A new approach based on the limit analysis upper bound theorem is proposed to study the seismic stability of earth-rock dams. First

according to the upper bound analysis

a perfectly plastic soil model is assumed with an associated flow rule. Then

the dam slope is divided into horizontal slices with regarding the sliding surface as an arbitrary surface. In order to obtain the maximum anti-seismic capability of dams and the corresponding sliding surface

the multivariate function is established by the energy-work balance equation and optimized by intelligent algorithm. For the study of the influences of shear strength parameters and horizontal slice number on the maximum anti-seismic capability and the sliding surface

the new approach is applied to a typical earth-rock dam with core wall. It is shown by the results that the horizontal slice number has a great influence on the sliding surface but a small influence on the maximum anti-seismic capability. When the horizontal slices achieve a certain number

the maximum anti-seismic capability of dams is ultimately a stable value. Meanwhile

the shear strength parameters of the rockfill materials have a great influence on the maximum anti-seismic capability. Compared with the limit equilibrium method the result illustrates the correctness and feasibility of the proposed method.