Analysis of Rock-Breaking Load Characteristics and Efficiency Optimization of Conical Cutterhead Hobs in Urban Hard-Rock SBM

To investigate the load characteristics and rock-breaking efficiency of the hobs on the conical cutterhead, a theoretical model of the hob’s rock-breaking load was established based on the plastic-brittle characteristics of rock, with a verification error of less than 5%. A numerical model of dual-hob rotary rock breaking was developed using ABAQUS 2022 software to comparatively study the influence of penetration depth (P), cutter spacing (S), and rotational speed (V) on the hob’s load behavior and rock-breaking efficiency. The specific energy of rock breaking under various test conditions was obtained through orthogonal experiments. The results indicate that, as the penetration depth increases, the average rock-breaking load of the hob gradually increases, while the specific energy first decreases and then increases. With larger cutter spacing, the average load shows a modest increase, and the specific energy exhibits a gradually rising trend with a diminishing growth rate. As the rotational speed increases, the average load increases slightly, while the specific energy rises with an accelerating growth rate. Range analysis revealed that the order of influence of factors on rock-breaking efficiency is P > S > V. The highest rock-breaking efficiency was achieved at P = 2 mm, S = 60 mm, and V = 7 r/min. At a significance level of 0.05, the penetration depth was found to have a significant effect on specific energy. This study provides a valuable reference for the design of hob layouts and parameter settings of conical cutterheads, contributing to improved rock-breaking efficiency.