【作者】 李志斌；

【导师】 卢耀如； 徐超；

【作者基本信息】 同济大学 ， 地质工程， 2007， 博士

【摘要】 近年来，土工织物膨润土垫(GCL)被越来越多地应用到各种防渗工程之中，它的防渗有效性越来越引起了人们的重视，同时对室内试验研究和机理分析也提出了越来越高的要求。GCL的防渗有效性至少包括三个方面：①工程应用条件下GCL渗透系数的大小；②在液体渗过GCL的过程中，膨润土对液体中有害物质的吸附能力；③用于防渗系统的GCL内部剪切强度的高低。这三方面重要特性指标将直接影响防渗工程的稳定安全性和功能有效性。本文针对土工织物膨润土垫的室内试验以及试验结果的机理分析，从上述三个方面入手进行了研究工作，并得到一些有价值的结论和成果： 1)研制土工合成材料渗压仪Geo-Syn，可以实现GCL试样在竖向常应力或水平常应变条件下对不同水化液、渗透液的渗透试验； 2)对GCL及其中膨润土进行自由膨胀试验和水化膨胀试验，以研究GCL所表现出来的膨胀特性及其影响因素，包括正应力、加压水化顺序和水化液体类型。结果表明上述因素都对GCL的膨胀特性产生了影响，两种试验的结果可以得到类似的影响规律。 3)采用蒸馏水、垃圾渗滤液等液体和含单一种类阳离子的溶液作为水化液和渗透液，对GCL表现出来的渗透性能进行了试验研究。结果发现水化、渗透液体中阳离子的离子价、浓度以及水化离子半径都对GCL的渗透系数产生了影响。 4)采用X射线衍射、压汞试验和扫描电子显微镜等试验手段，对GCL中膨润土的微观结构进行了研究，揭示了水化、渗透液体对GCL渗透性能产生影响的原因。并采用膨润土分阶段水化理论和双电层理论对GCL所表现出来的膨胀特性和渗透性能变化规律进行了机理分析。 5)通过渗透试验研究了应力水平及加压水化顺序对GCL渗透性能的影响，结果发现GCL所承受的竖向应力、水平应变大小以及加压水化顺序都影响着渗透系数的变化。 6)对渗入、渗出GCL的液体进行等离子光谱分析，研究在液体渗透过程中GCL所表现出来的吸附能力及其影响因素，包括水化液类型、渗透时间。采更多还原

【Abstract】 In recent years, geosynthetic clay liners (GCLs) are widely used in different kinds of anti-seepage projects, and the anti-seepage availabilities of GCLs are regarded as increasingly important by engineers. Meanwhile, increasing needs and requests of laboratory test and mechanism analysis are being asked. Anti-seepage effectiveness of GCLs involves at least three aspects followed: l)Hydraulic conductivity of GCLs under engineering practice conditions, 2)Absorption ability of bentonite in GCLs in the course of liquid permeation and 3)GCL internal shear strength while used in anti-seepage system. The above aspects are so important that they could directly affect the factor of safety and effectiveness of anti-seepage project. In this dissertation, a series of research work including about the laboratory tests of GCLs and the mechanism analysis of test results, is conducted and several valuable conclusions are obtained:1) A geosynthetic hydraulic conductivity device is designed and manufactured to measure hydraulic conductivity of GCLs under constant normal stress or horizontal strain conditions. Hydraulic conductivity of GCLs is measured for different hydrated and permeated liquids using the device.2) Free swelling tests and hydration swelling tests of GCLs and bentonite are performed in order to research the swelling characteristics of GCLs and its influencing factors, including normal stress, loading-hydration sequence and hydration liquid. The results show that the above factors have influences on GCLs swelling characteristics. Similar influencing laws can be obtained in the two types of tests.3) Hydraulic conductivity tests are performed to obtain hydraulic conductivity of GCLs, taking liquids such as distilled, deioned water and landfill leachate, and solutions with single-species cation as the hydration and permeation liquid. The results show that cation valence, cation concentration and hydration ionic radius in hydration and permeation liquids have influences on hydraulic conductivity of GCLs.更多还原