膨润土防水毯搭接界面力学性能的影响因素

Factors affecting mechanical properties of interface at geosynthetic clay liner overlaps

膨润土防水毯(geosynthetic clay liner,GCL)作为高防渗柔性土工合成材料,被广泛应用于各类防渗阻污工程中.GCL多幅搭接区经过防绕渗措施处理后亦能表现出较强防渗性,但在地下复杂外力作用下GCL搭接存在受拉失效的潜在问题.针对GCL搭接界面处展开室内抗拉试验,综合分析了搭接参数对GCL搭接处抗拉强度的影响.研究结果表明,GCL搭接界面处抗拉强度随搭接时间的延长先增加后趋于稳定,在90 min时搭接处抗拉强度达到最大值;GCL搭接界面处抗拉强度受膨润土膏涂抹量和搭接宽度的影响明显,保持单位面积膨润土膏量不变,随着搭接宽度增加GCL搭接界面处抗拉强度近似呈线性增加;保持搭接宽度不变,随着单位面积膨润土量增加,GCL搭接界面处抗拉强度呈线性增加;增加搭接宽度同时保持搭接区膨润土膏涂抹总量,不同搭接宽度下GCL搭接界面处抗拉强度基本一致;模拟潮湿环境,对GCL搭接界面喷水处理后,GCL搭接界面处抗拉强度略有下降,且单位面积膨润土膏量越多,搭接界面处抗拉强度损失越少.研究成果可以为GCL搭接界面处理提供指导,为GCL搭接区的完整性提供保障,降低因施工导致GCL垂直防渗墙防渗性能下降的风险.

Geosynthetic clay liner(GCL),as a highly impermeable flexible geosynthetic materials,are extensively used in various underground projects for anti-seepage and pollution control.Even after being treated with antiseepage measures,GCL overlap regions also exhibit strong impermeability.However,there is a potential problem of tensile failure in the GCL overlap under complex external forces for underground project.This paper focuses on indoor tensile tests of the interface at GCL overlaps and analyzes the effect of the overlap parameters on the tensile strength of GCL overlaps.Experimental results show that the tensile strength of the GCL overlaps tends to increase gradually with the duration of overlap treatmentreaching its maximum at 90 minutes.The tensile strength at the GCL overlap interface is significantly influenced by the amount of bentonite paste and the GCL overlap width.When the amount of bentonite paste per unit area remains unchanged,the tensile strength of the GCL overlap increases linearly with the increase of overlap width.Whereas the overlap width remains unchanged,the tensile strength of the GCL overlap increases linearly with the increase of the amount of bentonite paste per unit area.Maintaining a consistent total amount of bentonite paste at the overlap interface while widening the overlap results in nearly consistent tensile strengths across different overlap widths.Additionally,the tensile strength of GCL overlaps slightly decreases in humid environments,with less loss observed when more bentonite paste is applied per unit area.The research results can provide guidance for treatment of GCL overlaps,ensuring the integrity of the GCL overlap area,and mitigating risks of decreased anti-seepage performance in GCL vertical anti-seepage walls due to construction activities.