In Situ Stress Measurements in Italy
Most of the in situ natural state-of-stress measurements have been carried out in Italy at the sites of large underground hydroelectric powerhouses and at the sites of important mines. The method successfully used was in all cases based on the measurement of the deformations caused by the stress release on the bottom of boreholes. Some of the rock masses in which measurements were taken, showed a considerable anisotropic behavior; for these cases the interpretation of the results provided by the measurements appeared to be more complex and not so reliable. A method of approximate interpretation has been adopted in order to overcome such difficulties.
An overall assessment of the results seems to indicate that the measured state of stress is strongly influenced by the morphological situation and it is not easily related to the regional tectonic situation; in fact, the measurements were often taken at shallow depths and in localities having rather uneven morphology (for example on narrow valley beds or on very steep slopes). In some cases the values of the horizontal component of the state of stress along the axis of the valleys appeared to be quite high; high horizontal stresses were measured also in the Raibl mine which is subject to considerable rock bursts.
KeywordsStress Measurement Rock Mechanics Rock Burst Radial Pressure Mountain Slope
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