Abstract: With the rapid development of urban infrastructure and the further development of rail transit, the existing shield tunnels will inevitably be affected by the surrounding construction. The adjacent construction will cause the stress redistribution of the soil around the existing tunnels, thus causing additional deformation of the tunnels. The influences of ground surface surcharge on the deformation of the tunnels in service are studied in the three-dimensional spatially variable soil. The probabilistic analysis of the vertical settlement of the shield tunnels is investigated by using the finite element method and the random field theory. The influences of the scale of fluctuation and coefficient of variation on the probability of failure of the tunnel deformation are revealed as well. A simplified equivalent deterministic analysis method is proposed based on the random analysis results. The conclusions provide a simplified method for considering the spatial variability of soil parameters in similar engineering problems.