GCL/GM界面膨润土挤出机理研究  

Mechanism of bentonite extrusion of GCL/GM interface

作　　者：林伟岸[1] 詹良通[1] 陈云敏[1] 邓红卫 

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 [2]苏州市政公用局,江苏苏州215002

出　　处：《岩土工程学报》2010年第6期832-837,共6页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金重点项目(50538080);国家杰出青年科学基金项目(50425825);苏州市科技计划项目(SS0733)

摘　　要：土工复合膨润土垫(GCL)具有良好的防渗隔气及抗张拉等性能,在填埋场中具有较好的应用前景。GCL/GM界面由于膨润土挤出而导致其剪切强度较小,将影响GCL在填埋场边坡中的使用。因此,采用改进的固结仪进行了膨润土挤出机理的研究,重点探讨了正应力、加载速率、加载与水化的顺序、土工织物类型以及渗滤液等因素对膨润土挤出的影响,并在实验结果的基础上提出了超孔隙水压力挤出机理:快速加载时,GCL内部产生了较大的超孔隙水压力,导致膨润土颗粒在该渗透力的作用下通过土工织物中的孔隙往GCL/GM界面的间隙迁移。GCL possesses many advantages such as low hydraulic conductivity and good compliance with differential settlements.Consequently,GCL has been extensively used as a hydraulic barrier in landfill engineering.The bentonite from the GCL may extrude into the GCL/GM interface,resulting in a significant reduction in interfacial shear strength,and it has important effects on the application of GCL in landfill slopes.Three conventional oedometers are modified to study the mechanism of bentonite extrusion.The influence of normal stress,type of geotextile and type of hydration fluid on bentonite extrusion are investigated.The experimental results reveal that the bentonite extrusion is due to the excessive pore-water pressure during rapid normal loading.It is found that when the prehydrated GCL specimen is subjected to rapid one-dimensional loading,an excessive pore-water pressure tends to build up in the GCL,then the seepage force drives bentonite extruding through the geotextile and attaching on the GM.

关 键 词：土工复合膨润土垫 土工膜 膨润土挤出 超孔隙水压力 

分 类 号：TU411[建筑科学—岩土工程]