土体干燥过程中的体积收缩变形特征.docx

土体干燥过程中的体积收缩变形特征唐朝生1,2，崔玉军3，Anh-MinhTang3，施斌1（1.南京大学地球科学与工程学院，江苏南京210093；2.中国矿业大学深部岩土力学与地下工程国家重点实验室，徐州221008；3.法国国立路桥大学，巴黎77455）摘要：通过开展室内试验，分别研究了初始饱和的糊状试样和不同压实状态的压实试样的体积收缩变形特征。对于糊状试样，采用液体体积置换法测量了试样干燥过程中的体积变化，获得了完整的收缩曲线，试验结果表明：糊状试样的收缩过程可分正常收缩、残余收缩和零收缩3个阶段；绝大部分收缩变形发生在进气点之前即土体处于饱和状态。对于压实试样，初始干密度和含水率对收缩特征有重要影响：初始干密度增加对体积收缩变形起抑制作用，而初始含水率的增加对体积收缩变形起促进作用。此外，压实试样的体积收缩存在明显的各向异性，且对初始含水率的敏感程度高于初始干密度。最后，根据试验结果，提出了压实试样收缩应变与初始干密度和含水率之间的函数关系式。关键词：土体收缩；收缩曲线；压实条件；影响因素；土结构；含水率中图分类号：TU411文献标识码：A文章编号：1000–4548(2011)08–1271–09作者简介：唐朝生(1980–)，男，湖南衡阳人，博士，副教授，主要从事环境岩土工程和工程地质方面的教学和研究工作。E-mail:tangchaosheng@。VolumetricshrinkagecharacteristicsofsoilduringdryingTANGChao-sheng1,2,CUIYu-jun3,TANGAnh-Minh3,SHIBin1(1.SchoolofEarthSciencesandEngineering,NanjingUniversity,Nanjing210093,China;2.StateKeyLaboratoryforGeoMechanicsandDeepUndergroundEngineering,ChinaUniversityofMiningTechnology,Xuzhou221008,China;3.EcoledesPonts-ParisTech,URNavier/CERMES,Paris77455,France)Abstract:Dryingshrinkageisoneoftheintrinsiccharacteristicsofsoil,andhasprofoundeffectsonitsengineeringproperties.Inthisinvestigation,laboratorytestsareconductedoninitiallysaturatedpaste-likespecimensandcompactedspecimenswithdifferentcompactionparameters.Forthepaste-likespecimens,thefluidvolumedisplacementtechniqueisemployedtomeasurethevolumetricchangeofspecimensduringdrying,andthecompleteshrinkagecurveisdetermined.Itisfoundthatthreestagescanbedistinguishedintheshrinkageofpaste-likespecimens,namelynormalshrinkage,residualshrinkageandzeroshrinkage;mostofthevolumetricshrinkagedeformationoccursbeforetheair-entrypointwhilethesoilisstillfullysaturated;thevolumeshrinkagebehaviorandshrinkagecurveshapesignificantlydependonsoilmicrostructurecharacteristics.Forthecompactedspecimens,theshrinkagebehaviorissignificantlycontrolledbytheinitialdryingdensityandwatercontent.Ingeneral,shrinkagestraindecreaseswiththeincreaseoftheinitialdrydensityandincreaseswiththeincreaseofthecompactionwatercontent.Inaddition,theresultsshowthattheshrinkageofcompactedspecime