Abstract: Core drilling technology for subglacial bedrock is an important means to study glaciology, palaeoclimatology and geology in polar regions. Cable-suspended electromechanical drills and rotary core drill rigs have been successfully used in subglacial bedrock coring drilling; however, use of cable-suspended electromechanical drills involves the technical challenges of drilling in hard rock and inefficient discharge of cuttings from the borehole, and for the rotary core drill rigs there are the difficulties with drilling-fluid leakage in firn and hydraulic fracturing in ice. In addition, the existing rotary core drill rigs are heavy and have a simple function. Coring drilling of subglacial bedrock in polar regions involves additional technical challenges, such as difficulty in drilling warm and debris-rich ice, borehole melting caused by heat produced in bedrock drilling, insufficient capacity of low-density drilling fluid to carry cuttings, and existing meltwater at the ice-rock interface. In this paper, based on the literature research on subglacial bedrock core drilling technologies in recent decades, the application conditions and the advantages and disadvantages of various drilling methods are systematically reviewed, and a technical optimization scheme is proposed to provide technical guidance for the implementation of subglacial bedrock core drilling projects. In the future, it will be necessary to further improve the existing subglacial bedrock core drilling technology that makes use of cable-suspended electromechanical drills and rotary core drill rigs, and to develop coiled tubing core drilling technology and the rapid air ice drilling technology. In general, there are still many disadvantages in the current technologies of subglacial bedrock core drilling. In the future, it is necessary to further develop the subglacial bedrock core drilling technology that will need to be further developed to promote the development of polar science.

Key words: subglacial bedrock, core drilling technology, review, polar regions