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| TESTING METHOD STUDY OF MODE-I DYNAMIC FRACTURE TOUGHNESS UNDER BLASTING LOADS |
| XU Wentao，ZHU Zheming，ZENG Ligang |
| (College of Architecture and Environment，Sichuan University，Chengdu，Sichuan 610065，China) |
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Abstract Fragmentation is widely applied in rock excavation，and fracture strength under blasting loads is one of the key issues in rock dynamic study. In this paper，blasting experiments with detonators and cement mortar specimens were conducted. The dynamic toughness was computed with experimental-numerical method. The loading and cracking time was determined by strain signals. The displacement field of crack tip was determined by finite element code ANSYS with 1/4 nodes element，and the loading acting on the borehole was determined according to the loading-time curve obtained from the experiments. Using displacement extrapolation method the curve of dynamic intensity factor KI(t) versus time was obtained. The dynamic toughness was determined by the dynamic intensity factor value at the crack initiation time，then a new test method of dynamic fracture toughness under blasting was proposed.
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2015, Vol. 34 
