Research On The Layout Optimization Method For Disc Cutters Based On Rock-breaking Energy Of TBM's Cutters

Full-face tunnel boring machine which also called TBM is widely used in tunnel construction due to its superior tunneling performance.In recent years,with the laying of high-speed rail lines and the promotion of urban underground space projects,the demand for TBM of domestic market has increased year by year.However,due to the late domestic research on TBM,foreign TBM equipment has occupied most of the market.In order to break the technical blockade of foreign companies and realize the independent design and localization of TBM equipment,we must pay attention to the research related technologies of TBM.Based on the previous studies,this paper analyzes the rock breaking process of disc cutters from the perspective of energy,completes the optimization of the radial arrangement and the circumferential arrangement of the disc cutter,and gives the evaluation method of the cutter-head's performance.The main contents of the paper are as follows:(1)Analyze the energy characteristics of the disc cutter during rock breaking process and the transformation law of energy inside the rock.According to the mechanism of energy-driven rock failure,the rock breaking energy of the disc cutter is defined.The formulas for the rock breaking energy of the disc cutters in each partition of the cutter-head are derived.(2)Based on the rock breaking energy of the disc cutter,the polar diameter optimization model of different sections of the cutter-head is established.The TBM cutter-head of MB264-311 type in the Dahuofang water delivery project is selected as the original cutter-head.According to the principle of the minimum variance of rock energy,the GA genetic algorithm is used to optimize the diameter of each disc cutter.Compared with the original rock breaking energy of the cutters,it is found that the distribution of rock breaking energy in the gaged cutters' area has been significantly improved in the optimization.(3)According to multiple performance evaluation indexes of cutter-head,the analytic hierarchy process is used to give a comprehensive evaluation function.The random arrangement mode and the m-shaped layout mode are selected to circumferentially arrange the cutters.It is found that the distribution of the cutters is more concentrated in the stochastic scheme.The meter-shaped scheme can make the cutters evenly distributed and the utilization of the discs is higher.Compared with the original design,the overturning moment of the cutter-head is reduced by 87.8%,the radial imbalance force is reduced by 23.5%,the cutters mass eccentricity is increased by 27%,and the eccentricity of rock breaking energy of the cutter-head is reduced by 73.2%,which proves the effectiveness of the optimization model.(4)The energy output prediction model of the improved cutter-head is given to provide reference for the selection of the operation parameters of the TBM.The efficiency of the output energy of the cutter-head was analyzed.It was found that the optimized cutter-head was more energy efficient and had lower frictional energy consumption.The rock energy distribution map of the cutter-head is drew,and the distribution of the cutter-head wear is predict combined with elastic energy conversion characteristics;compare the difference of rock energy of upper and lower parts between the original cutter-head and the improved cutter-head,as well as the left and right parts,the rationality of the improved rock breaker energy distribution is verified.