The strainburst is the most common type of rockbursts, which may cause injury and death to workers, ruin to underground engineering facilities and destruction to mining/civil infrastructures. However, it is still unknown how the energy released from the surrounding rock affects the strainburst. To explore the effect of the surrounding rock on the strainburst, uniaxial compression tests were carried out on coal-rock combinations to mimic strainburst with the combinations of high-speed camera and strain acquisition instrument. The results demonstrated that the strainburst process can be divided into four stages, i.e., the ejection of small coal fragments, the coal spalling, the transverse volume expansion of local failure area and the violent coal burst. Additionally, two strainburst modes were observed, i.e. tensile strainburst and shear strainburst, relating to the inclination angle of the pre-existent cracks and bedding of the coal blocks. Furthermore, a four-phase model is established for the failure process and energy evolution of the coal-rock combination. It is found that only the released energy in the surrounding rock during the coal burst can affect the strainburst with the energy transfer from the rock block to the coal block. During the coal burst, the post-peak modulus of the coal block grows with the increase in the energy released from the upper rock block. This relationship is accurately fitted by an exponential function, demonstrating a high determination coefficient of 93.5%. As a result, the energy partition of the coal block is modified at the post-peak stage, meaning more released energy in the coal block is converted into the kinetic energy of coal fragments. The findings in this study could promote a better cognition of the intrinsic process and energy evolution for the influence of surrounding rock on strainburst.

中文翻译：

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围岩对应变爆发影响的实验研究：从破坏过程和能量分配的洞察

应变爆裂是最常见的岩爆类型，可能导致工人受伤和死亡、地下工程设施毁坏以及采矿/民用基础设施破坏。然而，目前尚不清楚周围岩石释放的能量如何影响应变爆发。为了探究围岩对应变爆发的影响，结合高速相机和应变采集仪，对煤岩组合进行模拟应变爆发的单轴压缩试验。结果表明，应变爆裂过程可分为小煤块喷出、煤体剥落、局部破坏区横向体积膨胀和剧烈煤体爆裂4个阶段。此外，还观察到两种应变爆发模式，即拉伸应变爆发和剪切应变爆发，与煤块预先存在的裂缝和层理的倾斜角度有关。此外，还建立了煤岩组合破坏过程和能量演化的四相模型。研究发现，只有爆煤过程中围岩释放的能量才能影响应变爆发，能量从岩块传递到煤块。爆煤过程中，煤块的峰后模量随着上部岩块释放能量的增加而增大。该关系通过指数函数精确拟合，显示出高达 93.5% 的决定系数。因此，煤块的能量分配在峰值后阶段发生了改变，这意味着煤块中更多释放的能量转化为煤碎片的动能。这项研究的结果可以促进更好地认识围岩对应变爆发影响的内在过程和能量演化。