循环孔隙水压后的混凝土动态损伤特性研究

Study on Dynamic Damage Characteristics of Concrete after Cyclic Pore Water Pressure

利用10MN大型多功能静动力三轴仪对经历不同循环孔隙水压(0、1、3、5、7 MPa)作用后的混凝土进行不同应变速率(10^(-5)、10^(-4)、10^(-3)s^(-1))下的压缩试验,分析其力学特性,并基于改进的能量法损伤表达式研究了不同应变速率对混凝土损伤发展的影响。结果表明,当应变速率较低时,混凝土的峰值应力、峰值应变随循环孔隙水压力值的增大呈减小趋势,损伤曲线比较分散,且增加循环孔隙水压力混凝土损伤将提前;当应变速率较高时,峰值应力、峰值应变呈现不同程度的上升,曲线较为集中,增加循环孔隙水压力使混凝土的损伤发生滞后。

The different strain rate(10^-5/s,10^-4/s,10^-3/s)compression tests of concrete under different cyclic pore water pressures(0 MPa,1 MPa,3 MPa,5 MPa,7 MPa)were carried out by using 10 MN multi-functional static and dynamic three axis apparatus.Its mechanical properties were analyzed.Based on the damage expression of improved energy method,the impact of different strain rates on the damage development of concrete was studied.The results show that when the strain rate is low,the peak stress and peak strain of concrete decrease with the increase of cyclic pore water pressure,and the damage curve is more scattered,as well as the concrete damage occurred in advance after different cyclic pore water pressure.When the strain rate is high,peak stress and peak strain rise in varying degrees,and the damage curve is more concentrated,the damage was lagging behind with increase of cyclic pore water pressure.