Analysis On Covered Top-down Excavation Technique Adopted Impractical

With the rapid development of the city and urban rail transport, a growing number of subway stations are building in the heavy traffic, dense buildings, underground pipelines criss-cross the city downtown area and heavy traffic sites, which made us to face to station construction schedule at the same time we must ensure that no traffic, a great impact on the environment. How to do both on the ground to reduce the impact of traffic and the surrounding environment, but also to ensure the construction progress and anticipated technical and economic benefits, has become the focus of the station design and construction considerations.As the Covered Top-down Excavation method approach to any convenient construction, shorter construction period, low cost, less interference, ground transportation is beneficial to environmental protection and many other advantages, it has become home and abroad in the city center with heavy traffic around subway station, a valid suggestion Methods. More than 30 years ago, it have used the construction of foreign experience, especially in Japan, the Covered Top-down Excavation construction of the practice and research have accumulated a wealth of experience. In China, the first practice of using the Covered Top-down method had achieved success in February 1992 in two subway stations in Shanghai Shanxi Road and Changshu Road. In this paper, we gives a systematic analysis on the practice of the Covered Top-down method using in Tianjin Metro Line Water Park station construction of the subway station. First, we made a detailed elaborated in the main technical issues of the Covered Top-down Excavation method. The construction technology of cofferdam structure,the construction technology of middle temporary pillar, the construction technology of main part structure, the construction technology of waterproof, ect. Second, we point out that the construction of key elements of construction technology, construction technology and construction quality control measures.