不同侧应力状态下混凝土循环加卸载损伤特性

发布时间：2018-01-23 07:46

本文关键词： 混凝土滞回环侧压比耗散能损伤估计模型损伤演化　出处：《长江科学院院报》2017年11期 　论文类型：期刊论文

【摘要】：采用大型多功能液压伺服静动力三轴仪对不同单向恒定侧压下的混凝土进行应变速率为10-4s-1的等应变增量循环加卸载试验,恒定侧压为单轴静态抗压强度的0%,5%,10%。研究了不同侧应力水平下应力-应变全曲线中滞回环的变化规律,分析滞回环与耗散能的关系,并构建损伤估计模型,最后基于耗散能统计,研究混凝土的损伤特性。得出主要结论如下:(1)全曲线中滞回环在卸载初始阶段应力下降较快而变形恢复很慢,但随着应力的逐渐下降,应变恢复才开始加快;(2)在循环次数相同时,耗散能随着侧应力的增加而增加,且增加幅度明显,表明单位耗散能具有明显的侧应力敏感性;(3)建立的双参数损伤估计模型,能够很好地拟合循环加卸载损伤与累积残余应变的关系;(4)随着侧压比的提高,混凝土损伤发展速度逐渐减慢,损伤累积的路径大幅延长。
[Abstract]:A large multifunctional hydraulic servo static and dynamic triaxial instrument was used to test the loading and unloading of concrete under different unidirectional constant lateral pressure at the strain rate of 10 ~ (-4) s ~ (-1). The change of hysteresis loop in the whole stress-strain curve under different lateral stress levels is studied, and the relationship between hysteresis loop and dissipation energy is analyzed. The damage estimation model is constructed, and finally based on dissipative energy statistics. The main conclusions are as follows: 1) in the whole curve, the stress of hysteresis loop decreases rapidly and the deformation recovers slowly at the initial stage of unloading, but with the gradual decrease of stress. The recovery of strain only began to accelerate; 2) at the same number of cycles, the dissipation energy increases with the increase of lateral stress, which indicates that the unit dissipation energy has obvious sensitivity to lateral stress. 3) the two-parameter damage estimation model can fit well the relationship between cyclic loading and unloading damage and cumulative residual strain. 4) with the increase of lateral pressure ratio, the damage development rate of concrete gradually slows down, and the path of damage accumulation is greatly prolonged.
【作者单位】：三峡大学土木与建筑学院;三峡地区地质灾害与生态环境湖北省协同创新中心;
【基金】：国家自然科学基金项目(51279092) 三峡大学科研创新项目(CX2015025)
【分类号】：TU528
【正文快照】： 1研究背景混凝土结构在服役期间常处于复杂应力作用下,同时还会承受相应应力的循环作用,如机场跑道上飞机降落的冲击、桥涵隧道中车辆的来往、采油平台下海浪的往复等。研究循环加卸载作用下的混凝土力学性能与损伤机理更加符合实际工程情况,有利于提高人们对于混凝土建筑物抗

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