底框—砌体结构上部墙体刚度对不均匀沉降影响的研究

发布时间：2018-04-11 04:07

本文选题：底框-砌体结构 + 不均匀沉降　；参考：《湖南大学》2015年硕士论文

【摘要】：不均匀沉降是一项常见的工程事故。由于我国大规模的基本建设,可用于建设的土地不断减少,很多建筑物不可避免地坐落于不良地基上,加上其他各种原因,房屋发生不均匀沉降事故的现象一直难以杜绝。一旦发生较大的不均匀沉降,房屋将会出现开裂、倾斜、变形甚至倒塌等破坏,造成生命财产的损失。关于不均匀沉降的原因和防治方法,目前国内外都有了比较多的研究,也取得了很好的工程应用价值。房屋不均匀沉降变形和破坏,是地基基础和上部结构共同作用、内力重分布和协调变形的结果。目前,关于地基基础与上部结构共同作用的研究中,大部分以混凝土框架结构或钢框架结构为研究对象,砌体结构由于其材料力学性能的复杂性,针对其的研究较少。为此,本文基于有限元法对地基基础与上部结构的共同作用进行研究,深入地分析了底框-砌体结构中上部墙体刚度对不均匀沉降影响。本文首先介绍了国内外不均匀沉降的工程情况,并综述了不均匀沉降的研究现状。从地基、结构等方面总结房屋发生不均匀沉降的主要原因,阐述不均匀沉降所导致的房屋破坏特征。接着本文探讨和分析了砌体结构有限元模型的建立方法、单元类型选择、材料性质和相关参数设定及模型基本假定等。并对典型的底框-砌体结构不均匀沉降形式进行了介绍。本文重点研究了底框-砌体结构上部墙体刚度对不均匀沉降的影响。建立了在重力荷载下底框-砌体结构与地基基础共同作用的三维简化模型,在5种典型不均匀沉降形态的基础上,分析框架柱沉降和轴力对上部墙体刚度的响应特性。上部墙体刚度的调整通过改变墙体弹性模量(E)实现。研究结果表明,无论是中柱、角柱还是端柱沉降较大,通过提高上部墙体刚度都能降低基础沉降的不均匀性,且提高第2层墙体刚度时不均匀沉降改善效果最好。归纳在勘察、设计等阶段预防和控制不均匀沉降的常见措施,总结既有房屋不均匀沉降事故的治理对策,其中包括地基基础和上部结构的处理措施。指出墙体加固方案的确定不仅需要考虑加固完成后的效果,还需要考虑到经济环保方面的问题,如果对所有开裂墙体都进行加固处理,将导致成本过高以及资源的浪费。研究了钢筋网复合砂浆面层加固法对组合墙体弹性模量的影响,结果表明,该加固法能有效提高组合墙体弹性模量,从另一方面表明了钢筋网复合砂浆面层加固法改善不均匀沉降的可行性。本文最后部分介绍了某底框-砌体结构不均匀沉降事故的处理案例。详细分析了事故原因,并结合本文相关内容提出了综合加固处理方案,对地基、基础和上部结构等进行了加固处理,为类似事故治理提供借鉴。
[Abstract]:Uneven settlement is a common engineering accident.Because of the large scale capital construction in our country, the land that can be used for construction is decreasing constantly, many buildings are inevitably located on the bad foundation, and other reasons, the phenomenon of uneven settlement accident of the house has been difficult to eliminate all the time.Once a large uneven settlement occurs, the house will be cracked, inclined, deformed or even collapsed, resulting in loss of life and property.There are many researches on the causes and prevention methods of uneven settlement at home and abroad, and good engineering application value has been obtained.The uneven settlement and failure of buildings are the result of the joint action of foundation and superstructure, the redistribution of internal force and the coordinated deformation.At present, most of the researches on the interaction between foundation and superstructure take concrete frame structure or steel frame structure as the object of study, but the research on masonry structure is less due to the complexity of its mechanical properties of materials.Therefore, based on the finite element method, the interaction between foundation and superstructure is studied, and the effect of upper wall stiffness on uneven settlement of bottom frame-masonry structure is deeply analyzed.This paper first introduces the engineering situation of uneven settlement at home and abroad, and summarizes the research status of uneven settlement.The main causes of uneven settlement of buildings are summarized from the aspects of foundation and structure, and the damage characteristics of buildings caused by uneven settlement are expounded.Then this paper discusses and analyzes the building method of the finite element model of masonry structure, the selection of element type, the setting of material properties and related parameters, and the basic assumptions of the model, etc.The typical non-uniform settlement of bottom-frame-masonry structure is introduced.This paper focuses on the influence of the upper wall stiffness of the bottom frame-masonry structure on the uneven settlement.A three-dimensional simplified model for the interaction between bottom frame-masonry structure and foundation under gravity load is established. On the basis of five typical non-uniform settlement patterns, the response characteristics of frame column settlement and axial force to the stiffness of upper wall are analyzed.The stiffness of the upper wall is adjusted by changing the elastic modulus of the wall.The results show that the settlement of the upper wall can be reduced by increasing the stiffness of the upper wall, and the effect of uneven settlement is the best when the stiffness of the second floor wall is increased.The common measures to prevent and control uneven settlement in the stages of investigation and design are summarized, and the treatment measures of uneven settlement of existing buildings are summarized, including the treatment measures of foundation and superstructure.It is pointed out that the determination of wall reinforcement scheme should not only consider the effect of reinforcement, but also take into account the problems of economic and environmental protection. If all cracked walls are strengthened, the cost will be too high and the resources will be wasted.The effect of reinforcement method on the elastic modulus of composite wall is studied. The results show that the reinforcement method can effectively improve the elastic modulus of composite wall.On the other hand, it shows the feasibility of reinforcing reinforced mesh composite mortar surface layer to improve uneven settlement.In the last part of this paper, the case of uneven settlement of bottom frame-masonry structure is introduced.The cause of the accident is analyzed in detail, and combined with the relevant contents of this paper, the comprehensive reinforcement treatment scheme is put forward, and the foundation, foundation and superstructure are strengthened, so as to provide reference for similar accident treatment.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU433;TU364

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