中文摘要：

结构面的存在对岩块力学性质具有弱化作用，为揭示硬岩岩样单结构面倾角α大小对其力学性质影响的变化规律，同时检验Jaeger单结构面理论模型的可靠性，基于PFC2D建立了完整岩样及α分别为0°、15°、30°、45°、60°、75°和90°的双轴模型进行试验。研究表明：①α介于45°～75°时，试样沿结构面滑动，其余均为贯穿结构面的剪切破坏，围压增大使α＝75°试样的破坏模式向贯穿结构面剪切发展；②α＝60°时，位移场与完整岩样存在明显差别，其破坏模式不受围压影响；③试样微裂纹主要由切向黏结破坏引起，当强度超过峰值后法向黏结破坏逐渐增加，相同围压下贯穿结构面破坏引起的微裂纹数比沿结构面滑动的多；④结构面倾角和围压对试样峰值强度、轴向等效弹性模量和峰值前应变具有明显影响，理论的结构面倾角阈值并不明显存在。

英文摘要：

The existence of discontinuities always weaken the strength of rock mass ,to reveal the relationship between mechanical properties and discontinuity inclination ,to tell the reliability of Jaeger＇s shear failure theory ,based on PFC2D ,we establish eight bi‐axial test specimens include complete sample and discontinuity inclination α=0 ,15 ,30 ,45 ,60 ,75 and 90 degree .Research indicates that ：① as αbetween 45 and 75 degree ,sliding failure along discontinuities appear ,with the remaining specimenstensile fracture across discontinuities .Meanwhile failure mode turned more to tensile fracture across discontinuities follow confining pressure in‐creased whenα= 75 degree .② Whenα=60 degree ,displacement fields show a great difference with complete sample ,failure mode is independent of confining pressure .③The micro-crack was more caused by breaking down of tangential bond ,only when the force is equal or more than peak strength ,normal bond break increases .Total micro-crack is less while failure modes are sliding failure a‐long discontinuities .④ Confining pressures and discontinuity inclination had a great influence on peak strength ,equivalent axial elas‐tic modulus and strains before peak strength ,the value of the threshold discontinuity inclination supposed by Jaeger does not exist obviously .