关键词: 深部巷道, 锚喷层, 水泥石试件, 横向孔径, 单轴压缩, 应力应变, 失稳模式

Abstract: The releasing-hole size of bolting shotcrete in deep gateway influenced directly stress releasing and bearing strength of bolting shotcrete. Uniaxial compression test was produced on twelve cement specimens with six different hole size by rigid test machine, the stress-strain relationship of different hole-diameter specimens was analyzed, the effect of different hole size on specimen compressive strength, axial strain and elastic modulus, poisson ratio, was studied, and failure form and instability mode of cement specimens with different hole size were discussed. The results showed that: the larger the diameter of the pore cement specimen, the angle between the main fracture surface and the horizontal surface increases obviously, and the smaller the fracture bonding area of the specimen. The stress-strain curve of uniaxial compression cement specimen with different-size horizontal hole was whole, the larger the compressive strength was on the specimen, the larger the axial and horizontal strains were. As hole-diameter was from 0mm to 50mm, the compressive strength and elastic modulus reduced, the decreasing trend was slow down, and the attenuation rates were respectively 52.7396%, 22.31%and 34.6282%, the relationships between hole size and compressive strength, axial strain and elastic modulus could be represented by negative liner functions, but the linear relationship decreases. The crack in cement specimen with 0mm to 20mm hole-diameter started at the hole-walls in the upper and lower diagonal angles of specimen, the specimen was damaged at diagonal crack of hole-walls in the upper and lower diagonal angles, which was named small hole-size failure form. The crack in cement specimen with 30mm to 50mm hole-diameter started at the walls in the left and right holes of specimen, the specimen was damaged at both sides of hole-walls in vertical split, which was named large hole-size failure form. The instability mode of cement specimen with different-size horizontal hole was divided into shear dislocation instability and planar splitting one.