A four-component borehole deformation gauge for the determination of in situ stresses in rock masses

A four-component borehole deformation gauge was built to investigate high lateral stresses in certain granite quarries in central Minnesota. This gauge is essentially a more sophisticated version of the single-component gauge. It also contains the feature of a built-in check, not available on other multicomponent gauges. A description of the gauge is given, and the results of some stress determinations made on the floor of a granite quarry are presented. The additions necessary to make the gauge suitable for determining the complete state of stress from a single borehole are also indicated.