| 摘要 |
<p>PURPOSE:To reduce a construction cost, by a method wherein, after a truck having a drill is supported to the ceiling of a pneumatic caisson working chamber by the dint of a reaction force to a bedrock to be excavated, the drill is caused to act on the bedrock to be excavated with the aid of a hydraulic jack, and thereafter the truck is advanced for drilling or crashing. CONSTITUTION:After, with a hydraulic jack 5 actuated, the rear part of a truck 11 is floated to bring a rubber wheel 8 into firm adhesion to a working chamber ceiling 15, the forward end of a ripper 19 is slightly penetrated in a bedrock 16 through actuation of the jack 5 and a hydraulic jack 6. Rubber wheels 1 and 8 are released from braking, the rear end of a thrust jack 7 is forced into contact with a reaction force receiving metal 13, a jack 7 is expanded, and the truck 11 is moved forward to drill the bedrock 16 by a distance equal to the one full stroke of the jack 7. The jack 7 is contracted to force the rear end of the jack 7 into contact with the reaction force receiving metal 13 preceded by the present reaction force receiving metal 13, the jack 7 is expanded again, and the bedrock 16 excavated by a distance equal to one full stroke.</p> |
