SIMPLE EVALUATION METHOD OF SEISMIC SAFETY OF ROAD EMBANKMENT CONSIDERING SEISMIC RESPONSE OF EMBANKMENT

Abstract

 In the current seismic design, the safety of the road embankments is confirmed by comparing the analyzed sliding displacement with the allowable displacement. The sliding displacement is practically analyzed by the Newmark method. When the seismic response of the embankment is negligible, FEA is necessary to obtain the input acceleration (equivalent acceleration) to the sliding blocks. This study proposes a simple evaluation method of equivalent acceleration without conducting FEA, but with the simple analysis of SDOF model. The estimation method of equivalent SDOF system was proposed. With the proposed method, the sliding displacement which has the equivalent accuracy with the current seismic design can be estimated easily. Furthermore, the sliding displacement spectrum is proposed which express the effect of natural period, damping factor, yield coefficient and sliding coefficient of the embankment on the sliding displacement. Simple evaluation method of sliding displacement using the sliding spectra is also proposed.