混杂纤维混凝土剪力键滞回试验损伤及应变分析

Damage and Strain Analysis of Hybrid Fibre Shear Keys Under Hysteretic Tests

文中以沉管隧道为研究对象,通过采用拟静力滞回试验的方法,研究了沉管隧道接头间混杂纤维混凝土剪力键及普通混凝土剪力键的损伤积累过程、混凝土应变及钢筋应变的变化规律。试验表明,掺入纤维后的混凝土剪力键的损伤相比于普通混凝土剪力键的损伤有明显的减小。当剪力键的配筋及混凝土标号相同时,混杂纤维混凝土E3左侧剪力键及右侧剪力键在破坏阶段的累积损伤指数相比较于普通混凝土A3左侧剪力键及右侧剪力键分别减少了34.3%和30.8%。在一个混凝土应变片中可以有多条微裂缝同时穿过应变片,U型剪力键混凝土表面裂缝沿混凝土应变片h1-h2-h3顺序展开,T型剪力键混凝土表面裂缝沿混凝土应变片h4-h5-h6顺序展开。

The process of damage accumulation, variation law of concrete strain and steel strain of the shear keys between segments of immersed tunnel are investigated in this paper by hysteretic tests. The hysteretic test result shows that the damage of hybrid fibres shear keys is smaller than normal concrete shear keys in each stage during hysteretic tests. As the reinforcement ratio and the concrete grade are the same,the damage index of the left and right hybrid shear keys of E3 was 34.3% and 30.8% less than those of normal left and right shear keys of A3 due to the addition of fibres, respectively. The hysteretic test result also shows that there are multiple micro concrete cracks spreading on one concrete strain gauge. The concrete cracks of U-shape shear keys and T-shape shear keys are spreading via concrete strain gauge h1-h2-h3 and h4-h5-h6, respectively.