Liquid CO2 Phase-Transition Rock Fracturing: A Novel Technology for Safe Rock Excavation

Applied Sciences

Ruilin Hu¹  Yaxing Cheng¹  Tianming Su²  Haoyue Sui²  Ke Yang³ 

[1] Key Laboratory of Shale Gas and Geoengineering, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Key Laboratory of Transport Industry of Road Structure and Material, Research Institute of Highway Ministry of Transport, Beijing 100088, China;Land and Resources Exploration Center, Hebei Bureau of Geology and Mineral Resources Exploration, Shijiazhuang 050081, China;

关键词: liquid carbon dioxide;    phase-transition;    rock mass excavation;    fragmentation distribution;    HHT;   

DOI  :  10.3390/app12010068

来源: DOAJ

【 摘 要 】

In order to determine the applicability of liquid CO₂ phase-transition fracturing technology in rock mass excavations, the principles of CO₂ phase-transition fracturing were analyzed, and field tests of liquid CO₂ phase-transition fracturing were performed. An “Unmanned Aerial Vehicle (UAV) camera shooting + Microstructure Image Processing System (MIPS) analyzing” method was used to acquire the rock mass characteristics. Further, the Hilbert–Huang Transform (HHT) energy analysis principle was adopted to analyze the characteristics of fracturing vibration waves. The experimental results showed that during the process of fracturing, there were both dynamic actions of rock breakage due to excitation stress wave impacts, and quasi-static actions of rock breakage caused by gasification expansion wedges. In semi-infinite spaces, rock-breakage zones can mainly be divided into crushing zones, fracture zones, and vibration zones. At the same time, under ideal fracturing effects and large volumes, the fracturing granularity will be in accordance with the fractal laws. For example, the larger the fractal dimensions, the higher the proportion of small fragments, and vice versa. Moreover, the vibration waves of the liquid CO₂ phase-transition fracturing have short durations, fast attenuation, and fewer high-frequency components. The dominant frequency band of energy will range between 0 and 20 Hz. The liquid CO₂ phase-transition fracturing technology has been observed to overcome the shortcomings of traditional explosive blasting methods and can be applied to a variety of rock types. It is a safe and efficient method for rock-breaking excavations; therefore, the above technology effectively provides a new method for the follow-up of similar engineering practices.

【 授权许可】

Unknown