Distribution of ground displacement field owing to two overlapped shield tunneling interaction

Considering the interaction of overlapped shield tunneling,the boundary element method was applied to analyze the ground displacement distribution and interaction between two adjacent tunnels in three typical situations.It was shown that the maximum displacement occurred on the tunnel axis when one tunnel was excavated,while the maximum value happened near the shallow tunnel and between the area of two tunnels when two adjacent tunnels were excavated at the same time.The tendency of deformation of deep stratum was consistent with that of the shallow stratum,but the settlement of deep stratum over the tunnel was far larger than that of the shallow stratum.The embedded depth and relative location of two tunnels severely affected the displacement field.