Study On Cutter Wear And Cutter Optimized Layout Of Tunnel Boring Machine

With the implement of large-scale infrastructural project in our country, a largenumber of long distance tunnels are required to excavate during the construction ofrailway, highway, water conservancy, hydroelectricity and municipal administration.Tunnel boring machine (TBM) has been widely used in aforementioned tunnels due toits many advantages, such as high advance rate, high degree of automation, goodworking environment and favorable comprehensive benefit. The cutters mounted onTBM cutterhead are the key component of excavation and advancement, therefore thecutter’s wear and failure will directly influence the advance efficiency of TBM. If thecutter can’t be replaced timely when severe wear happened, the adjacent cutter’s wearwill accelerate due to the overload operation, also the cutterhead breakage orreduction of main bear life due to serious unbalanced load will take place. As a carrierof cutters, cutterhead transfer the force when rock-breaking while optimized layout ofcutters on cutterhead is of great significance in increasing advance efficiency.According to the problem of cutter wear prediction and cutterhead cutter layout, a fewresearch works has been accomolished in this paper based on the study of home andabroad.(1) TBM cutter’s type and its failure types were analyzed, and focus on the wearfailure of cutter. Based on work theory of cutter and rock interactional during rotaryrock breaking and the cutter wear mechanism, the four principal factors which affectcutter wear were summarized, that is cutter geometry, cutter material and process,TBM advance parameters, rock abrasion resistance. On the basis of present cutterwear prediction methods, wear prediction model that based on cutter rock breakingfriction work was put forward and the feasibility of this model was validated by theTBM used in the construction of Qingling tunnel.(2) ABAQUS analysis procedure and explicit dynamics basic theory werestudied. For hard granite, the17in constant cross-section (CCS) disc cutter thatwidely used on TBM, the Drucker-Prager constitutive model and fracture damagecriterion based on tensile property have been adopted to establish thethree-dimensional rotary rock breaking model of two disc cutter in succession, the influence of cutter spacing and penetration on cutting force and specific energy inrock breaking was obtained.(3) The factors for cutterhead design, cutters layout on TBM and method ofdetermining main cutting parameters were analyzed. The methods to determine maincutting parameter include experimental method based on linear cutting machine(LCM) and computer simulation method based on finite element theory. Then, twocutterhead design methods used present were compared, that is rock-breaking basedmethod and comprehensive optimization design method. Based on the theory of equalfriction work, cutter spacing arrangement of the cutters in peripheral region of TBMcutterhead was analysed and calculated for granite geology.