新型卸荷式板桩码头三维有限元数值模拟分析

发布时间：2018-05-25 23:57

本文选题：整体卸荷式码头 + 土压力计算　；参考：《中国海洋大学》2014年硕士论文

【摘要】：港口是一个国家或地区对外开放的窗口和桥梁，对于参与国际分工合作与竞争的区域经济是很重要的。作为三大码头结构之一的板桩码头，其优点是可以在地基承载力较低的软土地基上修建，可适当减少土方工程量和施工围堰困难等情况，但传统的板桩码头不能满足深水中对码头前板桩急剧增大的弯矩要求。因此需要提出能够适应深水化大型化发展的新型板桩码头结构，整体卸荷式码头就是其中之一。整体卸荷板式码头可以有效减少前墙的土压力，近年来正受到越来越广泛的应用。该结构型式也是板桩码头走向深水化、大型化的方向之一，并且在国外，尤其是欧洲国家是一种非常流行的结构型式。整体卸荷式板桩码头是一种在港口结构、航道软基支护工程中常用的较为新型的码头结构，它是由前板桩墙、卸荷平台和后排桩组成的复杂结构型式，卸荷平台将前墙和后排桩连接成一个整体，使得它有着比一般分离式卸荷码头更加稳定的基础和更加复杂的受力变形影响因素。正是由于卸荷平台的存在，使得承台上方的荷载通过桩基直接传递到土体上，使后排桩受力增加，而前墙受到的侧向土压力大大减小。但卸荷式板桩挡土结构不仅要承受较大的竖向荷载，而且还要约束土体的侧向变形，受力非常复杂。目前，并无明确的计算方法以及相应的力学特性分析。本文总结了土压力理论计算的发展、卸荷式板桩码头的土压力计算以及结构计算方法的现状，，并结合岩土中普遍存在的卸荷土拱，利用卸荷拱理论和平行墙理论，推导出整体卸荷式板桩码头土压力计算公式；另外对土体流变的基本理论做了简要的介绍，分析可知土体的蠕变对桩基的长期变形和结构的使用的有着显著的影响。本文以青岛市海鲜舫护岸工程为例，采用三维有限元数值模拟的办法对其新型码头结构进行了详细的计算和分析，并将结果与理论计算值做对比；同时，本文通过改变卸荷平台后排桩与前墙的距离，从桩体位移和应力方面研究其对结构工作性状的影响，从而验证了该结构设计的合理性。
[Abstract]:Port is a window and bridge for a country or region to open to the outside world. As one of the three big wharf structures, the sheet pile wharf has the advantage that it can be built on the soft foundation with low foundation bearing capacity, and can reduce the amount of earthwork and the difficulty of construction cofferdam, etc. But the traditional plate pile wharf can not meet the demand of bending moment in deep water for the rapid increase of the plate pile in front of the wharf. Therefore, it is necessary to propose a new type of plate pile wharf structure which can adapt to the large-scale development of deepwater, one of which is the integral unloading wharf. The integral unloading plate wharf can effectively reduce the earth pressure of the front wall, and has been more and more widely used in recent years. This type of structure is also one of the direction of deep water and large scale of sheet pile wharf, and it is a very popular structure type in foreign countries, especially in European countries. The integral unloading plate pile wharf is a relatively new type of wharf structure commonly used in port structure and waterway soft foundation support engineering. It is a complex structure type composed of front plate pile wall, unloading platform and rear row pile. The unloading platform connects the front wall and the back row pile into a whole, which makes it have a more stable foundation and more complicated forces and deformation factors than the common split unloading wharf. It is precisely because of the existence of unloading platform that the load above the cap is transferred directly to the soil through the pile foundation, which increases the force on the back row pile, while the lateral earth pressure on the front wall is greatly reduced. However, the unloading plate pile retaining structure not only bears large vertical load, but also constrains the lateral deformation of soil, so the force is very complex. At present, there is no clear calculation method and corresponding analysis of mechanical properties. This paper summarizes the development of earth pressure theory calculation, the present situation of earth pressure calculation and structure calculation methods of unloading plate pile wharf, and combines the unloading soil arch, the theory of unloading arch and the theory of parallel wall, which is widely existed in rock and soil, and makes use of the theory of unloading arch and the theory of parallel wall. The calculation formula of earth pressure of integral unloading plate pile wharf is deduced, and the basic theory of soil rheology is briefly introduced. The analysis shows that the creep of soil has a significant influence on the long-term deformation of pile foundation and the use of structure. In this paper, taking Qingdao Seafood Restaurant Bank Protection Project as an example, the three-dimensional finite element numerical simulation method is used to calculate and analyze the new wharf structure in detail, and the results are compared with the theoretical calculation values, at the same time, By changing the distance between the rear pile and the front wall of the unloading platform, the influence of the pile displacement and stress on the structural performance is studied in this paper, and the rationality of the structure design is verified.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U656.112

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