| Rock fracture toughness is one of the most important parameters and indicators in the field of rock fracture mechanics, it is used to character rock materials'ability to resist crack propagation. However, due to the size effect, temperature, confining pressure, loading rate and other factors, to accurately obtain the dynamic fracture toughness of rock material values rather difficult. Therefore, studying how to accurately obtain rock fracture toughness testing techniques and experimental methods, fracture mechanics has been the joint efforts of workers in the direction, is also an urgent need for practical engineering problems. And with different rate of loading the mechanism of rock crack will change, so it is necessary to in-depth study dynamic fracture toughness of the loading rate dependency, master of rock under different loading rates the dynamic mechanical properties, this is the safety of structures under dynamic loading design and improve the material's ability to resist dynamic fracture appears to prevent the construction of rock fracture caused by the occurrence of catastrophic accidents are a very important theoretical and practical significance.In view of the most common and the most dangerous crack is pure type I crack, in order to determine reasonable test plan and reasonable rock specimen size, ensure the reliability of the test results, the paper firstly make a three-dimensional dynamic finite element analysis on pure I type of loading test system. Meanwhile, the paper discussed the influence of larger diameter bar on the principle of one-dimensional and the influence on the fracture experiments. In this paper, cased study central cracked circular disk of marble specimens loading case of pure typeⅠ, making dynamic fracture test under different loading rates using CCCD-SHPB test system, discussed the dynamic fracture toughness of rock material loading rate dependency. |
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