Abstract：Based on the method of effective stress analysis using a multiple shear plasticity model and the concept of liquefaction front，numerical modeling for deformations and dynamic earth pressures acting on the shallow duct-type reinforced concrete(RC) structures subjected to earthquake motions is presented. Moreover，the change rules of the relative displacement between the underground structures and liquefiable soils，dynamic earth pressures acting on the sidewall of RC structures，shear stress and excess pore water pressures in liquefiable soil during earthquake for the cases with a crest input motion of 0.85 g are further investigated. The results indicate that the values of deformations and bending moments，curvatures of RC structures increase with the level of input motions. And plastic yield area firstly occurs on the corners of structure and expands to other areas. The interaction factors in liquefied models with strong motions are less than those of non-liquefied models with a motion of 0.1 g. The values of relative displacement between ground and structure increase sharply up to a stable value after the soil is liquefied during earthquakes. The maximum and residual values of dynamic earth pressures acting on sidewalls increase with shaking. However，the growth is not a simple linear relationship with the input motion. On the contrary，the shear stresses acting on the top and the bottom slab，and the horizontal effective stresses acting on sidewall decrease sharply when the soil is liquefied. These results provide the foundation and references for the seismic design of shallow underground structures in the liquefiable soils.
