From the point of view of insufficient statistical data

a non-probabilistic reliability method for implicit performance function of geotechnical engineering is developed

which is a useful complement to the probabilistic reliability method.Firstly

we use the series of interval extension functions to reduce the interval correlation

and establish the iterative program for implicit function interval solution based on the subinterval method.Then

the experiment design is utilized to establish the statistical optimization model from the point view of comprehensive design to search the optimal solution and further to achieve a target range.Finally

by setting the confidence interval for the interval solution to stress function in the performance function

the non-probabilistic reliability model of the implicit performance function with limited computational cost is obtained.Moreover

through the solution for external function of support pressure

the detailed operation procedures of the non-probabilistic method are demonstrated.The results of the engineering examples show that the relative error between the maximum support resistance obtained by the proposed method and the maximum value of Monte-Carlo simulation is 0.83%

and the proposed method has a preference for absolute security.