【作者】 祝振宇；

【导师】 王元战；

【作者基本信息】 天津大学 ， 港口、海岸及近海工程， 2007， 博士

【摘要】 近年来的调查资料显示,突堤式和顺岸式高桩码头接合位置的码头结构变形和横向错位情况十分严重,本文从这些问题入手,系统地研究了该区域码头结构和岸坡相互作用机理、影响因素和变形特点。目前对突堤式和顺岸式码头接合位置的码头结构与岸坡土体相互作用的研究十分缺乏,本文对该区域码头及岸坡的研究开辟了高桩码头研究的新方向。现场情况表明,突堤式和顺岸式高桩码头接合位置的码头结构的受力和变形具有较为明显的空间特点,而目前对高桩码头的研究基本停留在二维层面上,用平面理论显然无法解释该区域出现的问题。本文以天津港二突堤根部转角区域为对象,建立了码头结构和岸坡土体耦合的大型三维弹塑性有限元模型,为了客观反映结构受力和变形的空间特征,按实际码头结构的空间布局和结构型式进行了真实模拟,提高了研究的针对性和可信度。在土的数值模拟中,土体参数的确定对计算结果有很大影响,为了给土体数值模拟提供可靠的参数,对二突堤根部转角区域进行了详细的地质勘测并对土样进行了直剪、压缩、回弹和固结不排水三轴剪切等室内土工实验,不仅提供了数值计算中土的D-P本构模型需要的参数,而且通过对土体的压缩指数、膨胀指数,以及球应力和广义剪应力关系的分析,进一步分析了土体的物理力学特性,并为引入其他更为精确的本构模型打下坚实的基础。对天津港二突堤根部转角区域首次开展了岸坡内部土体位移的监测工作,对高桩码头和堆场的沉降、桩基的倾斜也进行了观测。获得的数据是对数值计算的验证,为预测岸坡土体和码头结构的变化趋势提供了依据,并为港口运营时荷载布局调整提供参考。这项工作不仅具有很高的科研参考价值,而且具有指导码头运营的实际意义。岸坡稳定是学术界和工程界中十分关心的问题,但现行的设计方法中无法直接计算高桩码头岸坡的稳定性。在应用强度折减有限元方法分析岸坡稳定的过程中,以一定幅值剪应变贯通作为判断岸坡失稳的必要条件具有一定的人为性,以土体塑性区从坡脚到坡顶贯通作为依据则比较客观,但塑性区的可视化显示存在一定困难。本文定义并提出以应力比作为判断土体屈服的参数,解决了塑性状态土体的可视化显示问题。本文通过对有限元强度折减法的发展,把节点不平衡力标准和土体塑性区从坡脚到坡顶贯通标准结合起来作为岸坡失稳的判断依据,提出了一种可以分析存在桩基的岸坡的稳定性的方法,解决了采用传统的极限分析方法不能直接计算高桩码头岸坡稳定性的问题,并可以对岸坡稳定性受桩基的影响程度进行量化分析。更多还原

【Abstract】 It is showed by survey data that more serious deformation of the wharf structure occurred on the joint zone of the shore and croy. In order to solve these problems, the paper research on the piled wharf and slope interaction in the zone. There is no similar research on the problem. So this job in the paper brings us new research project.The deformation of the piled wharf structure in the joint zone of the shore and croy showed space characteristics. Now 2D analysis methods are applied the research on the piled. In order to analysis on the deformation characteristics of piled wharf and slope in the corner of No. croy of Tianjin port, the paper set up a 3D elastic-plastic finite elements model. The model simulated the true port structure, which improved the pertinence and reliability.The soil parameters had obvious effect on the numerical calculation. In order to provide reliable parameters to the numerical calculation, geologic reconnaissance and some soil experiments were carried out. The experiments included simple shear test, compress test, rebound test and triaxil undrained shear test, etc. Through the contrast of the compress exponent, expand exponent, sphere stress and generalized shear stress, analysis were done on soil’s stress, yielding characteristics, which established the base of application of new constitutive relationship.Observation work on the slope soil was carried through for the first time in No. 2 croy of the Tianjin port. The settlement of the piled wharf structure and heap were observed. Data were not only the complementarities to the numerical calculation, but also provided the forecasting reference to the movement trend. The job had actual significance to port management.In the progress of strength reduction FEM analysis on the slope stability, the using shear strain as the necessary condition of the judgments for slope stability had some disadvantage. The plastic zone criterion is more objective, but the display of plastic zone had some difficulty. The paper provided the stress ratio as the yielding parameter, which solved the display difficulty of plastic zone.Slope stability is a concerned problem in the academe and engineering. The existing method cannot solve piled wharf slope stability. The paper developed the strength reduction FEM, and provided a new method which cans calculation the stability of the piled wharf slope. The node imbalance force creition and plastic zone criterion were used as the judge standard for the stability calculation. The paper used the method to calculate the stability of the piled wharf slope, which solved the difficulty of the stability calculation for the piled wharf slope.更多还原