微波作用下深部砂岩单轴抗压强度弱化机理

• 作 者: 杨本高 高明忠 谢晶 刘军军 王飞 王明耀 王轩 温翔越 杨钊颖
• 出 处: 中南大学学报（英文版）
• 发表日期: 2022年2期
• 关键词: microwave sandstone uniaxial compressive strength weakening mechanism

传统的机械破岩方法劳动强度大、效率低,制约了深部资源和深部空间的开发.而微波技术作为一种新型破岩手段有望破解此类难题.本文从宏观到细观综合运用力学测试、细观试验以及数值模拟等手段探讨了微波场内埋深1050 m砂岩试样的破坏特征、弱化规律及破裂机制.研究表明,微波作用下砂岩单轴抗压强度会大幅降低,当1000 W功率作用60 s时,强度折减幅度可达50％;结合单轴和细观试验发现,矿物不均匀膨胀导致砂岩内部热应力增大的同时,高温环境下部分矿物会同步发生熔融,从而使试样内部孔裂隙结构发生急剧改变然后体现为强度的大幅下降;微波场内试样的中下部温度较高,高应力区出现在试样底部并沿轴向扩展.本文研究结果将为类似岩石破碎工程提供破岩理论依据与技术支撑.“,”Traditional mechanical rock breaking method is labor-intensive and low-efficient, which restrictes the development of deep resources and deep space. As a new rock-breakage technology, microwave irradiation is expected to overcome these problems. This study examines the failure characteristics, weakening law, and breakdown mechanism of deep sandstone (depth=1050 m) samples in a microwave field. The macroscopic and microscopic properties were determined via mechanical tests, mesoscopic tests, and numerical simulations. Microwave application at 1000 W for 60 s reduced the uniaxial compressive strength of the sandstone by 50％. Thermal stress of the sandstone was enhanced by uneven expansion of minerals at the microscale. Moreover, the melting of some minerals in the high-temperature environment changed the pore structure, sharply reducing the macroscopic strength. The temperature remained high in the lower midsection of the sample, and the stress was concentrated at the bottom of the sample and along its axis. These results are expected to improve the efficiency of deep rock breaking, provide theoretical and technical support for similar rock-breakage projects, and accelerate advances in deep-Earth science.