激光照射岩石热裂特性与裂隙分布研究  

Thermal-breaking characteristics and crack distribution of rock irradiated by laser beams

作　　者：王义江 郁东旭[1] 孙立鹏 朱启银 王建州 WANG Yijiang;YU Dongxu;SUN Lipeng;ZHU Qiyin;WANG Jianzhou(School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou 221116,China;Yunlong Lake Laboratory of Deep Underground Science and Engineering,Xuzhou 221116,China;State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering,China University of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]中国矿业大学力学与土木工程学院,江苏徐州221116 [2]深地科学与工程云龙湖实验室,江苏徐州221116 [3]中国矿业大学深地工程智能建造与健康运维全国重点实验室,江苏徐州221116

出　　处：《岩土工程学报》2024年第9期1809-1819,共11页Chinese Journal of Geotechnical Engineering

基　　金：深地科学与工程云龙湖实验室重点攻关项目(104023006);国家自然科学基金项目(51978653);国家高等学校学科创新引智计划项目(B14021)。

摘　　要：激光辅助破岩是一种非接触式破岩技术,破岩效果主要受激光功率、照射时间和离焦距离等参数影响。选择石灰岩、砂岩和花岗岩3类岩石,开展了不同照射参数的破岩试验,分析了温度、射孔参数、比能、热裂效能、裂隙分布、矿物组分和微观结构等变化规律。结果表明,激光照射下3类岩石表面温度均超过2000℃、温度梯度最高可达1500℃/mm,相同位置处花岗岩表面温度和温度梯度最高、砂岩次之、石灰岩最低;3类岩石射孔直径、射孔深度和射孔速率均与照射参数密切相关,砂岩、石灰岩和花岗岩最大射孔速率分别为3.18,2.68,0.8 mm/s。相同照射参数下,比能较热裂效能高1~2个数量级,3类岩石比能排序为:花岗岩>石灰岩>砂岩。照射后岩样均存在数条主裂隙,沿径向延伸至试样边缘,石灰岩和花岗岩次生裂隙发育,砂岩未发现明显次生裂隙。照射后岩石矿物衍射强度和微观结构发生显著改变。The laser-assisted rock breaking is a non-contact technology employed for the rock fragmentation,with its efficiency contingent upon the laser power,irradiation time and defocusing distance.To explore the effects of various irradiation parameters,the rock-breaking tests are conducted on three distinct rock types,including limestone,sandstone and granite.The temperature field,perforation parameters,specific energy,thermal-cracking energy,crack distribution,mineral composition and microstructural characteristics are studied.The results demonstrate that the rock surface temperature subjected to laser irradiation experiences a substantial increase,with the maximum temperature and temperature gradient of 2000 oC and 1500 oC/mm,respectively.The granite sample exhibits the highest surface temperature and temperature gradient,followed by sandstone,and the limestone displays the lowest values.The perforation diameter,depth and speed of rocks are closely associated with the corresponding irradiation parameters.The sandstone,limestone and granite exhibit the maximum perforation speeds of 3.18 mm/s,2.68 mm/s and 0.8 mm/s,respectively.The relationship between specific energy and irradiation parameters mirrors that of thermal-cracking energy under the same irradiation parameters.However,the specific energy values are approximately 1-2 orders of magnitude higher than the corresponding thermal-cracking energy values.The specific energy ranking for the three rock types is as follows:granite>sandstone>limestone.The rock samples exhibit a notable presence of radial cracks that extend to the edges.The limestone and granite samples display extensive development of the secondary cracks,whereas the sandstone shows no significant presence of the secondary cracks.The irradiated rock samples demonstrat evident alterations in both diffraction intensity and microstructures when compared with their corresponding original samples.

关 键 词：激光破岩 温度分布 比能 热裂效能 裂隙分布 

分 类 号：TU458[建筑科学—岩土工程]