水电能源科学

为探究地震作用下纤维混凝土的损伤演化和失效机制，开展了一系列钢纤维混凝土单调和往复轴压试验，分析纤维掺入对混凝土应力应变行为的影响，重点探讨循环轴压下混凝土塑性应变、刚度退化及能量耗散等力学行为衰退与内部损伤累积的关系。结果表明，单调加载曲线接近于往复轴压曲线的包络线。钢纤维的掺入显著改善混凝土峰后延性，并提高残余应力。由于钢纤维的阻裂增韧作用，掺入纤维后混凝土破坏形态由单个竖向主裂缝的脆性破坏演变为多缝开裂的延性破坏模式。钢纤维还能有效改善混凝土抗震力学行为，掺入纤维后混凝土弹性刚度退化和塑性应变发展均得到有效控制，能量耗散性能增强。

To investigate the damage evolution and failure mechanism of fiber-reinforced concrete under action of earthquake, a series of monotonic and reciprocating axial compression tests were conducted on steel fiber reinforced concrete to analyze the influence of fiber addition on the stress-strain behavior of concrete. The focus was on exploring the relationship between the mechanical behavior degradation and internal damage accumulation of concrete under cyclic axial compression, including plastic strain, stiffness degradation, and energy dissipation. The results indicate that the monotonic loading curve is close to the envelope of the reciprocating axial compression curve. The addition of steel fibers significantly improves the post peak ductility of concrete and increases residual stress. Due to the crack resistance and toughening effect of steel fibers, the failure mode of concrete after adding fibers has evolved from brittle failure of a single vertical main crack to ductile failure mode of multi crack cracking. Steel fibers can effectively improve the seismic mechanical behavior of concrete. After adding fibers, the degradation of elastic stiffness and plastic strain development of concrete are effectively controlled, and the energy dissipation performance is enhanced.