基于声发射循环加卸载时侧压混凝土损伤特性研究  

Damage Characteristics of Concrete under Lateral Stress and Vertical Cyclic Loading and Unloading Based on Acoustic Emission

作　　者：马小亮[1] 彭刚[1] 吴彬[2] 胡伟华 

机构地区：[1]三峡大学土木与建筑学院,湖北宜昌443002 [2]湖北工业职业技术学院建筑工程系,湖北十堰443000 [3]十堰市建筑设计研究院,湖北十堰443000

出　　处：《长江科学院院报》2017年第1期135-141,共7页Journal of Changjiang River Scientific Research Institute

基　　金：国家自然科学基金(51279092);三峡大学培优基金(2016PY025)

摘　　要：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 ana- lyzed. 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 characteris- tics of concrete were analyzed based on the damage variable determined by the number of AE event. Results re- vealed that 1 ） throughout the course of cyclic loading and unloading tests, the number of AE event was concentrat- ed 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 differ- ent 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

关 键 词：混凝土 循环荷载 声发射 损伤特性 刚度退化 

分 类 号：TU528[建筑科学—建筑技术科学]