土岩结合基坑监测及变形规律研究

发布时间：2018-10-17 11:14

【摘要】：随着我国国民经济的迅速发展,城市建设步伐的加快,仅对地上空间的开发利用已经不能满足现有的设施需要,同时,由于高层建筑、地下停车场及地下管线等公共设施的大规模兴建,城市用地日趋紧张。因此,很多新建工程都处于城市的繁华地段,基坑周边建筑物、重要的城市道路及地下管线密集,随之而来的出现了很多深基坑设计和施工问题,如基坑支护结构的变形及稳定、基坑开挖对周边环境的影响、基坑内外部地下水的控制以及基坑监测等问题。因此,对基坑工程的稳定性问题的研究成为了岩土工程界急需解决的关键问题。土岩结合基坑与岩体或者土质基坑有很大的差异,现在国内外尚无比较成熟的计算方法,其理论研究远远落后于工程实践,并且现有的研究成果中针对衡阳红砂岩地区土岩基坑工程的变形并没有特别详细的论证,使得很多工程没有经验可循。本文以衡阳地区某一土岩结合基坑为依托,采用理论分析及现场实测的方法,分析研究了该基坑的变形规律,主要内容如下:(1)详细阐述了目前深基坑、土岩结合基坑以及土岩结合基坑设计和监测的研究现状及存在问题;(2)采用经实践证明的比较经济合理的土岩结合基坑几种支护方式、设计计算方法及稳定性分析方法,分析土岩结合基坑的变形模式,阐述影响其变形的主要因素及其与土质基坑影响因素的异同,并对如何保证基坑质量提出了几点建议。(3)详细介绍了本基坑的监测方法、监测点布设情况,并针对每一不同分段的监测点进行分别布置,通过合理布设监测点,研究如何保证监测质量的可靠、合理。把监测得到的数据进行科学分析,特别针对坡顶水平及竖向位移、深层土体水平位移、周边建筑物沉降及锚索拉力的分析,掌握施工过程中各监测元件的变形规律,及时做出调整,使基坑工程顺利进行。(4)通过对监测数据的分析,验证了所设计的支护结构的合理性、安全性;研究得出土岩结合基坑变形规律,通过对每一支护分段交叉对比分析,发现其与土质基坑的不同之处,以及影响基坑变形的因素。为类似基坑的设计和施工提供依据。
[Abstract]:With the rapid development of our national economy and the acceleration of urban construction, the development and utilization of aboveground space can no longer meet the needs of existing facilities. At the same time, due to high-rise buildings, With the construction of underground car parks and underground pipelines and other public facilities, urban land is becoming increasingly tight. Therefore, many new projects are located in the bustling parts of the city, the buildings around the foundation pit, the important urban roads and underground pipelines are dense, and a lot of problems in the design and construction of deep foundation pit appear. For example, the deformation and stability of foundation pit support structure, the influence of excavation on the surrounding environment, the control of underground water inside and outside the foundation pit and the monitoring of foundation pit, etc. Therefore, the research on the stability of foundation pit engineering has become a key problem that needs to be solved in geotechnical engineering field. The soil-rock combined foundation pit is very different from the rock mass or soil foundation pit. There is no mature calculation method at home and abroad, and its theoretical research lags far behind the engineering practice. And the existing research results in Hengyang Red Sandstone area soil and rock foundation pit deformation is not particularly detailed argument, so that many projects have no experience to follow. Based on a soil-rock combined foundation pit in Hengyang area, the deformation law of the foundation pit is analyzed and studied by the method of theoretical analysis and field measurement. The main contents are as follows: (1) the deep foundation pit at present is described in detail. The present situation and existing problems in the design and monitoring of soil-rock combined foundation pit and soil-rock combined foundation pit are discussed. (2) the design calculation method and the stability analysis method are adopted, which are proved to be more economical and reasonable in practice. This paper analyzes the deformation mode of soil-rock combined foundation pit, expounds the main factors affecting its deformation and its similarities and differences with that of soil foundation pit, and puts forward some suggestions on how to ensure the foundation pit quality. (3) the monitoring method of this foundation pit is introduced in detail. The monitoring points are arranged separately according to the monitoring points in different sections, and how to ensure the reliability and reasonableness of the monitoring quality is studied by setting up the monitoring points reasonably. The monitoring data are analyzed scientifically, especially for the horizontal and vertical displacement of slope top, the horizontal displacement of deep soil, the settlement of surrounding buildings and the tension of anchor cable, so as to master the deformation law of each monitoring element in the construction process. Timely adjustment is made to make the foundation pit project proceed smoothly. (4) through the analysis of monitoring data, the rationality and safety of the designed supporting structure are verified, and the deformation law of excavated rock combined with foundation pit is studied. Based on the comparative analysis of each support section, it is found that the foundation pit is different from the soil foundation pit, and the factors that affect the deformation of the foundation pit are also found. It provides the basis for the design and construction of similar foundation pit.
【学位授予单位】：南华大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU753

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