| In the rock tunneling process of Tunnel Boring Machine (TBM), the disc cutter and the front rock mass contacts directly and interacts with each other, rock breaking load is the im portant factor of the t unneling perform ance. Th erefore, the rock breaking load is the key factor to design cutter and to decorate the cutter dish of TBM, and the deeply study of it under the action of single and double cutter not only has theoretical value, but also has guidance to engineering practice. In addition, the study of rock breaking load can provide the re ference for TBM desi gn and cutter dish decorate.In this paper, failure problem of th e brittle rock under the disc cutter is numerically simulated. Numerical simulation uses linear elastic fractu re mechanics theory, through the Hertz crack propagati on and coalescence th e m eans of cutter broken rock by numerical simulation, this article discusses the different factors on the disc cutter broken rock the e ffect of load. Specifically, the major works of the paper are as below:(1) Based on the maximum circumferential stress criterion of brittle fracture, the crack propagation m odel uses APDL progr am to realize the crack propagatio n adaptively. The existing elem ent splitti ng m ethod is supplied and is reasonably simplified, using the node m oving algorithm to avoid the distortio n of the grid. The crack tip uses 1/4 node elem ents and refi nes division, g ets accu rate crack stress intensity factor, and calculates crack propagation angle and expansion ability. Tensile plate, uniform uniaxial com pression rocks, and double concentrated load function of rock crack propagation process are simulated respectively, verifying the effectiveness and adaptability of the algorithm.(2) Under the action of single cutter rock fracture pro cess by num erical simulation, discusses different confining pr essure, different init ial crack length and angle of broken rock the effect of load. The results show that the single cutter role can make lateral crack pro pagation an d the generation of broken block. In certain conditions of initial angle for 45°crack, rock breaking load is the smallest.(3) On the double cutter and on the role of rock fracture pr ocess, num erical simulation discusses different confining pre ssure, different crack length and angle of initial broken rock the effect of load. Th e results show that the double role in top meets the crack and confines pressure. The greater the crack is the easier it is to reach the level intersection.(4) Under no confining pressure and 20M Pa confining pressure, the spacing of the double cutter are o ptimized respectively. With the increase of cutter space, the breaking ratio has a process of decreasing first and then increasing. On the condition s of no confining pressure and 20MPa role s, the best cutter spicing are 65mm and 60mm respectively. |
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