Method and apparatus for determining shifts at terrain and in structures

Abstract

In the medium to be examined there is embedded a measuring tube which possesses at its inner surface essentially equidistantly spaced measuring markers. These measuring markers are in the form of mechanical stops or impact members having an impact surface forming part of a right circular cone. To determine the spacing between neighboring measuring markers there is provided a measuring probe or sensor having two measuring heads connected with one another, by means of a connection tube, such that they are relatively shiftable in the lengthwise axis of the measuring probe. Each measuring head is constructed as a mechanical counter stop having an impact or stop surface forming part of a spherical surface. Internally of the connection tube there is arranged an inductive length transmitter producing an output signal characteristic of the spacing between the measuring heads. By means of a traction rod and a dynamometer and a tension spring both of the measuring heads are brought into contact, by means of their counter impact or stop surfaces, with the stop surfaces of the stops or impact members. The signal generated by the length transmitter is proportional to the spacing or spacing change between both of the measuring heads and thus, also to both of the measuring markers. Relative displacements between both of the measuring markers in the direction of the lengthwise axis of the measuring tube can therefore be directly determined.