Study on Acoustic Emission Characteristics of Helankou Rock Damage under Freezing-thaw Cycles
Helankou rock is an important carrier of petroglyphs,which has suffered from severe weathering due to the natural environment.This study investigates the damage characteristics of Helankou rock by simulating its natural environment through freezing-thaw cycle tests,triaxial compression tests,and acoustic emission tests.The cycles were set to 0,10,20,30,and 40,respectively.The stress-strain curves were obtained,and the variation laws of peak stress,residual stress,and elastic modulus were analyzed.The relationship between acoustic emission signals and the number of freezing-thaw cycles,as well as confining pressure,was explored.The results indicate that the more freezing-thaw cycles the rock undergoes at the same confining pressure,the lower its strength becomes.The peak stress and elastic modulus show a positive correlation with confining pressure under the same number of freezing-thaw cycles.The variation stages of the acoustic emission signal align with the stress-strain curve,going through initial small growth,stable growth,sharp increase,and post-peak persistence.With an increasing number of freezing-thaw cycles,the early acoustic emission activity in the initial small growth and stable growth stages becomes more pronounced,while the peak reached during the sharp increase stage decreases.Before failure,the acoustic emission count rapidly increases to a peak,indicating that this parameter can be used to predict rock failure instability.The research results provide a theoretical basis for the protection of Helankou rock paintings.
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