A study of the stability of rock excavated slope based on rockmass structure and unascertained measure evaluation models

Based on the investigation of excavated layered slopes in the Qianxi area, it was found that the structure characteristic of rock mass is the main determinant of instability mechanism and failure mode of layered slopes. Therefore, in combination with the differences of layered slopes in this area, it is particularly important to analyze the slopes by specifically classifying the rock masses. The structure of rock mass can be systematically divided into 4 categories and 10 sub-categories, considering the lithology combination of layers, geological structure and weak interlayer (structural surface) as factors, and for every type of rock mass, the engineering geological properties are evaluated, and the failure mode and mechanism are explicated. Based on the structure type of rock mass, 12 impactors, including 6 quantitative indexes and 6 qualitative factors, are selected for slope stability prediction using the uncertainty measure theory. A new evaluation system of “rock mass-indicator combination weighting-uncertainty measure theory” is proposed. This method is applied to predict the stability of eight slopes, the prediction results are nicely conform to the actual situations. This method is highly reliable and can be used in practical slope engineering.