Failure analysis of an 80m high geogrid reinforced wall in Taiwan

摘要

During the magnitude 7.3 Chi-Chi earthquake that occurred in Taiwan on September 21st 1999, an 80 m high geogrid reinforced wall failed. The failure site is located about 20 km from the epicenter, and peak ground acceleration at the site is believedto have been in excess of 0.5g during the earthquake. The GRS wall used geogrids as reinforcement and the backfill was an on-site lateritic soil. Because geosynthetic reinforced soil (GRS) structures have generally performed well under seismic conditions, this failure offered a rare opportunity to investigate the ultimate seismic behavior of a full-scale GRS structure. A series of field observations and measurements were made in an attempt to establish the possible failure mechanisms of the wall. Laboratory experiments were conducted on the soils and geosynthetics to obtain appropriate material properties. The results of these studies and the postulated failure mechanisms provided some valuable lessons learned from the failure.