Fig 1.
The flowchart of the research project.
Fig 2.
Distribution histograms for inputs (in blue) and outputs (in green).
Table 1.
Training dataset.
Table 2.
Validation dataset.
Table 3.
Statistical analysis of collected database.
Table 4.
Pearson correlation matrix of the dataset.
Fig 3.
Typical illustrative framework for the genetic programming model.
Fig 4.
Typical illustrative framework for the ANN.
Fig 5.
Typical framework for the RSM model.
Fig 6.
Layout for the developed ANN models.
Fig 7.
Relative importance of input parameters.
Table 5.
Weights matrix for the developed ANN.
Fig 8.
Relation between predicted and calculated (UCS7) values using the developed models.
Fig 9.
Relation between predicted and calculated (UCS28) values using the developed models.
Fig 10.
Comparing the accuracies of the developed models using Taylor charts, a) For UCS7, b) For UCS28.
Table 6.
Accuracies of developed models.
Table 7.
Fit Statistics of the RSM UCS model.
Fig 11.
Normal plot of residuals for normal percentage probability and externally studentized residuals for the unconfined compressive strength RSM model.
Fig 12.
Illustrative representation of the externally studentized residuals and the predicted values of the UCS model.
Fig 13.
Illustrative representation of the externally studentized residuals and the entry runs of the UCS model.
Fig 14.
Illustrative representation of the Cook’s distance of the UCS model.
Fig 15.
Illustrative representation of the Box-Cox Plot for Power Transform of the UCS model.
Fig 16.
Illustrative representation of the predicted versus actual values of the UCS model.
Fig 17.
Illustrative representation of the residuals versus gravel parameter values of the UCS model.
Fig 18.
Illustrative representation of the leverage versus run values of the UCS model.
Fig 19.
Illustrative representation of the DFFITS versus run values of the UCS model.
Fig 20.
Illustrative representation of the DFBETAS versus run values of the UCS model.
Fig 21.
Illustrative representation of the perturbation, FDS, and 3D surface behavior of the UCS model with selected parameters.