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D. Kohlböck:
"Rock Chisel Usage in variable Groundwater Conditions";
in: "14th Danube-European Conference on Geotechnical Engineering", 14th Danube-European Conference on Geotechnical Engineering, Bratislava, 2010, ISBN: 978-80-227-3279-6, 9 S.

The installation of large-diameter pile foundations by hammer grab and chisel is a long-standing method of construction. The use of chisel devices is to break rock or other subsurface obstacles by means of percussive impact. However, frictional and inertial forces within the system and especially free-fall through water can result in an energy loss of 60% and more. Thus, the construction process can be considerably prolonged. In this paper comprehensive investigation of chisel usage is presented. Analytical solutions for chisel motion and computational fluid dynamics calculations are given, which allow for comparison and optimization in chisel design. Small-scale tests in the laboratory and full-scale tests on construction sites and the development of a monitoring system are presented in order to combine theory with practice. Based upon the results, recommendations for the application of the chisel devices can be provided, under conditions representative of those encountered in engineering practice.

bored piles, hammer grab, rock chisel, groundwater