Effect of a heated drilling bit and borehole liquid on thermoelastic stresses in an ice core

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概要

• 論文の詳細を見る

• Thermal ice coring processes are accompanied by stresses in an ice core; micro-and macro-cracks are formed. Contamination under mechanical and thermal drilling usually penetrates from 5 to 30mm into the ice core. The quality of ice core acquired by thermal drilling depends on thermal stresses. To improve ice core quality, experimental and theoretical studies have been done. A prototype model of an antifreeze thermal electric drill (ATED) was tested. Temperature distribution in an ice core during thermal drilling was measured with thermocouples. To study temperature and stress distributions in an ice core, a mathematical model was developed. Impacts of ethanol-water solution (EWS) and kerosene on temperature and thermal stresses in an ice core were also studied. The experiments and model simulations have shown that thermal stresses in an ice core are proportional to the ratio of drilling bit length to penetration rate. The maximal thermal stresses in an ice core during thermal drilling exhibit only weak dependence on the type of borehole liquid. Forced circulation of the borehole liquid at the kerf leads to reduced depth of cracks by about 10mm.

• 国立極地研究所の論文

著者

• Zagorodnov V.

  Polar Ice Coring Office, University of Alaska Fairbanks

• Kelley J.

  Polar Ice Coring Office, University of Alaska Fairbanks

• Kelley J.

  Polar Ice Coring Office University Of Alaska Fairbanks

• Zagorodnov V.

  Polar Ice Coring Office University Of Alaska Fairbanks

• Nagornov O.

  Moscow Engineering Physics Institute

関連論文

• Continuous study of an ice core: ECM, fine stratigraphy, air bubbles and crystals
• Effect of a heated drilling bit and borehole liquid on thermoelastic stresses in an ice core
• Drilling of glacier boreholes with a hydrophilic liquid
• Fluids for use in deep ice-core drilling
• The Guliya Ice Cap, China: Retrieval and return of a 308-m ice core from 6200 m altitude

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