ANALYSIS OF SURFACE MOVEMENT IN ADVANCING SHIELD INTERCHANGE TUNNELS

It is an important phenomenon that in constructing theinterchange tunnels in soft soil by shield, the surface will riseup when a tunnel is advanced over another nearby built tunnel, even ifthere is no under-excavation or over-injection of slurry in the course.A formula for the surface rise is presented based on the theory ofelasticity to explain the phenomenon, and a mathematical model toevaluate the entire movement of the surface in construction of theinterchange tunnels is established by combining the present formulawith Peck's formula for the surface settlement. The case of HuangpuRiver Sightseeing Tunnel advanced over Shanghai Metro Line No.2 isstudied, and the model gives results in a good agreement with thein-situ data.