Settlement Analysis And Control Of Subway Tunnel Sheild Tunneling Construction

In recent years,metro construction has been developing vigorously all over the country,and shield method for tunnel construction has begun to reach maturity.The character of metro construction determined that tunnel routes usually set under main roads in cities and surrounded by large numbers of buildings.Tunneling process would easily cause uneven degrees of building subsidence and incline.This would damage buildings or even endanger citizens' lives and properties.Therefore,the simulation analysis about the condition of shield construction when tunneling under buildings and the research about the construction parameters are significant for improving shield method and preventing risks.This report will take the example of the engineering project about seventh sections in Nanchang metro line two Hong-Xin shield zone to analyse how to control building subsidence and incline led by shield method,and will mainly focus on designing the parameters of shield tunneling and constructing pre-reinforcement measures for buildings around tunneling area.Also,verification implementation demonstrates that the measures employed in this project are effective.For buildings around shield tunneling area,information about building structure,types,foundations,relation with metro tunnels and so on have been particularly sorted out at the beginning of this report.Based on the safety authentication of building structure,numerical simulation methods have been employed for assessing the risks when shield tunneling under buildings,valuing the subsidence and incline degree of non-reinforced buildings led by shield tunneling.Thereafter,related risks level will be rated for ensuring the range of buildings that need to be reinforced.According to the character of those pre-reinforced buildings includes building structure,foundations and relation with tunnels,numerical simulation methods will imitate the process of shield tunneling under buildings,do comparative analysis based on the data from building subsidence and incline before and after reinforcement,judge the effectiveness of pre-reinforcement measures on controlling building subsidence and then establishing the best pre-reinforcement solutions for each building.Moreover,this report represented the field-test research about conducting more difficult static pressure grouting in the process of reinforcement construction.The research solved the problem of static pressure grouting into deep layer with wide-angle and inclined hole.These provided technique support for pre-reinforcement solutions.Furthermore,this report stated that when tunneling in water-rich sand stratum,different shield tunneling parameters have been projected for passing under buildings which have various risk levels.Also,in order to reach the best effectiveness on managing subsidence,dynamic adjustment carried out on the basis of monitoring data.Finally,the comparison between the monitoring data from construction process and the data from numerical simulation analysis found that the objective of controlling subsidence has been reached.Also,the comparison demonstrated that the design of building pre-reinforcement measures and shield tunneling parameters are effective and rational.