CONDUIT LINE FOR MEASURING DISPLACEMENT USING INERTIA SENSOR AND ITS MEASURING METHOD

PURPOSE:To perform a measurement with high accuracy by a method wherein at least one conduit element whose bend data is known and which is rigid is provided, other conduit elements are connected and the bends of the conduit elements are compared with the known bend of the rigid conduit element. CONSTITUTION:Flange parts F1 to F5 are constituted in such a way that their wall thickness is thick and that they are not buckled or the like. Consequently, when an outside pipe OP is deformed due to the influence of the subsidence or the like of the ground, its deformation is transferred as it is as the deformation of individual connecting pipes C1 to C5 corresponding to the individual flange parts F1 to F5. Since individual conduit elements P1 to P4 are held in a state that they are levitated inside the outside pipe OP, the individual conduit elements P1 to P4 are not bent even when the ground 10 subsides. Then, regarding the conduit elements P1 to P4 whose bend data is known and which are rigid, a gyro drift during a measurement traveling operation is determined by comparing a measured angular output in the travel of an inertia sensor 12 with the known bend data of the rigid conduit elements, and measured data is corrected.