Centrifuge modelling of effects of shield tunnels on existing tunnels in soft clay

With the rapid development of the subway network, the phenomena of shield tunnels going across the adjacent tunnels are becoming more and more common. The interaction between shield tunneling and nearby tunnels is more complicated than the ordinary shield tunneling in intact soil strata. Based on the project of Shanghai Bund Passage crossing Metro Line 2, the method of centrifuge modeling together with the field measurement is employed to study the effects shield tunneling on nearby strata and existing tunnels. In centrifugal model tests, the effects simulation techniques considering the unloading of excavation, ground loss and grouting are developed to analyze the longitudinal settlement of the shield tunnel and the existing tunnel induced by the shield tunneling. Besides, the deformation distribution and settlement curves of the existing tunnels during shield construction are studied by using the monitoring data.