Numerical Simulation And Cutter Layout Design Study Of Full-face Tunnel Boring Machine

With the need of rapid excavation of underground engineering and improving the science and technology level, shield tunneling construction technology has been rapid application and development in China. The development of shield machine application and construction of underground space engineering have induced the growing attention of related government departments and businesses to the investment in the employment of shield machine in the underground tunnel Projects.Disc cutter is an important tool of shield machine to crush the rock during excavating tunnel, cracking efficiency of it directly impacts on the construction effieieney. To date, the research on the rock breaking properties of disc cutters of shield machine, compared with foreign countries, is still in its initial stage. Based on wide reading and in-dePth study of the related articles and books centering on the rock breaking theory, through research on failure criteria of rock medium under breaking process of disc cutter, it can lay a theoretical foundation for further comprehensive research rock breaking mechanism. Study on cutting property of disc cutter, it also can provide theoretical basis for structure improvement of disc cutter and cutter optimal layout on shield cutter head, at last, achieve our research objective of improving crushing efficiency. The specific content of this paper include:(1) The rock under cutter effect breaks mechanism and cutter force model:To study the mechanical properties of disc cutter, rock damage and failure mechanism of the phenomenon of rock subtle statistical damage constitutive model, summed up the theory-based cutter force models, including the Iraqi Vance (Evans) prediction equation, autumn Mifuji Saburo Prediction equation, the Colorado school of Mines prediction equation and so on. In order to cutter layout optimization design tool force model provides theoretical basis.(2) Based on the systematic study of the existed rock constitutive model achievements and introduction of rock breaking mechanism, main failure mode of rock in the breaking process of disc cutter is added and revised in order to meet the actual situation. The method of establishing finite element model of disc cutter breaking process using ANSYS software is introduced. Through dynamic simulation we can obtain that geotechnical interface disturbance insulted by disc cutter as well as force size in the disc cutter. Based on plenty of experiments, it confirms reliability of numerical methods and provides a method to study cutting performance for different geological conditions.(3) Based on a large number of single-factor cutting simulation, the influence of many cutting conditions such a blade angle, cutting depth and cutting speed on cutting property are discussed. Subsequently, use of interactive multi-factor orthogonal test method, impact of significant factor during the breaking process has been obtained.(4) Cutter layout optimization design:An integrated mechanism to consider breaking rock, construction parameters, and two kinds of typical geological conditions of rock, through access to domestic and foreign literature, as well as with the co-operation with a first-line engineering and technical experts to explore, given the general layout design needs cutter TBM to meet the technical requirements, and then in order to meet these technical requirements, the establishment of the whole TBM hob layout optimization model, given the whole TBM cutter layout rules and hob layout based on genetic algorithm design methods.