力计算时,功能函数为隐式的特点,提出了板桩结构的可靠度分析方法。对选取的国内14个典型的板桩码头的可靠度进行了分析,并提出了板桩码头结构设计的目标可靠指标,提出了“踢脚”稳定验算和锚碇结构稳定性验算抗力系数调整的建议;(3)提出一种分析单桩水平承载力的新方法,可以考虑桩顶自由和桩项固定两种情况,与ANSYS进行了对比,结果较吻合;基于本法,对单桩水平承载力进行了可靠度分析;(4)根据搜集的国内港口工程试桩资料,对不同土类别的桩侧阻力和桩端阻力参数与规范值进行了对比分析;以试桩资料为基础,对按规范中的经验公式法计算的桩基承载力进行了可靠度分析。(5)由于试桩数据的小样本性质,首先推导了一种适于小样本的最佳线性无偏估计量的概率分布函数,采用蒙特卡罗方法进行了验证。然后以此为基础提出了按试桩结果确定极限承载力标准值的概率方法,并对按试桩确定的桩基承载力可靠度进行了分析。更多还原

【Abstract】 Sheet pile quaywalls and pile foundations of harbour engineering shall be designed, constructed and maintained in such a way that they are suited for their use during the design working life and in an economical way.The rationality of design method is implied in the safety level prescribed in design code.Thus,the rationality may be considered as the basis of structure design.For revising the design code of sheet pile quaywalls and code of pile foundations of harbour engineering,the reliability of sheet pile quaywalls and pile foundations is studied in this paper.The main contents are summarized as follows:(1) A new method called "virtual simply supported beam" method is presented in this paper,in which only the soil layer is necessary to divide.A set of equations are set up based on deformation compatibility principles and the boundary equilibrium conditions of sheet pile. The solution of the equations gives the results of deformations and internal forces of sheet pile, and the tension of tie rod.Forteen sheet pile quaywalls are selected from practice to check the validation of the new method.It is indicated that there is a good agreement between the results analyzed using the new method and those obtained from software ANSYS.The results show that the new method can be used in the design of sheet pile.(2) Factors influencing the reliability of sheet pile quaywalls are discussed and limit state functions are established for different failure modes.Based on the analysis results in this paper and target reliability indexes prescribed in various reliability based design codes,the target reliability indexes are presented for structural design of sheet pile quaywalls in China. The partial factors for resistance in design equations are presented in order to ensure the reliability indexes resulting from design equations approach the target ones.(3) An analytical method is developed to predict the responses of laterally loaded pile in layered soils.The method uses fundamental basis of structural mechanics to obtain the governing equations of the soil and pile systems.Both free head and fixed head piles are considered in this method.The pile deflections,bending moments and soil reactions can be calculated using this method.Deflections and bending moments calculated using this method are found to be in good agreement with those obtained from ANSYS,thus verifying the reliability of the proposed method.Based on the presented method,the reliability of pile subjected to lateral load is analyzed. (4) The measured ultimate shaft resistances and point resistances of soil are compared with those given in Code for Pile Foundation of Harbor Engineering based on collected static load test data.The reliability of axially loaded single pile designed in accordance with formula prescribed in the code is analyzed.(5) The probability density functions of the statistics related to the best linear unbiased estimate method are derived,allowing for the small sample properties of static load test data. The confirmation of analytical results is accomplished by the use of Monte-Carlo simulations. The characteristic value determination of ultimate bearing capacity of piles from static load test data is discussed.Furthermore,a method is presented for analyzing the reliability of pile designed based on static load test data.更多还原