EXCAVATION EARTH REMOVAL METHOD, PRESS-FITTING SUBMERGEMENT METHOD OF CAISSON, AND ENLARGED-DIAMETER EXCAVATION DEVICE

摘要

PROBLEM TO BE SOLVED: To improve in-take efficiency of excavated earth and sand into an earth-and-sand intake opening formed in a casing pipe.;SOLUTION: Three expandable excavation airfoils 3 are radially provided on the outer periphery of the casing pipe which is rotary-driven, and each of the excavation airfoils 3 comprises a fixed excavation airfoil 12 and a movable excavation airfoil 13. The movable excavation airfoil 13 is provided with an earth-and-sand forward returning plate 18 comprised of an upper plate 19 and an inclined plate 20, and the cross-sectional profile of the movable excavation airfoil 13 is shaped in a form having what is called a fogging amount α, namely, a forward-facing blade shape which is concave against the front side of the excavation-running direction. The earth and sand excavated by the excavation airfoil 3 is guided to the front of the excavation-running direction of the excavation airfoil 3 and to the side which is more upward than the position of an excavation blade 17, and is taken into the casing pipe and removed.;COPYRIGHT: (C)2008,JPO&INPIT