土工膜/GCL界面剪切强度特性的试验研究  

Experiment study on shear strength of GM/GCL interface

作　　者：张宏伟[1] 林伟岸[1] 詹良通[1] 陈云敏[1] 

机构地区：[1]浙江大学软弱土与环境土工教育部重点实验室,浙江杭州310058

出　　处：《土木工程学报》2013年第2期123-130,共8页China Civil Engineering Journal

基　　金：国家自然科学基金青年科学基金(51008273);973项目课题(2012CB719802);基本科研业务费专项资助(2010KYJD006);浙江省重点创新团队支持计划资助(2009R50050)

摘　　要：土工复合膨润土垫(GCL)是一种新型复合材料,其良好的防渗隔气功能以及抗张拉的能力使其与HDPE土工膜(GM)的联合使用在填埋场具有广泛的应用前景,但GM/GCL界面较低的剪切强度易导致填埋场衬垫系统等失稳。利用大尺寸界面直剪仪进行三种不同土工膜与GCL界面的剪切试验,重点研究GCL不同加载水化顺序对膨润土挤出及界面强度的影响。试验结果表明:干燥状态下,粗糙土工膜/GCL界面的峰值强度较大于光滑土工膜/GCL界面的峰值强度,但粗糙土工膜/GCL界面表现出强烈的应变软化特性,其残余强度接近于光滑土工膜/GCL界面的强度;不同加载水化顺序是影响膨润土挤出的重要因素,并严重影响界面剪切强度;膨润土挤出造成粗糙土工膜/GCL界面的峰值摩擦角降低3.5°,大位移摩擦角降低7.6°,接近光滑土工膜/GCL界面的摩擦角。GCL is a new kind of composite material which possesses many advantageous properties such as low hydraulic conductivity and good compliance with differential settlement. Consequently, GCL combined with HDPE geomembrane （GM） have been extensively used as a hydraulic barrier in landfill engineering. But low shear strength of GM/GCL interface could easily lead to instability of landfill. The shear properties of three different geomembrane/GCL interfaces are studied using a large size direct shear apparatus, and the effect of sequence of swelling and loading on bentonite extrusion and interface strength is studied. The results show that the peak shear strength of rough geomembrane/GCL interface is greater than that of smooth geomembrane/GCL interface in dry state, but the rough geomembrane/GCL interface shows a strong softening property whose residual strength is close to peak strength of smooth geomembrane/GCL interface. The sequence of swelling and loading has a great influence on bentonite extrusion and seriously affects the interface strength. The influence of bentonite extrusion shows a loss of 3.5° in terms of peak friction angle and 7.6° in terms of large displacement friction angle of rough geomembrane/GCL interface.

关 键 词：土工复合膨润土垫 土工膜 剪切强度 应变软化 膨润土挤出 

分 类 号：TU411.3[建筑科学—岩土工程]