Experimental investigations on loading-rate dependency of compressive and tensile mechanical behaviour of hard rocks

Abstract

Effects of loading rate on mechanical behaviour of brittle rocks are of great importance for stability assessment of underground structures. Brazilian splitting tension tests were performed under different loading rates ranging from 0.001 to 10 kN/s. The tensile strength increased with the increasing of the loading rate. There were clear transgranular microcracks in the specimen with loading rate of 10 kN/s, but intergranular microcracks in the one of 0.001 kN/s. Uniaxial compression tests were also performed under different loading rates. All the stress–strain curves under loading rates of axial stress ranging from 0.05 to 10 MPa/s show the typical mechanical responses of brittle rocks. The uniaxial compression strength and elastic modulus increased with the increasing of loading rate. The failure mechanism under uniaxial compression was similar to the Brazilian splitting tension tests. With the increasing of loading rate, intergranular microcracks became dominant instead of transgranular microcracks.

Keywords:

• loading rate
• brittle rock
• Brazilian splitting tension tests
• uniaxial compression tests
• intergranular microcracks
• transgranular microcracks

Acknowledgements

Financial supports from the National Program on Key Basic Research Projects of China (No. 2014CB046902) and from the National Science Foundation of China (Nos. 51279201, 51479193, 51209085 and 41172288) are gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Program on Key Basic Research Projects of China [grant number 2014CB046902]; National Science Foundation of China [grant numbers 51279201, 51479193, 51209085 and 41172288]; the Main direction Project of the Knowledge Innovation Program [grant number KZCX2-EW-QN115] and the Cross-disciplinary Collaborative Teams Program for Science and Technology Innovation [grant number 2012.119] as well as the Hundred Talent Program from the Chinese Academy of Sciences.