Monitoring And FLAC3D Simulation Study Of Deformation Laws Of Excavation In Metro Station In Hefei Wangjiang Road Station

With the prosperity of China's economy and the prosperity of science and technology,the deep excavation has become the mainstream of today's underground project,and subway station is its outstanding representatives.Therefore,how to ensure security and stability in deep excavation,it will certainly be the focus of our concern.How to have a scientific and effective calculation and analysis in deep excavation,which is the key to guarantee the smooth progress of the underground engineering,and it has great practical significance to the excavation.The design and construction of pit will certainly be the core among of the whole project,and the project cost which account for a large proportion with regarded to the metro station design.On the one hand,it mainly includes how to excavate in pit design and design issues in the envelope,on the other hand that the construction which were accompanied throughout the excavation,and because the subway project is generally the deep excavation and under the ground which belong to the hidden underground works,thus,it puts more high demand on how to have a informational construction.This article comes to the main research results by analyzing principle,monitoring the data and simulating by the FLAC3 D together based on the actual engineering background of Line 3 of Hefei Wangjiang West Road subway station,which as follows:(1)This article focuses on the key factors which can be related to the security and stability of Deep Foundation: the appropriating of engineering and hydrogeological conditions,the reasonable of deep excavation in the design and construction,the forces of the foundation and the overall problem of seepage pit.In addition,the deeper reason of the pit deformation can be specifically reflected to three aspects: uplifting in the bottom of the pit,deforming in the wall and the surface subsidence which is especially the most important factor in deformation of deep foundation,and it is the most important feature.(2)To select its selection as well as the design which contains the specific form of the envelope selection and support system in the envelope of the Hefei Deep Station Foundation by selected and compared the plan of envelope in the deep foundation pit,and it highlighted the specific features of bored pile and steel pipe support systems.(3)Depending on the actual situation to choose the appropriate and feasible construction monitoring program,which includes an arrangement for monitoring points and monitoring instrumentation choice.It is demonstrated in three aspects that the analysis of Steel support shaft forces changing,the analysis of Vertical settlement around the surface and the horizontal displacement variation on the top of the pile by analyzing the informational monitoring results of the deep foundation supporting structures,It can be concluded that the steel support has a certain effect on the deformation of the foundation itself and has limiting effect.Also,it can not be neglected for the horizontal displacement on the top of pile,and the vertical settlement around the surface also has its own characteristics.It shows that it has the practical value of the monitoring settlement or not mainly depends on the factors which the article said.(4)We can find a basic law that the change of horizontal and vertical displacement in the deep foundation by simulated and analyzed the excavation and the processes about the Hefei Wangjiang West deep foundation by FLAC3 D.It has similar conclusions among the calculated value and actual value of the horizontal displacement of the pile,especially their tendency.In addition,the foundation uplift mainly transited from middle to both sides.From top view,it is reasonable and feasible in simulating the deep foundation with FLAC3 D by the theory and reality.