The Technique Of Diaphragm Wall Treatment And Its Application In Hongxing Road Station Project Of Tianjin Metro Line 2

The Hongxing Road Station Project of Tianjin Metro Line 2 is located at the joint of Huachang Street and Hongxing Road and nearby Shunchi Bridge. The construction site used to be apartment buildings. The superstratum consists mostly of miscellaneous fill and waste building foundations and substratum consists mainly of sandy clay and sand. Diaphragm wall, which is a kind of highly mechanized complex construction technique affecting greatly on subsequent work, is adopted as the retaining structure of Hongxing Road Station. Its construction is an important subsection of this project due to the great influence of its quality on the safety of deep excavation and main structure.Based on this project a reasonable scheme of the parameter design of diaphragm wall and the management of construction technique, quality and safety is presented in this thesis. According to the characteristics of site, buildings and geological condition every aspects of diaphragm is reasonably designed. The request of diaphragm wall design and construction management is proposed after the comparing and analyzing various aspects such as the environmental and economical interest, the affection on environment around during construction, the schedule and arrangement of construction and the request of excavation and main structure. The design, construction and examination of diaphragm wall are particularly described.Based on the analysis of potential problems in diaphragm wall construction some practical precautionary measures are advanced. Firstly, the guide wall should be built on the original state soil in case of the concrete in diaphragm wall exceeding the structure sideline during construction, increasing workload of concrete clearance and affecting on construction schedule and quality seriously. Secondly, much attention should be paid on the trench verticality directly affecting on the subsequent excavation and water precaution. The trench verticality mainly depends on the trenching machine operator's management of trench quality and the pitch metering device in trenching machine. Besides, guide hole can also be adopted to control the trench quality. Finally, high quality of bottom-clearing replacement should be ensured lest too thick sediment makes coarse gravel in the bottom and grout in the top affecting the seepage precaution of diaphragm wall.In this thesis the examination data of diaphragm wall is deeply analyzed and the integrality of wall is determined through the wall lacuna and its position. It is found that the impermeability increases with the concrete strength and gradation.After the retaining treatment of the pit in this project using diaphragm wall, during excavation less deformation and seepage of pit and affection the buildings nearby the site on occur compared with the structure using retaining pile. Besides, there is little affection on environment around due to little noise in construction.