【作者】 张捷；

【导师】 孙克俐；

【作者基本信息】 天津大学 ， 港口、海岸及近海工程， 2009， 硕士

【摘要】 沉入式大直径薄壁圆筒结构(简称大圆筒结构)是近年来发展起来并极具应用前景的一种新型的水工结构型式,具有结构简单、受力条件好、施工工期短、造价低、耐久性好等优点,可用于防洪护堤、导流堤、码头以及海洋平台等水工建筑物。该结构一般应用于具有较厚软土层的地基上,通过软土插入持力层。大圆筒下沉过程中,结构与地基土体的相互作用分析是一个十分复杂的三维问题,不管是结构本身的强度计算,还是结构系统的整体变形以及地基土体的应力状态,目前还没有成文的规范可以借鉴,此外因为其计算工作量又大而且繁杂,也很难用常规的算法来确定其合理的力学模型。因此采用计算机数值方法是研究该课题的可行和有效的方法。本文应用大型通用有限元软件ANSYS建立大圆筒结构与土体互相作用三维有限元模型,采用节点耦合与接触面模拟大圆筒与土体的互相作用。并且以长江口工程为例,有限元法计算的下沉力与该工程中大圆筒实际下沉力相比较验证该有限元模型的有效性。另外,本文还初步分析了大圆筒施工过程中出现的偏移问题,并提出相应解决办法。主要研究工作如下：1、建立大圆筒下沉整体有限元模型,其中大圆筒和土体都采用实体单元。考虑到土体塑性等非线性,用D-P材料模拟土体,该准则也定义了土体的破坏条件。2、分别用节点压缩和接触面模拟大圆筒与土体的互相作用,并根据它建立一系列数值方案,从中分析大圆筒下沉过程。3、结合长江口大圆筒防波堤工程实例,验证该模型的有效性,并以此模拟计算出大圆筒静力下沉所需的下沉力。4、根据以上建立的有限元模型,模拟大圆筒下沉过程中出现的偏移问题,并根据该模型的计算结果,确定纠偏控制角度。本文确定了大圆筒下沉过程数值模型及其纠偏模型,给出了计算大圆筒下沉荷载有效方法,对于大圆筒推广应用具有重大意义。更多还原

【Abstract】 In the field of harbor and offshore engineering, the embedded large-diameter cylinder shell is a new-type structure and being brought into use gradually at present. With simple structure, good mechanical condition, short construction period, low cost and good durability, etc, it can be used for flood control berm, diversion dike, harbor, as well as hydraulic structures such as offshore platforms. In addition because of its large workload and the computing complexity, it is difficult to use conventional algorithms to determine the reasonable mechanical model. Therefore the use of computer numerical method is to study the subject and effective way possible. The major research work can be summarized as follows.Firstly, Establishment the large cylinder sinking process finite element model, in which the cylinder and soil are established using solid element. Considering the soil non-linear, such as plasticity, D-P model is used to simulate soil materials, which also defines the criteria for the destruction of soil conditions.Secondly, with node coupled pair and contact pair simulating respectively the interacting between the cylinder and soil. A series of numerical model are establishd based on above methods, from which the process of large cylindrical sinking are studied.Thirdly, combined with the Yangtze River estuary large cylindrical breakwater project example to verify the validity of the model and gain the large cylinder sinking static force required to the cylinder sink.Finally, established the basis of the above finite element model simulating the large cylinder sinking offset issues, and in accordance with the calculation to determine the corrective force and control the angle, as well as corrective.This article establishes the numerical model sinking process of large cylinder and the correction model, the way of calculating large cylinder sinking load is putted forward.It is of great significance for large cylindrical promotion application.更多还原