Analysis On Rock Bursting And Impact Factors Of Broken Rock Force

In recent years, the rapid development of the world economy has promoted the process of urbanization. Facing the problem of traffic congestion caused by Urbanization, the development of underground space has become an important measure for the construction of the city. Shield Tunnel Boring Machine is the most advanced and most effective special large-scale construction machinery, which has the advantages of high speed, high efficiency, high safety, good construction quality and so on. So it has been widely used at home and abroad. Disc cutter is a key component of shield machine, its crushing performance directly affects the efficiency and cost of the underground construction. At present, a lot of achievements have been made in the study of the rock breaking of the disc cutter. However, most of the research is based on the related research of the disc cutter rolling, and the research of the disc cutter impact-rolling is still in the exploratory stage. Aiming at geological conditions of high hardness, high quartz content and high confining pressure, the research on rock breaking mechanism and influencing factors of rock breaking by impact rolling of disc cutters is of great guiding significance to improve the performance of cutting tool and the efficiency of shield tunneling. The main contents fall into such parts as follows:In the first place, the classification and structural style of the disc cutters has been introduced. The fracture mechanism of rock has been discussed. The crushing process of impact-rolling of disc cutters has been studied and a method of force analysis of impact-rolling of disc cutters has been put forward. Combined with the characteristics of impact-rolling, the problem of rock breaking force of impact-rolling of disc cutter by using the method of dimension analysis was studied. Then a mathematical model of normal breaking force with the consideration of the whole factor is established. To reveal the relationship between the geotechnical parameters, disc cutter parameters and tunneling parameters which affect rock breaking of disc cutter.The second part studied that the rock-breaking processes of disc cutters under rolling cutting and impact-rolling cutting respectively were dynamically simulated by LS-DYNA. Then, the rock-breaking characteristics and the load characteristics of the cutting tool were analyzed in the two rock breaking models. By comparing with effect of rock breaking, Research results show that the effect of impact-rolling on rock breaking is obvious. Meanwhile, the test of disc cutter rock breaking was carried out to verify the correctness and reliability of the simulation analysis.In the end, the influence factors of the impact-rolling of the disc cutter on the rock breaking have been studied deeply. By changing cutting parameters of impact-rolling rock breaking of the disc cutter in the finite element model, the cutting speed, penetration (depth of cut) and the impact frequency and depth of impact under the effect of single factor were respectively studied on the tool cutting performance effects. Then by using orthogonal experimental design method, the influence degree of the cutting performance of the tool is studied under the interaction of the above four factors, and the optimum combination parameters are obtained.