Research On The Control Technology Of Deep Foundation Pit Surrounding Buildings Along The Yangtze River Under The Condition Of Long-term Precipitation

This topic on nanjing plum chau river-crossing tunnel connection- the axis of the underground transportation system and related engineering is one of the main auxiliary project of the 2014 young, mainly composed of river channel connecting cables, green plum state the axis of the underground transportation system and the axis of the youth Olympic plaza underground space of three parts. The mainline tunnel total length of1668 m; Binjiang avenue tunnel line line is 1258 m long; River channel connecting plum state above, youth Olympic square below set underground large underground space, the total development area of 21000 m2. Research projects for the construction of area, plum chau river-crossing tunnel connecting J1- J5 area, including the mainline tunnel span 1668 m, 1603 m ramp. The area is mainly for strip foundation pit, the biggest excavation depth of 27.5 m, the largest excavation width 50 m. Structure according to different excavation depth, slope, were used respectively to SMW pile,borehole pile + three-axis mixing pile high pressure jet grouting pile and stop water heavy curtain underground continuous wall + high-pressure rotary jet grouting pile the forms in water. Except the B2- J1 area has a hydraulic contact part of the inside and outside the foundation pit retaining structure partition of foundation pit, the rest are "hanging" retaining structure, the groundwater in the pit inside and outside has hydraulic connection.This project is located in the nanjing Yangtze river, for the first phase of the river channel, nanjing plum state. The project area humid climate, abundant rainfall, rainfall time is long, the Yangtze river, such as the connection surface water and groundwater is better, in the same of groundwater recharge function; In the formation of regional groundwater supply plays an important role. According to geographic information, and the survey results, according to the lithology of aquifer, buried conditions and groundwater conditions and hydraulic characteristics, can be divided into loose rock pore water and clastic rock pore water. Loose rocks can be divided into the pore water and pore water pore confined water. In the confined water is mainly distributed in the upper bedrock loose bed, its sediment formed a dual or multiple structure, fine coarse, at Yellow River silt soil and clayey soil, covering with water directly in the Yangtze river area is same.Deep foundation pit precipitation for a long time under the condition of the surrounding buildings settlement control technology research. Reference domestic literature of deep foundation pit construction on the surrounding buildings settlement control study, studied in deep foundation pit construction along the Yangtze river on the surrounding buildings settlement control theory, studies the partition precipitation technology on the surrounding buildings settlement control effect. And relying on the project, using the partition precipitation technology in large, deep foundation pit partition precipitation technology to save costs, reduce the settlement of surrounding is studied. Under the geological conditions of deep foundation pit of large span tunnel hasnot been as reference for similar projects. The application of underground tunnel in nanjing youth Olympic axis will fill in a gap in the application of deep foundation pit construction along the Yangtze river, through the research to the similar engineering construction accumulated valuable technical reference and construction experience.This topic research is in view of the river channel connecting nanjing plum state-youth Olympic axis connecting underground traffic system construction project of specific engineering problems, and on the construction technology applied to engineering under complex geological conditions, on the basis of comprehensive research results at home and abroad, through the field test, numerical simulation and theoretical analysis, the study of complex geological conditions of all kinds of construction technology of large underground control project of safety, reliability and economy. Solve the problem for the project, construction technology of large underground hub project is scientific and economic analysis, to ensure safety, economy,and this project for construction at the same time, in a reliable way to provide a basis for engineering in the future similar project and design experience, for its further promotion in the project under complicated geological conditions of super-large city underground project construction technology applications to provide practical and theoretical basis,has significant economic and social benefits.