Temperature Dependence of Microdamage Accumulation in Granite under Impact Fracture
I. P. SHCHERBAKOV, V. S. KUKSENKO, A. E. CHMEL’
A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, ul. Politekhnicheskaya 26, Saint-Petersburg, 194021 Russia
Keywords: dynamic fracture, granite, acoustic emission, temperature dependence
Abstract
It has been not once noticed that origination and accumulation of fractures in rocks in the full scale and in laboratory specimens have much in common. The lab test data on rock specimen deformation and fracture are often used to interpret natural seismic events. Usually the laboratory tests are carried out at room temperature, whereas the temperature of rocks at the depth of origination of rock bursts and earthquakes can reach a few hundred degrees by Celsius. To assess the weight of this difference, the authors have obtained time series of acoustic emission impulses during origination of microcracks in granite specimens subjected to impact fracture at varied temperatures. The kinetics of damage accumulation and the cooperative effects differ greatly in the test temperature range from 20 to 600° С.
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