Cutterhead Design Methods Of Rock Tunnel Boring Machine

Being a crucial factor in influencing the performance of Full Face Rock Tunnel Boring Machine (TBM), the cutterhead design is one of the key issues of TBM. The cutterhead needs to be designed according to geological conditions and construction requirements of a tunneling. Thus the cutterhead design is a complex issue of engineering system design. It is of important strategic meaning to study the key technologies and improve independent innovation design capability of the cutterhead. In general, complex equipment, such as TBM, is expensive and to perform vital tasks. The environment in which complex equipment operates has a great impact on equipment's performance. The external environment can change in an unanticipated way, which usually leads to inferior performance and even not meeting current expected performance requirements. So the adaptable design of complex equipment absorbs people's attention and becomes an urgent topic to be resolved.Based on the above engineering application backgrounds and supported by National Hi-Tech Research and Development Program (863 Program) of China and National Natural Science Foundation of China, this paper firstly studies the principal parameter design and cutter layout design method of TBM cutterhead. Then this paper studies the issue of TBM local redesign responding to unanticipated ground change. The cutterhead design is a wide issue, and only a part is studied in this paper. The main contents of this dissertation are as follows:(1) A case-based reasoning design approach considering geological conditions for TBM cutterhead principal parameters is proposed to quickly design the cutterhead principal parameters, which includes cutterhead number, cutting geometry, thrust and torque, etc. The design case description method of the cutterhead is proposed. Since there exist both numerical and symbolic attributes in cutterhead design cases, this paper uses local similarities to measure the similarities of various case attributes. The calculating ways of local similarities are provided correspondingly. For the local attribute whose value is at interval, this paper presents an interval similarity calculating method based on the probability distribution of the attribute value in the interval range. A combined case modification method is used to obtain the proposed solution of the new cutterhead design issue. The proposed method corresponds to the current design activities of TBM designers. Finally, a design example is given to verify the proposed method.(2) On the basis of summing up the related research, engineering practice and domain expert experience, this paper gives the description model of TBM cutter layout. The model matches the actual engineering conditions and considers more engineering factors and technical requirements, which is different from the traditional models. As for the characteristic of the layout problem, this paper proposes the solving method based on multi-objective evolutionary algorithm NSGA-II and presents the Pareto solution selection method based on fuzzy objective preference and distributing distance of the allocated objects. Finally, a TBM cutter layout example is given to verify the proposed model and method.(3) Another design method of TBM cutter layout is studied, which is based on fuzzy logic reasoning and evolutionary algorithm. In this methd, the fuzzy logic reasoning is used to express expert experience rule knowledge, imitate the expert reasoning process and obtain the layout districts of the allocated objects. The reasoning outcome corresponds to a fuzzy layout scheme and is input into evolutionary algorithm to evolve with the evolutionary computing programs so as to obtain better design scenarios. Finally, a TBM cutter layout example is given to verify the proposed method.(4) Taking the local redesign of TBM cutterhead responding to unanticipated changes of geological environment as example, the adaptable local redesign issue of existing equipment (ALRE~2) responding to unanticipated environment change is studied. The characteristic of ALRE~2 is to make adaptable local change design (including adding on new function components) on the basis of existing equipment architecture. The design objectives are to adapt existing equipment to new external environment so as to meet current expected performance requirements. The key issue of ALRE~2 is how to solve the architecture coupling contradiction of existing equipment. The design strategies of ALRE~2 are proposed. The key elements of ALRE~2 are discussed including new function derivation, function-structure analysis, structure change propagation prediction, coupling contradiction elimination and change design decision of the equipment. A design decision model of adding on diagnostics subsystem for equipment is proposed.In practice, Tunnel Boring Machine is large and key equipment, which relates to the national geology secret. Most TBMs are imported or cooperatively produced in our country. It is urgent to master the design technology with independent intellectual copyright. The cutterhead design is one of the key technologies of TBM. Thus it is of engineering application value to study TBM cutterhead design method, which matches with engineering practice. In theory, the research of cutterhead layout design method and ALRE~2 is helpful for promoting the research progress of TBM design theory and adaptable design responding to unanticipated environment.