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时间:2020-03-25
《用土水特征曲线分析膨胀土的改良效果.pdf》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、第28卷第lO期2011年10月公路交通科技JournalofHighwayandTransportationResearchandDevelopmentVoL28No.10Oct.20lldoi:tO.3969/j.issn.1002—0268.2011.10.001用土水特征曲线分析膨胀土的改良效果杨和平,林丽萍,肖杰,湛文涛(长沙理工大学特殊土工程研究所,湖南长沙410004)摘要:为建立非饱和土理论与工程问题的联系,探讨用土水特征曲线来评价膨胀土的改良效果。将石灰、粉煤灰2种改良剂(均用4种掺量)掺入百色膨胀土,开展
2、自由膨胀率试验,同时按改进葡式击实法确定的各改良土最佳含水率制备试样,通过压力板仪完成脱湿土水特征曲线试验(吸力范围5~1000kPa),获得不同改良土的膨胀性及土水特征曲线线系。基于非饱和土理论并参照膨胀土判别的国家标准,采用VG模型进行曲线拟合后,分析不同改良荆及掺量对土水特征曲线的影响,发现可用饱和重力含水率、进气值、残余含水率和曲线斜率4个指标来评价膨胀土的改良效果。进一步的分析研究表明,4个指标中只要3个满足要求就能确定该土已达改性目的,其中饱和重力含水率是必备指标,其余3指标只需满足2个即可。关键词:道路工程;非
3、饱和土;土水特征曲线;膨胀土;化学改良;效果评价中图分类号:U416.101文献标识码:A文章编号:1002—0268(2011)10—0001—06AnalysisOffImprovementEffectofExpansiveSoilbySoil-waterCharacteristicCurveYANGHeping,LINLiping,XIAOJie,ZHANWentao(ResearchInstituteofSpecialSoilEngineering,ChangshaUniversityofScienceandTech
4、nology,ChangshaHunan410004,China)Abstract:Forestablishingtherelationshipbetweenthetheoryofunsaturatedsoilandengineeringproblem,thesoil—watercharacteristiceurvewasusedtodiscusstheimprovementeffectofexpansivesoil.Fourcontentsoftwoimprovers,i.e.,limeandfly—ash,wereadd
5、edintotheBaiseexpansivesoilrespectivelyforfreeexpansionratiotesting.BasedontheoptimummoisturecontentsdeterminedbythemodifiedProctorcompactionmethod,thetestingspecimensofeachimprovedsoilweremade.Throughdewettingsoil-watercharacteristiccurvetestingintherangeof5~1000K
6、Paconductedbypressureplateapparatus,theexpansionpropertiesandsoil—watercharacteristiccurvebunchoftheimprovedexpansivesoilswereobtained.Theimpactofdifferentimproversandmixingcontentsonthesoil-watercharacteristiccurvesfittedbyVGmodelwereanalyzedbasedonthetheoryofunsa
7、turatedsoilandthenationaldeterminationcriterionforexpansivesoils.Itisfoundthatsaturatedgravitywatercontent,airentryvalue,residualwatercontentandcurveslopecanbeusedtoevaluatethechemicalimprovementeffectonexpansivesoils.Furtheranalysisshowsthattheimprovementeffectcan
8、bedeterminedifthreeofthefourindexesofexpansivesoilhavemettherequirements.However,saturatedgravitywatercontentisindispensable,anytwooftherestthree
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