Abstract
In order to evaluate the applicability of high-speed waterjets technology to slot cutting in rocks from economic point of view, it is necessary to predict the depth of cut of an objective rock for various cutting conditions. The depth of cut is influenced by the cutting parameters such as driving pressure, traverse rate, standoff distance and nozzle diameter in addition to the mechanical properties of the rock.
In this paper systematic experiments were carried out both in air and in water for five rocks including mortar to know the effects of both driving pressure up to 98.1 MPa and traverse rate up to 198mm/min.
Main results obtained in this study are summarized as follows:
1) There exists a critical-driving pressure below which no cutting occurrs for both in air and in water.
2) The depth of cut in water is often greater than that in air when driving pressure is sufficiently large and traverse rate is small enough except granite. This is due to the cavitation errosion in water.
3) The depth of cut h can be expressed by the following equation as a function of driving pressure p and traverse rate V for both in air and in water.
h=A1V-n (p-pc)
where Pc is a critical pressure, A1 and n are coefficients.
4) The critical pressure is less dependent on the traverse rate in the range of this study and increases almost linearly with tensile strength of rocks.
5) The coefficient n is almost independent of the mechanical properties of rocks but depends mainly on the environmental medium.
