# Monitoring of the Variation in Pore Sizes of Woven Geotextiles with Uniaxial Tensile Strain
## 4 Monitoring of Variation in Specific Pore Sizes
### Monitoring of Distribution of Pore Sizes  
Figure 7 demonstrates a random distribution of various pore sizes within the illuminated region of unstrained geotextile W120\({}^{\circ}\). The specific large pore sizes ranging from O\({}_{80}\)\({}^{\circ}\) to O\({}_{100}\)\({}^{\circ}\) are marked with red squares. The yellow circles and blue diamonds mark the specific medium pore sizes ranging from O\({}_{40}\)\({}^{\circ}\) to O\({}_{60}\)\({}^{\circ}\) and the specific small pore sizes ranging from O\({}_{0}\)\({}^{\circ}\) to O\({}_{20}\)\({}^{\circ}\). For the selected region of geotextile W120\({}^{\circ}\), the large pore sizes are identified to be mainly located on the outer sides, the small pore sizes are located inside the district and the medium pore sizes are located randomly in the selected region. The MATLAB code contributes to monitoring pore locations and displaying the visual distributions of various pore-opening sizes. Figure 8 provides the visual distribution of pore sizes along the warp direction and weft direction for the selected region of geotextile W120\({}^{\circ}\) shown in Figure 7. Colored dots along the weft direction and the warp direction indicate the arrangement of pores. Ten columns and twenty rows of dots are arranged in sequence in the weft direction and the warp direction, respectively. Each colored dot area demonstrates the corresponding pore-opening size. Therefore, the larger dot area illustrates a larger pore-opening size of geotextile W120\({}^{\circ}\). Different pore-opening sizes are demonstrated by dots with contrasting colors. The dark red colored dot indicates the largest pore size of geotextile W120\({}^{\circ}\), while the smallest pore size is described with the dark blue colored dot. The transition of contrasting colors indicates the various pore sizes ranging from 0 to 0.8 mm. Figure 8: The visual distribution of various pore sizes with uniaxial strain for W120\({}^{\circ}\): (**a**) Unstrained; (**b**) Under strain of 3%; (**c**) Under strain of 6%; (**d**) Under strain of 9%. To verify the deformation of various pore sizes with detailed distribution, Figure 8 monitors all pore sizes within the selected region of geotextile W120c under the tensile strain of 0, 3%, 6%, and 9%, respectively. Figure 8a shows the visual distribution of unstrained pore sizes of geotextile W120c. The contrasting colors and various dot areas indicate a wide range of unstrained pore size distribution. The red dots on the outer sides suggest the distribution of large pore sizes. The blue dots inside the selected region describe the small pore size distribution. The yellow dots demonstrate the medium pore sizes, which are randomly distributed in the selected region of the specimen. Three typical colored dots are selected to monitor the pore size deformation in a visual way with uniaxial tensile strain. The blue dot in the third column and the seventeenth row (C3R17) indicates a small specific unstrained pore diameter of 0.088 mm, as shown in Figure 8a. The red dot in C10R8 illustrates a large specific unstrained pore size of 0.66 mm and the yellow dot in C5R13 shows a medium specific unstrained pore size of 0.39 mm. The dark blue dot in C3R17 shown in Figure 8a transforms to a light blue dot, as shown in Figure 8b. The pore diameter in C3R17 increases to 0.27 mm as the uniaxial tensile strain increases to 3%. Then it becomes 0.39 mm with tensile strain increasing to 6%, as shown in Figure 8c. Figure 8d suggests the specific pore diameter is 0.46 mm as tensile strain increases to 9%. Figure 8b-d illustrate that the yellow dot in C5R13 has pore diameters of 0.39 mm, 0.39 mm, and 0.45 mm under the tensile strain of 3%, 6%, and 9%, respectively. Both the unstrained small pore size in C3R17 and the unstrained medium pore size in C5R13 become medium pore sizes under the tensile strain of 9%. Figure 8b-d indicate the red dot area in C10R8 increases with a slower growth rate, has pore sizes of 0.68 mm, 0.69 mm, and 0.73 mm under the tensile strain of 3%, 6%, and 9%, respectively.