Indirect estimation of the rock deformation modulus based on polynomial and multiple regression analyses of the RMR system

摘要

From the collected data, multiple and polynomial regression analyses were conducted to build a predictive model of the in situ deformation modulus. The following results can be drawn from the analysis: Sixty-one data sets were used to produce the predictive model of the deformation modulus from the multiple regression analysis. The entire data set was compared with the sigmoid function type correlation suggested by Hoek and Diederichs [18] under the condition of disturbance factors of 0, 0.5, and 1. The collected data were found in the regions near D = 0 and 0.5. Prior to the multiple regression analysis, the correlations between the six parameters of the depth, uniaxial compressive of intact rock (UCS), RQD, JS, JC, and GW were evaluated. JS showed the strongest correlation with the modulus while the GW condition had no correlation with the modulus. These results imply that the GW can be excluded from the group of independent parameters in the multiple regression analysis. In addition, the VIF was calculated for each parameter to investigate the existence of multicollinearity. The calculated values of the VIF indicate that no severe correlation exists between the five independent parameters.