Journal of Textile Research ›› 2023, Vol. 44 ›› Issue (04): 92-99.doi: 10.13475/j.fzxb.20211110108

• Textile Engineering • Previous Articles     Next Articles

Analysis on pore characteristics of braided geotextiles based on topological sorting method

TANG Xiaowu1,2(), LI Keyi1,2, ZHAO Wenfang1,2, CHEN Shihua3, LIN Weikang1,2, LIANG Jiaxing1,2   

  1. 1. Research Center of Coastal and Urban Geotechnical Engineering, Zhejiang University, Hangzhou, Zhejiang 310058, China
    2. Engineering Research Center of Urban Underground Development of Zhejiang, Hangzhou, Zhejiang 310058, China
    3. Zhejiang Institute of Hydraulics & Estuary, Hangzhou, Zhejiang 310020, China
  • Received:2021-11-26 Revised:2022-10-04 Online:2023-04-15 Published:2023-05-12

Abstract:

Objective It is evident that the traditional digital image methods are prone to errors in sorting pores in braided geotextiles. Current studies have used statistical methods to analyze pore changes, which do not allow the morphological and dimensional changes of each pore to be traced during the tensioning process. The method of characterizing the pores in braided geotextiles is investigated to address this problem.
Method Topological sorting was used to correct the sorting error of braided geotextiles digital image method, and then the area, length, and width of each pore were accurately obtained based on pixel statistics and minimum area bounding rectangle (MABR). Finally, the sorting results of the digital image method and topological image method, three-dimensional area distribution, and length-width statistics diagram are compared.
Results The error rate associated with the digital image method for braided geotextiles in the initial state was found to be the highest, at 19.5% (Fig. 7), and it can be seen that the error rate of the digital image method for all three geotextiles gradually decreases with increased strain. The digital image method was found to produce errors in the ordering of the geotextile pores, which would have an impact on the subsequent experimental analysis and processing, and would not truly reflect the changes in the pore parameters of the braided geotextile during the stretching process. The improved image sorting method based on topological sorting can correct the sorting errors of the digital image method for geotextiles with different masses and tensile strains per unit area, thus achieving accurate acquisition of the sorting of geotextile pores.
The topological image method was used to correct the area of the upper ten pores in the first column on the left side of W150(Fig. 6). The area of the pore obtained by the digital image method under different tensile strains was corrected, and accurate tracking of the area was achieved.
The three-dimensional distribution of the area is plotted according to the location and area of each pore in W150, with the X and Y coordinates representing the location of the pores and the Z axis representing the area of the pores(Fig. 8), which depicts the distribution of pore area and its variation with strain over a large area range. It is shown that the improved image method based on the topological principle can improve the accuracy of the pole area acquisition results and enable large-scale tracking of geotextile pore areas.
The effectiveness of the topographic image method for tracking the length and width of geotextile pores over a wide area is verified(Fig. 11). As the geotextile stretches, it causes some of the pores to tilt or come back into alignment. The improved image method based on the topological principle can identify and locate pores in woven geotextiles at any angle and accurately track the length and width of pores on a large scale.
Conclusion 1) Comparison of the sorting results of the digital image method and the improved image method based on topological sorting shows that topological sorting can correct the sorting errors of the digital image method for geotextiles with different unit area masses and tensile strains to obtain the sorting of geotextile pores accurately. 2) The area correction of geotextile pores and the three-dimensional distribution of the area show that the topological image method can visually reflect the distribution of pore areas and their variation with strain over a large area of geotextile and achieve large-scale accurate tracking of geotextile pore areas. 3) The comparison of the area of each pore and the geotextile length and width statistics chart shows that the MABR method can improve the accuracy of the pore length and width acquisition, and based on this method, the topological image method can accurately acquire and track the changes of pore length and width from any angle on a large scale.

Key words: braided geotextile, pore characteristic parameter, digital image method, topological sorting, uniaxial tensile strain

CLC Number: 

  • TU531.7

Fig. 1

An example of digital image sorting"

Fig. 2

Topological sorting"

Fig. 3

Pore sorting. (a) Before topological sort; (b)After topological sort"

Fig. 4

Directed acyclic graph before topological ordering"

Fig. 5

External rectangle. (a) MBR; (b)MABR"

Tab. 1

Properties of woven geotextiles"

名称 单位面积质量
μ/(g·m-2)
厚度T/
mm
经向强度/
(kN·m-1)
纬向强度/
(kN·m-1)
W120 119.07 0.20 22.6 17.5
W150 159.00 0.22 25.3 22.5
W250 246.30 0.58 47.2 43.8

Fig. 6

Correction of W150's pore sorting and area. (a) W150 under strain of 0; (b) W150 under strain of 6%; (c) W150 under strain of 12%"

Fig. 7

Sorting error rate of fabrics under different tensile strains"

Fig. 8

Three dimensional distribution of W150 pore area. (a) Under strain of 0%; (b) Under strain of 3%; (c) Under strain of 6%; (d) Under strain of 9%; (e) Under strain of 12%"

Fig. 9

Experimental pores"

Fig. 10

Area of every pore"

Fig. 11

Pore length and width statistics of W120. (a) W120 under strain of 0; (b) W120 under strain of 9%"

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