| 摘要 |
PROBLEM TO BE SOLVED: To solve the problems wherein, in a method for sending an alternating current into conductive liquid injected into a non-conductive conduit buried in the ground and surveying an induction field generated from the alternating current, a wire for returning the current flowing in the conduit is often impossible to be placed sufficiently separately from a survey place, making accurate prediction of the conduit position difficult. SOLUTION: The ground or a metallic conduit buries in parallel to the survey object conduit is used as a return route of the current sent into the conductive liquid injected into the survey object conduit. By using the ground as the return route of the survey current, the return current flows in the spread state in an extremely wide range of the ground, to thereby reduce an influence by the return current to extremely small one, and the induction field generated by the alternating current flowing in the conductive liquid in the conduit can be detected surely and accurately by a magnetic field measured on the ground surface. COPYRIGHT: (C)2007,JPO&INPIT |
