【作者】 李淼；

【导师】 李同春；

【作者基本信息】 河海大学 ， 防灾减灾及防护工程， 2003， 硕士

【摘要】 软土地区常见的地下基础型式有桩基础和地下连续墙，近年来随着设计理论和施工工艺设备的发展，桩基础及地下连续墙基础的型式都有了很大的发展，如薄壁筒桩、集挡土、防渗及承重多功能于一体的地下连续墙等。这类复杂的软基基础结构与土体相互作用的受力机理相当复杂，目前相关的研究资料比较少。 目前，在研究结构与土相互作用的问题时，常采用数值分析方法，建立结构与土共同作用体系的数学模型，通过有限元法计算出整体结构的应力和位移。由于结构与土的材料特性，受力性能等方面的差异，为了满足有限元计算精度和效率的要求，合理的反映结构与土体之间的位移协调，需要在结构与土体之间设置恰当的接触面单元，正确的模拟土的本构关系，并尽可能地简化结构的数值模型。 本文在总结已有的结构与土相互作用问题中的接触面单元形式、土的本构关系以及结构的数值模拟方法的基础上，对满足摩尔库仑屈服条件的土体材料用常规的薄层单元模拟进行了更加深入的验证，在已有实心矩形截面桩与土相互作用描述模式的基础上推导了薄壁筒桩用梁模拟时与土相互作用分析模式，和考虑与土相互作用时用板单元模拟地下连续墙的分析方法。通过算例验证了本文提出的分析方法和导出的相应公式的正确性，同时指出用常规实体单元描述地下连续墙是不合适的，但若用文中介绍的西穆等提出的强化假定不连续应变元则可以得出与板单元相似的结果。这些为软基中的地下连续墙等复杂地下结构与土相互作用问题的有限元计算提供了一条简便的途径。 文中对上海勘测设计院进行的薄壁筒桩水平承载能力试验进行了相应的计算分析，所得结果规律与试验结果较为吻合，使得本文提出的分析方法得到了现场试验的验证。 文中最后将本文研究成果应用于上海浦南东海出海闸在典型荷载作用下的受力分析，得到了合理的结果。更多还原

【Abstract】 Pile foundation and continuous wall foundation are widely used in coastal regions, where the character of local soil is always very weak. With the development of design method and the advancement of constructing technology, many new types of pile and continuous wall are applied, like the thin-wall hollow pile and the multi-function continuous wall, which can be used not only as temporary fencing structure, but also as permanent loading structures. The interactional mechanics characteristic between such kind of complex underground structures is difficult to realize. Unfortunately, few systemic researches have been engaged on this topic, and there are few references can be consulted up till now.At present, numerical analysis is widely used in such complex structure-soil interaction questions. It is effective to apply 3D nonlinear finite element in practical projects after setting up the numerical models for them. Due to the difference of material characters and mechanics performance between concrete structures and soils, it is necessary to pay great attention to model the interface element, simulate the soil behavior and the optimization of the finite elements to satisfy the numerical precision and the compatibility relation of the whole project.Several classical methods of interface element, soil behaviors and structure characters are presented in this paper. The author made great effort on the modeling of the interface element and the underground structure element, while considering the soil obey the Mohr-Columnb yielding principle, modified the existing beam element for solid rectangle pile and applies this element into thin-wall hollow pile, proposes a kind of board element. Some examples are presented in the paper to test these new concepts and corresponding formulas. The calculation results also prove that the standard solid element is not appropriate for modeling these complex underground structures. All these efforts intend to obtain a convenient numerical method for analyzing the interaction between complex foundations and soft soil.The test on horizontal bearing capacity of thin-wall hollow pile is analyzed in the paper, which has been carried by Shanghai investigation and design institute. The calculation results conform to the testing results. So, the analysis methods presented in the paper are validated by the results from field test.In the end, these methods are used to analyze the continuous wall foundation of the outlet-gate in east Punan, Shanghai and find its internal force under typical load. The final conclusions are retional.更多还原