Improved fourth-moment method for reliability analysis of geotechnical engineering

In reliability analysis of geotechnical engineering, the performance function is usually implicit and has strong nonlinearity. However, practical moment methods such as JC method and SORM are mainly applicable to the explicit performance function. In this paper, an improved fourth-moment method for reliability analysis of geotechnical engineering is presented by combining the efficient point estimate method for probability moments with the high order moments method for reliability analysis. Firstly, by introducing independent transformation and linear transformation, the performance function becomes a function of the reference variables, and then an efficient estimate method for the first four moments of performance function is established, which combines the univariate dimension-reduction method for multivariable function with the method for the points and weights of reference variables. Secondly, based on the combination of the estimated probability moments estimation and the cubic normal transformation, an improved fourth-moment method to assess reliability of geotechnical engineering is proposed. Finally, two numerical cases are investigated to verify the proposed point estimate method for probability moments, and results indicate that the proposed estimate method is efficient and accurate, and a classical geotechnical engineering case is used to illustrate the easy-implementation, efficiency and accuracy of the proposed fourth-moment method for reliability analysis of geotechnical engineering.