Study on the effect of loading rate on the shear performance of ACC structures

Through experimental and numerical simulation analyses, the shear mechanical properties and deformation damage mechanism of the double structural planes of traditional anchor cables and new anchor cable with C-shaped tube structures (abbreviated as ACC) under different loading rate conditions were investigated. Dual structural face shear tests were conducted at shear displacement loading rates of 2, 10, 20, 30, and 40 mm/min under 55 MPa concrete specimen strength and 200 kN preload. The tests were conducted with shear deformation curves, peak structural shear loads, steel wire damage patterns and structural plane shear strength contributions as the main parameters to be considered. The results show that the loading rate has a significant effect on the shear performance of the structure, and within a certain loading rate interval, affected by the damage accumulation rate and the strain rate strengthening effect, the structure will show the characteristics of strength weakening and strength strengthening respectively, and the shear load carrying capacity will show a large variation interval. In the vicinity of the structural plane, the support structure will show a combination of tensile and shear damage, but the ACC structure, due to the presence of the C-shaped tube, makes the stress concentration effect lower, the fluctuation of the test curve is weakened, and the damage of the internal steel wires by the shear action is significantly weakened compared with the traditional anchor cable. Meanwhile, the numerical model of double shear test of ACC structure constructed on the basis of the test results has high accuracy, and the numerical simulation of dynamic loading test shows that the anchoring system formed by ACC structure has good energy absorption effect, and the larger the impact energy, the more obvious the energy absorption effect; and the ACC structure under the action of high-speed impact is affected by the strain rate reinforcement effect significantly, and the larger the impact speed, the higher the shear bearing capacity.