Measuring fracture toughness of crystalline marbles under modes I and II and mixed mode I-II loading conditions using CCNBD and HCCD specimens

作者：Amrollahi H; Baghbanan A^*; Hashemolhosseini H

来源：International Journal of Rock Mechanics and Mining Sciences, 2011, 48(7): 1123-1134.

DOI：10.1016/j.ijrmms.2011.06.015

• Fracture toughness
• Grain size distribution
• CCNBD specimen
• HCCD specimen
• Fracture criteria

Fracture toughness of three crystalline Calcite marbles, which are different only in grain size and distribution, is determined under modes I and II and mixed mode I-II loading conditions using Cracked Chevron-Notched Brazilian Disc (CCNBD) and Hollow Centre Cracked Disc (HCCD) specimens. The results show that mode I fracture toughness (K-IC) is correlated negatively with grain size. For each marble, HCCD yields lower values of fracture toughness, compared with CCNBD. This difference is negligible under mode I loading condition; while it becomes larger as loading condition transits from mode I to mode II. Measured values of P-wave velocity (V-P), Brazilian tensile strength (sigma(tB)) and Schmidt hammer hardness are indirect relation with K-IC of the marbles. The obtained results are compared with three fracture criteria, in which the Minimum Strain Energy Density (MSED) criterion has provided better correlations with different critical combinations of modes I and II Stress Intensity Factors.

• 出版日期2011-10