上海冻融淤泥质软黏土孔隙结构特征分形研究
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摘要
对上海第④土层淤泥质软黏土进行了冻融试验、压汞试验和渗透性试验,并结合分形理论,确定了冻融对土壤孔隙结构的影响.根据分形计算,将上海软黏土中的孔隙分为3类.结果表明,在冻融过程中,中孔和大孔的总分形维数和表面分形维数随渗透系数的增加而增大.最后,提出了由小孔隙和中、大孔隙组成的渗透系数与孔隙结构参数之间的关系,小孔隙的渗透系数比中、大孔隙低几个数量级.
In this paper, the muddy clay that obtained from Shanghai 4 th stratum has been selected to conduct a freezing-thawing test, MIP test, and permeability test to figure out the freezing-thawing effect on soil pore structure, especially on pore size distribution and surface fractal dimension. Combined with the fractal theory, the pores in remolded muddy clay have been divided into three categories. The results indicate that the total percentage and surface fractal dimension of medium and large pores increase after freezing-thawing, with the increase of permeability. Finally, a relationship between permeability and pore-structure parameters has been proposed, which consists of small pores, and medium and large pores. The permeability for small pores is several orders of magnitudes lower than that of medium and large pores.
In this paper, the muddy clay that obtained from Shanghai 4 th stratum has been selected to conduct a freezing-thawing test, MIP test, and permeability test to figure out the freezing-thawing effect on soil pore structure, especially on pore size distribution and surface fractal dimension. Combined with the fractal theory, the pores in remolded muddy clay have been divided into three categories. The results indicate that the total percentage and surface fractal dimension of medium and large pores increase after freezing-thawing, with the increase of permeability. Finally, a relationship between permeability and pore-structure parameters has been proposed, which consists of small pores, and medium and large pores. The permeability for small pores is several orders of magnitudes lower than that of medium and large pores.
引文
[1] TANG Yiqun,YAN Jingjing.Effect of freezing-thawing on hydraulic conductivity and microstructure of soft soil in Shanghai area[J].Environmental Earth Sciences,2015,73:7679.
[2] 肖朝昀,胡向东,张庆贺.四排局部冻结法在上海地铁修复工程中的应用[J].岩土力学,2006,27(增刊1):300.XIAO Zhaoyun,HU Xiangdong,ZHANG Qinghe.Application of limited depth freezing method with four-row freeze-tubes to recovering collapse tunnel in Shanghai Metro[J].Rock and Soil Mechanics,2006,27(S1):300.
[3] ZHOU Jie,TANG Yiqun.Artificial ground freezing of fully saturated mucky clay thawing problem[J].Cold Regions Science and Technology,2015,117:1.
[4] CHAMBERLAIN E J,ISKANDAR I,HUNSICKER S E.Effect of freeze-thaw cycles on the permeability and macrostructure of soils[J].Cold Region Research and Engineering Laboratory,1990(1):145.
[5] KIM W H,DANIEL D E.Effects of freezing on hydraulic conductivity of compacted clay[J].Journal of Geotechnical Engineering,1992,118(7):1083.
[6] 查甫生,崔可锐,吴燕开.冻结法施工冻融作用对土的工程性质影响研究[J].路基工程,2008(6):30.CHA Fusheng,CUI Kerui,WU Yankai.Study on freeze-thaw action impacts on engineering character of soil in freezing method constraction[J].Subgrade Engineering,2008(6):30.
[7] LEE W,BOHRA N C,ALTSCHAEFFL A G,et al.Resilient modulus of cohesive soils and the effect of freeze-thaw[J].Canadian Geotechnical Journal,1995,32(4):559.
[8] SIMONSEN E,JANOO V C,ISACSSON U.Resilient properties of unbound road materials during seasonal frost conditions[J].Journal of Cold Regions Engineering,2002,16(1):28.
[9] 郑郧,马巍,邴慧.冻融循环对土结构性影响的机理与定量研究方法[J].冰川冻土,2015,37(1):132.ZHENG Yun,MA Wei,BING Hui.Impact of freezing and thawing cycles on the structares of soil and a quantitative approach[J].Journal of Glaciology and Geocryology,2015,37(1):132.
[10] PERFECT E,KAY B D.Applications of fractals in soil and tillage research:a review[J].Soil & Tillage Research,1995,36(1/2):1.
[11] PERFECT E.Fractal models for the fragmentation of rocks and soils:a review[J].Engineering Geology,1997,48(3/4):185.
[12] RIEU M,SPOSITO G.Fractal fragmentation,soil porosity,and soil water properties:I theory[J].Soil Science Society of America Journal,1991,55(5):1231.
[13] TURCOTTE D L.Fractals and fragmentation[J].Journal of Geophysical Research,1986,91(B2):1921.
[14] 王清,王剑平.土孔隙的分形几何研究[J].岩土工程学报,2000,22(4):496.WANG Qing,WANG Jianping.A study on fractal of porosity in the soils[J].Chinese Journal of Geotechnical Engineering,2000,22(4):496.
[15] XU Yongfu,SUN Dean.A fractal model for soil pores and its application to determination of water permeability[J].Physica A,2002,316:56.
[16] BONALA M V,REDDI L N.Fractal representation of soil cohesion[J].Journal of Geotechnical and Geoenvironmental Engineering,1999.DOI:10.1061/(ASCE)1090-0241(1999)125:10(901)
[17] XU Yongfu,XIA Xiaohe.Fractal model for virgin compression of pure clays[J].Mechanics Research Communications,2006,33(2):206.
[18] LU Yang,LIU Sihong,WENG Liping,et al.Fractal analysis of cracking in a clayey soil under freeze-thaw cycles[J].Engineering Geology,2016,208:93.
[19] QI Jilin,VERMEER P A,CHENG Guodong.A review of the influence of freeze‐thaw cycles on soil geotechnical properties[J].Permafrost and Periglacial Processes,2006,17(3):245.
[20] 余占奎,黄宏伟,王如路,等.人工冻结技术在上海地铁施工中的应用[J].冰川冻土,2005,27(4):550.YU Zhankui,HUANG Hongwei,WANG Rulu,et al.Application of the artificially ground freezing method to shanghai metro engineering[J].Journal of Glaciology and Geocryology,2005,27(4):550.
[21] 张志强,何川.用冻结法修建地铁联络通道施工力学研究[J].岩石力学与工程学报,2005,24(18):3211.ZHANG Zhiqiang,HE Chuan.Study on construction of cross connection on shield tunnel and connecting aisle by freezing method[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(18):3211.
[22] FRIESEN W I,MIKULA R J.Fractal dimensions of coal particles[J].Journal of Colloid and Interface Science,1987,120(1):263.
[23] ZHANG Baoquan,LI Shaofen.Determination of the surface fractal dimension for porous media by mercury porosimetry[J].Industrial & Engineering Chemistry Research,1995,34(4):1383.
[24] AVNIR D,FARIN D,PFEIFER P.Molecular fractal surfaces[J].Nature,1984,308:261.
[25] CHAMBERLAIN E J,GOW A J.Effect of freezing and thawing on the permeability and structure of soils[J].Engineering Geology,1979,13:73.
[26] EIGENBROD K D.Effects of cyclic freezing and thawing on volume changes and permeabilities of soft fine-grained soil[J].Canadian Geotechnical Journal,1996,33:529.
[27] BENSON C H,OTHMAN M A.Hydraulic conductivity of compacted clay frozen and thawed in situ[J].ASCE Journal of Geotechnical Engineering,1993,119:276.
[28] LAL R.Soil structure and sustainability[J].Journal of Sustainable Agriculture,1991,1(4):67.
[29] YAN Chunling,TANG Yiqun,LIU Yuting.Study on fractal dimensions of the silty soil around the tunnel under the subway loading in Shanghai[J].Environmental Earth Sciences,2013,69:1529.
[30] 周洁.地铁隧道管片周围人工冻结软黏土融沉机理与动力变形特性研究[D].上海:同济大学,2015.ZHOU Jie.Thaw settlement mechanism and dynamic deformation of soft clay surrounding subway tunnel after artificial ground freezing[D].Shanghai:Tongji University,2015.
[31] SHEAR D L,OLSEN H W,NNLSON K R.Effects of desiccation on the hydraulic conductivity versus void ratio relationship for a natural clay[R].Washington D C:Transportation Research Record,NRC,National Academy Press,1993:1365-1370.
[32] 李珺.人工冻结饱和软黏土的变形特性及微观结构研究[D].上海:同济大学,2016.LI Jun.Deformation mechanism and microstructure behavior of artificial freezing-thawing soft clay[D].Shanghai:Tongji University,2016.
[33] TAYLOR D W.Deformation mechanism and microstructure behavior of artifical freezing-thawing soft clay[M].New York:John Wiley and Sons,1948.
[34] TERZAGHI K,PECK R B,MESRI G.Soil mechanics in engineering practice[M].3rd ed.New York:John Wiley and Sons,1996.
[35] RODRIGUEZ E,GIACOMELLI F,VAZQUEZ A.Permeability-porosity relationship in RTM for different fiberglass and natural reinforcements[J].Journal of Composite Materials,2004,38(3):259.
[36] JANG J,NARSILIO G A,SANTAMARINA J C.Hydraulic conductivity in spatially varying media—a pore-scale investigation[J].Geophysical Journal International,2015,184(3):1167.
[37] GIMENEZ D,PERFECT E,RAWLS W J,et al.Fractal models for predicting soil hydraulic properties:a review[J].Engineering Geology,1997,48(3/4):161.
[38] XU Yongfu.Calculation of unsaturated hydraulic conductivity using a fractal model for the pore-size distribution[J].Computers & Geotechnics,2004,31(7):549.
[2] 肖朝昀,胡向东,张庆贺.四排局部冻结法在上海地铁修复工程中的应用[J].岩土力学,2006,27(增刊1):300.XIAO Zhaoyun,HU Xiangdong,ZHANG Qinghe.Application of limited depth freezing method with four-row freeze-tubes to recovering collapse tunnel in Shanghai Metro[J].Rock and Soil Mechanics,2006,27(S1):300.
[3] ZHOU Jie,TANG Yiqun.Artificial ground freezing of fully saturated mucky clay thawing problem[J].Cold Regions Science and Technology,2015,117:1.
[4] CHAMBERLAIN E J,ISKANDAR I,HUNSICKER S E.Effect of freeze-thaw cycles on the permeability and macrostructure of soils[J].Cold Region Research and Engineering Laboratory,1990(1):145.
[5] KIM W H,DANIEL D E.Effects of freezing on hydraulic conductivity of compacted clay[J].Journal of Geotechnical Engineering,1992,118(7):1083.
[6] 查甫生,崔可锐,吴燕开.冻结法施工冻融作用对土的工程性质影响研究[J].路基工程,2008(6):30.CHA Fusheng,CUI Kerui,WU Yankai.Study on freeze-thaw action impacts on engineering character of soil in freezing method constraction[J].Subgrade Engineering,2008(6):30.
[7] LEE W,BOHRA N C,ALTSCHAEFFL A G,et al.Resilient modulus of cohesive soils and the effect of freeze-thaw[J].Canadian Geotechnical Journal,1995,32(4):559.
[8] SIMONSEN E,JANOO V C,ISACSSON U.Resilient properties of unbound road materials during seasonal frost conditions[J].Journal of Cold Regions Engineering,2002,16(1):28.
[9] 郑郧,马巍,邴慧.冻融循环对土结构性影响的机理与定量研究方法[J].冰川冻土,2015,37(1):132.ZHENG Yun,MA Wei,BING Hui.Impact of freezing and thawing cycles on the structares of soil and a quantitative approach[J].Journal of Glaciology and Geocryology,2015,37(1):132.
[10] PERFECT E,KAY B D.Applications of fractals in soil and tillage research:a review[J].Soil & Tillage Research,1995,36(1/2):1.
[11] PERFECT E.Fractal models for the fragmentation of rocks and soils:a review[J].Engineering Geology,1997,48(3/4):185.
[12] RIEU M,SPOSITO G.Fractal fragmentation,soil porosity,and soil water properties:I theory[J].Soil Science Society of America Journal,1991,55(5):1231.
[13] TURCOTTE D L.Fractals and fragmentation[J].Journal of Geophysical Research,1986,91(B2):1921.
[14] 王清,王剑平.土孔隙的分形几何研究[J].岩土工程学报,2000,22(4):496.WANG Qing,WANG Jianping.A study on fractal of porosity in the soils[J].Chinese Journal of Geotechnical Engineering,2000,22(4):496.
[15] XU Yongfu,SUN Dean.A fractal model for soil pores and its application to determination of water permeability[J].Physica A,2002,316:56.
[16] BONALA M V,REDDI L N.Fractal representation of soil cohesion[J].Journal of Geotechnical and Geoenvironmental Engineering,1999.DOI:10.1061/(ASCE)1090-0241(1999)125:10(901)
[17] XU Yongfu,XIA Xiaohe.Fractal model for virgin compression of pure clays[J].Mechanics Research Communications,2006,33(2):206.
[18] LU Yang,LIU Sihong,WENG Liping,et al.Fractal analysis of cracking in a clayey soil under freeze-thaw cycles[J].Engineering Geology,2016,208:93.
[19] QI Jilin,VERMEER P A,CHENG Guodong.A review of the influence of freeze‐thaw cycles on soil geotechnical properties[J].Permafrost and Periglacial Processes,2006,17(3):245.
[20] 余占奎,黄宏伟,王如路,等.人工冻结技术在上海地铁施工中的应用[J].冰川冻土,2005,27(4):550.YU Zhankui,HUANG Hongwei,WANG Rulu,et al.Application of the artificially ground freezing method to shanghai metro engineering[J].Journal of Glaciology and Geocryology,2005,27(4):550.
[21] 张志强,何川.用冻结法修建地铁联络通道施工力学研究[J].岩石力学与工程学报,2005,24(18):3211.ZHANG Zhiqiang,HE Chuan.Study on construction of cross connection on shield tunnel and connecting aisle by freezing method[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(18):3211.
[22] FRIESEN W I,MIKULA R J.Fractal dimensions of coal particles[J].Journal of Colloid and Interface Science,1987,120(1):263.
[23] ZHANG Baoquan,LI Shaofen.Determination of the surface fractal dimension for porous media by mercury porosimetry[J].Industrial & Engineering Chemistry Research,1995,34(4):1383.
[24] AVNIR D,FARIN D,PFEIFER P.Molecular fractal surfaces[J].Nature,1984,308:261.
[25] CHAMBERLAIN E J,GOW A J.Effect of freezing and thawing on the permeability and structure of soils[J].Engineering Geology,1979,13:73.
[26] EIGENBROD K D.Effects of cyclic freezing and thawing on volume changes and permeabilities of soft fine-grained soil[J].Canadian Geotechnical Journal,1996,33:529.
[27] BENSON C H,OTHMAN M A.Hydraulic conductivity of compacted clay frozen and thawed in situ[J].ASCE Journal of Geotechnical Engineering,1993,119:276.
[28] LAL R.Soil structure and sustainability[J].Journal of Sustainable Agriculture,1991,1(4):67.
[29] YAN Chunling,TANG Yiqun,LIU Yuting.Study on fractal dimensions of the silty soil around the tunnel under the subway loading in Shanghai[J].Environmental Earth Sciences,2013,69:1529.
[30] 周洁.地铁隧道管片周围人工冻结软黏土融沉机理与动力变形特性研究[D].上海:同济大学,2015.ZHOU Jie.Thaw settlement mechanism and dynamic deformation of soft clay surrounding subway tunnel after artificial ground freezing[D].Shanghai:Tongji University,2015.
[31] SHEAR D L,OLSEN H W,NNLSON K R.Effects of desiccation on the hydraulic conductivity versus void ratio relationship for a natural clay[R].Washington D C:Transportation Research Record,NRC,National Academy Press,1993:1365-1370.
[32] 李珺.人工冻结饱和软黏土的变形特性及微观结构研究[D].上海:同济大学,2016.LI Jun.Deformation mechanism and microstructure behavior of artificial freezing-thawing soft clay[D].Shanghai:Tongji University,2016.
[33] TAYLOR D W.Deformation mechanism and microstructure behavior of artifical freezing-thawing soft clay[M].New York:John Wiley and Sons,1948.
[34] TERZAGHI K,PECK R B,MESRI G.Soil mechanics in engineering practice[M].3rd ed.New York:John Wiley and Sons,1996.
[35] RODRIGUEZ E,GIACOMELLI F,VAZQUEZ A.Permeability-porosity relationship in RTM for different fiberglass and natural reinforcements[J].Journal of Composite Materials,2004,38(3):259.
[36] JANG J,NARSILIO G A,SANTAMARINA J C.Hydraulic conductivity in spatially varying media—a pore-scale investigation[J].Geophysical Journal International,2015,184(3):1167.
[37] GIMENEZ D,PERFECT E,RAWLS W J,et al.Fractal models for predicting soil hydraulic properties:a review[J].Engineering Geology,1997,48(3/4):161.
[38] XU Yongfu.Calculation of unsaturated hydraulic conductivity using a fractal model for the pore-size distribution[J].Computers & Geotechnics,2004,31(7):549.