基坑开挖及降水对邻近建筑物沉降及安全影响研究

发布时间：2018-02-22 19:08

本文关键词： 基坑开挖降水邻近建筑物沉降安全影响　出处：《东南大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着城市地下空间的大规模开发,基坑工程己成为城市建设中重要的岩土工程课题之一。目前国内的基坑工程大多处于城市中心,基坑施工影响范围内往往存在邻近建筑物。因此,基坑工程不仅要保证基坑与围护结构本身的安全,还要保证邻近建筑物的安全和正常使用。实际基坑工程的开挖与场地的工程地质环境、基坑邻近建筑等诸多因素有关,因此基坑工程的研究成果应涉及不同地区各类特殊复杂的工程问题。本文以南京河西地区典型的软土工程地质为背景,针对基坑开挖及降水对邻近建筑物的影响进行了具体而深入的研究,主要研究工作包括以下几个方面：(1)总结和分析了土体渗流固结理论、基坑开挖及降水过程中邻近土层位移的影响因素、基坑开挖及降水对邻近建筑物的影响机理、影响类型。(2)根据南京河西地区的工程地质特征建立了考虑基坑开挖全过程的三维有限元模型,并分析了基坑周边土层位移变化规律以及围护结构变形规律,分析过程中考虑了施工降水、开挖方式的影响,并将考虑降水和不考虑降水、不同开挖方式的计算结果进行分析对比。计算结果表明,降水作用对基坑周边土层位移影响明显,不同开挖方式间基坑周边土层位移也有较大差别。(3)建立了考虑基坑及邻近建筑物(框架结构、框架剪力墙结构)的整体三维有限元模型,并分析了不同因素下基坑开挖及降水对邻近建筑物(框架结构、框架剪力墙结构)的沉降影响规律,包括建筑物与基坑相对距离、开挖深度、降水情况、围护结构厚度及深度、开挖方式、基础类型等。计算结果表明,不同因素影响下基坑邻近建筑物(框架结构、框架剪力墙结构)的沉降变化规律基本一致,但沉降量及沉降差有较大差别。(4)研究了基坑开挖及降水引起的邻近建筑物(框架结构、框架剪力墙结构)内力变化规律,并对结构构件安全性和适应性进行验算。计算结果表明,邻近建筑物底部楼层将产生较大附加内力,且当基坑邻近建筑物自身的地基变形超过《建筑地基基础设计规范》限值时,部分结构构件会发生承载力破坏。
[Abstract]:With the large-scale development of urban underground space, foundation pit engineering has become one of the most important geotechnical engineering topics in urban construction. Adjacent buildings often exist in the influence area of foundation pit construction. Therefore, foundation pit engineering should not only ensure the safety of foundation pit and enclosure structure itself, It is also necessary to ensure the safety and normal use of adjacent buildings. The actual excavation of foundation pit works is related to the engineering geological environment of the site, the adjacent building of the foundation pit, and so on. Therefore, the research results of foundation pit engineering should involve various kinds of special and complex engineering problems in different areas. This paper takes the typical soft soil engineering geology in Hexi area of Nanjing as the background. In this paper, the influence of excavation and dewatering on adjacent buildings is studied in detail. The main research work includes the following aspects: 1) summarize and analyze the theory of soil seepage consolidation. The influencing factors of the displacement of adjacent soil layer during excavation and dewatering of foundation pit, the influence mechanism of excavation and dewatering of foundation pit on adjacent buildings, According to the engineering geological characteristics of Hexi area in Nanjing, a three-dimensional finite element model considering the whole process of foundation pit excavation is established, and the variation law of soil displacement around the foundation pit and the deformation law of enclosure structure are analyzed. In the process of analysis, the influence of construction precipitation and excavation mode is considered, and the calculation results of different excavation methods are analyzed and compared. The results show that the effect of dewatering on the displacement of soil around the foundation pit is obvious. The displacement of soil layer around the foundation pit between different excavation modes is also different. A three-dimensional finite element model considering the foundation pit and adjacent buildings (frame structure, frame shear wall structure) is established. The influence of excavation and dewatering on the settlement of adjacent buildings (frame structure, frame shear wall structure) is analyzed, including the relative distance between the building and the foundation pit, the excavation depth, the dewatering situation, the thickness and depth of the enclosure structure. The calculation results show that the settlement of adjacent buildings (frame structure, frame-shear wall structure) is basically the same under the influence of different factors. However, there is a great difference between settlement and settlement difference. (4) the internal force variation law of adjacent buildings (frame structure, frame shear wall structure) caused by excavation and dewatering of foundation pit is studied. The safety and adaptability of structural members are checked and calculated. The calculation results show that there will be a large additional internal force near the bottom floor of the building. The bearing capacity of some structural members will be destroyed when the deformation of the foundation near the foundation pit exceeds the limit value of the design code for the foundation foundation.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU753

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