Abstract
The amount of deformation in the slope collapse represents the index of quantitative evaluation, and the Newmark method is one of the recognized evaluation methods applied for the embankment. There is no seismic response acceleration of the embankment but the ground acceleration that shows seismic force on the slide clod with the usual Newmark method. However, the embankment itself seismic response properties weren′t taken into consideration by this perspective, so the modified Newmark method, with the seismic response character added by modeling the embankment with the SDOF model was proposed. Therefore we must compute the natural frequency of embankments accuracy and easily in the seismic design. So, in this study, a simple calculation method of the natural frequency in consideration of the shape of embankments was derived by using Rayleigh′s method, the validity of the proposed formulation in comparison of the result of shaking table tests and theoretical calculation.
That was examined as the results, the natural frequency of embankments can be computed accuracy and easily from the proposed method. And, we indicated that the result of calculation of the seismic permanent displacement of embankments varies in the adopting method of computation of the natural period with the modified Newmark method very greatly.
