MODELISATION 3D DU CREUSEMENT DE TUNNEL PAR TUNNELIER A FRONT PRESSURISE VALIDATION SUR LE METRO DE SHANGHAI

Abstract

The excavation of shallow tunnels in urban areas requires a previous evaluation of their effects on the existing constructions. In the case of shield tunnel boring machines, the different achieved operations are very complex to represent in a complete numerical simulation. Therefore the assessment of the tunneling-induced soil movements is difficult. In the case of shield tunnel boring machines, the different achieved operations is a highly three-dimensional problem of soil/structure interaction and are very complex to represent in a complete numerical simulation. Therefore the assessment of the tunnelling-induced soil movements is difficult. A three-dimensional simulation procedure, using finite differences code Flac-3D (Fast Lagrangian Analysis of Continua in 3 Dimensions), taking into account in an explicit manner the main sources of movements in the soil mass is proposed. It is illustrated in the particular case of the Yangtze River Tunnel of Shanghai for which experimental data are available and where the crossed soils are saturated and characterised by weak shear strength. The comparison of the numerical simulation results with the in-situ measurements shows that the 3D procedure of simulation proposed is relevant, in particular in the adopted representation for the different operations achieved by the tunnel boring machine (excavation, confining pressure, advancement, installation of the tunnel lining, grouting of the annular void, …).