Abstract: An excessive deformation is often occurred when a tunnel underpass the existing highway. This paper presents a case history of Shenzhen Metro No. 7 Line crossing the GuangzhouShenzhen Expressway. The tunnel excavation was numerically simulated and the deformation results were compared with the construction observation data. The observed settlement data indicate that the ground settlement has a normal distribution. For the double tunnel excavations, when the net spacing between the tunnels is smaller than one diameter of the tunnel diameter, the settlement through on the ground surface has a single V shaped other than W shaped. When the tunnel at the highway is not perpendicular, the eccentric pressure might influence the tunnel liners. The results also indicate that the full section grout can have a better control of the ground subsidence but grouting might also cause ground heaving. Combining the numerical analysis and the construction observation the ground deformation can be effectively controlled.

Key words: Numerical Simulation, Monitoring and Measurement, Underpass, Subway Construction