摘要:
通过试验和数值模拟分析，研究了传统锚索和新型管索组合结构(简称ACC)在不同加载速率条件下的双结构面剪切力学特性和变形破坏机制。在55MPa混凝土试块强度，200kN预紧力条件下，分别以2、10、20、30、40mm/min的剪切位移加载速率进行双结构面剪切试验。试验以剪切变形曲线、结构峰值剪切荷载、钢丝破坏形态和结构面抗剪强度贡献为主要考量参数。结果表明：加载速率对结构的抗剪性能具有显著的影响，在一定的加载速率区间内，受损伤累积速度和应变率强化效应的影响，结构分别会表现出强度弱化和强度强化的特性，抗剪承载能力会出现较大的变化。在结构面附近，支护结构会表现出拉剪组合破坏情况，但ACC结构由于C形管的存在，使得应力集中效应降低，试验曲线波动情况减弱，内部钢丝受剪切作用破坏的情况与传统锚索相比明显减弱。同时以试验结果为基础构建的ACC结构双剪试验数值模型准确性较高，数值模拟动荷载试验表明，ACC结构形成的锚固系统具备良好的吸能效果，冲击能量越大吸能效果越明显；且ACC结构在高速冲击作用下，受应变率强化效应影响显著，冲击速度越大，抗剪承载能力越高。
Abstract:
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.
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