热焊法对工程常用土工膜焊缝质量的影响

Effect of heat welding method on weld quality of geomembrane commonly used

土工膜焊缝剥离强度和剪切强度是整个防渗结构可靠性保障的关键因素之一。为了得到热焊法对土工膜焊缝质量的影响，本文选择7种不同厚度的工程常用的HDPE土工膜在不同充气时间和充气压强条件下进行焊缝剥离试验和剪切试验。试验结果表明：在土工膜热焊法接缝条件下，热焊法的土工膜焊缝接缝质量稳定，接缝效率1最大为0．99，最小为0．85；接缝效率2最大为0．86，最小为0．37；接缝效率1在薄膜区0．25～0．75mm范围内受压强影响相对较大且成反比，受时间影响很小；土工膜在0．75～2．0mm范围内大小相近；土工膜焊缝效率2随着充气时间和充气压力均成反比，且在薄膜区0．25～1．00mm范围受影响较大，在厚膜1．00～2．00mm范围内影响很小。

Geomembrane welding seam peel strength and shear strength is one of the key factors for the impervious structure reliability. In order to get the effect of air inflation time and air inflation pressure on geomembrane seam peel strength and shear strength, in this paper, seven different thickness kinds of HDPE geomembrane were selected to make the welding seam peel strength and shear strength test at different aera- tion time and filling pressure conditions. The test results show that： In the condition of geomembrane seam＇s heat welding method, heat welding method makes geomembrance weld quality stable, the maximum of seam efficiency 1 is 0.99, the minimum is 0.85, the maximum of seam efficiency 2 is 0.86, and the minimum is 0.37; In the thin geomembrance region, 0.25 mm- 0.75 mm, seam efficiency 1 is inversely pro- portional to air inflation pressure and influenced relatively large by air inflation pressure, while influenced by time very little, in the thick geomembrance region, 0.75 mm- 2.00 mm, each test team＇s seam efficien- cy 1 is similar to each other; Seam efficiency 2 is both inversely proportional to air inflation pressure and air inflation pressure, and the impact is large in the thin geomembrance region, 0.25 mm- 1.00 mm, while very little in the thick geomembrance region, 1.00 mm - 2.00 mm.