The seismic coefficient suggested in the present Specifications for Seismic Design of Hydraulic Structures (DL5073-1997) is suitable for earth-rock dams lower than 150 meters. While at the present time

many earth-rock dams to be constructed are higher than 150 meters. Compared with low dams

high dams get less constraint from stiffness of foundation

and its natural vibrating period becomes prolonged. During the seismic response

high order naturalvibrating period gets more opportunities to coincide with the seismic predominant period

and the vibrations of high orders are easily to be activated and amplified

which result in the seismic acceleration distribution is somewhat different from low dams. With the finite element method

the seismic acceleration distribution of high earth-rock dams is analyzed. The figure of the seismic coefficient of earth-rock dams higher than 150 meters is put forward. Based on the above analysis

further research of the slope seismic stability of earth-rock dams higher than 150m is made. The conclusion is

with the decrease of the seismic coefficient in the dam body

the critical value of safety factor of the dam slope increases.