방조제 해수유입 구간 탐지를 위한 전기, 전자탐사 적용

Abstract

To identify the possibility of seawater inflow through the surrounding of reinforced regions by sheet pile and cement grouting in embankment dike, we carried out small-loop electromagnetic and electrical resistivity surveys. We also monitored both groundwater levels and electrical conductivity variations with tidal variation in seven observation wells located inside and outside of reinforced region in order to analyze the relationship between them and support the survey results. To verify the applicability of electrical resistivity method, the electrical resistivities of compaction material of embankment dike were measured under conditions with dry, saturated by reservoir water and seawater. From the survey results, it was identified that seawater inflow regions were through both bottom and side of sheet pile. These results were matched well with electrical resistivity survey results performed before and after the grouting. From this study, small-loop electromagnetic and electrical resistivity surveys accompany with monitoring for both groundwater levels and electrical conductivity variations are revealed to be effective for identifying seawater inflow pathway through embankment dike.