应力-渗流-化学多场耦合作用下混凝土蠕变特性试验研究——以龙口港工程为例

为研究混凝土在海水侵蚀、荷载及水力渗透复杂条件下的蠕变特性,对不同浸泡时间条件下的港口混凝土进行三轴分级加载蠕变试验。试验结果表明:①海水侵蚀对港口混凝土强度具有明显的弱化效应,浸泡时间为0,30,60,120 d下混凝土的长期强度分别为12.8,11.5,10.6,10.2 MPa;②随着海水浸泡时间的增加,混凝土试件的初始渗透率逐渐增加,浸泡时间为0,30,60,120 d下混凝土初始渗透率分别为8.15×10^-17, 1.12×10^-16, 1.49×10^-16, 1.60×10^-16 m²,海水的腐蚀效果逐渐降低,初始渗透率与腐蚀时间之间呈负指数关系;③改进的西原模型非线性蠕变本构方程与试验数据拟合效果理想,决定系数分别达到0.98,0.96,0.95,0.92,能较好地反映港口混凝土在应力-渗流-化学多场耦合作用下蠕变变形的阶段性特征与时效特征。研究结果可为我国港口工程的长期运行提供指导性参考。

Experimental Study on Creep Behavior of Concrete under Stress-Seepage- Chemical Interaction:Case Study on Longkou Port Project

In order to study the creep characteristics of concrete under the complex conditions of seawater corrosion, load and hydraulic seepage, we conducted triaxial staged-loading creep test on port concrete immersed in seawater for different days. Test results demonstrate that: 1) seawater corrosion has a significant weakening effect on the strength of port concrete. The long-term strengths of concrete immersed for 0,30,60,120 days are 12.8 MPa, 11.5 MPa, 10.6 MPa, and 10.2 MPa, respectively. 2) As the time of immersion elongates, the initial permeability of concrete increases gradually. The initial permeability of concrete immersed for 0,30,60,120 days are 8.15×10^-17 m², 1.12×10^-16 m², 1.49×10^-16 m², and 1.60×10^-16m², respectively. However, the corrosion effect of seawater attenuates gradually, and the initial permeability is negatively correlated with the corrosion time. 3) The non-linear creep constitutive equation of improved Nishihara model has an ideal fitting effect with the test data, and the determination coefficients are up to 0.98, 0.96, 0.95, and 0.92, respectively, well reflecting the stage characteristics and aging characteristics of creep deformation of port concrete under the coupled action of stress, seepage and corrosion. The research results can provide guidance for the long-term operation of port project in China.