Recently, many large earth-or rock-fill embnakments have been constructed in Japan. And it is an urgent problem to establish a reasonable method of designing these structures to resist earthquake forces.
　This woluld be more definetely explained by the following brief consideration.Firstly, the period range of main shocks of earthquakes in the harbour area in Japan could be estimated about 0.1 to 2.0 sec. Secondly, the natural period of vibration of a homogeneous and wedge-shaped fill-type embankment is giben by Dr.Mononobe as follows:
　T=0.026H√γ/Gg
　in which Tis the natural period of vibraion of an embankment (sec), H is the height of an embankment (m),γ and G are the unit weight (kg/m3) and the shear modulus (kg/cm2) of a fill material respectively, and g is the acceleration of gravity (m/sec2) Substituting γ=2,000 kg/m3 and G=900kg/cm2 (these would be average values for γ and G respectively) into this equation yields
　T≒0.012H
　From this relation and the above mentioned period range of earthquakes, it would be concluded that the natural period of vibration of an embankment with the height beyond 10 m is just in this period range and hence there is the fair possibility of occuring the resonance during earthquakes. This is the reason why the problem of designing large fill-type embankments to resist earthquakes is immediately　necessary.
　From this point of view, a series of dynamic field tests were carried out to　investigate the dynamic behaviour of model embankments. Also, the behaviours of homogeneous truncated wedges having visco-elastic properties under sinusoidal excitation are analyzed theoretically. Comparison of dynamic test results to the analytical results shows that both agree comparatively well.