필댐 월류피해 및 원인에 대한 지반공학적 관점의 고찰

초록

This paper presents a field investigation, data collection, and analysis of an overtopping event at a medium-sized agricultural earth fill dam (completed in 1975) that experienced overflow during a typhoon in September 2023. The overflow caused downstream slope erosion around the embankment core and prompted evacuation warnings for downstream residents. Ongoing rainfall and concerns about further embankment collapse limited the opportunity for detailed geotechnical testing during emergency repairs. Therefore, this study analyzed on-site visual and photographic records and dam water-level measurements taken immediately after the overflow, along with existing research data documenting pre- and postevent conditions. Results suggest that the combined effects of downstream slope vegetation, grouting reinforcement within the embankment during repair, overflow velocity, and overflow duration likely contributed to preventing catastrophic failure under the emergency overflow. However, limited information prevented quantification of each factor’s contribution. The findings underscore that deficiencies in any single design or maintenance element could produce more severe damage and highlight the importance of faithful implementation of design, construction, and maintenance practices to mitigate overtopping risk.

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