WIDENING EXCAVATOR AND SUPPORT PILE CONSTRUCTION METHOD FOR EXISTING STRUCTURE

摘要

To provide a widening excavator capable of widening a previously excavated hole efficiently with a simple structure.SOLUTION: The widening excavator comprises: a drilling rod 11 which has an outer tube 17 and an inner tube 18 provided in the outer tube 17 so as to be elevated and lowered; a rotation drive mechanism 12 which rotates the outer tube 17; an elevating/lowering drive mechanism 13 which elevates and lowers the inner tube 18; a plurality of expansion/contraction bit blades 14 in which base parts are rotatably attached to a distal end of the outer tube 17 at intervals in the peripheral direction, and which are movable between a contracted position in which the distal end is lowered and an expanded position in which the distal end is elevated; an expansion/contraction operation member 15 which is provided at a distal end of the inner tube 18 protruding from the distal end of the outer tube 17; and a link 16 which connects between each of the expansion/contraction bit blades 14 and the expansion/contraction operation member 15. The expansion/contraction bit blade expands and contracts via the link 16 as the expansion/contraction operation member 15 is elevated and lowered as the inner pipe 18 is elevated and lowered.SELECTED DRAWING: Figure 1