A Fracture Mechanics Stability Analysis of a Rock Slope with a Tensile Crack

 

Chih-Hao Chen

Ph.D. Student, Department of Resources Engineering, National Cheng Kung University, Tainan, Taiwan
n4891111@mail.ncku.edu.tw

Chein-Lee Wang

Associate Professor, Department of Resources Engineering, National Cheng Kung University, Tainan, Taiwan
clwang@mail.ncku.edu.tw

ABSTRACT

This study proposes a fracture mechanics model for the stability analysis of a rock slope with a tensile crack. The slope failure under a general compression-shear condition is considered as a crack extension problem. To avoid the unrealistic crack interpenetration under the action of compression in modeling, this study takes contact conditions between crack surfaces into account. The stress intensity factors are then calculated by the displacement extrapolation method. A fracture mechanics approach to evaluate factors of safety for the jointed rock slope is developed and applied to an example. From the parametric study, the factors of stress intensity have been calculated for different slope geometries. In addition, the factors of safety with respect to the length of crack extension have been derived from results of the example. The comparison between the results from fracture mechanics approach and other methods shows that the fracture mechanics approach is most conservative in dealing with the slope with a tensile crack. This study demonstrates that the fracture mechanics approach provides an alternative analysis of rock slope stability.

KEYWORDS: Rock slope, Fracture mechanics, Finite element method, Limit equilibrium method, Factor of safety.

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