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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用土水特征曲線分析膨脹土的改良效果楊和平,林麗萍,肖杰,湛文濤(長沙理工大學(xué)特殊土工程研究所,湖南長沙410004)摘要:為建立非飽和土理論與工程問題的聯(lián)系,探討用土水特征曲線來評價膨脹土的改良效果。將石灰、粉煤灰2種改良劑(均用4種摻量)摻入百色膨脹土,開展
2、自由膨脹率試驗,同時按改進葡式擊實法確定的各改良土最佳含水率制備試樣,通過壓力板儀完成脫濕土水特征曲線試驗(吸力范圍5~1000kPa),獲得不同改良土的膨脹性及土水特征曲線線系?;诜秋柡屯晾碚摬⒄张蛎浲僚袆e的國家標(biāo)準(zhǔn),采用VG模型進行曲線擬合后,分析不同改良荊及摻量對土水特征曲線的影響,發(fā)現(xiàn)可用飽和重力含水率、進氣值、殘余含水率和曲線斜率4個指標(biāo)來評價膨脹土的改良效果。進一步的分析研究表明,4個指標(biāo)中只要3個滿足要求就能確定該土已達(dá)改性目的,其中飽和重力含水率是必備指標(biāo),其余3指標(biāo)只需滿足2個即可。關(guān)鍵詞:道路工程;非
3、飽和土;土水特征曲線;膨脹土;化學(xué)改良;效果評價中圖分類號:U416.101文獻標(biāo)識碼:A文章編號: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