复合衬垫中污染物一维瞬态扩散-对流运移规律研究  

One-dimensional transport of transient diffusion-advection of organic contaminant through composite liners

作　　者：冯世进[1] 彭明清 陈樟龙 陈宏信 FENG Shi-jin;PENG Ming-qing;CHEN Zhang-long;CHEN Hong-xin(Department of Geotechnical Engineering,Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200029,China)

机构地区：[1]同济大学地下建筑与工程系岩土及地下工程教育部重点实验室,上海200029

出　　处：《岩土工程学报》2022年第5期799-809,I0003,I0004,共13页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金杰出青年基金项目(41725012);国家自然科学基金重点基金项目(41931289);国家自然科学基金面上项目(42077250);国家重点研发计划项目(2020YFC1808104)。

摘　　要：采用GMB(土工膜)/GCL(膨润土防水毯)/SL(土质垫层)复合衬垫全瞬态扩散-对流运移解析模型,考察了对流区域对污染物运移计算结果的影响;探讨了用渗滤液水头高度替代衬垫水头差的简化计算的可行性;探究了土工膜类型对复合衬垫防污阻隔性能的影响;分析了对流、扩散、吸附作用对渗沥液中典型有机污染物运移规律的影响。研究结果表明:①渗沥液水头为10,5,3,0.3 m的情况下,采用全局对流模型相比局部对流模型的击穿时间相应分别高出了233%,151%,111%,24%;②采用渗沥液水头替代水头差的简化计算结果是可行的;③采用f-HDPE土工膜的复合衬垫,其击穿时间比采用PVC,LLDPE,HDPE的分别提高了36%,33%,22%;④渗沥液水头为10,5,1 m时,忽略对流作用会使击穿时间分别被高估68%,34%,6%;⑤孔洞频数由2.5增大到50,30,10,5个/(10^(3) m^(2)),击穿时间分别缩短了54%,41%,16%,6%;⑥SL有效扩散系数降低90%,衬垫击穿时间提高了2~6倍;SL吸附系数从1 mL/g提升到5,15,30,50 mL/g,击穿时间分别提升了311%,1086%,2249%,3798%。以上对复合衬垫防污阻隔机理的研究结果,可为实践中衬垫的使用和改进提供一定的参考和建议。Using the fully transient diffusion-advection transport model for transport of organic contaminant in GMB/GCL/SL composite liner, a series of parameter sensitivity studies are conducted to analyze the influences of several important parameters on the barrier performance of the composite liner. The results show that:(1) When the leachate head is 10, 5, 3 and 0.3 m, the breakthrough time obtained by the full advection model is higher by 233%, 151%, 111% and 24% than that obtained by the local advection model, respectively.(2) It is appropriate to use hw as an alternative for hd for simplification.(3) The breakthrough time of the composite liner with f-HDPE geomembrane is 36%, 33% and 22% higher than that with PVC, LLDPE and HDPE, respectively.(4) When the leachate head is 10, 5 and 1 m, the breakthrough time will be overestimated due to ignoring the effects of advection by 68%, 34% and 6%, respectively.(5) When the frequency of holes increases from 2.5 to 50,30, 10 and 5 ha;, the breakthrough time decreases by 54%, 41%, 16% and 6%, respectively.(6) The effective diffusion coefficient of SL decreases by 90%, and the breakthrough time of the liner increases by 2 ~ 6 times. The adsorption coefficient of SL increases from 1 mL/g to 5, 15, 30 and 50 mL/g, and the breakthrough time increases by 311%, 1086%, 2249% and 3798%, respectively. The above research results may provide some reference and suggestions for the use and improvement of the liner in practice.

关 键 词：垃圾填埋场 复合衬垫 扩散 对流 吸附 运移规律 土工膜 

分 类 号：TU43[建筑科学—岩土工程]