双轴循环荷载下混凝土动态力学特性研究

摘要

进行了不同侧压力(0、80、230、390 kN)、不同应变速率(10-2/s、10-3/s、10-4/s、10-5/s)下，混凝土的轴向循环加卸载压缩试验，研究了循环加卸载下，混凝土在不同应变速率和侧压下的动态力学特性变化规律。结果表明：随着侧压的增加，混凝土抗压强度的率敏感性降低；混凝土的峰值应变随应变速率的增大总体呈现减小的趋势，且随着侧压的增大，峰值应变逐渐增大。随着应变速率的增加，混凝土循环加卸载应力–应变全曲线所经历的循环次数逐渐减小，且全曲线外包络线上升段形状愈来愈“陡”。当应变速率一定时，随着侧应力的增大，峰值应力以前循环次数不断增多，即侧应力延缓了损失，推迟了破坏。%The axial compression test under cyclic loading and unloading with side pressure of the concrete is conducted in this paper. The law of dynamic change of mechanical property of the concrete is studied under cyclic loading and unloading with different side pressures and strain rates. The results show that with the increase of confining pressure, the compressive strength of concrete rate sensitivity decreased; the concrete peak strain with strain rate increasing showing an overall decreasing trend and with the increase of confining pressure, peak strain increases gradually. With the increase of strain rate, the cyclic number of cyclic loading and unloading stress-strain curves of concrete decreases gradually, and the curve of the whole curve is getting more and more steep. When the strain rate is constant, with the increase of the lateral stress, the peak stress of the cyclic number is increasing, that is, the side stress has delayed the loss, and has delayed the damage.