[This article belongs to Volume - 54, Issue - 09]
Gongcheng Kexue Yu Jishu/Advanced Engineering Science
Journal ID : AES-13-11-2022-396

Title : Study on the Influence Law of Pre-cutting Groove on the Crack Expansion of Rock Breaking by Disc Cutter
GUO Lu, LUO Xingchen, HE Shan, HAN Weifeng, XIA Yimin,

Abstract :

To solve the problems of low penetration, serious wear and low rock-breaking efficiency during traditional disc cutter rock breaking under the geological conditions of hard rock, many new auxiliary rock breaking methods have been proposed, such as creating pre-cutting grooves on the rock through laser, water jet, and other non-contact rock-breaking methods to assist disc cutter rock breaking. To clarify the rock breaking mechanism of the disc cutter under the condition of the pre-cutting grooves, the particle discrete element method is used to establish two auxiliary rock breaking simulation models for the pre-cutting grooves at the side of the disc cutter (side-type) and in front of the disc cutter (front-type). The influences of the depth of the pre-cutting grooves and the cutter spacing on the propagation of rock-breaking cracks by the disc cutter are explored. The research results show that: 1) The pre-cutting grooves in the side-type auxiliary rock-breaking model mainly affect the expansion of cracks, and the lateral cracks propagate to the bottom of the pre-cutting grooves during the process of inducing rock breaking. The pre-cutting grooves in the front-type auxiliary rock-breaking model mainly affect the initiation of cracks, and only lateral cracks are generated at the early stage of penetration, and the lateral cracks are promoted to propagate to both sides; 2) The vertical force of the disc cutter and the number of cracks decreases with the increase of the depth of the pre-cutting grooves, while the vertical force of the disc cutter increases with the increase of the cutter spacing, and the number of cracks first increases and then decrease with the increase of the cutter spacing; 3) Under the same condition, the side-type auxiliary rock-breaking model is higher than that of the front-type auxiliary rock-breaking model, but the vertical force of the disc cutter in the front-type auxiliary rock-breaking model is much smaller than the vertical force of the disc cutter in the side-type auxiliary rock-breaking model. The auxiliary effect of the pre-cutting grooves can be fully utilized by further increasing the penetration of the disc cutter in the front-type auxiliary rock-breaking model; 4) When the penetration of the disc cutter is constant, the side-type auxiliary rock-breaking model is suitable for the case where the depth of the pre-cutting grooves is greater than the penetration of the disc cutter, and the front-type auxiliary rock-breaking model is suitable for the case where the depth of the pre-cutting grooves is less than the penetration of the disc cutter