In situ stress measurements

Overcoring CSIRO Triaxial Hi-Cell

The overcoring test CSIRO Triaxial HI-CELL is one of the most accurate methods for the measurement of the Natural State of Stress in the rocks.

A single CSIRO test gives a punctual measurement of the three dimensional stress tensor while, with the other techniques, it is necessary to compose more tests results in order to obtain a three dimensional  measurement.

The ability to use a “local approach” for the measurement of the elastic modulus, makes this test particulary reliable and accurate.

This stress test method is suitable for underground small-medium size tunnels, quarry excavation faces, concrete dam bodies:

  • the maximum depth is 25-30 m, in order to ensure the success of the chemical bonding rock-cell;
  • the rock must have a low degree of fracturing; it must be easy to obtain rock samples 70 cm long,  in order to allow the overcoring without damaging the cell;
  • the borehole can be from sub-horizontal to vertical; it must point upward, due to necessity to perfectly clean and dry the pilot hole, where the cell must be glued.

Interested in our services?