Mechanical responses, failure behaviours and stability of soft–hard interbedded antidip slopes under various degrees of anisotropy
Erhu Jiang, Penghai Deng, Quansheng Liu, Xiangliang Xing, Haifeng Lu, Xiaoxuan KongPurpose
This study was aimed at investigating the mechanical responses and failure characteristics of soft–hard interbedded rock samples under uniaxial compression and Brazilian splitting tests with varying strength ratios between the hard and soft layers (i.e. anisotropy degrees, λ). How the degree of anisotropy influences the safety factors, failure mechanisms, and failure modes of soft–hard interbedded antidip slopes (SHIADSs) was also examined.
Design/methodology/approach
By setting different anisotropy degrees (λ = 1.5, 2, 4, 6, 8 and 10) and layer dip angles (θ = 0°, 15°, 30°, 45°, 60 and 75°), the finite-discrete element method (FDEM) was adopted to determine the strength characteristics and failure behaviours of soft–hard interbedded rock samples under uniaxial compression and Brazilian splitting. In addition, different combinations of the anisotropy degree (λ = 1.5, 2, 4, 6, 8 and 10), layer dip angle (θ = 0°, 15°, 30°, 45°, 60 and 75°) and slope angle (β = 70°, 75°, 80°, 85°, 90°, 95° and 100°) were designed to investigate the effects of the degree of anisotropy on the stability of SHIADSs.
Findings
With increasing degree of anisotropy, the compressive strength of soft–hard interbedded rock samples may either increase exponentially (when θ = 0°, 15 and 75°) or change slightly (when θ = 30°, 45 and 60°). The tensile strength increases exponentially with increasing λ, independent of the layer dip angle. At the same slope angle (β = 80°), the safety factors of SHIADSs may either increase exponentially (when θ = 0–30°) with an increase in the value of λ or change slightly (when θ ≥ 45°). However, at the same layer dip angle (θ = 30°), the safety factor increases exponentially with increasing λ, independent of the slope angle.
Originality/value
The results indicate that the influence of the degree of anisotropy should be considered when investigating the stability and failure mechanisms of SHIADSs. In addition, the findings provide meaningful guidance for controlling the stability of SHIADSs; for example, reducing the slope angle is the preferred stability control measure.