高港水利枢纽闸站混凝土力学劣化试验研究

Experimental Study on Mechanical Degradation of Concrete at the Gate Station of Gaogang Water Control Project

为研究高港水利枢纽闸站混凝土材料力学劣化效应,基于工程环境设计了物化影响因素,并开展了三轴力学试验。研究成果显示,化学溶液侵蚀浓度不影响混凝土应变破坏特征,对承载应力水平影响更显著;化学溶液侵蚀时间会改变混凝土应力应变趋势,侵蚀时间超过25 h后,具有应变硬化特性,而低于25 h时呈应变软化特征,化学侵蚀劣化效应在侵蚀时间25 h后更为显著。围压增大,可约束化学侵蚀效应。干湿物理作用不改变混凝土应力应变趋势特征,但交替愈多承载愈弱,尤以交替超过12次更为明显,围压5 MPa下交替12~20次峰值应力为21.4~53.4 MPa,每梯次下平均下降36.7%,交替较低时,混凝土具有一定抗干湿劣化能力。本成果可为研究水工建筑混凝土材料的力学劣化效应提供参考。

In order to study the mechanical deterioration effect of concrete material in the gate station of Gaogang Water Control Project,the physical and chemical influencing factors were designed based on the engineering environment,and triaxial mechanical tests were carried out.The results showed that the corrosion concentration of chemical solution did not affect the strain failure characteristics of concrete,but had more significant influence on the bearing stress level.The corrosion time of chemical solution would change the stress and strain trends of concrete.When the corrosion time exceeded 25h,the concrete appeared the strain hardening characteristics,while strain softening characteristics when the corrosion time was less than 25h.The deterioration effect of chemical attack was more significant after 25h of corrosion.The increase of confining pressure could not only promote the bearing stress,but also restrain the chemical erosion effect.The dry and wet physical effects did not change the stress and strain trends of concrete.However,the more alternation,the weaker the bearing capacity,especially when the alternation was more than 12 times.Under the confining pressure of 5MPa,the peak stress of alternating 12~20 times was 21.4~53.4MPa,with an average reduction of 36.7% under each step.When the alternation was low,the concrete had certain resistance to dry and wet deterioration.This paper can provide a reference for studying the mechanical deterioration effect of concrete materials in hydraulic construction.