In light of the randomness

fuzziness and interval feature of values of geotechnical parameters

the triangular distribution functions

normal distribution functions and quasi-normal distribution membership functions are separately proposed to express the distribution of the parameter values. The methods to determine the distribution functions of geotechnical parameters and their interval values with different cut-levels are presented. And the interval values can be expressed by the boundary values of the membership functions. The boundary values of triangular distribution functions and quasi-normal distribution functions are suggested to be determined with their average values and standard deviations. The upper or lower limit of triangular distribution function boundary value can be got by the average value plus or minus two point five times standard deviation. And the upper or lower limit of quasi-normal distribution function boundary value can be got by the average value plus or minus three times standard deviation. Then the fuzzy point estimate method is proposed to analyze the fuzzy reliability of slope engineering. The results show that the slope fuzzy reliability index determined by eleven cut-levels are approximately equal to the probabilistic reliability index got by the Monte Carlo method. The number of cut-levels is proposed to be nine. And the cut-levels can be selected from 0.1 to 0.9. The fuzzy point estimate method with the determined boundary values of different distribution functions can be used to evaluate the slope fuzzy reliability; this method is simple and practical.