PSI - Issue 13

Guiyun Gao / Procedia Structural Integrity 13 (2018) 51–56 Guiyun Gao/ Structural Integrity Procedia 00 (2018) 000 – 000

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confining stress (as shown in Fig. 4.), and the fracture process zone increase with confining stress. The increase of fracture process zone indicates that more micro cracks around the crack path are induced.

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Crack propagation velocity Final crack length

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Final crack length (mm)

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Fig. 4 The crack propagation velocity and final crack length versus confining stress

Conclusions

The dynamic fracture behavior under different loading rates and static compressive stress were studied by using the digital image correlation method combined with an ultra-high speed photography. And the crack initiation and propagation subjected to different confining stress during dynamic loading process were analyzed. Results show that the crack propagation velocity and fracture toughness increase with incident velocity of the impact bar. Crack propagation velocity and crack arrest length decrease with increase of the hydraulic confining pressure. Micro cracks could be observed near the crack path and the crack tip when the rock plate subjected to hydraulic compression and dynamic loading. DIC method combined with ultra-high speed photography could be used to study the dynamic rock fracture under confining stress, which provides a new method for high speed fracture investigation of underground rock that concerned in geophysics and geoengineering application.

Acknowledgements

This work was supported by the National Natural Science Foundation for Young Scientists of China (Grant No. 41704096) and Fundamental Research Fund for State Level Scientific Institutes (Grant No.ZDJ2017-13).

References

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