Abstract：The reinforced soil structures are employed widely due to the technical and economical advantages in static state. In addition，the use of reinforced soil structures in seismic areas has been increased due to their excellent seismic stability，but the vertical seismic effects on the stability of reinforced soil structures are seldom considered. The effects of horizontal and vertical pseudo-static forces on reinforcement soil slopes are investigated by applying the kinematical approach of limit analysis theory. In particular，the effects of the distribution mode of the reinforcement force on the seismic stability of reinforced soil slopes have been investigated as well. Both rotational failure surface and planar slip surface are considered and each analytical expressions is derived to calculate the reinforcement force，which are required to prevent failure and the critical height of reinforced slopes subjected to earthquake loading. The upper bound solutions for each analytical expression are presented by applying a nonlinear sequential quadratic programming algorithm. From the contrastive analysis，it is shown that the solutions presented here agree well with available predictions both in simple static state and dynamic state. All of the seismic force，the material characteristic of soil and the gradient of slope have significant effects on the seismic stability of reinforcement slope. The effect of vertical seismic acceleration on the stability of reinforcement slopes is significant，especially for steep slope，poor quality filler and high value of horizontal seismic acceleration，which means that ignoring the effect of the vertical seismic acceleration could result in an unsafe design. Besides，some suggestions for engineering practice are proposed.
