# Monitoring of the Variation in Pore Sizes of Woven Geotextiles with Uniaxial Tensile Strain
## 6 Conclusions  
The composite of large pore sizes, medium pore sizes, and small pore sizes is encouraged in filter design, considering the variation in pore size distribution frequency and pore size distribution scale with uniaxial tensile strain. This paper compares the deformation of various pore-opening sizes obtained by using image analysis with uniaxial tensile strain, for five different woven slit-film geotextiles. The following conclusions are drawn:  
1. The different variation behaviors of characteristic pore-opening sizes and POAs are monitored under each uniaxial tensile strain of 1% for five woven geotextiles. The measured large pore diameters and POAs under low tensile deformation indicate a slow growth rate and then increase moderately in the late period of tensile strain. The smaller pore diameter of tested woven geotextiles indicates a faster growth rate as uniaxial tensile strain increases.
2. Fifteen typical specific pore diameters are selected and monitored to identify the change of various pore diameters. Then colorful pore size distribution diagram is generated to monitor the variation of pore diameter distribution in a quick, visual way. As uniaxial tensile strain increases, the specific large pore-opening sizes of woven geotextiles have a gentle growth rate under the low tensile deformation followed by a moderate increase rate in the late period of uniaxial tensile strain. The specific medium pore sizes indicate a similar variation behavior to the large pore sizes. The specific small pore sizes increase with a steady growth rate during the whole tensioning. More than half of the specific small pore diameters become medium pore diameters at the late period of uniaxial tensioning.
3. The pore sizes of unstrained and strained woven geotextiles exhibit a bell-shaped Gaussian distribution curve. The medium pore-opening sizes have the largest distribution proportion among all pore sizes. Considering the higher growth rate of smaller pore sizes of woven geotextiles with uniaxial tensile strain, the variation of equivalent geotextile pore size is mainly influenced by the medium pore sizes and the large pore sizes. The small pore sizes have a slight effect on the equivalent pore size variation because of a small distribution proportion among various pore sizes.  
Conceptualization, W.Z. and X.T.; methodology, W.Z., X.T. and K.L.; software, W.Z., K.L. and W.L.; validation, W.Z., X.T. and K.L.; formal analysis, W.Z., K.L. and J.L.; investigation, W.Z., W.L. and X.C.; writing--original draft preparation, W.Z. and X.T.; writing--review and editing, W.Z., X.T. and J.L.; funding acquisition, X.T. and X.C. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China, grant number 51779218 and the Key Water Science and Technology Project of Zhejiang Province, grant number RB2027.  
Not applicable.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Geotextile** & **Tensile Strain, \%** & \(y_{\text{50}}\) & \(y_{\text{0}}\) & \(x_{\text{c}}\)**, mm** & \(A\) & \(w\) & \(R^{2}\) **(COD)** \\ \hline \multirow{5}{*}{W120\({}^{\text{c}}\)} & 0 & 0.187 & 0.00932 & 0.507 & 0.0407 & 0.215 & 0.950 \\  & 3 & 0.182 & 0.00941 & 0.527 & 0.0406 & 0.222 & 0.905 \\ \cline{1-1}  & 6 & 0.187 & 0.00149 & 0.520 & 0.0485 & 0.245 & 0.947 \\ \cline{1-1}  & 9 & 0.201 & 0.00103 & 0.571 & 0.0490 & 0.230 & 0.943 \\ \cline{1-1}  & 12 & 0.221 & 0.00258 & 0.649 & 0.0530 & 0.221 & 0.970 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Parameters of Gaussian distribution curve of woven geotextile W120\({}^{\text{c}}\).