導どう坑こうどうこうじ字FuriganaMeanings1nounpilot tunnelcivil engineering›A small preliminary tunnel excavated to investigate ground conditions or to facilitate construction of a larger tunnel. Technical term used in civil engineering.導どう坑こうを掘ほって地ち質しつを調ちょう査さした。They excavated a pilot tunnel to investigate the geology.
