Analysis Of Factors Influencing The Failure Of TBM Disc Cutters And Numerical Simulation Study

TBMs are widely used in the construction of railroads,highways,urban subways,water conservancy and hydropower,and submarine tunnels.the study of TBM disc cutter wear is a popular topic of research,and is an important reference for TBM selection,design,and duration cost prediction.Therefore,it is important to study the wear of disc-shaped hobs in complex formations to prevent and control the wear rate of hobs and ensure the safe construction of long-distance TBMs.The paper takes the disc cutter,a common tool of double shield TBM,as the research object,conducts field tests to obtain the rock element and mineral content,and uses data analysis software to study the influence of parameters such as lithology,surrounding rock grade,rock element content,rock mineral content,cutter speed,digging thrust,cutter torque,penetration degree on the wear pattern of disc cutter,and finally establishes a numerical simulation model by discrete element software to study the influence of rock strength,cutting speed and cutting depth on the wear of disc cutter.The specific research results are as follows:（1）It introduces the hob wear mechanism,hob wear influencing factors,hob wear research methods,summarizes the classification basis and criteria of disc hobs,and analyzes the hob cutting process,wear mechanism and the causes of different failure types.（2）The types of hob failure and their influencing factors were studied.The hob failure types include normal wear and abnormal wear,and the causes of abnormal wear of hobs are described in detail,and the probability of occurrence of different failure types of hobs is also counted.（3）The influence of geological factors,TBM boring parameters and cutter installation position on the cutter wear rate was studied.Geological factors have an important influence on cutter wear,the higher the surrounding rock grade,the greater the cutter wear rate;Si O₂ content is positively correlated with cutter wear rate,Si element content is more correlated with cutter wear rate,Ca,K and Fe elements are less correlated with cutter wear rate.The cutter wear rate was investigated by using the control variable method on the cutter speed,cutter torque,digging thrust and penetration degree respectively.It was found that the cutter wear rate tends to increase with increasing cutter torque,digging thrust and penetration,while the cutter wear rate tends to decrease with increasing cutter speed.（4）The discrete element numerical simulation method and the discrete element numerical simulation software PFC are introduced,and the principles and methods of discrete element parameter calibration are described.The inverse calibration of indoor and numerical experiments was carried out,and the fine-scale parameters of five rock strengths were calibrated.The particle flow model of cutter-rock interaction was established,and the effects of three factors,namely,rock strength,cutting speed and cutting depth,on the wear rate of cutter were studied separately.（5）Based on the field cutter wear data and the analysis of tunnelling parameters,suggestions and measures to reduce the cutter wear rate and the probability of abnormal cutter wear are proposed.