Risk assessment model of expansive soil slope stability based on Fuzzy-AHP method and its engineering application

To systematically evaluate the risk grade of stability of expansive soil slope during construction, the recognition model is established by using the fuzzy recognition theory and the analytic hierarchy process (AHP). Based on the characteristics of shallow slide of 22 expansive soil road sections constructed in China, the condition of slope body, swell-shrink grade, hydraulic and meteorological characteristics, supporting and improvement measures and other factors such as the construction technology and management level, vegetation coverage, soil layer, and drying-wetting cycles are selected as the evaluation indices, and the corresponding criteria of risk assessment system of expansive soil slope stability are also established. The weights of evaluation indices are obtained by using AHP method, and the measure functions are established to assess single index measurement and synthetic measurement. The maximum membership degree criterion is adopted to discern the risk grade of expansive soil slope stability. Based on this, the stability of expansive soil slope with different condition located in Nanyou highway and Beijing west 6th ring highway of China are analysed to verify the reliability of the present method. For practical purposes, the present risk assessment methodology can be used to systematically assess the slope stability in expansive soil zones.