Monitoring And Numerical Analysis And Research Of Influences Of The Surrounding Environment Near A Deep Excavation In Tianjin

Due to more and more tense contradiction of land resources, the construction ofhigh-rise buildings and the development of underground space has become adevelopment trend of the city in the21stcentury, resulting in a large number of deepfoundation pit engineering, and its scale and depth increasing. Deep excavations inthese cities are generally in a rather complicated engineering environment, surfacebuildings standing in great numbers, underground pipelines densely covered, roadtraffic crowded, construction site narrow, and condition complicated. For thegeological conditions of weak formation and rich water in Tia njin, the difficulty ofdeep foundation design and construction is extremely great, so it must ensure thestability of the excavation and safety of the environment.Based on deep excavation of the first period of Tianjin hospital renovation andexpansion engeneeeing, this paper discusses the various influencing factors of deepexcavation to surrounding buildings, using composite methods of theoretical analysis,on-site monitoring and numerical simulation. Treating the surrounding soil, adjacentbuildings and deep foundation as a whole, deformation laws of surrounding buildingsin the influencing factors are further studied. This paper mainly includes the followingseveral aspects:1. In this paper, the characteristics of deep foundation pit retaining system anddeformation mechanism of deep foundation pit are analyzed, and the influences ofdeep excavation to adjacent buildings are introduced.2. According to the design scheme and construction monitoring program ofretaining structures of Tianjin hospital deep foundation pit, on-site monitoring iscompleted and variation of surrounding surface subsidence and building deformationwith the staged construction of excavation is analyzed.3. MIDAS/GTS, a large geotechnical finite element numerical simulationsoftware, is used in this paper. Considering the joint action of retaining piles andinternal support, a three-dimensional numerical model is established and thesimulation of deep excavation step-by-step construction process is completed. Inaddition, the simulation result is compared with the monitoring result. 4. By changing the design parameters of the retaining structures and internalsupport, using numerical simulation, the variation trend of surrounding surfacesubsidence and building deformation is calculated and analyzed to study thedeformation laws of surrounding surface and adjacent buildings in all influencefactors.Through the research of this paper, some meaningful conclusions are received,which can provide the reference for determination of design and construction ofsimilar deep excavation and protection of the environment.