In situ stress measurements

Shallow large overcoring

The Surface Overcoring tests are used to measure the plane stress state existing on the surface of rock excavations and concrete structures.

Typical areas of application are:

  • underground excavations, niches, tunnel walls, tunnels, chamber-pillar mining crops
  • concrete lining of the tunnels
  • beams, pillars, concrete slabs
  • body of concrete dams both from the internal tunnels and from the faces

The know-how, the equipment and the experimental / interpretative procedures used by us cover a wide range of applications:

  • perforations in any direction
  • core drilling diameter 150-240 mm
  • measurements performed using a removable 200 mm mechanical strain gauge on 4 measuring bases positioned at 45 ° from each other
  • measurements performed outside the over-cored surface (for small diameter perforations) or inside it (for large diameter perforations)
  • drilling depth: up to the exhaustion of the deformations

The drilling with a special electric core drill is at our expense: the drilling is an integral part of the test we provide.

The determination of the elastic modulus of the material is included; it is performed on a cylindrical specimen taken from the center of the overcored sample.

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