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利用大型静动真三轴试验机,进行了高强高性能混凝土在各种应力比下的多轴拉压试验,多轴拉压试件尺寸为100mm×100mm×100mm立方体。试件受压面的减摩垫层为三层塑料薄膜中间夹三层甘油;受拉面先用打摩机去掉表面层,然后用结构胶与加载板粘结。阐述了试件破坏形态特点以及观察了裂缝发展方向,测得了多轴强度与应变,剖析了应力状态和应力比对高强高性能混凝土多轴拉压强度与变形的影响规律性。试验结果表明:多轴拉压强度与变形变化规律取决于应力状态和应力比。多轴拉压强度σ1f、σ3f在所有应力比下分别小于其单轴拉压强度ft、fc;主拉峰值应变ε1p在单轴拉时最小,主压峰值应变ε3p在单轴压时最大。建立了高强高性能混凝土在多轴拉压应力状态下的破坏准则公式。
The multi-axial tension-compression test of high-strength high-performance concrete at various stress ratios was carried out by using a large-scale static and dynamic triaxial testing machine. The dimensions of the multi-axial tension-compression test pieces were 100mm × 100mm × 100mm cubes. The pressure-reducing surface of the test specimen was laminated with three layers of glycerin in the middle of the three-layer plastic film. The surface of the tensioned surface was first removed by a friction stirrer, and then adhered to the loading plate by structural glue. The morphological characteristics of specimens were observed and the direction of fracture development was observed. The multiaxial strength and strain were measured. The influence of stress state and stress ratio on the strength and deformation of high strength and high performance concrete under multiaxial compression was analyzed. The experimental results show that the strength and deformation of multi-axial tension-compression depends on the stress state and stress ratio. The multi-axial tensile strength σ1f and σ3f are smaller than their uniaxial tensile strength ft and fc under all stress ratios respectively. The main tensile peak strain ε1p is the smallest at uniaxial tension and the main peak strain ε3p is the maximum at uniaxial compression. The failure criteria formula of high strength and high performance concrete under multiaxial compression and stress conditions is established.