Abstract
73 slope disaster cases on national roads occurred between 2008FY and 2010FY were analyzed to reveal features of recent slope disasters and notice points for disaster prevention. These disaster cases contain both disasters occurred by heavy rainfall and disasters under the condition of small rainfall. It needs detail analysis of pattern and cause of each disaster for suitable countermeasures. Patterns of disasters revealed by analysis, for example, are as follows: collapse or deformation at the sites where deformation or past disasters have been recorded, collapse or deformation of cut slope consisted of soft earth (highly weathered earth, earth of recent geological age, etc.), collapse or debris flow at small valleys, and collapse at the sites where surface water concentrates by road or channel, etc. Based on these disaster cases, we summarized notice points for slope disaster prevention on roads.
