在水平单向侧压应力作用下,进行了竖向等应变步长循环加卸载的混凝土抗压性能试验。对不同侧应力状态下的外包络线、共同点轨迹线和循环加卸载全曲线进行了分析,研究了侧应力对累积残余塑性应变和刚度退化的影响,探索了混凝土在加载全过程中的能量释放特性,基于声发射事件数构建的损伤变量分析了混凝土的损伤规律。研究结果表明:①在整个循环加卸载试验过程中,声发射事件数主要集中在峰值应力以前,峰值应力以后出现较少,峰值应力后的声发射能量随侧向压应力的增大而增大;②混凝土刚度退化速度及累积残余塑性应变随侧压应力的增加而减小;③不同侧向压应力下混凝土损伤发展路径各异,侧压应力越高,损伤路径越短,水平与竖向荷载间的大小比例,决定了混凝土损伤的主导因素与损伤机制。

The compressive performance of concrete was tested under uniaxial lateral stress and vertically equal strain cyclic loading and unloading. The envelopes, cyclic loading and unloading curves, and common-point (point of the intersection between unloading curve and reloading curve) tracks under different lateral stresses were analyzed. Moreover, the influence of lateral stress on stiffness degradation and cumulative residual plastic strain was studied. The energy release characteristics in the whole loading process were explored, and the damage characteristics of concrete were analyzed based on the damage variable determined by the number of AE event. Results revealed that 1) throughout the course of cyclic loading and unloading tests, the number of AE event was concentrated before the peak stress, and became less after the peak stress, and the AE energy also increased with the increase of lateral stress after peak stress; 2) with the increase of lateral compressive stress, concrete’s stiffness degradation rate and accumulated residual plastic strain decreased; 3) the damage development path was different under different lateral stresses. The higher the lateral stress, the shorter the damage path. The size ratio between horizontal and vertical loads determines the dominant factors and damage mechanism of concrete.