In order to improve the prediction accuracy of rockburst proneness of hard granite,the rock mechanics tests were carried out under Brazilian splitting,uniaxial,triaxial and different unloading confining pressure rates,and the characteristics of granite strength and rockburst proneness were systematically analyzed.It is found that the strength of granite in σ3-σ1 plane is significantly affected by the confining pressure and the rate of unloading confining pressure,distributed in a band zone.In τoct-(σ1+σ3)/2 plane,the strength under different loading and un-loading stress paths shows good linear characteristics,and a general formula for calculating the octahedral strength of granite under loading and different unloading rates was obtained.According to the characteristics of hard granite that the compression and yield stages are not significant but the elastic stage is significant,a rock-burst classification method of the simplified residual elastic energy index was proposed.The rockburst grade of granite was subdivided on the basis of rockburst classification in existing literature according to the failure mor-phology and acoustic characteristics of granite samples.Under the same initial confining pressure,the larger the unloading rate of confining pressure is,the larger the simplified residual elastic energy index is,and the rockburst proneness becomes stronger.At the same unloading rate of confining pressure,the larger the initial confining pressure is,the larger the simplified residual elastic energy index is,and the rockburst proneness becomes stronger.The research results lay a theoretical foundation for a more scientific and reasonable evaluation of the rockburst proneness of granite.
granitestress pathrockburstfailure characteristicsstrength of unloading confining pressure
维普
万方数据
