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1、第32卷增刊2岩土力学Vol.32Supp.22011年8月RockandSoilMechanicsAug.2011文章编号：1000－7598(2011)增刊2－0424－07荆门弱膨胀土的胀缩与渗透特性试验研究1,211周葆春，孔令伟，郭爱国（1.中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室，武汉430071；2.信阳师范学院土木工程学院，河南信阳464000）摘要：以荆门弱膨胀土为研究对象，开展了完整的胀缩与渗透特性试验，获得了5种不同压实度下膨胀土及其石灰改良土的胀缩与渗透特征。结果表明：膨胀土的膨胀力-干密度关系可用幂函数表达，而无荷膨胀率、有荷膨胀率、体缩率与干
2、密度均非单调关系；由于压实与膨胀效应的耦合作用，95%压实度下膨胀土的无荷膨胀率、有荷膨胀率和体缩率均较小，若直接利用膨胀土进行路基与地基填筑，该压实度下土样不仅具备较大的刚度与强度且胀缩变形较小。经石灰改性后，膨胀力与湿胀变形基本消除，干缩变形大幅降低，胀缩总率仅为0.7%。膨胀土与石灰土渗透系数均很小，且都随干密度的增大而降低，其与干密度的关系仍可用幂函数描述；石灰土的渗透系数大于相应压实度下的膨胀土；而当二者干密度相近时，渗透系数接近。关键词：膨胀土；胀缩特性；渗透特性；压实度；干密度中图分类号：TU443文献标识码：AExperimentalstudyofcharacteris
3、ticsofswelling-shrinkageandpermeabilityforJingmenweakexpansivesoil1,211ZHOUBao-chun,KONGLing-wei,GUOAi-guo（1.StateKeyLaboratoryofGeomechanicsandGeotechnicalEngineering,InstituteofRockandSoilMechanics,ChineseAcademyofSciences,Wuhan430071,China;2.CollegeofCivilEngineering,XinyangNormalUniversity,X
4、inyang,Henan464000,China）Abstract:Aseriesoftestsforcharacteristicsofswelling-shrinkageandpermeabilityarecarriedoutonJingmenweakexpansivesoilunderfivedifferentcompactnessesandonthelime-treatedsoil.Thetestresultsshowthattheswellingpressure-drydensityrelationcanberepresentedbyapowerfunction;whileth
5、erelationsbetweennon-loadedswellingratio,linearswellingratio,volumeshrinkageratioanddrydensityareallnon-monotonous.Theexpansivesoilwiththecompactnessof95%hasthelowerswellingratioandvolumetricshrinkageratio,whichisduetoeffectsofcoupledcompactionandswelling.Therefore,thecompactnessshouldbeselected
6、as95%inweakexpansivesoilembankmentconstruction.Ontheotherhand,thelimetreatmentcanreduceswellingandshrinkageofexpansivesoil,indicatingbythefactthattheswelling-shrinkagetotalratioofthelime-treatedexpansivesoilisonly0.7%.Inaddition,thepermeabilitycoefficientofthelime-treatedanduntreatedexpansivesoi
7、lalldecreasewithincreasingdrydensity.Thisrelationcanberepresentedbythepowerfunctionaswell.Thepermeabilitycoefficientofthelime-treatedsoilislargerthanthatoftheuntreatedexpansivesoilunderthesamecompactness;however,fortheapprox
