Field Monitoring And Numerical Simulation Research On The IKEA Foundation Pit With Pile Anchor Supporting

In this paper,a combination of theoretical analysis,field monitoring and numerical simulation is adopted and deformation of support structure caused by deep foundation pit excavation,surrounding ground surface subsidence,displacement of deep soils,and change rule of surrounding road settlement are studied under the engineering background of deep excavation of pile foundation in Harbin IKEA,and the main research contents and results are as follows:(1)The deforming rule of deformation of support structure caused by deep foundation pit excavation and deep soil displacement and bottom heave are studied by three dimensional space model of foundation pit established by FLAC3D The results show that surrounding ground settlement caused by foundation pit presents a parabolic curve with increased distance from the pit wall,and that horizontal displacement of deep soil is increasing linearly with depth,thus resulting in skirting failure under the same working conditions in the excavation depth of 6m.Bottom heave whose middle part is big and whose boundary is small belongs to elastic heave.(2)The result on site monitoring shows that the maximum value reaching 16mm of horizontal displacement of pile top appear at the midspan of long side of foundation pit,and displacement of shade horn is smallest.By comparing numerical simulation and measured value,value of numerical simulation is greater than the value of monitoring,however,the two change trends remain consistent,therefore the supporting structure is reasonable.Axial force of anchor cable has loss of prestress after locking after a small range decreases and finally tends to be stable.(3)After the end of condition two,the maximum sedimentation value is 0.4mm on the north side of Fudan Road.The third stages of excavation is forecasted by unbiased grey model,and the result shows that the maximum of settlement is 1.1mm at the end of the third stage,which indicates that the impact of foundation pit excavation on the north side of Fudan Road is weak...