堆石坝防渗土工膜薄壁圆筒双向拉伸性能测试方法

Thin-Walled Cylinder Biaxial Tensile Test Method of Waterproof Geomembrane for Rockfill Dams

由于堆石坝防渗用土工膜拉伸性能在抵抗外部荷载变化中发挥重要作用,文章对规范中的土工膜拉伸性能测试方法以及国内外有关研究成果进行对比分析,并在此基础上提出了薄壁圆筒双向拉伸测试方法,最后,利用有限元软件中的线弹性模型对相同位移荷载条件下的各种试验方法进行数值模拟.结果表明:薄壁圆筒双向拉伸试验能够准确反应土工膜在双向拉伸条件下的力学特性;与现有的液胀试验和十字形双向拉伸试验相比,薄壁圆筒试样应力分布更加均匀,试验效果更优.

Tensile properties of waterproof geomembrane for rockfill dams play an important role in resistance of changing external loads. A discussion has been made about the standard test method for tensile properties in the specification of the geomembranes. At the same time, various research achievements at home and a- broad, which are related to this, have been analyzed and compared. Based on the discussion above,a new biax- ial tension test method is developed for loading a thin-walled cylinder specimen. Finally, a comparison about the various methods for tensile properties of geomembrane has been made in detail at the angle of mechanical properties by using the linear elastic model of the finite element software,which is under the condition of the same displacement load. The numerical simulation results show that the thin-walled cylinder biaxial tensile test can accurately reflect the mechanical properties of geomembrane under biaxial tensile test. In addition, the stress obtained by this new mechanism are more uniform than the existing mullen test and the cruciform biaxial tensile test, which shows a better test effects.