在有压水环境中的混凝土率效应特性研究

随着渗透孔隙水压的增加,混凝土的抗压强度、劈裂抗拉强度逐渐降低,其损失率逐渐增大。本文进行了混凝土处于不同围压值(0、2、5、10 MPa)大小的水环境中和不同应变速率(10-5/s、10-4/s、10-3/s、10-2/s)作用下的常三轴动态抗压试验,对不同水环境下的混凝土峰值应力及应变进行了分析,构建了动态本构模型。研究表明:混凝土的峰值应力与加载速率成正比,峰值应变与加载速率也成正比。在无压水环境下,混凝土的峰值应变和峰值应力都小于无水环境;随着围压的增加,峰值应力逐步增大,峰值应变先增大后减小。混凝土的损伤特性在常三轴压缩状态下,先服从Wei-bull统计分布后服从Lognormal统计分布,由此表明所选损伤本构模型模拟的力学行为有效。

Dynamic Characteristic Study of Concrete Under Pressure of Water Environment

With the increase of pore water pressure, the compressive strength and splitting tensile strength of the concrete decrease gradually, and the loss rate increases gradually. The conventional three-axial dynamic test is carried out to study the dynamic and static mechanical properties of the concrete under different confining pressures （ 0 , 2 , 5 , 10 MPa ） and different strain rates （ 10^-5 , 10^-4 , 10^-3 , 10^-2/s） . The peak stress, peak strain under different water environment are discussed. Dynamic constitutive model is constructed from the data of the experiment, and the validation analysis for the model is made. It indicates that the peak stress of the concrete is proportional to the strain rate, the same with the peak strain of the concrete. Under the non-pressure water environment, the peak strain and peak stress of the concrete are less than anhydrous environment. With the confining pressure increases, the peak stress increases gradually, but the peak strain increases at first and decreases then. By the conventional three-axial pressure, the concrete damage characteristic obeys Wei-bull statistical distribution before the peak stress, and Lognormal statistical distribution after the peak stress, which shows that the damage constitutive model is effective.