DETERMINATION OF CRITICAL CTOD AND ANALYSISOF INSTABLE RUPTURE ZONE FOR ROCK
岩石临界CTOD的确定及失稳断裂过程区的研究

Some regular patterns about the spread of main crack related to the increasingload and some relationships between formation of the microcrack zone and the load are obtained based on the study of fracture mechanics for the three-point bending specimens ofnotched granite and marble beams.The critical value of CTOD is measured.The effectsupon the fracture zone of the width of COD and the dimensions of rock grain are analysed.