明挖法和局部盖挖法地铁车站施工监测及数值模拟分析

发布时间：2018-06-18 23:08

本文选题：深基坑 + 数值模拟　；参考：《安徽建筑大学》2015年硕士论文

【摘要】：近些年,城市人口不断增加,城市交通拥挤问题越来越严重。我国很多大中城市都在修建地铁,充分利用地下空间缓解交通问题。地铁修建一般都是在人口众多、建筑物密集的城市中进行的。而地铁车站深基坑的深度一般都达到了十几米以上,一旦发生事故,将会带来严重的后果。因此,一定要确保地铁施工过程安全,其主要就是保证地铁车站深基坑在施工过程中稳定性不发生破坏。采用数值分析可以弥补传统的理论分析设计只能计算结果却不能反映基坑开挖施工过程中受力和位移变化的缺点,而且可以预先发现基坑施工中危险薄弱的地方,提前做好防范措施。目前,合肥地铁一号线和二号线正在施工。本文以合肥地铁一号线明光路站深基坑施工为例,进行了以下方面的研究和分析:文章分析总结明挖法和盖挖法的国内外研究现状,同时对深基坑的变形机理做了详细的阐述,对支护结构的变形、地表沉降、坑底隆起等影响深基坑变形的主要因素进行了研究,总结了目前国内外关于深基坑稳定性理论的计算方法。在施工过程中,进行了详细的监测分析。对监测数据整理,分析了围护结构顶部、地连墙侧移、地表沉降、建筑物沉降和立柱沉降的变化规律。在明光路站施工的过程中,采用了明挖法和局部盖挖法相结合的施工方法,基坑最深处达到了22.8米。针对施工的实际情况,利用大型有限元分析软件Midas GTS/NX对基坑开挖的施工过程进行了三维的数值模拟计算,并得出了施工地表沉降和围护结构的变化规律。地表沉降的最大值出现在距离基坑边缘15m附近的地方。地下连续墙的变形呈现两边小中间大的弓形曲线,最大值出现在约为基坑深度的三分之二位置。明光路桥段原方案采用明挖法施工,实际施工过程中为了减小对路面交通的影响,采用盖挖法施工。对明光路桥标准段采用明挖法和盖挖法分别进行了二维模拟,得出两种施工方法下地表沉降、围护结构和支撑轴力的变化规律,通过数据对比分析,得出明挖法更改为盖挖法是合理安全的。并通过支护结构的优化分析,对基坑支护的合理性进行了系统的分析,得出地连墙的嵌固深度35.2m,钢支撑间距为6m是经济合理的。
[Abstract]:In recent years, the urban population continues to increase, urban traffic congestion problem is becoming more and more serious. Many large and medium-sized cities in China are building subways to make full use of underground space to alleviate traffic problems. Subway construction is generally carried out in cities with large populations and dense buildings. The depth of deep foundation pit of subway station is generally more than ten meters, once an accident occurs, it will bring serious consequences. Therefore, it is necessary to ensure the safety of subway construction process, which is mainly to ensure that the stability of the deep foundation pit of subway station will not be destroyed during the construction process. Numerical analysis can make up for the shortcomings of traditional theoretical analysis and design which can only calculate the results but can not reflect the variation of force and displacement in the excavation process of foundation pit, and can find the dangerous weak place in foundation pit construction in advance. Take precautions in advance. At present, Hefei Metro Line 1 and Line 2 are under construction. Taking the construction of deep foundation pit of Mingguang Road Station of Hefei Metro Line 1 as an example, this paper studies and analyzes the following aspects: this paper analyzes and summarizes the domestic and foreign research status of open excavation method and cover excavation method, and expounds in detail the deformation mechanism of deep foundation pit. The main factors affecting the deformation of deep foundation pit, such as deformation of supporting structure, ground subsidence and uplift of pit bottom, are studied, and the calculation methods of stability theory of deep foundation pit at home and abroad are summarized. In the process of construction, detailed monitoring and analysis are carried out. According to the monitoring data, the variation rules of the top of the enclosure structure, the lateral displacement of the ground connection wall, the surface settlement, the settlement of the building and the settlement of the column are analyzed. In the construction process of Mingguang Road Station, the combination of open excavation method and partial cover excavation method is adopted, and the deepest part of the foundation pit reaches 22.8 meters. In view of the actual situation of the construction, the 3D numerical simulation of the construction process of foundation pit excavation is carried out by using Midas GTS / NX, a large-scale finite element analysis software, and the variation law of the construction surface settlement and the surrounding structure is obtained. The maximum value of surface subsidence occurs about 15 m from the edge of foundation pit. The deformation of underground continuous wall shows a large bow curve between the two sides, and the maximum value appears at about 2/3 of the depth of foundation pit. In order to reduce the influence on road traffic, the original project of Mingguang Road is constructed with the method of open excavation. In order to reduce the influence on road traffic, the method of cover excavation is adopted in the actual construction process. The two dimensional simulation of the standard section of Mingguang Road and Bridge is carried out by using the open excavation method and the cover excavation method respectively. The variation rules of the ground surface settlement, the enclosure structure and the supporting axial force under the two construction methods are obtained, and the data are compared and analyzed. It is concluded that it is reasonable and safe to change the open excavation method to cover excavation method. Through the optimization analysis of the supporting structure, the rationality of foundation pit support is systematically analyzed. It is concluded that the embedded depth of the ground connecting wall is 35.2 m and the steel bracing distance is 6 m.
【学位授予单位】：安徽建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U231.3;TU94

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