平原水库运行条件下的土工膜气胀试验研究
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摘要
为研究土工膜气胀及其与地下水位上升、水库蓄水及库水位骤降等影响因素的关系,研制了土工膜气胀模型试验装置,并对不同模拟工况下的土工膜位移、膜下气压、吸力、孔隙水压力以及竖向土压力的变化规律进行了试验研究。结果表明:膜下气压和孔隙水压力均随地下水位上升而增大,其大小由地下水位上升幅度决定;当地下水位与土工膜之间的非饱和区域较小时,膜下孔隙压力受库水荷载作用增加显著,在蓄水初期极易引发土工膜气胀变形,建议在膜上设置一定压重防止土工膜被顶起;膜下孔隙压力变化滞后于膜上荷载,库水位骤降时,膜下气压将大于膜上荷载,从而引起土工膜气胀破坏。
It is recognized that air expansion of geomembrane is essentially a three-phase coupled problem,which is water-air-solid in unsaturated soil,and is influenced by the rise of ground water level,storage of the reservoir and the rapid draw down of the water level in the reservoir. In this respect,a special laboratory equipment for the air expansion test of geomembrane is developed. Air expansion tests are then conducted to explore the variations of the displacement,gas pressure,suction,pore water pressure and vertical earth pressure under different working conditions. The test results show that the pore air pressure and pore water pressure are increased with the rise of the ground water level and the magnitude of the air pressure is dependent on the rising amplitude of groundwater level.It is found that the pore pressure of the soil under the geomembrane is significantly increased due to the increased water pressure during storage in the reservoir,and air expansion failure in the geomembrane is more likely to be induced at the initial storage period,especially when the unsaturated zone between the ground water level and geomembrane is small. It is therefore suggested that a certain amount of preloading could be applied over the geomembrane to prevent its expansion behaviour. As the pore pressure response below the geomembrane is usually later than the preloading above the geomembrane,pore pressure would become larger than the preloading applied during the rapid draw down of water level in the reservoir,which will lead to the air expansion failure on the geomembrane.
It is recognized that air expansion of geomembrane is essentially a three-phase coupled problem,which is water-air-solid in unsaturated soil,and is influenced by the rise of ground water level,storage of the reservoir and the rapid draw down of the water level in the reservoir. In this respect,a special laboratory equipment for the air expansion test of geomembrane is developed. Air expansion tests are then conducted to explore the variations of the displacement,gas pressure,suction,pore water pressure and vertical earth pressure under different working conditions. The test results show that the pore air pressure and pore water pressure are increased with the rise of the ground water level and the magnitude of the air pressure is dependent on the rising amplitude of groundwater level.It is found that the pore pressure of the soil under the geomembrane is significantly increased due to the increased water pressure during storage in the reservoir,and air expansion failure in the geomembrane is more likely to be induced at the initial storage period,especially when the unsaturated zone between the ground water level and geomembrane is small. It is therefore suggested that a certain amount of preloading could be applied over the geomembrane to prevent its expansion behaviour. As the pore pressure response below the geomembrane is usually later than the preloading above the geomembrane,pore pressure would become larger than the preloading applied during the rapid draw down of water level in the reservoir,which will lead to the air expansion failure on the geomembrane.
引文
[1]顾淦臣.土工膜用于水库防渗工程的经验[J].水利水电技术进展,2009,29(6):34-38.(GU Ganchen.Experience of applying geomembrane in reservoir seepage control[J].Advances in Science and Technology of Water R sources,2009,29(6):35-38.(in Chinese))
[2]束一鸣,吴海民,姜晓桢.中国水库大坝土工膜防渗技术进展[J].岩土工程学报,2016,38(增刊1):2-9.(SHU Yiming,WU Haimin,JIANG Xiaozhen.The development of anti-seepage technology with geomembrane on reservoirs and dams in China[J].Chinese Journal of Geotechnical Engineering,2016,38(Sup1):2-9.(in Chinese))
[3]杜晖.平原水库土工膜防渗技术研究与应用[D].南京:河海大学,2006.
[4]李旺林,魏晓燕,李志强,等.平原水库库盘防渗土工膜气胀现场试验研究[J].中国农村水利水电,2014(10):129-132.(LI Wanglin,WEI Xiaoyan,LI Zhiqiang,et al.Research on air expansion of geomembranes used in plain reservoir basins for anti-seepage[J].China Rural Water and Hydropower,2014(10):129-132.(in Chinese))
[5]王薇,崔化宇,李国伟.水平铺塑在新城水库库区防渗中的应用[J].人民黄河,2003,25(9):38-39.(WANG Wei,CUI Huayu,LI Guowei.Application of horizontal plastic paving in the seepage control of the new town reservoir[J].Yellow River,2003,25(9):38-39.(in Chinese))
[6]徐瑞兰,刘英豪,韦济生.浅析玉清湖水库中垂直铺塑的位置对自身及其坝坡稳定的影响[J].山东水利,1999(10):34-35.(XU Ruilan,LIU Yinghao,WEI Jisheng.Influence of the position of vertical plastic spreading Yuqing Lake Reservoir on its dam slope stability[J].Shandong Water Resources,1999(10):34-35.(in Chinese))
[7]陈云敏,施建勇,朱伟,等.环境岩土工程研究综述[J].土木工程学报,2012,45(4):165-182.(CHEN Yunmin,SHI Jianyong,ZHU Wei,et al.A review of geoenvironmental engineering[J].China Civil Engineering Journal,,2012,45(4):165-182.(in Chinese))
[8]陈云敏,谢焰,詹良通.城市生活垃圾填埋场固液气耦合一维固结模型[J].岩土工程学报,2006,28(2):184-190.(CHEN Yunmin,XIE Yan,ZHAN Liangtong.One-dimensional consolidation model for landfills considering solid-liquid-gas interaction[J].Chinese Journal of Geotechnical Engineering,2006,28(2):184-190.(in Chinese))
[9]CHEN Y M,XU X B,ZHAN L T.Analysis of solid-liquid-gas interactions in landfilled municipal solid waste by a bio-hydromechanical coupled model[J].Science China-Technological Sciences,2012,55(1):81-89.
[10]陈云敏.环境土工基本理论及工程应用[J].岩土工程学报,2014,36(1):1-46.(CHEN Yunmin.A fundamental theory of environmental geotechnics and its application[J].Chinese Journal of Geotechnical Engineering,2014,36(1):1-46.(in Chinese))
[11]李旺林,李志强,魏晓燕,等.土工膜缺陷渗漏引起气胀的研究[J].岩土工程学报,2013,35(6):1161-1165.(LI Wanglin,LI Zhiqiang,WEI Xiaoyan,et al.Air expansion caused by leakage water resulting from geomembrane defects[J].Chinese Journal of Geotechnical Engineering,2013,35(6):1161-1165.(in Chinese))
[12]袁俊平,曹雪山,和桂玲,等.平原水库防渗膜下气胀现象产生机制现场试验研究[J].岩土力学,2014,35(1):67-73.(YUAN Junpin,CAO Xueshan,HE Guilin,et al.Field test study of mechanism of bulge phenomenon under geomembrane in plain reservoir[J].Rock and Soil Mechanics,2014,35(1):67-73.(in Chinese))
[13]CAO Xueshan,YUAN Junping,HE Guilin,et al.In situ test and analysis method of air bulging under geomembranes in a shallow-lined reservoir[J].Geotextiles and Geomembranes,2015,43:24-34.
[14]张凯,刘斯宏,王柳江,等.土工膜防渗平原水库膜下气场数值模拟[J].南水北调与水利科技,2012,10(5):97-100.(ZHANG Kai,LIU Sihong,WANG Liujiang,et al.Numerical simulation of air field under geo-membrane in anti-seepage plain reservoir[J].South-to North Water Transfers and Water Science&Technology,2012,10(5):97-100.(in Chinese))
[2]束一鸣,吴海民,姜晓桢.中国水库大坝土工膜防渗技术进展[J].岩土工程学报,2016,38(增刊1):2-9.(SHU Yiming,WU Haimin,JIANG Xiaozhen.The development of anti-seepage technology with geomembrane on reservoirs and dams in China[J].Chinese Journal of Geotechnical Engineering,2016,38(Sup1):2-9.(in Chinese))
[3]杜晖.平原水库土工膜防渗技术研究与应用[D].南京:河海大学,2006.
[4]李旺林,魏晓燕,李志强,等.平原水库库盘防渗土工膜气胀现场试验研究[J].中国农村水利水电,2014(10):129-132.(LI Wanglin,WEI Xiaoyan,LI Zhiqiang,et al.Research on air expansion of geomembranes used in plain reservoir basins for anti-seepage[J].China Rural Water and Hydropower,2014(10):129-132.(in Chinese))
[5]王薇,崔化宇,李国伟.水平铺塑在新城水库库区防渗中的应用[J].人民黄河,2003,25(9):38-39.(WANG Wei,CUI Huayu,LI Guowei.Application of horizontal plastic paving in the seepage control of the new town reservoir[J].Yellow River,2003,25(9):38-39.(in Chinese))
[6]徐瑞兰,刘英豪,韦济生.浅析玉清湖水库中垂直铺塑的位置对自身及其坝坡稳定的影响[J].山东水利,1999(10):34-35.(XU Ruilan,LIU Yinghao,WEI Jisheng.Influence of the position of vertical plastic spreading Yuqing Lake Reservoir on its dam slope stability[J].Shandong Water Resources,1999(10):34-35.(in Chinese))
[7]陈云敏,施建勇,朱伟,等.环境岩土工程研究综述[J].土木工程学报,2012,45(4):165-182.(CHEN Yunmin,SHI Jianyong,ZHU Wei,et al.A review of geoenvironmental engineering[J].China Civil Engineering Journal,,2012,45(4):165-182.(in Chinese))
[8]陈云敏,谢焰,詹良通.城市生活垃圾填埋场固液气耦合一维固结模型[J].岩土工程学报,2006,28(2):184-190.(CHEN Yunmin,XIE Yan,ZHAN Liangtong.One-dimensional consolidation model for landfills considering solid-liquid-gas interaction[J].Chinese Journal of Geotechnical Engineering,2006,28(2):184-190.(in Chinese))
[9]CHEN Y M,XU X B,ZHAN L T.Analysis of solid-liquid-gas interactions in landfilled municipal solid waste by a bio-hydromechanical coupled model[J].Science China-Technological Sciences,2012,55(1):81-89.
[10]陈云敏.环境土工基本理论及工程应用[J].岩土工程学报,2014,36(1):1-46.(CHEN Yunmin.A fundamental theory of environmental geotechnics and its application[J].Chinese Journal of Geotechnical Engineering,2014,36(1):1-46.(in Chinese))
[11]李旺林,李志强,魏晓燕,等.土工膜缺陷渗漏引起气胀的研究[J].岩土工程学报,2013,35(6):1161-1165.(LI Wanglin,LI Zhiqiang,WEI Xiaoyan,et al.Air expansion caused by leakage water resulting from geomembrane defects[J].Chinese Journal of Geotechnical Engineering,2013,35(6):1161-1165.(in Chinese))
[12]袁俊平,曹雪山,和桂玲,等.平原水库防渗膜下气胀现象产生机制现场试验研究[J].岩土力学,2014,35(1):67-73.(YUAN Junpin,CAO Xueshan,HE Guilin,et al.Field test study of mechanism of bulge phenomenon under geomembrane in plain reservoir[J].Rock and Soil Mechanics,2014,35(1):67-73.(in Chinese))
[13]CAO Xueshan,YUAN Junping,HE Guilin,et al.In situ test and analysis method of air bulging under geomembranes in a shallow-lined reservoir[J].Geotextiles and Geomembranes,2015,43:24-34.
[14]张凯,刘斯宏,王柳江,等.土工膜防渗平原水库膜下气场数值模拟[J].南水北调与水利科技,2012,10(5):97-100.(ZHANG Kai,LIU Sihong,WANG Liujiang,et al.Numerical simulation of air field under geo-membrane in anti-seepage plain reservoir[J].South-to North Water Transfers and Water Science&Technology,2012,10(5):97-100.(in Chinese))