宁波地铁深基坑围护结构变形控制研究

发布时间：2018-02-23 16:19

本文关键词： 饱和软土深基坑围护结构变形　出处：《石家庄铁道大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着经济的发展,城市建(构)筑物的高度、密度都在持续增加,同时因为城市地下轨道交通发展的需要,大量地铁车站深基坑工程不可避免设计建造于密集既有建(构)筑物附近,因此基坑的施工受到了越来越严格的环境制约。本文以宁波市轨道交通1号线一期工程TJ-VII标海晏北路站西延段为工程研究对象,针对宁波富水软土地区地铁深基坑施工工程地质、水文地质条件差的现实情况,通过缜密理论分析、计算及对监测数据的整理,分析了宁波富水软土地区地铁深基坑施工过程中基坑内外水土变化特点和围护结构的变形特征,提出了该地质条件下深基坑施工中基坑变形控制的技术措施。论文从土力学基本原理出发,采用深基坑支挡结构分析计算软件(FRWS)进行基坑围护结构内力及变形计算分析,施工全过程的跟踪监测、数据采集、变形分析,得出了宁波富水软土地区基坑开挖所引起的围护变形多呈现为弧线形,即凸鼓形或凹槽形。围护结构最大变形位置随着开挖面的加深而逐步下移,并基本稳定处于开挖面以下3~5 m范围。坑外地表变形曲面、围护结构变形曲面、坑外墙边地层水平位移曲面均为不规则弧线形,具有相似性。坑内土体的回弹隆起及塑性变形应由基坑开挖卸载、围护结构变形和挤压、深部承压含水层水压及墙趾下部或围护结构地下连续墙薄弱部分外部地层水土的流入等四方面主要因素引起。基坑施工时,围护结构的变形规律由设计方案、基坑开挖方案、支撑架设质量、施工过程控制水平、工程地质和水文地质条件等综合决定,拐角效应所影响的范围很小,围护结构变形长边效应不明显。软土地区地铁深基坑施工变形控制是一项系统工程,它是一个与时间、空间赛跑的过程,一项集加固、降水、开挖、支撑架设、结构施作等分项作业综合控制的系统作业。所有的基坑变形控制措施都要以过程控制为重中之重,施工过程控制的规范程度决定了措施的效果。因此,对于宁波富水软土深基坑工程施工过程中时间、空间的控制和把握是精神,过程控制是关键。
[Abstract]:With the development of economy, the height and density of urban buildings are increasing continuously, and at the same time, because of the need of the development of urban underground rail transit, A large number of subway station deep foundation pit projects are inevitably designed and built near dense existing structures. Therefore, the construction of foundation pit is more and more strictly restricted by the environment. This paper takes the west extension section of Haiyan North Road Station as the research object of the first phase project of Ningbo Rail Transit Line 1. In view of the fact that the construction engineering geology and hydrogeological conditions of deep foundation pit of subway in Ningbo water-rich soft soil area are poor, through careful theoretical analysis, calculation and collation of monitoring data, The characteristics of soil and water change inside and outside the foundation pit and the deformation characteristics of the retaining structure during the construction of deep foundation pit of subway in Ningbo water-rich soft soil area are analyzed. Based on the basic principles of soil mechanics, the internal force and deformation of the retaining structure of deep foundation pit are calculated and analyzed by using the software of FRWS, which is based on the basic principle of soil mechanics, and puts forward the technical measures to control the deformation of the foundation pit in the construction of the deep foundation pit under this geological condition. Tracking and monitoring, data acquisition and deformation analysis during the whole process of construction, it is concluded that the surrounding deformation caused by excavation of foundation pit in rich water soft soil area of Ningbo is mostly arcuate. That is, convex drum or groove shape. The maximum deformation position of the retaining structure gradually moves down with the deepening of the excavating surface, and is basically stable in the range of 3 ~ 5 m below the excavating surface. The horizontal displacement surfaces along the outer wall of the pit are all irregular arcs, which are similar. The springback and plastic deformation of the soil in the pit should be unloaded by the excavation of foundation pit, and the deformation and extrusion of the surrounding structure should be carried out. The water pressure of the deep confined aquifer and the inflow of soil and water from the weak part of the underground continuous wall are mainly caused by the water pressure of the deep confined aquifer and the water and soil inflow of the weak part of the underground continuous wall. During the construction of the foundation pit, the deformation law of the retaining structure is caused by the design scheme and the excavation scheme of the foundation pit. The influence of corner effect on the quality of support erection, construction process control level, engineering geology and hydrogeological conditions is very small. Deformation long side effect of retaining structure is not obvious. Deformation control of deep foundation pit construction in soft soil area is a systematic engineering, it is a race with time and space process, a consolidation, precipitation, excavation, support erection, All the deformation control measures of foundation pit should take process control as the most important one, and the standard degree of construction process control determines the effect of the measures. Space control is the spirit and process control is the key to the construction of deep foundation pit with rich water and soft soil in Ningbo.
【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU753

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