应用于复杂地层锚索孔施工的机具--潜孔锤跟管钻具和投球式反吹接头的使用
응용우복잡지층묘색공시공적궤구--잠공추근관찬구화투구식반취접두적사용
MECHANICAL FACILITIES APPLYING FOR COMPLEX STRATA ANCHOR LINE OILLET CONSTRUCTION