The burst test (Abou-Sayed, 1978) is a method for measuring the fracture properties of rocks subject to high compressive forces such as the ones encountered deep underground. Its analysis requires linking the fracture properties of a sample with the critical pressure upon which is fails. In many situations, this test can provide inconclusive or erroneous results. In an article just published in Rock Mechanics and Rock Engineering (Yoshioka et al., 2022), we perform a careful analysis of this test focussing on stability of cracks instead of the classical argument based on criticality. We propose modifications to the testing protocol to improve its accuracy, or an alternate interpretation of the classical results. Just like our article on network of hydraulic fractures (Tanné, Bourdin, & Yoshioka, 2022), this analysis highlights the relevance of variational characterizations of crack propagation.
- Abou-Sayed, A. S. (1978). An experimental technique for measuring the fracture toughness of rocks under downhole stress conditions. VDI-Berichte, 313, 819–824.
- Yoshioka, K., Zhang, Y., Lu, G., Bunger, A., Adachi, J., & Bourdin, B. (2022). Improving the Accuracy of Fracture Toughness Measurement in Burst Experiments. Rock Mech. Rock Engng. DOI:10.1007/s00603-022-03097-y
- Tanné, E., Bourdin, B., & Yoshioka, K. (2022). On the loss of symmetry in toughness dominated hydraulic fractures. Int. J. Fracture. DOI:10.1007/s10704-022-00623-5 Download