Seismic vulnerability assessment of gravity retaining walls based on performance

The retaining structures in the high earthquake intensity areas face the severe tests of devastating earthquake, and so far, the seismic vulnerability of gravity retaining walls has not been studied systematically at home and abroad. The increment dynamic analysis method is used in this study. Taking into account the uncertainty of seismic input, the PGA and displacement index are selected as the seismic intensity parameter and performance parameter, respectively, and the classification of the performance level of retaining walls is determined based on shaking table tests. The seismic response and seismic vulnerability of a 8 m-high gravity retaining wall are analyzed by applying FLAC^3D, and the fragility curves are derived to assess and compare the seismic performances of the retaining wall under different ground motions. It is shown that the displacement index exponentially relates to the PGA. When the PGA is less than 0.4g, the displacement index increases slowly. When it exceeds 0.4g, the displacement index increases quickly, and it is greatly affected by site conditions. When the PGA is less than 0.4g, the retaining wall keeps slight damage or good situation; when it is more than 0.6g, the retaining wall is damaged completely, and the probability of severe damage increases. When the PGA is more than 0.8g, the retaining wall suffers serious damage, and even collapse is caused, and reinforcing measures should be taken to maintain the stability of the retaining wall.