Experimental study of the drilling process in debris-rich ice

Abstract

Debris-rich ice is often encountered when drilling into basal ice and rock glaciers. The standard steel bits used for ice core drilling are not suitable because the cutters are very easily broken by rock particles because their hardness and abrasiveness are higher than that of the ice. The tool steel and tungsten carbide inserts are easily damaged in intermixed ice-rock formations. To obtain high-quality core samples in debris-rich ice, it is necessary to find drill bits that can drill ice-rock mixtures with minimal load and acceptable penetration rate and torque. A special testing stand has been designed and constructed to study both standard and custom-made carbide and polycrystalline diamond compact (PDC) drill bits. The results show that both the carbide and the PDC drill bits can drill with high penetration rates in debris-rich ice containing very hard and abrasive granite particles at low drill loads of 500-1200 N. When the rock volume content is 30%, the penetration rates are 4.68 m/h, 5.9 m/h and 11.12 m/h for the standard six-tooth carbide drill bit, a PDC bit with a round compact and a PDC bit with a semi-round compact, respectively, under a drill load of 500 N with a rotation speed of 100 rpm. Within the range of drill loads of 500 to 1200 N and rotation speeds of 50 to 200 rpm, the maximum torque is no more than 45 Nm, and the power consumption is less than 0.8 kW. In addition, the temperature changes of the bit cutters caused by their cutting action were also measured. Results of the preliminary tests show that temperature variations increase from 3.67 to 5.96 ˚C when the drill load increases from 450 to 1200 N and from 4.17 to 6.21 ˚C when the rotation speed increases from 50 to 200 rpm.

Design of bionic locust mouthparts stubble cutting device

“…The cutting torque -cutting time curves were plotted on MATLAB, so as to observe the changing trend of cutting torque and find out the maximum cutting torque. The cutting power consumption could be determined via Equation 10on MATLAB by collecting the cutting torque and cutting time [30,31] .…”

Adaptation of the Winkie Drill for subglacial bedrock sampling

“…Impregnated bits cannot be used if ice is present in the kerf of the bit, as the ice glazes the bit surface. PDC bits have successfully been tested (Cao and others, 2015) and recovered cores with other subglacial drill systems (ASIG and RAID). Use of PDC bits was attempted unsuccessfully in two field seasons.…”

Retrieval of Ice Samples Using the Ice Drone

“…High sediment loads and larger debris can damage or break cutting teeth (Cao et al, 2015) and IceDrone has yet to be tested under these conditions. Similarly, drilling is only possible on ice that is free of any appreciable snow and/or firn layer.…”