# The Application of Computed Tomography to Study the Soil Porosity of Mountain Red Earth
## 3 Results and Discussion
### Three-Dimensional Morphology of Pores  
Avizo software (v2022.2) is widely used for 3D visualization and reconstruction based on CT scan data. It effectively partitions components and quantifies geological properties like porosity and permeability, making it popular in geology [46]. Figure 15 illustrates the 3D reconstruction of Mountainous Red Earth, involving stages such as image preprocessing, pore separation, and rendering. CT slice data are superimposed to create a grayscale 3D image (Figure 15a), with soil boundaries marked (Figure 15b). By extracting and rendering the pores (Figure 15c,d), their spatial distribution, connectivity, and curvature are clearly represented. The 3D pore structures were rendered, revealing both overall and localized details, as shown in Figure 16. Most pores are concentrated in the upper part of the soil column with an intermingled and connected distribution, suggesting the presence of transverse and longitudinal connective channels. Isolated pores are relatively fe \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Pore Parameters** & **Average** & \begin{tabular}{c} **Standard** \\ **Deviation (SD)** \\ \end{tabular} & \begin{tabular}{c} **Box-Counting** \\ **Dimension (D)** \\ \end{tabular} & \begin{tabular}{c} **Number of** \\ **Pores** \\ \end{tabular} & \
\begin{tabular}{c} **Sphericity** \\ **Pore Area** \\ \end{tabular} \\ \hline Box-counting Dimension (D) & 1.487 & 0.210 & \(1\) & & & \\ \hline Number of Pores & 147.793 & 32.690 & 0.711 ** & \(1\) & & \\ \hline Sphericity & 0.840 & 0.021 & \(-0.545\) ** & \(-0.565\) ** & \(1\) & \\ \hline Percentage of Pore Area & 21.547 & 13.692 & 0.934 ** & 0.507 ** & \(-0.357\) ** & \(1\) \\ \hline \hline \end{tabular}
\begin{tabular}{c} \(p<0.05\); ** \(p<0.01\). \\ \end{tabular}
\end{table} 
Table 1: Results of Pearson correlation analysis between the parameters of the pores. Figure 14: The relationship between the box-counting dimension and the number of pores (**a**) and the percentage of pore area (**b**). Figure 15: Reconstruction process of soil sample. pores, formed by surface biomass and organic-inorganic colloid aggregation, facilitate water storage and infiltration. The number of pores decreases vertically from top to bottom, with noticeable differences between the surfaces, indicating dynamic changes. This structure allows for rapid surface water accumulation, potentially leading to supersaturation, erosion, and soil loss in slope areas. Based on the results of CT scanning and utilizing 3D visualization technology, the 3D morphology of Mountain Red Earth was reconstructed from multiple perspectives. The results indicate that CT non-destructive testing technology can better qualitatively observe and quantitatively characterize the pore structure of Mountain Red Earth, rendering the macro- and microstructures of soil samples in three dimensions. This allows us to delve into the analysis of pore size, shape, distribution, and connectivity. Three-dimensional reconstruction not only provides a more intuitive viewpoint but also quantitatively describes the features of pore space. Building upon this, simulated experiments and computational models can be used to explore the impact of different pore structures on moisture, gases, and microbes in the structures formed by CT 3D reconstruction. Finally, through model building and parameter adjustment, the distribution and connectivity of pores under different soil types and humidity conditions can be simulated, thereby predicting soil responses to external rainfall. This method provides a powerful tool for studying soil moisture movement and gas exchange and for revealing the complexity and diversity of soil internal structures, thus providing a fundamental basis for studying the processes and mechanisms of soil and water loss in Mountain Red Earth. Through analysis of the 2D and 3D reconstructed structures, it was observed that smaller pores were not extracted, leading to their oversight. Nonetheless, these small pores play a crucial role in influencing soil properties.