抄録
The framework of a methodology proposed by the authors to evaluate the permanent deformation of embankments due to earthquake motions is briefly presented first. In the proposed method, both static and dynamic stress analyses are performed by the finite element technique to determine the stress conditions of the finite elements in an embankment both before and during an earthquake. Based on the characteristic features of the dynamic stresses during earthquakes, static and dynamic stresses are applied to laboratory specimens to simulate the in-situ stresses as precisely as possible. The moduli of the soils used in the original static analysis are modified through softening parameters in accordance with the residual strain potentials of each element. Using the modified moduli, the residual deformation of the embankment is evaluated. The methodology is applied to two embankments in Japan which suffered severe damage during past earthquakes. The first case study gives a calculated permanent displacement as large as 1.81m, indicating considerable instability of the embankment which actually failed completely. In the second case study, the calculated settlement is 27cm, compared to the observed settlement of 21cm. Therefore, the results of the analyses show reasonably good agreement with the observed deformations of the embankments due to the earthquakes.
