High　in-situ　stress　commonly　exists　in　deep　rock　engineering　and　causes　great　difficulties　in　underground　mining　support　systems.　To　elucidate　the　relationship　between　the　anchoring　effect　of　bolts　and　confining　pressures,　triaxial　compression　tests　were　performed　to　study　the　deformation　characteristics,　mechanical　properties,　and　failure　behaviour　of　anchored　granite　with　two　pre-existing　fissures.　The　results　demonstrated　that　the　deformation　characteristics　or　mechanical　properties　of　anchored　granite,　including　triaxial　compressive　strength,　elastic　modulus,　and　stored　or　dissipated　energy,　increased　with　increasing　confining　pressure　under　low　confining　pressures.　Rockbolt　boreholes　significantly　weaken　the　mechanical　properties　and　failure　behaviour　under　high　confining　pressures　and　have　a　negative　impact　on　the　peak　axial　strength　and　stored　or　dissipated　energy　of　the　anchored　granite.　The　fissure　angle　and　confining　pressure　have　a　direct　impact　on　the　failure　mode　of　anchored　granite.　With　increasing　confining　pressures　or　fissure　angles,　shear　cracks　and　anti-wing　cracks　instead　of　tensile　wing　cracks　are　more　likely　to　cause　ultimate　failure.　In　addition,　four　modes　of　crack　coalescence　were　identified:　no　coalescence,　two　types　of　direct　crack　coalescence,　and　indirect　crack　coalescence.