高强混凝土和页岩陶粒混凝土的三轴受压破坏准则

发布时间：2018-06-29 02:58

本文选题：全轻页岩陶粒混凝土 + 高强混凝土　；参考：《河南理工大学》2014年硕士论文

【摘要】：近年来,随着社会发展和特种结构的需求,对混凝土应用提出了更高的要求,轻质、高强、高性能混凝土已经成为2020年中国科技发展目标实施纲要之一。其中,全轻页岩陶粒混凝土和高强、高性能混凝土作已经在部分工程得到了应用。由于混凝土结构大多处于复杂应力状态下工作,若仅以单轴力学性能进行设计,已经不能满足工程实际需要,尤其是对于像核电站安全壳、海洋采油平台等特种结构。因此,本文主要开展了全轻页岩陶粒混凝土和高强混凝土的三轴受压力学性能研究工作。利用大连理工大学的大型静、动真三轴试验机,分别对强度等级为LC30、LC40、LC50的全轻页岩陶粒混凝土和C70、C80、C90的高强混凝土,以及其相应的钢纤维维混凝土,进行了等比例三轴受压试验。试验中,观察并分析了试件的破坏形态,并以柱状破坏、层状破坏、劈裂破坏和斜剪破坏为四种典型破坏特征,而全轻页岩陶粒混凝土则还有挤压流塑破坏特征;测得了试件的三轴受压极限强度、塑性应变、峰值应变、总应变以及应力-应变曲线。结果表明,全轻页岩陶粒混凝土和高强混凝土在三轴受压状态下,强度和变形较单轴受压有显著增大,并且全轻页岩陶粒混凝土伴随有明显的平台流塑现象。因此,全轻页岩陶粒混凝土在工程设计中将应力平台流塑段强度及其对应的塑性应变作为轻骨料混凝土的设计强度和设计应变。此外,分析了中间主应力对不同强度等级的全轻页岩陶粒混凝土和高强混凝土的三轴压强度和变形的影响,探索了不同混凝土种类和强度等级对三轴受压强度和变形的影响,并通过三轴强度模型对极限应力进行了预测,其相对误差的绝对值均小于7%,说明试验结果是准确、可靠的。最后,基于八面体应力-应变空间,分别对不同强度等级的全轻页岩陶粒混凝土和高强混凝土,分别建立了其相应的破坏准则和本构关系。其中,全轻页岩陶粒混凝土的拉、压子午线与静水压力轴在高压应力区有交叉点,其破坏曲面是闭口的;而高强混凝土的拉、压子午线与静水压力轴在高压应力区无交叉点,其破坏曲面是开口的。
[Abstract]:In recent years, with the development of society and the demand of special structure, the application of concrete has put forward higher requirements, light weight, high strength, high performance concrete has become one of the implementation outline of China's science and technology development goal in 2020. Among them, full-light shale ceramsite concrete and high-strength and high-performance concrete have been used in some projects. As most concrete structures work under complex stress conditions, if only uniaxial mechanical properties are used to design them, they can no longer meet the practical engineering needs, especially for special structures such as nuclear power plant containment and offshore oil recovery platforms. Therefore, the study of triaxial compressive mechanical properties of full light shale ceramsite concrete and high strength concrete is mainly carried out in this paper. By using the large static and dynamic triaxial testing machine of Dalian University of Technology, the equal proportion triaxial compression tests were carried out on the full light shale ceramsite concrete with strength grade LC30, LC40 and LC50, and the high strength concrete of C70 C80C80 and C90, as well as its corresponding steel fiber reinforced concrete. In the experiment, the failure patterns of the specimens are observed and analyzed, and the four typical failure characteristics are columnar failure, layered failure, split failure and oblique shear failure, while all light shale ceramsite concrete has the characteristics of extrusion flow plastic failure. The ultimate strength, plastic strain, peak strain, total strain and stress-strain curve of the specimen were measured. The results show that the strength and deformation of full light shale ceramsite concrete and high strength concrete under triaxial compression are significantly higher than that of uniaxial compression. Therefore, the strength of flow plastic section of stress platform and its corresponding plastic strain are taken as the design strength and design strain of lightweight aggregate concrete in the engineering design of full light shale ceramsite concrete. In addition, the effect of intermediate principal stress on the triaxial compressive strength and deformation of full light shale ceramsite concrete and high strength concrete with different strength grades is analyzed, and the effects of different types and strength grades of concrete on triaxial compressive strength and deformation are explored. The ultimate stress is predicted by triaxial strength model, and the absolute value of relative error is less than 7, which shows that the test results are accurate and reliable. Finally, based on the octahedron stress-strain space, the corresponding failure criteria and constitutive relations of full light shale ceramsite concrete and high strength concrete with different strength grades are established respectively. Among them, the tensile, meridian and hydrostatic pressure axis of full light shale ceramsite concrete have intersection points in the high pressure stress region, and the failure surface is closed, while the tensile, meridian and hydrostatic pressure axis of high strength concrete have no intersection points in the high pressure stress region. The broken surface is open.
【学位授予单位】：河南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528

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