Cooperative Breaking Rock Of Double Disc Cutters And Optimal Layout Of Disc Cutter On Cutterhead

Full face tunnel boring machine(TBM)is an essential equipment for long tunnel construction.There is a huge requirement for TBM in China construction market due to the investment increasement in domestic infrastructure construction.Cutterhead is one of the core parts of TBM,the disc cutter layout on cutterhead directly affects the construction speed,TBM life,rock breaking efficiency and cutterhead force.Unbalanced forces can easily cause cutterhead vibration and accelerate the wear of cutter.The disc cutter layout on cutterhead mainly depends on the characteristic of breaking rock decided by geological conditions,however,are difficult to be determined due to lacking of rock breaking data under the condition that the breaking rock force cannot be accurately calculated by prediction model.There is short of research on disc cutters layout considering TBM disc cutter breaking rock characteristic.The performance parameters of equipment for disc cutter breaking rock can not satisfy velocity varying range requirement of all cutters on cutterhead and the design requirement of designing TBM cutterhead.The analysis of disc cutter rock breaking mechanism and the related test using the new developed equipment can obtain accurate data of the rock breaking force,which can solve disc cutter layout on cutterhead in engineer and has theoretical value and engineering significance.Hence,the cooperative breaking rock characteristic of double disc cutters was analyzed and the test bed with double disc cutter was developed which can adjust spacing to simulate all cutter breaking rock.The disc cutter layout on cutterhead was optimized based on analysis and experiment data.The main works are as follows:(1)The disc cutter breaking rock model was built based on rock compositon and micro structure characteristic.The rock micro structure,pore and crack were tested by SEM and industrial CT and the rock characteristic was further analyzed based on rock compositon and rock mechanics influencing factors.The breaking rock mechanism of double disc cutters was analyzed based on above analysis.The mathematical model of disc cutter breaking rock was established and the constitutive relation was selected.The geometric model of cooperative breaking rock of double disc cutters was built and the mesh was generated,which established the foundations for simulation analysis.(2)The multi-factors influence on cooperative breaking rock characteristic of double disc was analyzed.The influence degree should be confirmed considering that the design and construction parameters have complicated influence on rock breaking characteristic.The influence degree of parameters on breaking force was confirmed by variance and extreme analysis on the results of orthogonal experiment.The influence of parameters variation on rock breaking characteristic was obtained.The jointed characteristic and parameters influence on rock breaking characteristic were analyzed.The research can provide a method and reference for disc cutter layout on cutterhead.(3)The high-speed test bed with double disc cutter which can change spacing along double direction was developed and the rocks were broken and analyzed.There were many parameters affecting rock breaking and all disc cutters on the cutterhead have wide range velocity.The design parameters were determined by combining static rock breaking force obtained by rock crush experiment with simulation data.The structure of test bed and hydraulic driver system were designed,the force analysis of test bed and driver system characteristic were analyzed.The rock breaking experiments were carried out by test bed,the law of parameters affecting different rock breaking force and characteristic was obtained.The simulate data was validated by experiment data.The equipment satisfies the rock breaking requirements.The simulate method possesses feasibility and accuracy.(4)The disc cutter layout on TBM cutterhead was design and verified based on tao river diversion project.The cutterhead applied in tao river diversion project was used to explain the disc cutter layout method.The PSO optimization algorithm combined with the analysis and experiment data of cooperative breaking rock of double disc cutters was established.The disc cutter layout on cutterhead was optimized and the thrust force and torque were calculated.The force and mode of vibration were analyzed.The paper provides a method for disc cutter layout optimization in TBM cutterhead design.