Numerical Simulation Andanalysis Of The Field Measurement Of Deep Foundation Pit Of A Metro Station In Zhengzhou

The national subway is in a high speed development stage, which has caused thekey issues in the engineering construction: environmental problems and geotechnicalproblems. Based on current research status and theory of space-time effect, took deepfoundation pit of the Tongbai Road Station of first line rail transport in Zhengzhou foran example, this paper has made the following research works:（1）Through reading numbers of literature and books, got familiar with thebackground, theoretical basis of current research status and theory of space-time effectof foundation pit at home and abroad. This paper also studied the design andconstruction methods when considering theory of space-time effect. The paperdeveloped a monitoring program of deep foundation pit of a subway station inZhengzhou. According to analyzing and sorting the monitored data of horizontaldisplacement, steel support axial force, surrounding buildings and surrounding groundsettlement of supported pile in each construction stage, this paper obtained some lawsabout deformation conclusions of building envelope.（2）Took GTS large-scale finite element analysis software as tool, formed surfacedomains according to pit plane model established by CAD and split pit plane. Based onsoil materials, and properties this paper made the gradual establishment ofthree-dimensional stratified excavated pit model based on Mohr-Coulomb yieldcriterion. Through the simulation analysis of horizontal displacement and groundsettlement of building envelope, which compared with the actual monitored data, thispaper analyzed of laws about deformation of deep foundation and illustrated the defectof the model. （3）Due to size effect when excavating foundation pit, its length, width and depthof foundation pit, can all result in changes of space characters such as displacement ofthe building envelope, ground settlement, bottom uplift, distribution of soil pressure andso on. Therefore, established the foundation pit ladder excavation model consideringspatial effect, and analyzed of laws about deformation of building envelope. Accordingto comparing and analyzing of results calculated in this paper with the actual measuredvalue, it shows that the foundation pit ladder excavation model considering spatialeffect can receive a better reflection of the actual construction conditions.（4）In the condition of other construction parameters unchanged, only changingthe excavation depth at support position of first and second floor, this article hasanalyzed the deformation of building envelope, and compared with the formersimulation results, it shows the impacts extent by changing excavation dimensions onbuilding envelope deformation and on entire foundation stability. Through thesimulation analysis of the deformation of building envelope under different excavationconditions, it came to a conclusion that the design of foundation pit structure can bedesigned according to considering the space-time effect.