About the author:

1. CCCC Tunnel Engineering Bureau Co., Ltd., Beijing 100024, China; 2. China First HighwayEngineering Co., Ltd., Beijing 100024, China

Abstract:

The undercrossing construction of large diameter shield tunnel will cause the deformation ofsoil around the tunnel,which will lead to the settlement of existing roads or railways in the city. Based onthe reconstruction project of the East Sixth Ring Road in Beijing, this paper adopts the method of fieldmeasurement and finite element simulation to discuss the influence of shield tunnel undercrossingconstruction on surface settlement and deformation of existing railway subgrade by considering thehardening process of synchronous grouting slurry, aiming at the special risk source of shield tunnelundercrossing existing railway line. The research results show that with the excavation of the shieldtunnel, the settlement of the existing railway subgrade gradually appears, the settlement of the centralarea of the subgrade is the most significant, and the settlement on both sides is relatively small. With theincrease of synchronous grouting strength, the overall settlement and maximum settlement of the surfaceshow a significant downward trend. In the process of shield tunnel undercrossing, reasonable synchronousgrouting strength can be ensured,which can effectively control the settlement of surface and railwaysubgrade. The actual monitoring data of surface settlement are in good agreement with the simulationprediction results, and the established model is accurate and reliable.