The shear tests were carried out on anchored joints of a series of size (100-400 mm)to reveal the size effect mechanism of shear strength of anchored rock joints. The changes in shear strength before and after joint an-choring and the shear resistance of anchor bolt were compared and analyzed,and the deformation and damage char-acteristics of anchors and joints were studied. The results show that the rock joint shear strength before and after an-choring exhibits a negative size effect,and this size effect gradually weakens with the increase of normal stress. The shear resistance of rock bolt increases nonlinearly with the increase of joint size. The rock bolt exhibits a "S"shaped deformation feature,and the deformation angle,shear deformation,and axial deformation increase nonlin-early with the increase of joint size. The degree of joint squeezing caused by bolting decreases with the increase of joint size. Introducting the concept of"anchor bolt action area",the action area of the anchor bolt exceeds the joint when the joint size is small,resulting in "edge effect",which leads to the anchor bolt not fully exerting its shear resistance performance. As the rock joint size increases,the performance of the anchor bolt is fully utilized,and the shear resistance of the anchor bolt rapidly increases.
anchored jointsshear strengthsize effectdeformation of rock boltsanchor bolt action area
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