Study on Rockburst Tendency and Fracture Characteristics of Thermal Damage Basalt Based on RA-AF
In order to reveal the rock burst mechanism of basalt under the influence of high temperature,the uniaxial compression test and acoustic emission monitoring of basalt under high temperature were carried out.The mechanical properties,acoustic emission characteristics,rock burst tendency and fracture characteristics of basalt under different temperatures were studied.It is found that the increase of temperature has a significant effect on the mechanical properties,acoustic emission characteristics and rockburst tend-ency of basalt.With the increase of temperature,the uniaxial compressive strength,elastic modulus and rockburst tendency of basalt increase first and then decrease,and reach the turning point when the temperature reaches 200℃.In the uniaxial compression test,basalt mainly shows tensile cracks,and when the applied stress exceeds 80%of the peak stress,the shear cracks increase.When the temperature exceeds 600℃,the propor-tion of shear cracks begins to increase,and when the temperature exceeds 800℃,the proportion of shear cracks suddenly decreases.Therefore,600℃and 800℃are the key temperature points for the transformation of basalt damage properties.At the same time,the two indexes of RA value and AF value effectively identify the distribution of different crack types in the process of basalt damage.
high temperaturebasaltmechanical propertiesacoustic emissionrockburst pronenessfracture characteristics
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