A Fuzzy-AHP-based variable weight safety evaluation model for expansive soil slope

Due to the expansion and shrinkage deformation caused by the cyclic drying and wetting process, the expansive soil slope often slides in a shallow, long-term and repetitive way, resulting in the changing contribution rate of safety evaluation factors to the stability of the slope constantly changes. In this work, a variable weight Fuzzy-AHP method was constructed to constantly evaluate the safety of expansive soil slopes. Firstly, considering the effects of differences in expansibility, two variable weight models for strong and medium-weak expansive soils were proposed, respectively, based on the cohesion-water content relationships in published articles. Meanwhile, the ridge-shaped membership function was adopted in the proposed method, aiming to timely response the deterioration of evaluation factors. Using the proposed variable weight Fuzzy-AHP method, analyses were conducted on an expansive soil slope in Guangxi, China. Results show that the method proposed in this work could dynamically evaluate the stability of the expansive soil slope comparing to that obtained by the traditional constant weight Fuzzy-AHP method, verifying the reliability and superiority of the variable weight Fuzzy-AHP stability evaluation method established in this work.