Abstract: Random-fuzzy statistical method can be used to reflect the space variation of geotechnical parameters. The method for determining the weight coefficient is discussed. Especially, the significance of “reference point” is studied. The results show that when the reference point limitlessly approaches the core point, the corresponding maximum membership degree is just the desired correct result. Based on the principle of random-fuzzy statistical method, an iterative calculation procedure is proposed to calculate the objective function. To analyze the geotechnical parameters in a certain nuclear power plant project, the curves of membership degree of each rock sample against reference point, as well as the procedure curves of reference point approaching core point, are obtained. The results show that the exponential function well expresses the function of membership degree. The distribution of membership degrees of samples exhibits normal distribution of narrow region. Therefore, the random-fuzzy statistical method is consistent with the practice; and then it is better than the conventional random method.

Key words: geotechnical characteristic parameter, random-fuzzy statistical method, function of membership degree, weight coefficient