Research On Key Technology Of Design And Construction Of Deep Foundation Pit In The Ming Dynasty

Along with the rapid development of China's scientific and technological progress and economy, demand for large buildings and underground engineering construction of each big city. The resulting project grow with each passing day with a series of problems, such as the maintenance of foundation pit structure damage caused by uneven settlement of surrounding buildings and environmental destruction. The excavation of deep foundation pit engineering construction plays an important role in the large buildings and underground engineering construction. Therefore, how to formulate the construction plan and the design parameters and the support form a scientific and reasonable, to ensure the security and stability of the construction process, minimize the impact on the surrounding environment, has very important practical significance.In this paper, based on the deep foundation pit project of Wuhan Tianhe Airport, this paper is based on the theory analysis and field monitoring. The main research contents are as follows:(1) Introduces the basic theory of deep Foundation pit construction, laying a good foundation for design of deep Foundation pit.(2) As the embedded depth of foundation pit retaining structure increase can effectively reduce the pit horizontal displacement of the wall as a whole, a more significant impact on the formation of horizontal displacement, the palisade structure there is a "critical depth", on the basis of increasing soil depth, impact on the surrounding basic remains the same, the critical value of this engineering embedded depth of retaining structure of 26 m. In the excavation of foundation pit, by setting the critical depth of retaining pile to avoid retaining pile horizontal move, to maintain the stability of foundation pit excavation and security, but also save engineering cost. But the palisade structure buried depth and the pit wall and the surrounding strata horizontal displacement has the close relation, and the settlement of surrounding environment influence is not obvious.(3) Digging the deep foundation pit monitoring scheme is given, and the retaining pile, the settlement and horizontal displacement of the slope, support concrete reinforcement stress, steel support axial forces and foundation pit water level monitoring project tracking, daily variation of the monitoring project and cumulative variance analysis compared with standard warning value, to ensure that the foundation pit construction safety.