Digging drilling machine null in all casing construction method

摘要

PROBLEM TO BE SOLVED: To continue excavation operation smoothly. ;SOLUTION: Crushed-rock recovery boxes 15a-15d recovering crushed rocks crushed by percussion crushers 6a-6d are installed in the lower section of an inner excavator body 5 for an all-casing method. When the percussion crusher 6a is driven, gravel-shaped excavated debrises are not deposited at an excavation front section because heavy crushed rocks in excavated debrises (the heavy crushed rocks and light soil and sand and dust) are recovered into the crushed- rock recovery box 15a set up to the lower section of the inner excavator body 5 through a branch discharge pipe branched from a discharge pipe, and excavation operation is continued smoothly.;COPYRIGHT: (C)1997,JPO