中文摘要：

历经不同孔隙水压循环次数（0,10,50和200次）后,进行了中低应变速率（10-4/s）下混凝土常三轴受压损伤特性试验研究,分析其峰值应力、应变和弹性模量等基本力学参数随孔隙水循环次数变化的关系。同时依据受压切线模量的退化定义了损伤变量,得到应力水平比-损伤曲线,对混凝土损伤特性进行了研究。结果表明：1历经不同孔隙水循环后,混凝土常三轴受压峰值应力和应变随循环次数的增加呈指函数增加的趋势;弹性模量随循环次数的增加呈幂函数减小趋势并逐渐趋于平缓。2历经不同孔隙水循环次数后,混凝土的损伤发展速度整体上均大于0次循环,且随着循环次数的增加损伤速度逐渐降低。3通过应力水平比-损伤曲线,将混凝土损伤演化过程分为3阶段：损伤起始阶段、损伤发展阶段和损伤失稳阶段,同时依据所求损伤变量数据,拟合构建了损伤随应力水平比的演化方程。4依据损伤3个发展阶段定义了损伤界点,分析了损伤界点和损伤3阶段的应力水平区间长度随不同循环孔隙水压次数的变化。分析表明,随孔隙水压循环次数的增加,损伤界点对应的应力水平先增后减。

英文摘要：

The triaxial compression tests of concrete are carried out to study damage properties after different number of pore water cycles at a middle strain rate of 10-4 s-1 . The relationships among mechanical properties including the peak stress, peak strain and elastic modulus with number of cycles are analyzed. And damage variable is defined according to the degeneration compressive tangent modulus. Thus, the curves of the stress levels？damage are obtained, and the damage properties of concrete are studied. The research results show that： ①after different pore water cycle, the peak stress and peak strain of concrete under the triaxial compression show an exponential increasing trend with numbers of cycles. The elastic modulus shows a decreasing trend of the power function with the cycles, and then becomes slow. ②damage growth rates under 10, 50, and 200 cycles are greater than that under 0 cycle as a whole, and it decreases with number of cycles. ③through the curves of stress levels？damage, the process of damage evolution can be divided into three parts： initial stage, development stage and instability stage. And according to the data of damage, the damage evolution equation is constructed by fitting. ④according to the three stages of damage development, the damage boundary points are defined. The relationships between the damage boundary points with length of stress level of damage and the different pore water cycles are analyzed. The stress level of the damage boundary points increases at first and then decreases with the pore water cycles.