关键词: 锚喷支护, 喷射混凝土, 力学性能, 强度参数, 粘聚力, 内摩擦角

Abstract: In order to study the mechanical properties of shotcrete in bolt shotcrete support roadway of coal mine, the "shotcrete large plate method" was used to make concrete standard test blocks in the construction site of coal mine. Through laboratory tests, the compressive, tensile, flexural, shear series strengths, cohesion, internal friction angle and other mechanical parameters of shotcrete under different curing ages were comprehensively and simply tested. The test results show that the compressive strength and tensile strength of shotcrete increase logarithmically with time, with rapid growth in the early stage and slow growth in the late stage. The growth rate is as high as 373%~406% on the 7th day and only 9%~12% on the 28th day. The bending strength and shear strength change in a parabola with time. They have been increasing in the early stage, reaching the peak value at about 21d. The maximum bending strength and shear strength are 5.04MPa and 5.26MPa respectively, and then they show a downward trend. The bending strength and shear strength decrease at 28d are 18% and 19% respectively. The 28d benchmark tensile, flexural and shear strengths of shotcrete are 3.04MPa, 4.11MPa and 4.29MPa, respectively 7%, 9% and 10% of the compressive strength. The cohesion and internal friction angle of shotcrete are respectively about C=0.20MPa、φ=50°. The experimental results provide a basis for the evaluation of mechanical properties of shotcrete and the selection of numerical simulation parameters.