# Monitoring of the Variation in Pore Sizes of Woven Geotextiles with Uniaxial Tensile Strain
## 4 Monitoring of Variation in Specific Pore Sizes  
### Monitoring of Specific Characteristic Pore Sizes  
Figure 6 shows that fifteen specific unstrained pore diameters are selected and their variation behaviors are monitored with uniaxial tensile strain for geotextile W120\({}^{c}\). In order to specify the deformation of large pore sizes, medium pore sizes, and small pore sizes, the variations in three specific characteristic pore diameters O\({}_{95}\), O\({}_{50}\)\({}^{8}\), and O\({}_{10}\)\({}^{8}\) are recorded under each uniaxial tensile strain of 1%. Five comparable pore sizes with each specific pore size (i.e., pore sizes ranging from O\({}_{95}\)\({}^{8}\) to O\({}_{97}\)\({}^{8}\) with O\({}_{95}\)\({}^{8}\)) are monitored as uniaxial tensile strain increases. The large specific unstrained pore sizes ('L' Size) are represented by five selected unstrained pore sizes O\({}_{93}\)\({}^{5}\), O\({}_{94}\)\({}^{8}\), O\({}_{95}\)\({}^{8}\), O\({}_{96}\)\({}^{8}\), and O\({}_{97}\)\({}^{8}\), as shown in Figure 6. These specific unstrained pore-opening sizes ranging from 0.618 mm to 0.647 mm are monitored with uniaxial tensile strain. As tensile strain increases to 6%, the selected pore size O\({}_{95}\)\({}^{8}\) increases by 5.24%. Then O\({}_{95}\)\({}^{8}\) increases by 15.84% with uniaxial tensile strain ranging from 6% to 14%. The results suggest a good consistency with the variation of characteristic pore  
Figure 5: Variation in five characteristic pore sizes (ranging from O\({}_{10}\) to O\({}_{95}\)) with uniaxial tensile strain for (**a**) W120\({}^{c}\); (**b**) W150\({}^{c}\). size O\({}_{95}\)s and the variation of the other specific large pore size O\({}_{95}\)s, O\({}_{94}\)s, O\({}_{96}\)s, and O\({}_{97}\)s, respectively, for geotextile W120s. The grey shaded area illustrates a possible range for monitored medium specific pore sizes (\"M\" Size) ranging from O\({}_{30}\)s to O\({}_{70}\)s as tensile strain increases to 14%. The possible lower bound of 'M' Size varies from 0.434 mm to 0.575 mm and the upper bound varies from 0.543 mm to 0.685 mm. Five representative unstrained pore diameters O\({}_{48}\)s, O\({}_{49}\)s, O\({}_{50}\)s, O\({}_{51}\)s, and O\({}_{52}\)s have a narrow range from 0.486 mm to 0.500 mm. The monitored characteristic pore size O\({}_{50}\)s increases by 6.67% with tensile strain increasing to 6%. Then O\({}_{50}\)s increases by 18.94% with uniaxial tensile strain ranging from 6% to 14%. There is a similar gentle variation trend between large pore size and medium pore size under the low tensile deformation. The results suggest a good consistency with the variation of medium characteristic pore size O\({}_{50}\)s and the variation of other four specific pore sizes O\({}_{48}\)s, O\({}_{49}\)s, O\({}_{51}\)s, and O\({}_{52}\)s for geotextile W120s. Figure 6 shows a relatively wide range of small specific unstrained pore sizes ('S' Size) O\({}_{8}\)s, O\({}_{9}\)s, O\({}_{10}\)s, O\({}_{11}\)s, and O\({}_{12}\)s ranging from 0.173 mm to 0.270 mm. The monitored pore size O\({}_{10}\)s increases by 179.00% with a steady growth rate during the whole tensioning, has a good consistency with the variations of specific pore sizes O\({}_{8}\)s and O\({}_{12}\)s. The specific pore sizes O\({}_{9}\)s and O\({}_{11}\)s have a slower growth rate. A slight deviation exists among the variations of five small specific pore sizes, particularly in the late period of uniaxial tensile strain. The pore diameters for both 'L' Size and 'M' Size appear to show minimal changes in the strain ranges of 3-7%, 3-7%, 4-8%, 3-6%, and 4-8% for geotextile W120s, W120s, W120s, W120s, W120s, and W250s, respectively. The reason is that geotextile pore diameters are likely to be deformed by the displacement of woven strips considering the complexity of their interface forces during the early and medium tensioning stage.