Abstract
Recent methods of instrumentation of underground deformation are discussed concerning accuracy and reliability of observed values. In order to improve the week points of a pipe strain meter of ordinary type, a instrument has been newly designed for the investigation of the underground deformation and the procedures of the instrumentation by use of the new strain meter and the data obtained are examined.
As shown in Fig. 1, this instrument is composed of a vinyle bar of guide and a sensor which has a vinyle plate with two strain gauges and two vinyle pipes. The curve of the vinyle pipe in boring hole accompanied with the deformation of soil mass has been measured by the strain gauges of the sensor part inserted into the pipe. It is ascertained that the underground displacement can be quantita tively measured to an accuracy of 2cm/400cm.
