土工膜和GCL防渗结构缺陷渗漏量试验研究

Experimental study on leakage of geomembrane-GCL composite liner under the different defective aperture

为评估土工膜和GCL防渗结构的缺陷渗漏量,给防渗结构设计提供有益参考,本文依据施工、特殊部位和偶然条件等对缺陷的影响程度,开展了土工膜防渗层和土工膜+GCL防渗结构在不同缺陷条件、不同GCL水化条件和不同水头条件下的室内渗漏试验,并对比分析了两种防渗结构的渗漏量及其影响规律。结果表明,土工膜+GCL防渗结构不仅可以降低整个防渗系统的破坏概率,还可以在相同破坏条件下有效降低缺陷渗漏量约一个数量级以上。土工膜+GCL防渗结构渗漏量与水头的关系受到防渗结构破坏形式的影响,基本成“S”形,对水头的敏感性随着水头增加而降低。只有在仅土工膜缺陷,且水头较高的条件下,GCL水化才能显著降低渗漏量。

Geomembrane-GCL composite liner(GGCL)was commonly used to isolate waste liquid from the evaporation pond to minimize potential groundwater contamination.Referring to the possible physical damage to the GGCL,the influences of defective aperture,hydration,and pressure head on the leakages of GGCL were investigated by experiments,and the leakages of GGCL were compared with Geomembrane liner(GL)under the same test conditions.It shows that the GGCL could significantly reduce the leakage,and the leakage of GGCL was less than ten percent of the leakage of GL.The leakage-pressure head relationship of GGCL is nonlinear,and the influence of the pressure head on the leakage decreases with the increasing of water head.The effect of hydration of GCL on the leakage is related to the physical damage of GGCL.The findings from the present study are helpful to the design of the barrier of the evaporation pond against leakage.