Study On Numerical Simulation And Layout Of Composite Shield Machine Cutters

With the acceleration of urbanization in China,rational development and utilization of underground space has become an important measure to improve the utilization rate of urban space and optimize urban spatial structure.As special engineering equipment for tunnel excavation,the shield machine can realize the functions of correcting deviation,segment assembling and slag conveying in the process of tunnel geotechnical excavation.Cutter head is the key component of shield system,and its design quality level will directly affect the excavation performance and safety and stability of shield machine cutter head.The layout design of cutter head is an important part of cutter head design,which has a direct impact on the wear state of cutter,the service life of bearings and the stress state of cutter head during excavation.Based on the composite shield machine,this paper analyses the cutting process and stress of the cutter head’s important rock-breaking tool,and studies the influence of different parameters on the rock-breaking performance of the cutter by numerical simulation method.According to different types of cutter head,the layout rules of different cutters are analyzed,and the design flow of cutter head layout for composite shield machine is put forward.Firstly,the main structure and types of cutter head and cutter of shield machine are summarized as a whole.The rock-breaking mechanism and stress state of scraper and disc cutter are analyzed respectively.On this basis,the main rock-breaking force models of each cutter are compared.Firstly,the main structure and types of cutter head and cutter of shield machine are summarized as a whole.The rock breaking mechanism of scraper and disc cutter of main cutting tool is analyzed separately.On this basis,the rock breaking force state of cutter is analyzed,and the main force models of each cutter are compared and analyzed.Secondly,the finite element simulation model of scraper cutting soil is established by numerical simulation method,and the influence of main structure and working parameters(rake angle,width and depth)of scraper on cutting performance is analyzed.By comparing the changing trend of cutting force in the process of cutting soil with the scraper,the influence of each parameter on cutting effect and stress state of the scraper is obtained.The finite element simulation model of sequential rock breaking by disc cutter combination is established by means of linear cutting.The rock breaking process of disc cutter under different working parameters(cutting speed,penetration and tool spacing)is simulated.The effects of various factors on rock breaking effect and stress state of hob are analyzed respectively.Based on the finite element simulation model of sequential rock-breaking by disc cutter combination,the significance of multi-factors affecting rock-breaking by disc cutter combination is analyzed by orthogonal method,and the difference between different levels of the same factor is further analyzed by multiple comparison method.Finally,according to the spoke type and spoke-board type cutter head,the cutter layout of composite shield machine cutter head is studied.By combining the principle of equal life with the principle of force balance,the scraper Archimedes spiral layout method is obtained.The principle of disc cutter layout is put forward and the corresponding calculation model is established.The layout method of auxiliary cutting tools and the design method of important parameters of cutting tools are analyzed.According to the process of cutter placement of shield machine,combined with the mechanism of cutter rock breaking and the rule of cutter placement,the main process of Tool layout design of cutter head of composite shield machine is put forward.