Key Techniques Of City Subway Open TBM Construction

At present,the construction of subway rail transit has become one of the main ways to alleviate urban traffic pressure.During the construction of subway construction,TBM construction is one of the most commonly used construction methods.The construction method saves construction time,Construction efficiency is high,and the safety factor is also high.Based on this background,this paper,based on the TBM project of Chongqing Rail Transit Line 6,carries out relevant research work on the engineering practice and the key technical problems of TBM construction.The main work includes the following aspects:(1)Evaluation and optimization of TBM equipment adaptability: From the aspects of route,geology,tunnel depth,T station,and technical safety,this paper summarizes the requirements of TBM selection in city subway.During the construction process,the design of the geology,the influence of the line,the influence of the site construction and the optimization of the skidding system are carried out to ensure the construction speed,efficiency and safety.(2)the impact of TBM construction on the environment: Overall,TBM tunnel construction under the level of control can be controlled at the same time the tunnel is relatively stable,high structural safety factor,the construction of the settlement does not have a significant impact on the surrounding environment And the maximum settlement deformation of the surface deformation is within four millimeters.The analysis of the axial stiffness curve of the bolt shows that the maximum axial force is measured at 0.8 m in the direction of the surrounding rock,The axial force of the bolt is relatively small,the amplitude of the axial force fluctuation is very small at 3.5 m,and the deformation law of the surrounding rock is 3.66 mm,the anchor of the surrounding rock is 3.66 mm,The maximum value of the shaft is 3.71 kN.The support parameters of TBM can be optimized by a certain method.The support parameters of TBM can be optimized by the method of TBM.(3)Study on TBM rapid excavation technology under mudstone geological conditions: Through the analysis of mudstone construction,the problem of softening of mudstone,the control problem of tunnel construction and the control of tunneling parameters are put forward.In the mudstone geological conditions,Vault out of the phenomenon,to take measures to strengthen the support in advance to deal with;in the prevention of mud mud in the treatment of cement,according to the principle of tool safety control of the cutter water spray.(4)urban subway TBM cross-site construction technology research: TBM tunneling station is suitable for the construction of the station when the station is not construction,due to construction and other factors,the use of direct road crossing;TBM flat step through the step Into the rack and step-by-step car to rely on stepping rack and ground friction to provide reaction step by step,the speed of the station structure on the small impact;TBM arc step through the construction technology,the construction of a great degree of difficulty,Such a station mode is not worth promoting.This paper provides a reference for the study of open TBM construction technology for urban metro in China,which has certain theoretical and practical significance.