On The Control Survey In The Shield Tunnel Construction Of Guangzhou Rail Traffic

China’s urban rail transit construction is at a stage of accelerated development. Rail traffichas gradually become the backbone of large cities, public transport, because of itsconvenience, environmental protection, energy saving, safety and traffic and othercharacteristics, to ease traffic bottlenecks, improve the urban transport structure, and promotesustainable economic and social development play an increasingly important role. Subwayshield tunnel construction with the traditional (open-cut method, mining method) method,compared with the ground operations less environmental impact on the surrounding highdegree of automation, speed of construction, etc., with the long-distance, large diameter,large depth, complex cross-section of shield construction technology, mature, shieldconstruction method more and more attention and favor, has become a major subway tunnelconstruction methods.In this paper, with the Guangzhou urban rail transit construction survey of shield forobjects, based on knowledge introduction of shield tunnel, the application of survey controltechnology in each stage of project is researched and summarized.The main research contents completed in this paper are as follows:(1) The layout and data processing of the shield tunnel GPS control network are studied.The adjustment computation and precision analysis of the crossing points in the rail transitlines between new and old are studied, and so are the translocation and check of every mainlines points, to solve high precision measurement datum plane for the correct attitudeheading of the shield tunnel and tunnel breakthrough.(2) The level of shield tunnel network and route design standards are studied, so are theprinciple of leveling network adjustment calculation, the measured level crossing method,elevation control of unified network fabric, uniform data processing, to setup a unified heightdatum for the construction of the different lines in different periods.(3) The horizontal run-through error estimation caused by GPS and traverse controlsurvey is studied, and so are the breakthrough error estimation caused by the elevationmeasurement accuracy, and also the accuracy analysis of the outside and inside the hole.Some suggestions are put forward to improve the precisionof the control survey of shieldtunnel.(4) The breakthrough error source of the shield is summarized; According to themeasurement error theory，the survey methods of shield tunnel construction work in allstages are analysed; In full consideration of the underground engineering experience and themeasurement error influence size, with stage guangzhou rail transit construction as the example of shield, taking different measuring methods, some feasible methods are putforward respectively for the ground control nets, shaft connection survey, and undergroundtraverse survey. And the feasibility and reliability of the scheme are studied in detail.(5) With the expansion of the scale of the subway construction, and the increasing of linelengthes, shield tunnel construction is increasing day by day. With the examples, the pointlayout and implementation method of the shield tunnel for automatic monitoring arediscussed, and so are the data transmission and processing, and also the result analysis,which has overcome the disadvantages of the traditional survey methods, and has greatlyenhanced the efficiency, and has provided real-time operation data for tunnel constructionand operation, and has provided the guarantee security.