International Journal of Rock Mechanics and Mining Sciences ( IF 7.2 ) Pub Date : 2021-01-09 , DOI: 10.1016/j.ijrmms.2021.104616 Zhenlong Ge , Qiang Sun
In recent years, microwave mechanical rock breaking—an energy-saving technology with environmental benefits and high efficiency—is increasingly being used to improve the rock-breaking efficiency of geothermal well drilling. Herein, we studied the evolution of different types of cracks in gabbro under uniaxial loading using the acoustic emission (AE) technique. The results show that, after microwave heating, the number of microcracks in gabbro increases and AE becomes more and more active. During the loading process, AE characteristics can be divided into three typical periods: the peak period, silent period, and active period, which are closely related to the deformation process of the rock. When the heating power exceeds 3.3 kW, the proportion of shear cracks increases with increases in irradiation energy. With an increase in stress level, the proportion of tensile cracks increases, but near failure, shear fracture is still dominant. Under the same irradiation energy, the combination of high heating power and low heating time is more conducive to rock failure. Further, when the heating power is greater than 3.3 kW, the damage to rock is more obvious. The test results provide a theoretical and experimental basis for determining the optimal microwave irradiation conditions to improve rock-breaking efficiency in geothermal development.
中文翻译:
微波加热后辉长壁的声发射特性
近年来,越来越多地采用微波机械破岩(一种具有环境效益和高效率的节能技术)来提高地热井钻井的破岩效率。在本文中,我们使用声发射(AE)技术研究了单轴载荷下辉长岩中不同类型裂纹的演变。结果表明,微波加热后,辉长岩中的微裂纹数量增加,AE变得越来越活跃。在加载过程中,声发射特征可分为三个典型时期:峰值时期,无声时期和活动时期,这与岩石的变形过程密切相关。当加热功率超过3.3 kW时,剪切裂纹的比例随着辐照能量的增加而增加。随着压力的增加,拉伸裂纹的比例增加,但在破坏附近,剪切断裂仍占主导地位。在相同的照射能量下,高加热功率和低加热时间的结合更有利于岩石破坏。此外,当加热功率大于3.3kW时,对岩石的破坏更加明显。试验结果为确定最佳微波辐照条件,提高地热开发的破岩效率提供了理论和实验依据。