Numerical Study On Abrasive Wear For TBM Disc Cutter Ring Based On Tribology

As the direct part contact with the rock surface, disc cutter rings are the mostimportant component and also the most vulnerable part of TBM during excavation.Wear extent prediction of TBM disc cutter rings can lower the engineering cost andshorten the project cycle. Most previous studies were on working performanceprediction of TBM, but less attention on quantitative calculation for wear extent ofdisc cutter ring. In this study, qualitative analysis for wear extent of disc cutter ringwas discussed; Theoretical calculation equation for abrasive wear calculation of disccutter ring was proposed for wear extent prediction of disc cutter ring and to providetheoretical guidance for tunnelling project. The specific contents are:1）Ignoring the side force of disc cutter and considering rock surface as a plane,the contact model for disc cutter ring and rock surface was established according tohertz contact theory, the dimension of ellipse contact area and the distribution ofpressure within the ellipse contact area was given as well; The distribution ofadhesion area and micro-slip area within the hertz contact area was presented basedon tribology; By analyzing the influence to the wear of disc cutter ring caused byquartz sands, and combined with the abrasive wear model, a theoretical calculationequation of abrasive wear extent for TBM disc cutter rings during excavation wasdeduced.2）Based on the calculation equation a calculative program was designed inFORTRAN language.3）The effect on TBM working performance due to the evolution of theparameters of disc cutter ring caused by wear during excavation was considered; Thevariation of normal force and penetration caused by wear of disc cutter ring wasanalyzed and as well as which had a higher efficiency of the two different projectconditions, which were maintain the same penetration and maintain the same normalforce.4）To illustrate the applicability and validity of the research proposed by thisstudy, data from on-site a particular project case were analyzed. The quantities of thedisc cutter rings consumed in the particular project case were calculated utilizing thecalculative program proposed in this study, and comparison between the calculative result and the actual quantities of the disc cutter rings consumed in the same case wasgiven.It revealed that the calculative result was almost the same with the actualcondition, the method proposed by this study could reflect the actual wear extent ofdisc cutter ring; Wear of disc cutter ring could lead to widening of cutting edge, and ifthe normal force acting on disc cutter didn’t increase, the penetration of disc cutterwould decrease, and then lead to reducing of excavation efficiency; But if we increasethe normal force to maintain the same penetration, then the wear of disc cutter ringper cutterhead rotation would aggravate, and the lifetime of disc cutter ring wouldshorten greatly; And it revealed that it had a higher efficiency to maintain the samenormal force during excavation.