The Study On Combined Cutting Rock Mechanism Of TBM Disc Cutters

Tunnel boring machine (TBM) is a kind of mechanical construction equipmentwhich is used to full-face excavation in underground engineering project. It is widelyused at home and abroad because of its lots of advantages, such as fast and efficientexcavation, high safety and reliability, good construction quality. Disc cutter is the keyexcavation tool on the cutterhead of TBM which has a great effect on excavationefficiency and construction costs. For this reason, to study the disc cutters cuttingmechanism and cutters layout law is very significant to optimize the cutters layout, toimprove cutting efficiency, to develop the working life of disc cutters and to reduceconstruction costs. This paper mainly studies the combined cutting mechanism ofTBM disc cutters. The main research content is as follows.(1) The classification and structural style of Disc cutters has been introduced.The elastic-plastic constitutive model and fracture mechanism of rock have beendiscussed. Several cutting rock models have been studied which are widely used athome and abroad. The design law of TBM cutterhead and cutters layout law havebeen studied. According to the characteristics of combined cutting model, Spacing andlayout radius of cutters have been studied.(2) The second part studied the explicit dynamics and Drucker-Prager nonlinearelastic-plastic constitutive model. Aiming for testifying the rightness of D-P model,the indentation model of disc cutters has been established by using ABAQUSsoftware. Otherwise, this model has studied the strain-tress value of rock and theforces of disc cutter which have compared with the results of indentation experiment.The linear cutting models have been established with the ductile damage fracture rule.This simulation has studied the relation between spacing and cutting force which havecompared with linear cutting experiment made by foreign researchers. Finally, basedon the characteristics of mutibody dynamics, a rolling cutting model with three cutterslied in helical line style has been established. This model has studied the interactionamong three cutters, cutting force of cutters and the stress-strain state of rock. Thedifference between the rolling cutting model of three-cutter and linear cutting modelhas been studied. (3) Smoothed Particle Hydrodynamics (SPH) method has been introduced. Thebasic principle and algorithm of SPH method have been studied. Then the necessity ofSPH-FEM coupling analysis has been discussed. Several2D cutting models of cutterswhich are based on SPH-FEM method have been established by using AUTODYNsoftware. These models have studied the effect of different layout parameters oncutters and rock, such as spacing, cutter velocity and loading methods.