为研究不同孔隙水压循环次数、不同加载速率下的混凝土的力学性能,对直径为300 mm,高度为600 mm的混凝土试件进行0,10,50,100,200次循环孔隙水压的预处理(孔隙水压的上限为3 MPa,下限为1 MPa),然后在3 MPa的围压下进行4种应变速率(10^-5,10^-4,10^-3,10^-2 /s)下的常三轴(σ₂=σ₃≥σ₁)抗压性能试验。结果表明随着应变速率的不断增加,混凝土的峰值应力增大,峰值应变整体上呈增大的趋势;随着循环孔隙水压次数的不断增加,混凝土的峰值应力呈阶段性变化,100次之前呈增大趋势,100次之后呈减小趋势,峰值应变无明显规律性变化,弹性模量呈减小趋势。

The concrete specimens with diameter of 300mm,height of 600mm, were preprocessed under 0 cycle,10 cycles,50 cycles,100 cycles,200 cycles of pore water pressure(upper limit of pore water pressure for 3MPa,the lower limit for 1MPa) .In order to study mechanical properties of concrete under different cycles of pore water pressures and different strain rates, we carried out conventional triaxial(σ₂=σ₃≥σ₁) compressive tests for these specimens under four strain rates(10^-5/s,10^-4/s,10^-3/s,10^-2/s)with confining pressure of 3 MPa. The results show that 1) with the increasing strain rate,the peak stress of concrete increases and the peak strain shows increasing trend. 2) Before 100 cycles of pore water pressure,the peak stress gradually increase, but after that the peak stress tends to decrease, so the peak stress of concrete changes by phase with the increasing cycles of pore water pressure. Variation of peak strain is irregular, whereas elastic modulus tends to decrease with the increasing cycles of pore water pressure.