【作者】 王卫；

【导师】 王兰生；

【作者基本信息】 成都理工大学 ， 地质工程， 2011， 博士

【摘要】 地铁建设带来大量的地铁深基坑开挖和支护的岩土工程问题,地铁深基坑工程的变形控制对周边环境至关重要。与沿海软土地区相比,虽然成都地区地层较好,基坑开挖所引起的周围地层变形较小,如适当控制,能很好地控制对周围环境的影响,但变形控制仍然是成都地铁设计、施工、监测的主导因素,对成都地铁深基坑变形控制进行研究,具有重要的理论意义和应用价值。本文以成都地铁2号线春熙路站深基坑为重点,结合成都地铁1号线、2号线的其他典型深基坑工程的现场实测资料,通过回归分析、统计分析和数值模拟等理论分析方法,研究成都地铁深基坑工程在不同地质条件、基坑深度、围护结构型式、以及不同施工参数条件下,基坑变形性状及其主要影响因素,研究成都地铁深基坑的变形控制方法。主要研究工作及贡献如下：(1)成都地铁1号线、2号线贯穿成都的南北、东西向,长度分别为14.975km和22.019km,为穿越城市中心地带的线性工程,地质环境条件复杂多变,具有很好的代表性。论文在收集整理大量勘察资料的基础上,分析成都地铁深基坑边坡岩土体工程地质特性,根据地铁1号线、2号线剖面展现的地质环境条件,提出成都深基坑工程具有代表性的的三种典型地质结构模式及其亚类,为以后成都地区深基坑的稳定性、变形的分析评价提供地质依据参考。(2)通过对成都地铁1号线、2号线的典型地铁车站深基坑的监测资料进行详细分析,概括和总结在不同基坑规模(长度、深度)、施工参数条件下,成都地铁条形深大基坑以砂卵石地层为主的不同地质结构模式与不同围护结构类型之间的相互作用、变形规律及其主要影响因素,为成都地区深基坑工程的工程实践和进一步研究提供借鉴和参考。(3)通过对地铁2号线大型换乘站春熙路站典型实例的解剖,对变形预估、变形预测、变形控制关键技术的研究,总结成都地铁深基坑时空效应规律,提出成都地铁深基坑工程变形控制的关键要素和方法,为建立成都地铁深基坑工程变形控制方法体系提供基础。通过数值模拟方法研究超挖对深基坑变形的影响,得到成都地区超挖会使深基坑工程发生较大的变形的结论。分析研究表明成都地铁深基坑时空效应明显,设计与施工紧密结合,施工严格按照设计提出的开挖与支撑的施工顺序及施工参数施工,加强施工监测的信息反馈和变形预测,实施动态设计和信息化施工,是成都地铁深基坑工程变形控制的有效途径。(4)针对成都地铁深基坑工程变形预警值的确定还缺乏系统的研究,还缺乏统一的定量化指标和判别准则,限制和削弱了对可能出现的险情和事故提出警报,论文对成都地铁1号线、2号线的22个地铁深基坑监测资料进行统计分析,对不同地质条件、基坑深度、围护体系类型的深基坑变形提出变形预警值建议。更多还原

【Abstract】 The subway construction brings a great deal geotechnical engineering problems of subway deep foundation pit excavation and support. The deformation control of the deep foundation pit engineering is very important to the peripheral environment. Compared with the coastal soft soil area, although the geologic strata is better in Chengdu area, the surrounding geologic strata deformation caused by deep foundation pit is smaller, if the appropriate control measures are adopted can control the influence to the surroundings environment nicely, but the deformation control still is the key factor to design, construction and observation of Chengdu subway. It is having important theories meaning and apply value to study the deformation control of Chengdu subway deep foundation pit. In addition, the paper studies observation data obtained in the field of other typical deep foundation pit engineerings of Chengdu subway No.1line, and No.2line, the primary contents of the paper is the Chunxi road station deep foundation pit of Chengdu subway No.2line. The paper studies the deformation characters and major influencing factors of deep foundation pit engineerings by regression analysis, statistics analysis and numerical simulation method etc, in the different geological conditions, the different depth of foundation pits, the different pattern of exterior-protected construction, and the different construction parameters. Then the paper studies the method of deformation control of deep foundation pit of Chengdu subway. The main research work and contribution as follows:(1) Chengdu subway No.1line and No.2line cross from north to south and from east to west in Chengdu,14.975kilometer and22.019kilometer long. It is a linear engineering which cross the city center area. The geological environment is complex and multivariate, having a good representation. Based on collecting a lot of investigation data, the thesis analyses the engineering geology character of the rock-soil body of deep foundation pit of Chengdu subway. According to the geological environment of the subway No.1line and the No.2line, puts forward three kinds of typical geological structural models and subtypes of Chengdu subway deep foundation pit, to provide a geological basis reference for the stability and the deformation analysis and evaluation of deep foundation in Chengdu region.(2) Through detailed analysing the observation data of deep foundation pit of typical stations of Chengdu subway No.1line and No.2line, the paper summarizes the interaction between various geological structural models and various patterns of exterior-protected construction, the deformation law and the major influencing factors of deep foundation pit of Chengdu subway station which is deep stripe foundation pit on the basis of sand-pebble layer, in the different foundation pit scale (length, depth), the different construction parameter condition, to provide a reference for the other analogical engineering practices and further studies on deep foundation pit of Chengdu region.(3) By studying and analysing the deformation forecast, the deformation prediction and the deformation control technology of Chunxi road station deep foundation pit of Chengdu subway No.2line, summarizes the space-time effect law of deep foundation pit of Chengdu subway, puts forward the key elements and methods of the deformation control for the deep foundation pit of Chengdu subway, provides the basis for the establishment of the deformation control system of deep foundation pit engineering of Chengdu subway.Research production of numerical simulation method indicates overexcavation will result in a rather large deformation for the deep foundation pit engineering in Chengdu region. The analysis shows that the space-time effect is obvious in the deep foundation pit of Chengdu subway. It is the effective way to control the deformation of deep foundation pit of Chengdu subway that combining design with construction closely, observing strictly construction program of excavation and support and the construction parameters proposed by design department, strengthenning the information feedback of construction and the deformation prediction, implementing dynamic design and information construction.(4)How to determine the deformation warning limit is still lacking in system research on Chengdu subway deep foundation pit engineering, also lacking in unified quantitative index and the discrimination standard. It will limit and weaken to give out warning aginst the possible emergency and accident. The statistic analysis of22deep foundation pit observation data of Chengdu subway No.1line and No.2line is carried out in the paper, and the deformation warning limit is putted forward to the different geological condition, the different foundation pit depth, the different patern of exterior-protected construction of the deep foundation pit.更多还原