According to the theory of fluid mechanics

considering liquefied soils as fluid

which analyzed the dynamic field by vector symbolic operation method and solved the analytical solution of dynamic field. It is used to analyze hydrodynamic characteristics of liquefied site by finite element method of ABAQUS/CFD; and the numerical solution of the dynamic field is calculated by the basic flow control equation. The results show that underground structure suffers pressure drag caused by surface pressure and frictional resistance caused by shear stress when liquefied soils flow in lateral. The flow velocity of liquefied soils around the tunnel is very small; but there is a velocity strengthening region below the tunnel structure. The analytical solution of the theoretical calculation is greater than the numerical solution of the finite element method; but the distribution of the overall trend is basically the same. The stress field near the tunnel structure is more intensive; and the stress distribution is mainly distributed in head position of liquefied soils.