建設現場におけるミリ波レーダーを用いた浸水検知に関する実験的検討
建設工事では, 豪雨による建設現場外への濁水等の流出を防ぐため，集水した雨水の排水等の対策を講じる。また豪雨予報時は安全管理の観点から工事関係者による対策や危険個所の巡視が行われる。本研究では，巡視の代替手法として，ミリ波レーダーにより浸水の有無を検知することを目的に，ミリ波レーダーの検知性能および設置等の諸条件を明らかにする「基礎実験」と，建設現場の浸水を想定した環境下で検知性能を検証する「実証実験」を実施した。その結果「基礎実験」では，浸水範囲内のミリ波レーダーの反射強度が弱くなることで，浸水の境界位置を把握できることを確認した。建設現場の調整池と仮排水路で実施した「実証試験」では，水面の擾乱でミリ波レーダーの反射強度と相対速度が変動し浸水を検知できること，検知可能範囲はミリ波レーダーから数メートルであること，反射強度と相対速度の併用で検知感度が向上することを確認した。
キーワード：ミリ波レーダー，浸水検知，反射強度，建設現場，安全管理
＊１ 技術センター 社会基盤技術研究部 水理研究室
＊２ 技術センター イノベーション戦略部 技術開発戦略室
＊３ 土木本部 作業所業務推進センター作業所支援室
Experimental Investigation for Flood Detection on Construction Sites Using Millimeter-Wave Radar Systems
At construction sites, stormwater collection and drainage measures are taken to prevent contaminated water from flowing out of the construction site. When heavy rain is forecast, construction personnel take safety measures and patrol the construction site for the purpose of safety management. In this study, two types of experiments were conducted with the aim of detecting the occurrence of flooding by using a millimeter-wave radar system, namely, "Fundamental Experiments" to evaluate the detection performance of a millimeter-wave radar system and its installation and other requirements and "Applicability Experiments" to verify the detection performance under assumed conditions at a flooded construction site. The Fundamental Experiments confirmed that the boundary of the flooded area can be determined because the reflection intensity of millimeter radar waves becomes weaker in the flooded area. The Applicability Experiments, conducted at a regulating reservoir and a temporary drainage channel at a construction site, confirmed that (1) the millimeter-wave radar system can detect flooding because the reflection intensity and relative velocity of millimeter radar waves fluctuate due to disturbances on the water surface, (2) the detectable range is several meters from the millimeter-wave radar system, and (3) detection sensitivity can be improved by using both reflection intensity and relative velocity.
Keywords: millimeter-wave radar systems, flood detection, reflective intensity, construction site, safety management
*1 Hydraulic Research Section, Infrastructure Technology Research Department, Taisei Advanced Center of Technology
*2 Research and Development Strategy Section, Innovation Strategy Department, Taisei Advanced Center of Technology
*3 Construction Site Works Promotion Center Project Support Section, Civil Engineering Department