Experimental and Numerical Investigations of Fracture Behavior for Transversely Isotropic Slate Using Semi-Circular Bend Method

Abstract

Slate with inherently transverse isotropy is abundant in metamorphic rock, in buildings, and in geotechnical engineering worldwide; the tensile and shear fracture behavior of layered slate is vital to know for engineering applications. In this paper, the Brazilian and semi-circular bend (SCB) tests of layered slate were performed. The fracture characteristics of the slate were investigated by numerical simulations developed by the hybrid finite and cohesive element method (FCEM). Results showed that the measured experimental tensile strength, and mode I fracture toughness of layered slate all showed a typical V-type trend as the bedding angle increased from 0° to 90°, and with divider type. The developed empirical relationship between tensile fracture toughness and tensile strength KIC = 0.094σt + 0.036 fitted experimentally and strongly correlated. The mechanical response and fracture patterns predicted by FCEM agreed well with those of the laboratory experiments. Moreover, the shear fracture behavior and mode II fracture toughness of the layered slate were explored by systematic numerical simulations. Research results provide potential insights for further prediction and improvement of the complex fracture behavior of anisotropic rock masses for rock engineering.

Slate–Cork Laminate Enhanced with Silicone for Habitat Industry Application

“…The parameters included a load cell of 1 kN and a testing rate of 10 mm/s. From the forcedisplacement curve, the strain (ε), maximum stress at failure (σ), and Young's modulus were determined, according to Equations ( 5)- (7), where σ represents the supported stress in MPa, F is the applied force in N, A is the specimen's cross-sectional area in mm 2 , the strain (ε) is calculated by dividing the length increase (∆L) by the specimen's original length (L 0 in the calibrate length of 10 cm), E is the Young's modulus in MPa, ∆σ is the stress increase in MPa, and ∆ε is the dimensionless strain increment in the initial linear zone.…”

“…The deformability and strength of slate rocks depend on the orientations of their planar structures relative to the applied stresses [2,3]. Extensive research has been conducted on the fracture of slate and its simulation, driven by the need to ensure its resilience in various structural or decorative applications [4][5][6][7][8]. In these studies, it has been consistently concluded that slate fractures invariably occur between the layers regardless of the direction of the external stresses.…”