【作者】 刘滔；

【导师】 窦宝松；

【作者基本信息】 北京工业大学 ， 水工结构工程， 2007， 硕士

【摘要】 土工合成材料黏土垫(Geosynthetic Clay Liner,简称GCL。)是一种新型防渗土工复合材料,上世纪80年代末土工合成材料黏土垫投入美国市场,我国于上世纪九十年代末开始引进。土工合成材料黏土垫渗透系数低,抗干湿循环、抗冻融循环能力强,有极强的自愈能力,不易被顶破或刺破而失效,能较好地适应不均匀沉降,施工方便,施工受天气影响小。目前已成为国内外公认最具发展前景的新型防渗材料之一。国外对于它的研究已经取得了一定的成果,但国内开展的研究工作尚少。本文首先探讨了土工合成材料黏土垫的防渗工作原理,随后从其的防渗工作原理出发,指出GCL最主要的特性低渗透性与其工作条件(主要是上覆有效应力)密切相关。而目前广泛采用的ASTM D5887标准试验方法采用固定上覆有效应力,它主要适用于环境工程,对于其它方面的应用有其不足之处。鉴于此作者提出了一种新的能适用于范围更为广的试验方法,并研制出了相应的试验仪器。结合中国水利水电科学研究院某科研项目,采用新研制的仪器进行了一系列的土工合成材料黏土垫渗透试验。通过对观测数据进行整理分析,得出如下结论:(1)土工合成材料黏土垫的水化时间随上覆有效应力的增加而缩短;(2)土工合成材料黏土垫的渗透系数随上覆有效应力的增加而减小;(3)土工合成材料黏土垫的渗透系数随渗透梯度的上升而增大;(4)渗透系数在土工合成材料黏土垫被扰动后,需要较长的时间才能达到稳定。最后,作者给出了确定土工合成材料黏土垫厚度的方法。更多还原

【Abstract】 GCL (Geosynthetics clay liner) is a new type of composite waterproofing geosythetics, and it has being widely used in many fields. It appeared in USA in the 80th of last century and was introduced to our country more than ten years ago. In recent years, the use of GCL is increasing in many fields. Some of the advantages of it are: (1) the lower coefficient of permeability; (2) more resistance to the effect of wetting/drying and freeze/thaw cycles; (3) excellent in self-healing; (4) easier to repair during and after installation; (5) more resistance to the unequal settlements. Some foreign researchers have been working on this filed, but it is rare in our country.First of all the principals of waterproof characteristic of GCL are discussed. Then the conclusion is drawn that the permeability of GCL is strongly correlated with the applying circumstance (mainly affected by the applied confining pressure), which must be taken into consideration in practical application. Because ASTM D5887 fixes the overburden effective stress, it is only proper to be used in environmental engineering and it has some limitations for other applications. The authors suggest a new kind of testing method and a new device is designed.The experiment was carried out in a project hosted by China Institute of Water Resources and Hydropower Research. According to observed data, the following conclusions can be drawn: (1) the hydration time of GCL will increase with the effective pressure; (2) the permeability coefficient of GCL will increase with the effective pressure as well; (3) the permeability coefficient of GCL will decrease when the hydraulic gradient increases; (4) when GCL is disturbed, it will take a long time before the permeability coefficient could become stable; (5)A new method to measure the thickness of GCL is also suggested.更多还原