Numerical Simulation Analysis Of Deep Foundation With Pile-anchor Structure In Deep Thick Sand Layer

Deep foundation pit project is a comprehensive engineering, which is constrained by hydrogeological conditions, surrounding environment, supporting structure and many other factors. All above makes it strong regional. Once there are some accidents during the process of deep foundation pit digging, it would not only endanger the foundation pit, but also likely to damage the surrounding buildings,underground pipelines and other infrastructure, which may cause huge losses. So, it’s extremely necessary to select suitable foundation pit supporting scheme according to the characteristics of engineering to ensure the safety of the foundation pit engineering.This research is focused on the Zhengzhou Lifeng International building deep foundation pit engineering.(1) On the basis of summing up the he supporting design and construction of deep foundation pit engineering practice at home and abroad, this article mainly analysed the composition, characteristics, mechanism and deformation of the pile anchor supporting system of deep foundation pits.(2) In combination with the investing data and the surrounding environment,use F-SPW to design and calculate this feature of the deep sand layer in the engineering site, and put forward a bored piles and prestressed anchor combined support form. A monitoring scheme was given according to related specifications and engineering requirements, through the real-time monitoring, the top horizontal displacement, deep horizontal displacement, anchor cable stress and other factor were obtained.(3) A numerical analysis model which is based on Hardening-Soil constitutive model was established relying on Plaxis finite element numerical simulation software.The digging process of deep foundation pit was simulated under the condition of pile anchor supporting and the results was analyzed.(4) The simulation result, the field monitoring results and the results calculated by F-SPW were compared. All the results are similar, which indicated that he design of pile anchor bracing deep foundation pit are safe and reasonable, and Plaxis numerical model’s accuracy and rationality of the selected parameters are verified.The analyses provided references for similar support optimum design and excavation construction in this area. At the same time, the results showed that numerical simulation software Plaxis can be used for dynamic analysis of the foundation pit excavation, predicting the deformation under different working conditions and workstatus of the supporting system, and providing guidance to the construction combining with field monitoring.