含非饱和导排层的毛细阻滞覆盖层长期性能分析
|
摘要
为了验证含非饱和导排层(UDL)毛细阻滞覆盖层的防渗性能,采用模型试验在中国东部湿润气候区自然气候条件下进行2年的长期监测.覆盖层模型尺寸为2.0 m×1.0 m×0.55 m(长×宽×厚),坡度为18.4°(坡率为1∶3).结构剖面从上至下依次为植被生长层(15 cm)、粉土层(20 cm)、砂层(10 cm)和碎石层(10 cm).长期监测试验结果表明:监测期累计降雨量为3 448.4 mm;渗漏量为2.62 mm,显著低于北美湿润气候区土质覆盖层的防渗标准.非饱和导排砂层(UDL)侧向导排量为581.77 mm,占降雨量的16.87%,导排作用明显.在一个典型的水文年中,4～11月自然降雨、气温和腾发作用三者高峰期重合;雨热同期的有利气候条件以及UDL层的侧向导排作用,有效控制了渗漏量. 6～9月的连续强降雨为覆盖层易发生渗漏的极端气象段,是防渗设计的控制性气象条件.冬季12月至次年3月气温低但降雨量较少,增设的非饱和砂层导排作用明显;避免了因腾发作用弱不能及时蒸散水分而发生渗漏的问题.含非饱和导排层(UDL)的毛细阻滞覆盖层由粉土、砂和碎石等非胀缩性土构成;湿胀干缩和开裂现象不明显.
Outdoor model test was carried out for two years in humid area of China in order to study the long-term performance of the capillary-barrier cover with an unsaturated drainage layer(UDL). The size of model was 2.0 m(length) ×1.0 m(width) ×0.55 m(thickness); meanwhile, the slope rate and gradient were 1∶3 and 18.4°,respectively. From top to bottom, the structural profiles were vegetation growth layer(15 cm), silt layer(20 cm),sand layer(10 cm) and gravel layer(10 cm).The monitoring results show that: with the annual rainfall of 3 448.4 mm, the percolation is 2.62 mm, which is in line with the impervious standard of soil cover layer in humid climate zone of North America. Lateral diversion is 581.77 mm, which accounts for 16.87% of the cumulative rainfall and the lateral diversion effect is obvious. From April to November in humid area of China, the three peaks of temperature, rainfall and evapotranspiration coincide every year. The favorable climatic conditions in the same period of rain and heat, and the lateral diversion of UDL, effectively control the percolation. The continuous heavy rainfall from June to September is high risk to percolation meteorological event which is a controlled meteorological condition for seepage prevention design. From December to March of next year with scarce rainfall and weak evapotranspiration, the lateral diversion effect is obvious and avoid to percolation. The capillary barrier cover with unsaturated drainage layer is made up of silt, sand and gravel. Swelling, shrinkage and cracking are not obvious.
Outdoor model test was carried out for two years in humid area of China in order to study the long-term performance of the capillary-barrier cover with an unsaturated drainage layer(UDL). The size of model was 2.0 m(length) ×1.0 m(width) ×0.55 m(thickness); meanwhile, the slope rate and gradient were 1∶3 and 18.4°,respectively. From top to bottom, the structural profiles were vegetation growth layer(15 cm), silt layer(20 cm),sand layer(10 cm) and gravel layer(10 cm).The monitoring results show that: with the annual rainfall of 3 448.4 mm, the percolation is 2.62 mm, which is in line with the impervious standard of soil cover layer in humid climate zone of North America. Lateral diversion is 581.77 mm, which accounts for 16.87% of the cumulative rainfall and the lateral diversion effect is obvious. From April to November in humid area of China, the three peaks of temperature, rainfall and evapotranspiration coincide every year. The favorable climatic conditions in the same period of rain and heat, and the lateral diversion of UDL, effectively control the percolation. The continuous heavy rainfall from June to September is high risk to percolation meteorological event which is a controlled meteorological condition for seepage prevention design. From December to March of next year with scarce rainfall and weak evapotranspiration, the lateral diversion effect is obvious and avoid to percolation. The capillary barrier cover with unsaturated drainage layer is made up of silt, sand and gravel. Swelling, shrinkage and cracking are not obvious.
引文
[1]焦卫国,詹良通,孔令刚,等.黄土-碎石覆盖层毛细阻滞效应及设计厚度分析[J].浙江大学学报:工学版,2016,50(11):2128-2134.JIAO Wei-guo,ZHAN Liang-tong,LAN Ji-wu,et al.Verification of capillary barrier effect of clayey loess-gravel cover and analysis of design thickness[J].Journal of Zhejiang University:Engineering Science,2016,50(11):2128-2134.
[2]张文杰,林午,董林兵.垃圾填埋场毛细阻滞型腾发封顶模型试验[J].岩土力学,2014,35(5):1263-1268.ZHANG Wen-jie,LIN Wu,DONG Lin-bing.Model test of a capillary barrier evapotranspiration cover for landfills[J].Rock and Soil Mechanics,2014,35(5):1263-1268.
[3]张文杰,邱战洪,朱成仁,等.长三角地区填埋场ET封顶系统的性能评价[J].岩土工程学报,2009,31(3):384-389.ZHANG Wen-jie,QIU Zhan-hong,ZHU Cheng-ren,et al.Evaluation of evapotranspiration covers of landfills in Yangtze river delta region[J].Chinese Journal of Geotechnical Engineering,2009,31(3):384-389.
[4]MORRIS C E,STORMONT J C.Evaluation of numerical simulations of capillary barrier field tests[J].Geotechnical and Geological Engineering,1998,16(3):201-2013.
[5]MORRIS C E,STORMONT J C.Parametric study of unsaturated drainage layers in capillary barrier[J].Journal of Geotechnical and Geoenvironmental Engineering,1999,125(12):1057-1065.
[6]KHIRE M V,BENSON C H.Field data from a capillary barrier and model predictions with UNSAT-H[J].Journal of Geotechnical and Geoenvironmental Engineering,1999,125(6):518-527.
[7]SCHNABEL W,LEE W,BARNES D L.A numerical simulation of evapotranspiration landfill cover performance at three cold-region locations[C]//Impacts of Global Climate Change.Anchorage:[s.n],2005:1-8.
[8]BENSON C H,ALBRIGHT W H,ROESLER A C,et al.Evaluation of final cover performance:field data from the Alternative Cover Assessment Program(ACAP)[C]//Waste Management.Tucson:[s.n],2002,2:1-15.
[9]STORMONT J C,MORRIS C E.Method to estimate water storage capacity of capillary barriers[J].Journal of Geotechnical and Geoenvironmental Engineering,1998,124(6):297-303.
[10]STORMONT J C.Unsaturated drainage layers for diversion of infiltrating water[J].Journal of Irrigation and Drainage Engineering,1997,123:364-366.
[11]赵慧,刘川顺,王伟,等.垃圾填埋场腾发覆盖系统控制渗滤效果的研究[J].中国给水排水,2008,24(9):86-89.ZHAO Hui,LIU Chuan-shun,WANG Wei,et al.Study of leachate control effect of evapotranspiration landfill cover system[J].China Water and Wastewater,2008,24(9):86-89.
[12]NG C W W,WOONA K X,LEUNGA A K,et al.Experimental investigation of induced suction distribution in a grass covered soil[J].Ecological Engineering,2013,52:219-223.
[13]张文杰,耿潇.垃圾填埋场毛细阻滞型腾发封顶工作机理及性能分析[J].岩土工程学报,2016,38(3):454-459.ZHANG Wen-jie,GENG Xiao.Performance and mechanism of capillary-barrier evaportranspiration cover of landfills[J].Chinese Journal of Geotechnical Engineering,2016,38(3):454-459.
[14]詹良通,焦卫国,孔令刚,等.黄土作为西北地区填埋场土质覆盖层材料可行性及设计厚度分析[J].岩土力学报,2014,35(12):3361-3369.ZHAN Liang-tong,JIAO Wei-guo,KONG Linggang,et al.Feasibility analysis of using loess as soil cover material for landfills in the northwest of China[J].Rock and Soil Mechanics,2014,35(12):3361-3369.
[15]邓林恒,詹良通,陈云敏,等.含非饱和导排层的毛细阻滞型覆盖层性能模型试验研究[J].岩土工程学报,2012,34(1):75-80.DENG Lin-heng,ZHAN Liang-tong,CHEN Yunmin,et al.Model tests on capillary-barrier cover with unsaturated drainage layer[J].Chinese Journal of Geotechnical Engineering,2012,34(1):75-80.
[16]KHIRE M,BENSON C H,BOSSCHER P.Capillary barriers in semi-arid and arid climates design variables and the water balance[J].Journal of Geotechnical and Geoenvironmental Engineering,2000,126(8):695-708.
[2]张文杰,林午,董林兵.垃圾填埋场毛细阻滞型腾发封顶模型试验[J].岩土力学,2014,35(5):1263-1268.ZHANG Wen-jie,LIN Wu,DONG Lin-bing.Model test of a capillary barrier evapotranspiration cover for landfills[J].Rock and Soil Mechanics,2014,35(5):1263-1268.
[3]张文杰,邱战洪,朱成仁,等.长三角地区填埋场ET封顶系统的性能评价[J].岩土工程学报,2009,31(3):384-389.ZHANG Wen-jie,QIU Zhan-hong,ZHU Cheng-ren,et al.Evaluation of evapotranspiration covers of landfills in Yangtze river delta region[J].Chinese Journal of Geotechnical Engineering,2009,31(3):384-389.
[4]MORRIS C E,STORMONT J C.Evaluation of numerical simulations of capillary barrier field tests[J].Geotechnical and Geological Engineering,1998,16(3):201-2013.
[5]MORRIS C E,STORMONT J C.Parametric study of unsaturated drainage layers in capillary barrier[J].Journal of Geotechnical and Geoenvironmental Engineering,1999,125(12):1057-1065.
[6]KHIRE M V,BENSON C H.Field data from a capillary barrier and model predictions with UNSAT-H[J].Journal of Geotechnical and Geoenvironmental Engineering,1999,125(6):518-527.
[7]SCHNABEL W,LEE W,BARNES D L.A numerical simulation of evapotranspiration landfill cover performance at three cold-region locations[C]//Impacts of Global Climate Change.Anchorage:[s.n],2005:1-8.
[8]BENSON C H,ALBRIGHT W H,ROESLER A C,et al.Evaluation of final cover performance:field data from the Alternative Cover Assessment Program(ACAP)[C]//Waste Management.Tucson:[s.n],2002,2:1-15.
[9]STORMONT J C,MORRIS C E.Method to estimate water storage capacity of capillary barriers[J].Journal of Geotechnical and Geoenvironmental Engineering,1998,124(6):297-303.
[10]STORMONT J C.Unsaturated drainage layers for diversion of infiltrating water[J].Journal of Irrigation and Drainage Engineering,1997,123:364-366.
[11]赵慧,刘川顺,王伟,等.垃圾填埋场腾发覆盖系统控制渗滤效果的研究[J].中国给水排水,2008,24(9):86-89.ZHAO Hui,LIU Chuan-shun,WANG Wei,et al.Study of leachate control effect of evapotranspiration landfill cover system[J].China Water and Wastewater,2008,24(9):86-89.
[12]NG C W W,WOONA K X,LEUNGA A K,et al.Experimental investigation of induced suction distribution in a grass covered soil[J].Ecological Engineering,2013,52:219-223.
[13]张文杰,耿潇.垃圾填埋场毛细阻滞型腾发封顶工作机理及性能分析[J].岩土工程学报,2016,38(3):454-459.ZHANG Wen-jie,GENG Xiao.Performance and mechanism of capillary-barrier evaportranspiration cover of landfills[J].Chinese Journal of Geotechnical Engineering,2016,38(3):454-459.
[14]詹良通,焦卫国,孔令刚,等.黄土作为西北地区填埋场土质覆盖层材料可行性及设计厚度分析[J].岩土力学报,2014,35(12):3361-3369.ZHAN Liang-tong,JIAO Wei-guo,KONG Linggang,et al.Feasibility analysis of using loess as soil cover material for landfills in the northwest of China[J].Rock and Soil Mechanics,2014,35(12):3361-3369.
[15]邓林恒,詹良通,陈云敏,等.含非饱和导排层的毛细阻滞型覆盖层性能模型试验研究[J].岩土工程学报,2012,34(1):75-80.DENG Lin-heng,ZHAN Liang-tong,CHEN Yunmin,et al.Model tests on capillary-barrier cover with unsaturated drainage layer[J].Chinese Journal of Geotechnical Engineering,2012,34(1):75-80.
[16]KHIRE M,BENSON C H,BOSSCHER P.Capillary barriers in semi-arid and arid climates design variables and the water balance[J].Journal of Geotechnical and Geoenvironmental Engineering,2000,126(8):695-708.