Research On The Construction Method Of Metro Station Built By Enlarging Existing Shield Tunnels

The construction method of constructing metro station through enlarging shield tunnels is a new multifaced technology. It includes the measures of support technology and methods of metro station construction. The method can be used to control the blasting vibration effects in the enlarging phrase. Moreover, it also can solve the conflicts of soil residue disposal, time limit for a project, the urban environment and ground traffics in construction practice. This is a critical and urgent research and has a wide application prospect in China. This paper has carried out a series studies in three main aspects, which include segment removal process, way of platform tunnel construction in enlarging shield tunnels construction, and effect of blasting vibration in enlarging stage on surrounding rock. This thesis took the Dongshankou station in Guangzhou as background and carried out the following research:(1)This chapter analyses the research status quo in domestic and abroad. The application of construction methods of metro station built based by enlarging shield tunnels and the interaction of tunnel excavating and surrounding rock were introduced briefly, which provides the necessary theoretical basis for the following research.(2) In connection with the technical problems encountered in enlarging shield tunnel, this paper put forward mainly from two aspects of mainly support technical measures and construction methods. The paper introduced construction technological sequences of enlarging based by shield tunnels and systematic exposition the main points and hay technology of main construction procedure. Through the research above, construction technologies of enlarging shield tunnel and construction methods were achieved in complex geological conditions. It effectively solved the technical problems of construction based by the existing tunnel.The study on construcion technologies and practical application has accumulated a wealth of construction experience in the subway and the underground construction.(3) Taking detailed analysis the basic process of blasting in the enlarging stage, the thesis illustrated the interaction of blasting vibration effect and surrounding rock.Using computer simulation of the the process of blasting and the enlarge excavating tunnel,the writer put into a deep study to the blasting vibration and the surrounding rock and the mechanism of supporting structure.(4) This paper takes deeply study on the vibration by drilling and blasting method during tunnel excavation produced by excavation,which is called "hollow effect".Taking the Least squares regression fitting function into the "hollow effect" fitting analysis in the first time,provides a method for the ground vibration prediction.(5) To the conflicts of soil residue proposal, time limit for a project,the urban environment and ground traffics in construction metro in urban dense buildings areas, this paper studied the possibility of the underground soil residue transport system in subway station construction. From the perspective of optimization theory, the writer submittes an underground soil residue rail transportation program.Research results of this thesis can be used for building metro station in bustling urban areas where will adopt this construction method, and favore the accumulation of experience of the construction of metro station.And the technology may satisfies well to the proliferation of subway construction. All these research results will have significant economic and environmental significance.