合肥高铁南站南广场土体开挖对隧道变形机理的研究

发布时间：2018-12-25 12:12

【摘要】：当前合肥正处在高速发展的状态,城市规模不断扩大,原有的地面交通已经不能满足日益拥堵的城市交通,地铁的建设可以有效的解决城市交通问题。同时城市地面建筑的发展也相当迅速,这就涉及到在地铁隧道上方施工的基坑开挖工程。上部的基坑开挖会影响下部地铁隧道结构的稳定性。因此基坑开挖对下部既有隧道变形机理的研究具有重要的意义。本文以合肥高铁南站南广场工程为背景,采用有限元软件MIDAS/GTS进行数值模拟的方法,分析比较基坑不同开挖方式对下部既有隧道变形的影响,整理分析监测数据,并将模拟值与监测数据比较,探讨基坑开挖对下部既有隧道纵向变形的影响,主要工作和结论如下:1.对国内外关于基坑开挖对下部既有隧道变形的研究进行了总结,得出了地铁隧道的相关变形规律,提出了本文的研究方法。2.研究基坑开挖对下部既有隧道变形的影响,总结了土压力的计算方法,基坑开挖的时空效应,隧道隆起值的计算方法。得出了基坑开挖对下部既有隧道变形的影响规律,提出了合理的开挖方式。3.根据实际的施工方案,选取合适的本构模型,采用有限元软件MIDAS/GTS分别对不同的施工方案进行数值模拟。分析比较不同施工方案的隧道变形的结果,研究基坑开挖对下部隧道拱顶隆起变形的规律,选取合理的开挖方式。通过分析模拟结果可以看出,基坑开挖会引起下部地铁隧道的纵向变形,隧道拱顶呈现隆起的趋势。拱顶隆起变形呈现两边小,中间大的弓形。方案三的模拟值要小于方案二的模拟值,因此方案三的开挖方式更有利于控制隧道的纵向变形。4.分析整理监测数据,并且与数值模拟的数据进行对比分析,验证了模型的合理性。根据数据分析基坑开挖对下部既有隧道的变形的影响。基坑开挖对下部既有地铁隧道纵向变形的影响与距离有关,隧道距离开挖土体越近,隧道拱顶的纵向变形越大,反之越小。
[Abstract]:At present, Hefei is in a state of rapid development, the scale of the city continues to expand, the original ground traffic can no longer meet the increasing congestion of urban traffic, subway construction can effectively solve the urban traffic problems. At the same time, the development of urban ground building is very rapid, which involves excavation of foundation pit over subway tunnel. The excavation of the upper excavation will affect the stability of the lower subway tunnel structure. Therefore, the excavation of foundation pit is of great significance to the study of deformation mechanism of the existing tunnel in the lower part. Based on the South Square Project of Hefei South Railway Station, this paper analyzes and compares the influence of different excavation methods on the deformation of the existing tunnel in the lower part of the foundation pit by using the finite element software MIDAS/GTS to carry out numerical simulation, and collates and analyzes the monitoring data. The effects of excavation on the longitudinal deformation of the existing tunnel in the lower part of the tunnel are discussed by comparing the simulated values with the monitoring data. The main work and conclusions are as follows: 1. This paper summarizes the research on the deformation of the existing tunnel in the lower part of the foundation pit excavation at home and abroad, obtains the relevant deformation law of the subway tunnel, and puts forward the research method of this paper. The influence of foundation pit excavation on the deformation of the existing tunnel is studied. The calculation method of earth pressure, the space-time effect of foundation pit excavation and the calculation method of tunnel uplift are summarized. The influence law of foundation pit excavation on the deformation of the existing tunnel in the lower part is obtained, and the reasonable excavation method is put forward. According to the actual construction scheme, the appropriate constitutive model is selected, and the numerical simulation of different construction schemes is carried out by using the finite element software MIDAS/GTS. This paper analyzes and compares the results of tunnel deformation with different construction schemes, studies the regularity of excavation deformation to the arch top of the lower tunnel, and selects a reasonable excavation method. Through the analysis of the simulation results, it can be seen that the excavation of foundation pit will cause longitudinal deformation of the lower subway tunnel, and the vault of the tunnel will show a tendency of uplift. The dome is shaped like a small arch in the middle. The simulation value of scheme 3 is smaller than that of scheme 2, so the excavation mode of scheme 3 is more favorable to control the longitudinal deformation of tunnel. 4. The rationality of the model is verified by comparing the monitoring data with the numerical simulation data. According to the data, the influence of excavation on the deformation of the existing tunnel in the lower part is analyzed. The influence of foundation pit excavation on the longitudinal deformation of the existing subway tunnel is related to the distance. The closer the tunnel is to the excavation soil, the greater the longitudinal deformation of the tunnel vault is, and the less the vertical deformation is.
【学位授予单位】：安徽建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U456.3

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