Block-flexure toppling failure of rock slopes using an equivalent deformation compatibility method

Abstract

Block-flexure toppling constitutes the predominant form of toppling failure in rock slopes. Although it has been extensively studied, the current theoretical models are often oversimplified by treating rock layers as rigid bodies that diverge from actual conditions. The proposed Equivalent Deformation Compatibility Method (EDCM) offers a fresh approach to assess the stability of rock slopes prone to block-flexure toppling. EDCM posits that blocky rock layers, with their inability to withstand significant bending and role in merely transferring forces, can be modeled as intact layers with a reduced modulus. The method simplifies the complex issue of analyzing discrete and continuous rock layers to the study of layered soft and hard rock, establishing deformation compatibility equations subsequently. Validation of the EDCM was achieved through numerical models, physical model testing, and application to an actual slope. The factor of safety (FS) for slopes corresponds with the results from both models and the actual slope, demonstrating the method's applicability for evaluating susceptibility to block-flexure toppling. When applying the EDCM, it is advised to set the elastic modulus reduction coefficient for blocky layers at a value below 0.1.