Cutting Through Hard Rock-Like Materials - a Review of the Process
Type:
Presented during:
WODCON XX: "The Art of Dredging" - 2013, Brussels, Belgium
Authors:
Helmons RLJ, Miedema SA
Abstract: To this date the design of cutting tools is mainly based on experience in the field and analytical relations, like the rock cutting models of Evans, Nishimatsu or the cutting model for sand, clay and rock of Miedema. When dredging or mining at large depths, the cutting of rock takes place under very high hydrostatic pressures of tens to hundreds of bars. These high pressures have an implication on the cutting process. Rock that behaves brittle under atmospheric conditions will behave in a more ductile fashion due to these high confining pressures. This pressuredependent brittle-ductile transition and also effects like pore-pressure and heterogeneities of the rock, which are of major influence on the cutting process, are not yet incorporated in the known cutting models. In order to extend the applicability of the existing models, a more fundamental approach on the interactions between the cutting tool and the intact rock is proposed.
With the aim of developing an improved model of the rock cutting process, in order to predict cutting forces and powers, the interactions between the tool, rock, the pore fluid and the high hydrostatic pressure all need to be included. In order to do this, a review of the state-of-the-art of the current modeling techniques is given. From this a new approach to model the corresponding physical phenomena, based on the Discrete Element Method, is presented.
The new model will be validated with field measurements and data available in literature. So this model will eventually give more insight in the physical processes that occur during cutting and it will help to improve the operational and design guidelines of the cutting process and equipment.
Keywords: rock mechanics, rock cutting, numerical modeling, poromechanics