Estimation of Fracture Toughness of Sandstone by Three Testing Methods

0456413 - ÚGN 2016 VN eng C - Konferenční příspěvek (zahraniční konf.)
Kataoka, M. - Yoshioka, S. - Cho, S. H. - Souček, Kamil - Vavro, Leona - Obara, Y.
Estimation of Fracture Toughness of Sandstone by Three Testing Methods.
Vietrock 2015 Conference Proceedings. Hanoi: ISRM, 2015. ISBN N.
[Vietrock 2015 - An ISRM Specialized Conference. Hanoi (VN), 12.03.2015-13.03.2015]
Institucionální podpora: RVO:68145535
Klíčová slova: fracture toughness * Chevron bend (CB) test * semi-circular bend (SCB) test
Kód oboru RIV: JQ - Strojní zařízení a nástroje

Several testing methods have been proposed for evaluating the mode I fracture toughness of rocks. Since the fracture toughness of rocks estimated from the different testing methods is generally not compared, it is still not well-known the effect of type of the testing methods on the fracture toughness. Therefore, in this paper, three testing methods, chevron bend (CB) test, semi-circular bend (SCB) test and straight notched disk bending (SNDB) test, were performed using Kimachi sandstone in order to evaluate the mode I fracture toughness. The CB specimen is cylindrical shape with a V-shaped notch, called chevron notch, perpendicular the specimen axis. The SCB specimen is a semi-circular disk and has a straight edge notch throughout the specimen thickness. In the SNBD test, a circular disk specimen with a straight edge notch throughout the diameter is used. In a series of tests, load was applied by three-point bending to produce the tensile stress state at the notch tip indirectly for all the specimens, and controlled by the constant displacement rate. As a result, the average fracture toughness was estimated as 0.64 MN/m3/2 in the CB test, 0.66 MN/m3/2 in the SCB test, and 0.46 MN/m3/2 in the SNDB tests, respectively.
Trvalý link: http://hdl.handle.net/11104/0256942