横观各向同性板岩层理角度与抗压强度及断裂韧度的相关规律

Relationship among Stratification Angle,Compressive Strength,and Fracture Toughness of Transversely Isotropic Slate

利用微机控制电液伺服试验机和高频疲劳强度试验机对不同层理角度的板岩进行了单轴压缩试验和双扭常位移松弛试验,获得了其弹性模量E,泊松比μ,剪切模量G和断裂韧度KIC的值.分析了不同组板岩试件的层理角度与其抗压强度及断裂韧度的相关规律.研究结果表明:板岩的抗压强度和断裂韧度都随着β角的增大呈现先减小后增大的趋势,关系曲线呈'U'形,并且当β为45°时其断裂韧度最小;在不考虑c和φ值的影响下,当层理角度为45°的板岩受载时最容易发生裂纹的起裂和扩展,从而导致板岩发生破坏;在已知β角的情况下,可以利用本试验得到的关系式求出所对应的断裂韧度的值.

Elastic modulus E,Poisson ratioμ, shear modulus G and fracture toughness KIC of the slates with different stratification angles were obtained by the uniaxial compression tests and relaxation method of double torsion constant displacement load using SANS and MTS-insight testing machines. The relationships among the stratification angle, compressive strength, and fracture toughness were examined. The a- nalysis results show that the uniaxial compression and fracture toughness decrease and then increase with the increase of angle β, which shows a U-shaped relationship curve. When the angle β of the slate is 45°, the fracture toughness is minimized. The crack initiation and crack propagation are developed under the axial load, and the slate is destroyed regardless of c and 9 values. Moreover, when the angle β is known, the value of the related fracture toughness can be estimated by using the experimentally derived relationship.