FAILURE OF REINFORCED EARTH AS ATTACKED BY TYPHOON NO. 23 IN 2004

摘要

In October 2004, Typhoon No. 23 attacked western part of Japan, causing severe damage to infrastructures over a wide area in Kansai. In the early morning on 21st October, failure of a large Reinforced Earth wall with the maximum height of about 23 m took place in a mountainous area in Yabu city, Hyogo Prefecture. The debris flow from the reinforced embankment attacked a warehouse at the foot of the mountain, however, no casualties were reported. Immediately after the incident, an investigation committee was set up with missions to investigate the causes of this catastrophic embankment failure and also to examine any possible occurrence of further slope disasters in this region. In this paper, the failure mechanism by considering causes of the slope failure is discussed based on the results of stability analysis performed using laboratory and field data, coupled with topological information and the rainfall data. Some lessons learnt from this unique case study are described with reference to the design and construction of Reinforced Earth wall in rainy mountainous areas, in particular.