Experimental investigation on concrete rock breaking performance of self-excited oscillation pulsed waterjet

Abstract

To obtain the influence of structural parameters, system pressure, standoff distance, rock characteristics on rock breaking volume and specific energy consumption, the rock breaking experiment using self-excited oscillation pulsed waterjet (SOPW) was carried out. The relationship among rock initial crushing pressure, fracturing pressure with rock compressive strength was investigated, and the change trend between rock breaking morphology and standoff distance was also observed. In addition, the order and optimal parameter combination of influential factors on rock breaking performance using SOPW was obtained through an orthogonal test. The research results show that the rock breaking performance under the impact of SOPW is better than that of continuous water jet in the initial stage, and the difference of rock breaking volume under the action of two-type jet is getting larger as the time going on. Moreover, the initial crushing pressure and fracturing pressure increases with the increase of the compressive strength, and the initial crushing pressure and the fracturing pressure is predicted as 54.4 MPa and 125.8 MPa, respectively, when the rock compressive strength is 80 MPa. Furthermore, the primary and secondary order of various factors on rock breaking performance is system pressure, standoff distance, oscillation cavity length, section cone angle, and the optimal combination is 40 MPa, 10 mm, 70 mm, and 140° for the system pressure, standoff distance, oscillation cavity length and section cone angle, respectively.