Stability analysis of wedges of rock slopes based on 3D network simulation of structural surface

High rock slopes in mountainous areas are increasingly encounted with the construction of expressways. As one of frequently observed stablility issues of high rock slopes, wedge failure differs greatly in scale and stability as well as location distribution. Such characteristics cause significant difficulty in the slope stability analysis during exploration and the subsequent project design. According to their geometric structure, the wedges are divided into two types: I-type wedges on the slope shoulder and surrounded by two intersecting structural surfaces, top and slope surface, and II-type wedges on the slope surface and surrounded by three structural planes and slopes. By means of the three-dimensional network simulation technology of structural surface, the random analysis and step-by-step screening of wedges in rock slope engineering are carried out. The methods for searching wedges and evaluating their stability are developed to guide the evaluation, design and reinforcement of slopes. The applicability of this developed method is demonstrated by a case study, the practical application in Xiamen-Shaxian Expressway. The research results demonstrate that for the wedge analysis of rock slopes, it is possible to draw wedges from the 3D structural digital model for rock mass and analyze their stability based on the three-dimensional network simulation technology of structural surface. Comparison of I-type and II-type wedges indicates that when the slope is higher, the number of II-type wedges is far greater than that of I-type ones, therefore, the II-type wedges cannot be ignored in the slope projects.