冻融劣化混凝土循环加卸载外包络线及能量演化

发布时间：2018-04-19 23:44

本文选题：冻融循环 + 循环加卸载　；参考：《水利水运工程学报》2017年06期

【摘要】：对历经不同冻融循环次数的混凝土进行了不同应变速率的单轴循环加卸载试验,分析了试验所得应力-应变曲线外包络线的特征,定义了单轴循环加卸载的耗散能、弹性应变能和塑性应变能,研究了这3种能量与冻融循环次数和循环加卸载次数之间的关系。结果表明:混凝土应力-应变曲线外包络线整体上呈先升后降的趋势;随着冻融循环次数的增多,混凝土的峰值应力逐渐减小而峰值应变逐渐增大;应变速率不影响应力-应变外包络曲线的形状;冻融循环影响混凝土的率敏感性;随循环加卸载次数的增加,混凝土的耗散能、弹性应变能和塑性应变能整体上均呈先增后减的变化规律;冻融循环削弱了混凝土的脆性;外力做功90%的能量用于不可逆转的变化过程。
[Abstract]:Uniaxial cyclic loading and unloading tests of concrete with different cycles of freeze-thaw cycles are carried out. The characteristics of the stress-strain curves are analyzed, and the dissipation energy of uniaxial cyclic loading and unloading is defined. The relationship between the three kinds of energy and the cycles of freeze-thaw cycles and cyclic loading and unloading is studied. The results show that the stress-strain curve of concrete increases first and then decreases as a whole, and with the increase of freeze-thaw cycles, the peak stress decreases and the peak strain increases. Strain rate does not affect the shape of stress-strain enclosing curve, freeze-thaw cycle affects the rate sensitivity of concrete, and the dissipation energy of concrete increases with the increase of cyclic loading and unloading times. The elastic strain energy and plastic strain energy are increased first and then decreased; freeze-thaw cycle weakens the brittleness of concrete; 90% of the external work energy is used for irreversible change process.
【作者单位】：三峡地区地质灾害与生态环境湖北省协同创新中心;三峡大学土木与建筑学院;
【基金】：国家自然科学基金资助项目(51279092) 三峡大学研究生科研创新基金项目(SDYC2016018)
【分类号】：TU528

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