Multiple failure modes-based practical calculation model on comprehensive risk for levee structure

Risk calculation of levee in the complex environment has significant theoretical values and practical meanings. As there still exists problems in present risk calculation models, a simple and efficient calculation model of the comprehensive levee risk is needed to be established. This paper studies the comprehensive risk calculation model of levee with multiple failure modes based on the analysis of levee instability and seepage failure. Firstly, coupling calculation of the seepage field and stress field is made using the finite element method, and safety factor of levee slope and critical failure hydraulic gradient of levee foundation are determined according to the strength reduction and piping theory. Then, particle swarm optimization is applied to conduct a comparative study on potential impact factors of levee stability and seepage, thus to determine explicit expressions for instability of levee body and seepage failure of levee foundation. Finally, Monte Carlo method is introduced to simulate the levee structure stochastically and calculated the comprehensive levee risk. Calculation results of the example show that the risk calculation method proposed in this paper has higher computational efficiency and can provide references for the decision of levee reinforcement.