南京地铁隧道盾构法施工地表沉降数值模拟研究

发布时间：2018-01-27 03:14

本文关键词： 地铁盾构土压平衡地表沉降数值模拟　出处：《安徽理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：目前,随着世.界人口的快速增长,土地资源显得越来越紧缺。在我国伴着城.市化进.程步伐的加快,土地资源也越来越宝贵。为了充分利用土地,人们加大建筑高度,产生了高层建筑和超高.层建筑；开发利用地下空间资源,产生了地下建筑,地铁等等；地铁的产生使得地面交通压力得到了相当大的缓解,修建地铁通常使用的一种重要施工方法就是盾构法,主要因为盾构法在地铁隧.道施工过程中有着其他施工方法所不具备的独特优势。另外盾构法对土体性质的要求也不是很高。然而事情的两面性决定了盾构法也有不足之处。由盾构法施工引起的地表沉降和地层移动规律一直都是盾构隧道设计以及施工过程中非常关心的问题。地铁隧道施工之时和施工后期诱发的地表沉陷是致使建、构筑物产生外观及功能上损害的主要原因,每年因此而产生的经济损失非常大。所以,研究分析由地铁隧道.盾构施.工引起的地表沉降规律是十分迫切和必要的。文章依托南京地铁4号线东流站～青龙站区间隧道为工程背景,并且从该隧道区间选取其中一段土层特性建立三维数值模拟模型。分析模拟开挖对于地表沉降地影响。通过分析研究,得出了一些有一定参考价值的结论：盾构不断向前推进的进程中,地表沉降值也是在逐渐增大的,在隧道开挖面后方40米左右处趋于稳定。开挖面前方15米处土体出现轻微隆起现象；依照施工顺序,左线隧道先行开挖,之后再进行右线开挖,由于左线开挖对周围土体产生扰动,导致右线土体强度弱化,从而使得在右线隧道中心线处上方的地表沉降最大值稍微大于左线；距盾构机刀盘前方15米处,地表出现向上的隆起现象,初期的沉降值大致为1-2mm,在开挖面的前方大致为-2～-3mm。盾构通过时的沉降值大致为-5～-7mm。盾尾间隙的沉降值大致为-8--14mm,它主要取决于所处地层的自稳能力；当盾构的外径一样时,地表沉降随着隧道上覆土层深度的增大呈现减小趋势,然而,当深度增大到一定的程度时,地表沉降减小的幅度越来越小；注浆及时与否对于地表沉降值的影响很大,由于注浆不及时引起的地表最大沉降量是注浆及时状态下的最大沉降量的至少2倍以上。研究所得的地铁盾构施工地层沉降机理和规律可以为类似工程方案的确定和施工组织设计,提供一定的参照价值。
[Abstract]:At present, with the rapid growth of population in the world, land resources are becoming more and more scarce. In our country, with the rapid pace of city and city development, land resources are becoming more and more valuable in order to make full use of land. People increase the height of buildings, resulting in high-rise buildings and super-high buildings; Development and utilization of underground space resources, resulting in underground buildings, subway and so on; The ground traffic pressure has been greatly alleviated by the generation of subway. The shield method is one of the most important construction methods used in subway construction. This is mainly due to the unique advantages of shield method in the construction of subway tunnel and tunnel. In addition, the requirement of shield method for soil properties is not very high. However, the dual character of shield method determines the shield method. The law of ground subsidence and stratum movement caused by shield tunneling is always a problem of great concern in the design and construction of shield tunnel. ground subsidence induced by subway tunnel construction and late construction. Trapping is the cause of construction. The main cause of damage to appearance and function of the structure is that the economic loss caused by it is very large every year. It is very urgent and necessary to study and analyze the law of ground subsidence caused by subway tunnel and shield tunneling. This paper relies on the engineering background of the tunnel between East Stream Station and Azure Dragon Station of Nanjing Metro Line 4. And from the tunnel interval selected one of the soil layer characteristics to establish a three-dimensional numerical simulation model, analysis of the impact of simulated excavation on the ground subsidence. Through analysis and research. Some conclusions with certain reference value are obtained: the ground subsidence value is increasing gradually in the process of shield machine moving forward. It tends to be stable at about 40 meters behind the excavating surface, and the soil appears slight bulge at 15 meters in front of the excavating surface. According to the construction sequence, the left tunnel is excavated first, and then the right line is excavated. Because of the disturbance of the surrounding soil caused by the left line excavation, the strength of the right line soil is weakened. Therefore, the maximum value of surface subsidence above the center line of the right line tunnel is slightly larger than that of the left line. There is an upward uplift on the surface 15 meters from the front of the cutter head of the shield machine, and the initial settlement value is about 1-2mm. At the front of the excavating surface, the settlement of the shield is about -2 ~ 3mm. the settlement value of the shield is about -5 ~ 7mm. the settlement of the clearance between the shield and the tail is about -8mm to 14mm. It mainly depends on the self-stability ability of the strata in which it is located. When the outer diameter of shield machine is the same, the surface settlement decreases with the increase of the depth of the overlying soil layer. However, when the depth increases to a certain extent, the extent of the decrease of the surface settlement becomes smaller and smaller. Whether the grouting is timely or not has a great influence on the surface settlement value. The maximum surface settlement caused by late grouting is at least 2 times of the maximum settlement under the condition of grouting. The mechanism and law of ground subsidence in shield tunneling construction can be proved to be similar engineering schemes. Fixed and construction organization design. Provide certain reference value.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.43;U456.3

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