| This paper discusses the utilization of fault tree for preventative maintenance of reinforced soil walls (RSWs). Generally speaking, earthworks are considered to stabilize with slow deformation with age if correctly designed and constructed. Just because there are deformations does not mean functional depression. Even if earthworks collapse, deformations often tend to progress slowly. If deteriorations can be detected at an early stage, collapse is preventable by appropriate measures. Maintenance method to detect deteriorations at early stage by daily inspection is reasonable for a huge number of earthworks.In Japan, RSWs are often used behind bridge abutments in late years. Bridges are often built at crossing points which are difficult to create a bypass. Damages of RSWs behind bridge abutments have a high impact on road traffic. In fact, some differences in level between bridge abutments and RSWs caused road closures in 2011 Great East Japan earthquake. And RSWs are more difficult to repair than embankments. Therefore, maintenance of RSWs behind bridge abutments needs to make the shift to preventative maintenance.Deterioration scenarios are essential to shift to preventative maintenance. Each deterioration scenario is a deterioration process which is the linkage among events. And a tree diagram which indicates interrelation among multiple deterioration scenarios is a fault tree. The fault tree of RSWs was built on the basis of 916 deterioration events. The deterioration events were detected by a visual inspection for national road in Japan in 2013. The fault tree was validated by previous damages for 14 years between 1999 and 2013. The presence or absence of inspection methods which can detect the hidden deteriorations in daily inspections is important to make the shift to preventative maintenance. The fault tree discloses some difficult deteriorations events to detect by a visual inspection. |
