Figure 4.
The image presents a comparative analysis of linear and nonlinear models, organised in a two by two grid format. The top two sections show the linear model, while the bottom two depict the nonlinear model. Each section is labelled, and there are annotations indicating the stages of comparison, specifically Stage 1, Stage 2, and Stage 3. The models illustrate different deformation characteristics, represented by colour gradients. Arrows between the stages indicate a flow of information or progression through the stages, facilitating visual understanding of how each model behaves under various conditions. The layout allows for direct comparison between the linear and nonlinear responses at each corresponding stage.Pipe–soil interaction process