Abstract: In order to optimize the layout of TBM cutters on deep jointed rock and improve the efficiency of TBM, two-dimensional discrete element software UDEC has been used to research the impact of joint spacing, angle and the cutter spacing on the rock fragmentation. The results show that when the joint spacing is 50 mm, cracks extend to the joint surface and spread along the tilt direction despite the barrier effect and the various angle of joints; when the joint spacing is not more than 100 mm, the rock cracks can extend to the joints but the crack propagations is controlled by the joints; when the joint spacing is no less than 150 mm, joints have no impact on the break rocks because the propagation of crack can’t reach the joints. When the spacing of horizontal joints is small, the joints will affect the rock fragmentation and the effects may gradually weaken until disappear with the increase of the joint spacing. The reducing joint spacing resulted in the best cutter spacing reduce when the small joint angle is 30° and the smaller joint spacing was better to break rock when the joint angle is 60°. The best penetration rises gradually with the joint angle increasing and increase more quickly from 2 mm to 7 mm when the joint angle increases from 0° to 90°.

Key words: deep jointed rock, TBM cutters, the best cutter spacing, the best penetration