EXCAVATION METHOD OF SMALL OVERBURDEN ZONE BY EARTH PRESSURE SHIELD MACHINE, AND PRESSURE CONTROL METHOD IN CHAMBER

摘要

PROBLEM TO BE SOLVED: To provide an excavation method for excavating a zone having a tunnel overburden depth of 1.0 D or smaller by employing a shield tunneling method without executing an assisting method.;SOLUTION: In a process of the execution of the excavation method, vertical earth pressure immediately above a working face is calculated based on a relationship between an overburden depth and weight per unit volume of the ground, and the interior of the chamber 5 is controlled so as to be set at set pressure P0 that is larger than vertical earth pressure P by a predetermined value. Then, by adjusting at least either a rotational speed of an earth removing screw 18 or a propelling speed of a shield jack 27, based on actual vertical earth pressure P1 measured by earth pressure gauges 20a, 20c, pressure in the chamber 5 is controlled. Further by measuring a variation caused by the subsidence or upheaval of the ground by means of a ground subsidence meter 14, the pressure in the chamber 5 is controlled based on a result of the measurement.;COPYRIGHT: (C)2008,JPO&INPIT