Research On Deformation Law And Control Method Of Operating Subway Station Structure Influenced By Close-contact Undercrossing Rectangular Tunnel

In recent years,as the rapid development of metro industry,lots of newly-built subway projects have sprung up,and the phenomenon of tunnel passing underneath operating underground structures also becomes a common engineering problem.The existing structure,especially the operating subway station,has densely populated and heavy traffic characteristics,which leads to controlling the structure deformation and guaranteeing the operation safety have become a significant issue for relevant researchers.For such reason,based on the tunnelling project of Shenzhen subway line 7 passing through line 4 Fu-Min subway station(engineering has tiny interval zone and special tunnel geometry),the essay research on how newly-built tunnels impact on existing subway station by using theoretical analysis and numerical simulation method,and eventually propose follow conclusions.(1)Based on the stochastic medium theory,propose stratum deformation prediction model for double-rectangular tunnel undercrossing construction process,and make contrastive analysis of stratum deformation law influenced by different cross-section shape tunnels.Furthermore,discuss on the prediction method of undercrossing construction with zero-distance.(2)Utilizing two-parameter foundation model,derivate the bend differential equations of elastic beam under arbitrary additional load.And cooperate with stratum theory to forecast the deformation of subway station structure.(3)Based on the tunnelling project of Shenzhen subway line 7 passing through line 4 Fu-Min subway station,using two-phase analysis method,provide specific deformation prediction example of twin tunnels passing underneath existing metro station with zero distance,and research on value of relevant parameters.Moreover,make comparative study with monitoring data to verify the rationality of prediction model.(4)According to actual working condition and construction design of Fu-Min tunnelling projects,establish 3-D numerical model and make numerical calculation.Research on the deformation and force distribution regularity of structure,and make comparative analysis with monitoring data.In addition,study on the optimal controlling of structure deformation during construction process.By setting multiple control groups,discuss on the deformation control from aspects of excavation method,step length and grouting parameters.Eventually,propose rational suggestions for structure deformation issue during undercrossing construction.