PROPOSED METHOD FOR DETERMINING THE ROCK MIXED MODE Ⅰ-Ⅱ FRACTURE LOCUS AND MODE II FRACTURE TOUGHNESS USING CRACKED CHEVRON NOTCHED BRAZILIAN DISC(CCNBD) SPECIMENS

【摘要】：正 With respect to rock fracture problems, most research work has concentrated on the simple case of mode Ⅰloading. Consequently, three standard methods have been recommended by the ISRM. However, in rock engineering it is clear that a pure mode 111111111111111111 form of loading seldom represents real conditions. On the contrary, mode Ⅱand mixed mode Ⅰ-Ⅱloading condition are commonly encountered in rock structures , such as rock