Experimental study on anchorage mechanical effect of rock bolts on cross-jointed rock mass using DIC and AE

Rock bolting is a commonly used reinforcement technique for jointed rock masses. This study investigates the anchorage effects of rock bolts on cross-jointed rock masses. Novel 3D-printed stainless steel bolts were used to reinforce rock-like specimens with main joint angles of 15 degrees, 30 degrees, 45 degrees, 60 degrees, and 75 degrees. The integration of Acoustic Emission (AE) and Digital Image Correlation (DIC) techniques enabled comprehensive monitoring of crack propagation and strain evolution. The results show that bolt reinforcement significantly enhanced specimen strength (up to 79.9 %) and elastic modulus (up to 37.9 %) at smaller joint angles (<= 45 degrees). However, the reinforcement effectiveness diminished considerably at larger angles (>= 60 degrees), with strength reductions of up to 10.6 %. The combined AE-DIC analysis revealed distinct failure mechanisms: tensile-dominated failure at small joint angles and shear-dominated failure at larger joint angles. This study provides practical guidelines for optimizing rock bolt applications in jointed rock masses, particularly highlighting the need for alternative support strategies at large joint angles.