| TBM is a kind of large-scale tunnel boring equipment and the cutterhead system is an important part of TBM.Domestic and foreign scholars have done a lot of research work from on disc cutter size,rock-breaking mechanism,force prediction formula,wear characteristics to on disc cutter layout of cutterhead,thrust and torque analysis.However,most of them are based on the analysis of the interaction between disc cutter and the rock in terms of elasto-plastic mechanicsDue to the unique characteristics of rock,the high local stress on the rock will only partially lose its strength and the rock will not be destroyed entirely.From the energy point of view,rock-breaking mechanism of dics cutter,energy characteristics and conversion process are analyzed,which provides a new idea for the research of rock-breaking.Based on the energy characteristics of rock-breaking,the optimal layout of disc cutter,the wear prediction and wear characteristics of disc cutter are proposed.The specific research work is as follows:First,according to the limitation of elasto-plastic mechanics analysis of rock failure,from the point of view of energy,energy characteristics,transformation process,strain softening mechanism and strain hardening mechanism of driving rock failure are analyzed.Then,aiming at the problem of large energy consumption and cutterhead deformation during tunneling,disc cutters are rearranged.Based on the force prediction model of CSM,the prediction formula of rock-breaking specific energy with cutter spacings variable is deduced.According to the minimum principle of rock-breaking specific energy,using standard GA algorithm,cutter spacings in the central and normal area and the tile angle between two gage cutters in the transition area are optimized,respectively.In order to minimize the weight of the radial force and the overturning moment,the polar angles of normal cutter and gage cutter are optimized.An example is given to demonstrate that the optimized disc cutter layout can not only reduce cutterhead rock-breaking specific energy by 1.41%,but also make the vertical force on the cutterhead distribute more evenly,and the radial force and overturning moment are close to zero,which reduce cutterhead deformation,and reduce the main bearing load;Finally,in view of the fact that the research on the factors that affect disc wear is not comprehensive enough and disc cutter wear prediction accuracy is not high,the wear prediction model is established from the influence of friction work on the wear.According to the energy conservation in rock-breaking,the friction work is indirectly calculated.Based on the previous tribological studies,an engineering example was used to verify the linear relationship between the abrasive volume of disc cutter and the friction work.,and the new wear prediction formula is established,and the influences of installation radius,length of excavation,uniaxial compressive strength of rock,penetration,disc cutter radius and blade width on friction work and disc cutter wear were studied,respectively.Compared with the actual engineering data,the prediction error is smaller and the accuracy is higher,which can improve the prediction ability of disc cutter wear. |
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