Abstract：The material parameters of rock and soil masses are often variables with uncertainty. They are mutually dependent as pairs of causes and effects，because of their cross influence. For cases of multi-variations，the correlation coefficients among these variables are not simple because of such interactions. The method of partial coefficient of correlation presented in this article can distinquish these interactive relations quantitatively. It has been shown that there is a significant difference between partial and simple coefficients of correlation from engineering application examples，and that the former is more accurate and realistic. The interactive relations among the variables that have large correlation coefficients must be taken into account during estimation on the reliability and risk of engineering works.
