| China is the largest developing country in the world.In order to solve the problems such as the reduction of viable land and the shortage of water resources,and to meet the increasing transportation demand of the people,it is imperative to expand underground space resources.The 2035 vision clearly requires the establishment of a new modern infrastructure construction system with complete systems,intelligent,green,safe and reliable characteristics.The full-section Tunnel Boring Machine(TBM)comes into being.Due to its construction efficiency,TBM is widely used in railway tunnels,water conservancy projects and other construction projects.The disc hob is located on the palm face and installed on the knife seat,which is in direct contact with the rock.Due to the bad working conditions in the tunneling process,various failures often occur in the knife ring,which is difficult to ensure the work efficiency and construction progress.Therefore,it has a good theoretical basis and engineering significance to study the rock breaking process of TBM disc hob,to obtain accurate rock breaking load and to predict the life of TBM tool,and to reduce the cost of tool replacement.In view of the above problems of disc hob,this paper carries out the load and fatigue life prediction of disc hob.The main content includes the following parts:(1)In the rock breaking process analysis of disc hob,aiming at the problem of large load impact in the working process of TBM disc hob,this paper statistics the main failure forms of the tool,combined with the analysis of the crushing mechanism and rock breaking process of rock and engineering rock mass,and compared the rock breaking force load prediction model,so as to provide a theoretical model for the load prediction and life prediction of TBM disc hob.(2)In the simulation analysis of the rock breaking process of the disc hob,the load of the TBM disc hob is very random,which leads to the problem that it is difficult to calculate accurately.In this paper,the nonlinear transient dynamics ANSYS LS-DYNA software is used to analyze the rock breaking process,the rock and soil changes around the tool and the load characteristics of the tool are analyzed,and the theoretical formula and the actual engineering data are verified to verify the accuracy of the rock breaking model established by the hob,which provides the basis for the follow-up research.(3)In the research and analysis of the influence of rock breaking parameters of disc hob on rock breaking force,based on a large number of single factor rock breaking results,the response surface method was used to analyze the interaction of four factors: The influence of cutting speed,edge width,edge transition corner radius,penetration degree and tool spacing on cutting load was analyzed.The regression equation of rock breaking load was given,and the variance and significance analysis were carried out.The second-order response model fitted well.(4)In the fatigue life prediction analysis of the hob consumption theory,the nominal stress method is selected to predict and calculate the fatigue life of the cutter ring based on the disc hob consumption prediction theory,and the life prediction calculation theory of the disc hob is summarized,which has certain practical guiding significance for the prediction of the life of the disc hob cutter ring under specific geological conditions in the actual rock break process. |
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