Research On Key Technologies Of Shield Construction In Guangzhou Subway

With the social progress and development,more and more underground space are used in the people's daily life more,the Urban Rail Transit is developed rapidly.Among all kinds of Urban Rail Transit,the subway has the advantages of large capacity,high speed,low noise,less pollution and small energy consumption.As a result,large cities have gradually formed a new pattern of modern urban rail transit,which is based on the subway and the coexistence of various types of rail transit.In the process of subway construction,the shield method is the most widely used technology,which has the advantages of safe and good reliability,high degree of mechanization,nice working environment,less earthwork,rapid progress,low construction cost and so on.One of the key factors of shield construction is to determine the type of shield and its configuration.The selection of shield is a comprehensive work.In this paper,according to the engineering conditions,geological conditions and schedule requirements of the tunnel in Guangzhou subway program,the author put forward the method and steps of selecting the shield.The different working modes of earth pressure balance shield are expounded,and it is proved to be suitable for various soil layers and the interlayer of all these different soil layers.In order to make sure that the performance of the shield machine could meet the requirements of engineering construction,the key parameters of the selected shield machine are checked and calculated,and it is proved the performance of the shield is capable meeting the reqiurement.The construction scheme and tehnical measures are also proposed in this paper.All aspects of the construction are analyzed,to make sure the the cutting,dumping,propulsion,transportation and erection etc could achieve the best configuration.Meanwhile,the shield construction in special region are analyzed from the aspects of the considerations and corresponding measures.The engineering practice shows that this set of shield tunnel construction technology is successful and it can provide successful experience for the construction in similar geological conditions.The monitoring network is established to ensure the safety of construction and save the capital investment.It provides an effective method for construction monitoring and information feedback.This research not only has the practical significance to the shield construction of Guangzhou subway line 21 shield section,but also to similar project shield construction.