Study On The Excavation Face Stability Of Shield Tunnel

At present, with the result of rapid population growth around the world, most area of the land is used for building residential areas, planting or production of grain and other uses, So in order to make full use of land resources, people have plenty of options, such as increasing the height of the building, which formed the high-rise and super high-rise building; we can also make full use of underground space resources, which formed underground construction, underground tunnel; people can also be moved to the outer planets, but the development situation for the current level of science and technology is not possible. So people can make full use of existing resources to achieve the goal we need to. This paper is aimed at second conditions-tunnel on the one hand, to study it in application of shield method construction encountered in the process of excavation face stability problems and subsidence of the relationship between, and control method of ground settlement.Tunnel application reduce the ground traffic pressure a lot, put forward good solutions on the surface of road construction which is not easily do. With the development of economic, and the increasing number of populations, demand for the quality of the tunnel is becoming more and more severe, the use value of the requirements of increasingly high. Because of the shield method is more powerful than other methods of competitiveness in the process of tunnel construction, it can be in the process of construction of the ground control in the smallest degree, but also on the formation properties of the request is not very high. So the construction of tunnel at home and abroad, people preferred the shield construction method in shield tunnel construction, but also some problems, such as the use of the process in the construction process and in the tunnel in the follow-up will cause a disturbance to the surrounding layer, influence of embedded in the vicinity of underground pipelines, will also affect the surface of the earth, serious when can cause the ground subsidence, collapse of the building, so the shield tunneling construction should pay attention to the choice of parameters. But for the general diameter tunnel has been unable to meet the needs of normal traffic, so in the process of increasing tunnel diameter will encounter some problems, the causes of these problems are what concern us at present. This paper is mainly research tunnel by earth pressure balance shield construction method of settlement in relation with the stability of the excavation surface to carry on a research, in order to actual engineering, choose three kinds of diameter of the tunnel to study, its diameter were Sm,10m,15m. To study the stability of tunnel excavation in three aspects of simulation were carried on the theoretical analysis, numerical calculation and model problem. The second focus of this paper is the study of ground settlement of earth pressure balance shield of the problems, and put forward the method of control of ground settlement. Through theoretical analysis and numerical simulation to study.Through the study of tunnel excavation with the diameter increasing, formation is more and more complex, also increases the influence of peripheral formation, surface subsidence have increased a certain amount, and increased significantly, in accordance with the strength analysis can be properly tunnel diameter increases, in front of the tunnel, the side with the increases of settlement a large degree of.