Abstract:
Uniaxially compressed samples of the M-400 rock cement were subjected to pointed impact directed to the orthogonally applied compression. The impact-induced generation of the acoustic emission (AE) was detected in the range of 400–600 êÃö. Preliminarily, the fracture (sample fragmentation) threshold Pul was measured without application of a compressive load. It has been found that the energy distributions in AE time sweeps recorded in uncompressed samples followed a power law specific for the process of the cooperative microcrack formation. The energy distributions of AE pulses recorded under a constant load evidenced the exponential function, which is typical for random, non-interacting AE sources excited in the densified cement rock. Under compression close to the ultimate strength, the shock action caused a “subthreshold” fracture of samples (trigger effect).
Keywords:cement rock, static load, shock damage, trigger effect, acoustic emission.
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