Dynamic fragmentation of microwave irradiated rock  

作　　者：Shuai Wang Ying Xu Kaiwen Xia Tianyang Tong 

机构地区：[1]State Key Laboratory of Hydraulic Engineering Simulation and Safety,School of Civil Engineering,Tianjin University,Tianjin,300072,China [2]Department of Civil and Mineral Engineering,University of Toronto,Toronto,M5S 1A4,Canada [3]Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines,Northeastern University,Shenyang,110819,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2021年第2期300-310,共11页岩石力学与岩土工程学报（英文版）

基　　金：This research was supported by the National Natural Science Foundation of China(Nos.51704211 and 51879184).

摘　　要：The microwave-assisted rock fragmentation has been proven to be a promising approach in reducing cutting tools wear and improving efficiency in rock crushing and excavation.Thus,understanding the influence of damage induced by microwave irradiation on rock fragmentation is necessary.In this context,cylindrical Fangshan granite(FG)specimens were exposed to microwave irradiation at a power of 6 kW for different durations up to 4.5 min.The damages of the specimens induced by irradiation were quantified by using both X-ray micro-CT scanning and ultrasonic wave measurement.The CT value and Pwave velocity decreased with increase of irradiation duration.The irradiated specimens were then tested using a split Hopkinson pressure bar(SHPB)system to simulate rock fragmentation.A momentum-trap technique was utilized to ensure single-pulse loading on the specimen in SHPB tests,enabling valid fragment size distribution(FSD)analysis.The dependence of dynamic uniaxial compressive strength(UCS)on the irradiation duration and loading rate was revealed.The dynamic UCS increased with increase of loading rate while decreased with increase of irradiation duration.Using the sieve analysis,three fragmentation types were proposed based on FSD,which were dictated by both loading rate and irradiation duration.In addition,an average fragment size was proposed to quantify FSD.The results showed that the average fragment size decreased with increase of loading rate.A loading rate range was identified,where a dramatic reduction of the average fragment size occurred.The dependence of fragmentation on the irradiation duration and loading rate was also discussed.

关 键 词：Microwave irradiation Split Hopkinson pressure bar(SHPB) Momentum-trap Dynamic compressive strength Fragment size distribution(FSD) Fangshan granite(FG) 

分 类 号：TU45[建筑科学—岩土工程]