| The paper took the underground transportation project(East Square)project of Zhengzhou Comprehensive Transportation Hub as the background.The finite element numerical simulation and field monitoring method were used to study the deformation of the metro tunnel caused by remove the soil above the surface and the approaching excavation.The Winkler foundation model was introduced into the additional stress formula at the tunnel axis under uniform load to predict the maximum settlement of the tunnel.The grouting test is carried out on site to optimize the grouting scheme.The main work and achievement of this paper were as follows:(1)Based on the literature and engineering geology,the paper studied the uplift and deformation character of the metro tunnel under the dumped soil above the surface,and derived the tunnel settlement calculation formula suitable for this project and predicted the maximum settlement of metro tunnel.The settlement value compared with the monitoring results.(2)Analyzed the metro tunnel heaving and convergence deformation during the removal process of the dumped soil by finite element software,and the simulation parameters were corrected with reference to similar engineering and literature.and set up various construction methods to remove dumped soil.The effects of dumped soil accumulation quantities and the soil removal order were studied.The safety,rationality,economy and efficient construction plan were recommended and used to guide the construction.The construction plan was verified by the field monitoring and measurement data.(3)Against the deformation of the metro tunnel and control its' deformation increase,ensured the safety of pit construction,research the technical parameters by the field grouting test,such as mixture,grouting pressure,number of grouting hole,diffusion radius of grout and grouting technology.Analyzed the monitoring data of the tunnel shows that the method of cement-silicate grouting can be achieved the good effect for reinforcing the soil and controlling convergence.(4)After the on-site monitoring data was graphically processed,the cumulative ridge deformation and cumulative convergence deformation curve of the tunnel were obtained.The reinforcement measures taken for the tunnel deformation during construction were analyzed according to the obtained deformation map,and the simulation model was established using the finite element software Midas GTS/NX.The model simulates the construction and verifies the reliability of the construction response measures in combination with the simulation results to guide the on-site construction and provide experience for subsequent similar projects. |
PDF Full Text Request