Risk analysis of shrinking and swelling of expansive soils and improved expansive soils with lime (IESL) for airport runway projection is a complex uncertainty problem. To select the rational foundation treatment plan and ensure the safe operation of runway, herein combined with the features of expansive soils in the runway area of Xinqiao international airport of Hefei, a novel risk analysis method was proposed to classify shrinkage and swell of expansive soils and IESLs by means of coupling set pair analysis with stochastic simulation of triangular fuzzy numbers. A function of six elements connection number was introduced to depict hierarchy and fuzziness of membership between the evaluation sample and the classification standard. Moreover, triangular fuzzy numbers simulated by a stochastic simulation method were presented to specify the component coefficients of discrepancy degree. Then a risk analysis model was described to calculate reliable degree corresponding to a confidence interval. Finally, comparisons of shrinkage and swell for foundation treatment plans of different lime content were conducted. The results will provide basis for the risk design and risk management of runway project on the expansive soils.
