公开(公告)号：US5040421A

公开(公告)日：1991-08-20

申请号：US608935

申请日：1990-11-05

申请人： Koichi Kimura ,  Kazuma Miyamoto ,  Kenichiro Mihara

发明人： Koichi Kimura ,  Kazuma Miyamoto ,  Kenichiro Mihara

IPC分类号： E02D1/00 ,  E02D33/00 ,  E21B47/00 ,  E21D1/00 ,  G01D21/00 ,  G01V3/26

CPC分类号： G01V3/26

摘要： A protective tube is vertically buried in the ground, and sinking elements for generating magnetism are buried at plural positions at different depths in the ground outside the side wall of this tube. Magnetic sensors capable of detecting magnetism are disposed in the tube to detect the magnetism generated by the sinking elements, and the depth position of the sinking elements in the ground is measured according to the detected signal, so that the fluctuations by settlement or uplift of the ground may be known by each bed differing in depth. A plurality of magnetic sensors are fixed to the side wall surface of the tube, corresponding to the individual sinking elements.