杭州淤泥质土的电渗电导率特性研究
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摘要
采用改进的MillerSoilBox试验装置,基于杭州淤泥质土,在3种不同含水量和含盐量下开展电渗试验,从总电导率和区域电导率2个方面分析土体电导率变化规律和分布特征,以揭示杭州淤泥质土的电渗电导率特性。结果表明:不同初始含水量下,土体总电导率相近,均随通电时间逐渐减小,同时土体总电导率与实时含水量呈近似线性变化,线性变化率随初始含水量的增加而降低;不同初始含盐量下,土体总电导率呈现先上升后下降并最终趋于平缓的变化,电渗前期,总电导率峰值随初始含盐量的增大而增大,峰值出现时间随初始含盐量提高而推迟,电渗后期,不同初始含盐量下土体总电导率趋于相近;随着电渗的开展,土体电导率分布不均匀性先逐渐增大后有所缓解,最终阴极附近区域土体电导率与其他区域差异较大;不同含水量或含盐量下,土体电导率分布在电渗前期差异较大,后期趋于相近。研究成果可进一步揭示电渗机制,为电渗法设计计算方法的提出提供理论依据。
Using the modified Miller Soil Box,a series of experiments for Hangzhou silty soil were conducted under three different levels of initial water content and salt content. In order to obtain the variation discipline and distribution feature of soil electro-osmotic conductivity,experiment results were interpreted from the perspectives of the overall soil conductivity as well as the regional soil conductivity. Under different initial water content,it is demonstrated that the overall soil conductivities are adjacent and decrease during electro-osmosis,meanwhile the overall soil conductivities change linearly with spot water content and the change rate decreases with increasing initial water content. Under different initial salt content,a variation of first increasing to the peak and then decreasing to the balance is observed for the overall soil conductivity. The peak value is higher and appears later with higher initial salt content while the overall soil conductivities are similar at later stages of electro-osmosis. It is also found that the inhomogeneity of the soil conductivity distribution firstly increases and then decreases during electro-osmosis and huge difference exists between the soil conductivity near the cathodic region and other regions.Under varied initial water content or salt content,the soil conductivity distributions vary at earlier stages of electro-osmosis and are similar at later stages of electro-osmosis. The obtained results can further reveal the electro-osmotic mechanism and provide references for the design and calculation methods of electro-osmotis technique.
Using the modified Miller Soil Box,a series of experiments for Hangzhou silty soil were conducted under three different levels of initial water content and salt content. In order to obtain the variation discipline and distribution feature of soil electro-osmotic conductivity,experiment results were interpreted from the perspectives of the overall soil conductivity as well as the regional soil conductivity. Under different initial water content,it is demonstrated that the overall soil conductivities are adjacent and decrease during electro-osmosis,meanwhile the overall soil conductivities change linearly with spot water content and the change rate decreases with increasing initial water content. Under different initial salt content,a variation of first increasing to the peak and then decreasing to the balance is observed for the overall soil conductivity. The peak value is higher and appears later with higher initial salt content while the overall soil conductivities are similar at later stages of electro-osmosis. It is also found that the inhomogeneity of the soil conductivity distribution firstly increases and then decreases during electro-osmosis and huge difference exists between the soil conductivity near the cathodic region and other regions.Under varied initial water content or salt content,the soil conductivity distributions vary at earlier stages of electro-osmosis and are similar at later stages of electro-osmosis. The obtained results can further reveal the electro-osmotic mechanism and provide references for the design and calculation methods of electro-osmotis technique.
引文
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[16]李瑛,龚晓南.含盐量对软黏土电渗排水影响的试验研究[J].岩土工程学报,2011,33(8):1 254-1 259.(LI Ying,GONG Xiaonan.Experimental study on effect of soil salinity on electro-osmotic dewatering in soft clay[J].Chinese Journal of Geotechnical Engineering,2011,33(8):1 254-1 259.(in Chinese))
[17]SEGALL B A,BRUELL C J.Electro-osmotic contaminant-removal process[J].Journal of Environmental Engineering,1992,118(1):84-100.
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[19]BERGADO D T,BALASUBRAMANIAM A S,PATAWARAN MA B.Electroosmotic consolidation of soft bangkok clay using copper and carbon electrodes with PVD[J].ASTM Geotechnical Testing Journal,2003,26(3):277-288.
[20]MOHAMAD E T,OTHMAN M Z,ADNAN S S,et al.The effectiveness of electrodes types on electro-osmosis of Malaysian soil[J].The Electronic Journal of Geotechnical Engineering,2011,16:887-898.
[21]查甫生,刘松玉,杜延军,等.非饱和黏性土的电阻率特性及其试验研究[J].岩土力学,2007,28(8):1 671-1 676.(ZHA Fusheng,LIU Songyu,DU Yanjun,et al.The electrical resistivity characteristics of unsaturated clayey soil[J].Rock and Soil Mechanics,2007,28(8):671-1 676.(in Chinese))
[2]焦丹,龚晓南,李瑛.电渗法加固软土地基试验研究[J].岩石力学与工程学报,2011,30(增1):3 208-3 216.(JIAO Dan,GONGXiannan,LI Ying.Experimental study of consolidation of soft clay using electro-osmosis method[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(Supp.1),3 208-3 216.(in Chinese))
[3]BURNOTTE F,LEFEBVRE G,GRONDIN G.A case record of electroosmotic consolidation of soft clay with improved soil-electrode contact[J].Canadian Geotechnical Journal,2001,41(6):1 038-1 053.
[4]吴辉,胡黎明.考虑电导率变化的电渗固结模型[J].岩土工程学报,2013,45(4):734-738.(WU Hui,HU Liming.Numerical simulation of electro-osmosis consolidation considering variation of electrical conductivity[J].Chinese Journal of Geotechnical Engineering,2013,45(4):734-738.(in Chinese))
[5]汪俊波,刘斯宏,徐伟,等.电渗法处理大连大窑湾超软土室内试验[J].水运工程,2010,(1):15-19.(WANG Junbo,LIU Sihong,XU We,et al.aboratory test for electro-osmotic treatment of ultra-soft soil in Dayao Bay,Dalian[J].Port and Waterway Engineering,2010,(1):15-19.(in Chinese))
[6]陈雄峰,荆一凤,吕鑑,等.电渗法对太湖环保疏浚底泥脱水干化研究[J].环境科学研究,2006,19(5):54-58.(CHEN Xiongfeng,JING Yifeng,LV Jian,et al.The research of environmental dredged sludge dewatering in Taihu Lake by electro-osmotic[J].Research of Environmental Sciences,2006,19(5):54-58.(in Chinese))
[7]ARCHIE G.The electrical resistivity log as an aid in determining some reservoir characteristics[J].American Institute of Mining Metallurgical and Petroleum Engineers,1942,146:54-61
[8]WAXMAN M H,THOMAS E C.Electrical conductivity in oil-bearing shaly sand[J].Society of Petroleum Engineers Journal,1968,(65):1 577-1 584.
[9]ABU-HASSANEIN Z S,BENSON C H,BLOTZ L R.Electrical resistivity of compacted clays[J].Journal of Geotechnical Engineering,ASCE,1996,122(5):397-406.
[10]储旭,刘斯宏,王柳江,等.电渗法中含水率和电势梯度对土体电阻率的影响[J].河海大学学报:自然科学版,2010,38(5):575-579.(CHU Xu,LIU Sihong,WANG Liujiang,et al.Influence of water content and potential gradient on soil resistivity in electroosmosis[J].Journal of Hohai University:Natural Sciences,2010,38(5):575-579.(in Chinese))
[11]李瑛,龚晓南,郭彪,等.电渗软黏土电导率特性及其导电机制研究[J].岩石力学与工程学报,2010,29(增2):4 027-4 032.(LIYing,GONG Xiaonan,GUO Biao,et al.Research on conductivity characteristics of soft clay during electro-osmosis and its conductive mechanism[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(Supp.2):4 027-4 032.(in Chinese))
[12]庞宽,刘斯宏,吴澎,等.电渗法加固软土地基基本参数室内试验研究[J].水运工程,2011,(3):148-153.(PANG Kuan,LIUSihong,WU Peng,et al.Lab experimental study on electro-osmotic parameters for soft soil consolidation[J].Port and Waterway Engineering,2011,(3):148-153.(in Chinese))
[13]王柳江,刘斯宏,朱豪,等.电极布置形式对电渗加固软土效果的影响试验[J].河海大学学报:自然科学版,2013,41(1):64-69.(WANG Liujiang,LIU Sihong,ZHU Hao,et al.Experimental study of effects of electrode configuration on electroosmosis reinforcement for soft soil[J].Journal of Hohai University:Natural Sciences,2013,41(1):64-69.(in Chinese))
[14]XUE Z,TANG X,QING T.Influence of voltage and temperature on electro-osmosis experiments applied on marine clay[J].Applied Clay Science,2017,141(6):13-22
[15]王宁伟,于辉,刘铁,等.电渗对不同塑性指数土电阻率影响的试验研究[J].水利与建筑工程学报,2017,15(4):117-121.(WANG Ningwei,YU Hui,LIU Tie,et al.Experimental study of plastic index on soil resistivity based on electro osmotic test[J].Journal of Water Resources and Architectural Engineering,2017,15(4):117-121.(in Chinese))
[16]李瑛,龚晓南.含盐量对软黏土电渗排水影响的试验研究[J].岩土工程学报,2011,33(8):1 254-1 259.(LI Ying,GONG Xiaonan.Experimental study on effect of soil salinity on electro-osmotic dewatering in soft clay[J].Chinese Journal of Geotechnical Engineering,2011,33(8):1 254-1 259.(in Chinese))
[17]SEGALL B A,BRUELL C J.Electro-osmotic contaminant-removal process[J].Journal of Environmental Engineering,1992,118(1):84-100.
[18]MOHAMEDELHASSAN E,SHANG J Q.Effects of electrode materials and current intermittence in electro-osmosis[J].Proceedings of the ICE-Ground Improvement,2001,5(1):3-11.
[19]BERGADO D T,BALASUBRAMANIAM A S,PATAWARAN MA B.Electroosmotic consolidation of soft bangkok clay using copper and carbon electrodes with PVD[J].ASTM Geotechnical Testing Journal,2003,26(3):277-288.
[20]MOHAMAD E T,OTHMAN M Z,ADNAN S S,et al.The effectiveness of electrodes types on electro-osmosis of Malaysian soil[J].The Electronic Journal of Geotechnical Engineering,2011,16:887-898.
[21]查甫生,刘松玉,杜延军,等.非饱和黏性土的电阻率特性及其试验研究[J].岩土力学,2007,28(8):1 671-1 676.(ZHA Fusheng,LIU Songyu,DU Yanjun,et al.The electrical resistivity characteristics of unsaturated clayey soil[J].Rock and Soil Mechanics,2007,28(8):671-1 676.(in Chinese))