Slope stability

Fracture toughness characterisation of Yosemite Granitic Rocks (California, USA). Collaboration project with USGS (B. Collins), Greg Stock (Yosemite National Park), and UNIL

Figure 1. On the right: CCNBD specimen geometry (after ISRM, 1995); on the left: a CCNBD specimen of Yosemite Granite before the test.

This research is developing new testing procedures for investigating the damage mechanisms of granitic rocks from Yosemite Valley, California (USA). The main objective is trying to reproduce the thermal effects on exposed rock slopes and to quantify their influence on rock fracture toughness. In particular, based on previous results obtained from a first testing campaign for the geomechanical characterisation of these rocks (i.e. uniaxial and triaxial compression tests, tensile test, static fracture toughness tests), a specific procedure for cyclic fracture toughness tests is being developed. The tests are being conducted on CCNBD samples (see Figure 1 here below), using a specific press that allows the application of cyclic loads that vary the maximum load, amplitude, and frequency. This research should assist in explaining why rock falls occur on cliffs subject to diurnal cycles of heating and cooling.

Principal Investigator Technical assistance
Dr. Federica Sandrone Laurent Gastaldo