Corruption prevention device of propulsion jack in jacking method

摘要

PROBLEM TO BE SOLVED: To prevent the damage of a propulsive jack by a method wherein a sudden pressure change is detected by a pressure transducer arranged between a hydraulic unit for a traction jack and a console panel, a hydraulic unit for the propulsive jack is controlled on the basis of the pressure fluctuation data, the propulsive jack is opened and an impact is absorbed. ;SOLUTION: A pressure transducer for a propulsive jack 2 has an operating mechanism controlling the expansion and contraction and neutralization of the propulsive jack 2 while a pressure transducer 15 is disposed between a hydraulic unit 16 for a traction jack 6 and a console panel 17. The pressure transducer 15 detects a pressure fluctuation data immediately before the lowering of an oil pressure value from the traction jack 6 to the hydraulic unit 16 after the oil pressure value reaches a set maximum value. When the traction operation of a caisson 1 is started by the traction jack 6, an operating valve 22 is controlled at the place of an anti-shock on the basis of the pressure fluctuation data. Accordingly, when a tail-section caisson starts a sudden advance by operating the fraction jack 6, the propulsive jack 2 is brought to an open state, and an impact is absorbed.;COPYRIGHT: (C)1998,JPO