Research On Field Monitoring Of Deformation Rule About Support Structure And It's Optimization In Deep Foundation Fit Engineering

The excavation of deep foundation for station is always one of the key problems in the subway construction. It is most valuable to research the deformation monitoring and its optimum design. The main jobs are as follows:Based on the Olympics subway in Beijing Datun road bus stop deep foundation pit engineering, the deformation laws and failure mode of retaining structures are researched by theoretical analysis and in-situ monitoring.In this way, the basic factors that influence the stability of deep foundation fit are concluded; The design plan of retaining structure and in-situ monitoring plan of deformation are given, and the in-situ monitoring work is accomplished.Through the analysis of monitoring data, the laws of deformation of steel supports, horizontal displacement of piles, and perforce of anchor wires are analyzed. Meanwhile , a numerical simulation by FLAC3D is accomplished. A consistency between the result of numerical simulation and of the survey in-situ is reached.Based on the survey data in-situ, an optimization design about retaining pile and prestressed anchorage is studied .By way of optimization method, the ratio of reinforcement in piles as well as the cable are redesigned. Meanwhile , a three dimensional model in FLAC is builded to study the regulation of deformation in deep foundation fit . In this model , interaction among the retaining piles ,brace and cable in considered ; by way of simulating the process of construction on site , deformation rule of retaining structure is accomplished.