HYDRAULIC BALANCE TYPE FORCE FEED EARTH DISCHARGING SHIELD CONSTRUCTION METHOD AND SHIELD EXCAVATOR

摘要

PURPOSE:To contrive stability in workability by supplying a hydraulic pressure higher than the groundwater level to a hydraulic chamber provided at the rear of a cutter head for excavating earth while stabilizing the working face, and by converting the earth and sand excavated into a high density slurry, so that it can be forcibly discharged towards the rearward. CONSTITUTION:A cutter head 5 on which a large number of cutters are projected is provided on the front of a shield body 1, and also a water supply pipe 10 is connected from a water supply tank 12 to a hydraulic chamber 1d formed behind the head 5, via a water supply pump 13. Further, to the chamber 1d, a closed earth discharging device 9 is connected via a screw conveyor 8. Thereby a hydraulic pressure higher than the groundwater level is supplied to the chamber 1d via the pipe 10 for stabilizing the working face, and also the shield jack for driving the body 1 forward and the device 9 are controlled, so that the earth and sand taken into the inside of the chamber 1d through the head 5 is reserved as a high density slurry of 50% to 90% by volume, and then is compressed and forcibly discharged towards the rearward. Thus, a stable workability can be provided.