全级配混凝土冻融循环后单轴动态抗压性能试验研究

摘要

In order to study the impacts of freezing-thawing and dynamic effect on the properties of ful⁃ly-graded concrete under uniaxial compressive stress state, fully-graded concrete are subjected to different cycles(0, 25, 50, 75 and 100)of freezing-thawing tests and uniaxial dynamic compressive tests under dif⁃ferent strain rates(10-5/s, 10-4/s, 10-3/s, 10-2/s). The quality loss, damage morphology of fully-graded con⁃crete after different freezing-thawing cycles and the uniaxial dynamic ultimate compressive strength and stress-strain curve of fully-graded concrete under different strain rates were measured. The results show that fully-graded concrete mass loss has a quadratic curve relationship with freezing-thawing cycles. Under the same strain rate, the uniaxial dynamic ultimate compressive strength of fully-graded concrete decreased with the increase of freezing-thawing cycles. Under the same freezing-thawing cycles, the uniaxial dynamic ultimate compressive strength of fully-graded concrete increased with the increase of strain rate. On the ba⁃sis of analyzing the test results, the unified failure criteria of fully-graded concrete considering freez⁃ing-thawing cycles and strain rate effect has been established. The results may serve as a test and theory reference for the design and maintenance of hydraulic structures.%为研究冻融及动力作用对全级配混凝土单轴抗压性能的影响，对全级配混凝土进行不同冻融循环次数（0、25、50、75、100次）的冻融循环试验及不同应变速率（10-5/s、10-4/s、10-3/s、10-2/s）的单轴动态抗压试验。实测了全级配混凝土经历不同冻融循环次数后的质量损失、损伤形态，以及不同应变速率下全级配混凝土的单轴动态极限抗压强度、应力-应变关系曲线。研究结果表明：全级配混凝土质量损失率与冻融循环次数呈二次曲线关系；在相同应变速率下，全级配混凝土单轴动态极限抗压强度随冻融循环次数的增加而降低；在相同冻融循环次数下，全级配混凝土单轴动态极限抗压强度随应变速率的增大而提高。对试验结果分析的基础上，建立了综合考虑冻融循环次数与应变速率影响的全级配混凝土的统一破坏准则，可为水工建筑物的设计、维修等提供试验及理论依据。