Abstract: Jointed and fissured rock masses are frequently encountered in tunnel and slope engineering projects. The distribution and geometric shapes of these structural planes with discontinuities in the rock masses, especially, the incline angle of the joint sets, have significant influence on the mechanical properties of rock mass and therefore might impact the safety and stability of engineering structures in the rock mass. In this paper, numerical simulations by using discrete element method were performed to evaluate the performance of the single set jointed rock with various inclination angles. The results indicate that the strength of jointed rock is less than that of the jointless rock mass. With the variation of the joint angles, the strength values demonstrated a Ushaped variation. When the joint inclination angles were between 45 and 60 degrees, rock mass failure usually occurred along the joint plane. Otherwise, split failure with welldeveloped internal joints was often observed.

Key words: single set jointed rock, obliquity, discrete element, failure modes, mechanical properties