Monitoring system for movement of tunnels and other structures

A wire system for monitoring movements in a structure, the wire system comprising a thin elongated wire, means for supporting said wire between at least two spaced points, a measuring plate having an aperture formed therein through which said wire extends, means for applying a constant tension to said wire, means for monitoring and measuring movement of said measuring plate with respect to said wire, means for mounting said plate on said structure including means for adjusting the position of said plate relative to the wire in a plane perpendicular to the wire, and a pair of mutually perpendicular cursors movably mounted on said plate relative to said wire, said cursors including means for determining the location of said wire within said aperture whereby said cursors may be moved to determine an initial location of the wire in the aperture, thereby establishing a point from which relative movement between the aperture and the wire may be measured, and thereafter to determine any change in the relative positions of the aperture and wire as a result of movement of the structure.

A wire system for monitoring movements in a structure comprising a thin elongated wire, means for supporting said wire between at least two fixed points, means for applying a constant tension to said wire and means for monitoring and measuring movement of said wire comprising a measuring plate having an aperture formed therein through which said wire extends, a pair of mutually perpendicular arranged cursors movably mounted on said plate and adapted to intersect at the center of said aperture, and means for moving said plate relative to said wire to locate said wire at the center of said aperture thereby to establish a reference point from which relative movement between the plate and the wire can be measured with the aid of said cursors.

A device for measuring relative movement of a wire passing therethrough including a measuring plate having a circular aperture formed therein through which said wire extends, means for mounting said plate on a fixed structure including means for adjusting the position of said plate relative to the wire in a plane perpendicular to the wire thereby to locate the wire at the beginning of the measuring operation at the center of said aperture;

• a pair of cursor means movably mounted on said plate in perpendicular relation to each other including cursor elements extending at least partly across the aperture to intersect and define a mobile cursor point;
• and linear scales on said plate having indicia thereon related to the coordinates of said aperture to permit the mobile cursor point to be located at the center of the aperture to guide adjustment of the plate in centering the aperture about the wire thereby establishing a fixed reference point and to measure deviation of the wire from said fixed reference point within the aperture.

A device for measuring movement of a wire passing therethrough including a measuring plate having a circular aperture formed therein through which said wire extends, means for mounting said plate on a fixed structure including means for adjusting the position of the plate relative to the wire in a plane perpendicular to the wire;

• a pair of cursor means slidably mounted on the plate for movement in perpendicularly related paths of travel each of which includes a cursor element extending across the aperture whereby the cursor elements overlie one another and, at their intersection, define a cursor point whose location may be varied upon movement of the cursors, and linear measurement scales having predetermined gradations thereon mounted on the plate parallel to the paths of travel of the cursors and below the cursor elements to provide numerical coordinates for the location of the cursor point within the aperture.

A device for measuring movement of a tunnel, the device comprising a monitoring plate fixed to a tunnel wall and a wire passing adjacent said plate under constant tension and having a known point marked on the wire whereby comparison of the relative positions of said point and said plate may be used to determine changes in the length of the tunnel.