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1、分類號(hào):P64210710-2015226071專業(yè)碩士學(xué)位論文非飽和黃土結(jié)合水的吸力研究張中華導(dǎo)師姓名職稱李萍副教授申請(qǐng)學(xué)位級(jí)別工學(xué)碩士專業(yè)學(xué)位類別地質(zhì)工程及領(lǐng)域名稱論文提交日期2018年4月16日論文答辯日期2018年5月27日學(xué)位授予單位長(zhǎng)安大學(xué)Researchonsuctionofunsaturatedloess-bondedwaterADissertationSubmittedfortheDegreeofMasterCandidate:ZhangZhonghuaSupervisor:AssociateProf.LiPingChang’anUniversity
2、,Xi’an,China摘要非飽和黃土的工程特性主要受土中吸力變化的影響,其對(duì)應(yīng)黃土中含水率的變化。目前對(duì)于非飽和黃土中水的賦存狀態(tài),尤其是結(jié)合水的含量以及其狀態(tài)的研究尚還欠缺。本文對(duì)甘肅正寧和陜西涇陽(yáng)黃土進(jìn)行了吸附結(jié)合水的測(cè)試,對(duì)黃土中結(jié)合水量以及界限進(jìn)行了確定;基于Halsey方程估算黃土結(jié)合水膜厚度;根據(jù)黃土中水的賦存狀態(tài)對(duì)吸力進(jìn)行了分類,結(jié)合Kelvin方程得到結(jié)合水的土水特征曲線。首先利用等溫吸附法測(cè)定了正寧、涇陽(yáng)黃土的結(jié)合水,結(jié)果表明黃土吸附結(jié)合水的含水率集中在4%-9%范圍,正寧黃土的強(qiáng)結(jié)合水與弱結(jié)合水的界限濕度為RH=0.90,涇陽(yáng)黃土的強(qiáng)結(jié)合水與弱結(jié)
3、合水的界限濕度RH=0.59,造成二者差異的主要原因是黃土中粘土礦物含量以及粒徑級(jí)配的差異;從涇陽(yáng)原狀黃土和散土樣的等溫吸附結(jié)果來(lái)看,黃土的結(jié)構(gòu)性對(duì)吸附結(jié)合水含水率的影響不大,但對(duì)黃土吸附過(guò)程有一定的影響。在等溫吸附試驗(yàn)的基礎(chǔ)上,利用Halsey經(jīng)驗(yàn)方程對(duì)等溫吸附曲線擬合,并得到方程中參數(shù)C、s的值。結(jié)果發(fā)現(xiàn)s=2,不同黃土具有相同的s值,參數(shù)C隨土性變化大,與土中膠粒的含量或其比表面積相關(guān),通過(guò)擬合得到了其相關(guān)方程。根據(jù)黃土中水的賦存狀態(tài)將土中吸力分為結(jié)合水的吸附作用和毛細(xì)水的毛細(xì)作用;并結(jié)合Kelvin方程得到黃土結(jié)合水的土水特征曲線SWCC,根據(jù)結(jié)合水的土水特征
4、曲線得到黃土的殘余含水率即為強(qiáng)結(jié)合水的含水率。關(guān)鍵詞:黃土,結(jié)合水,水膜厚度,Halsey方程,殘余含水率IAbstractTheengineeringcharacteristicsofunsaturatedloessaremainlyaffectedbythechangeofsuctioninsoil,whichcorrespondstothechangeofwatercontentinloess.Atpresent,thereisstillalackofresearchontheoccurrenceofwaterinunsaturatedloess,especia
5、llythecontentofwateranditsstate.Inthispaper,theadsorbedboundwatertestofloessfromZhengninginGansuprovinceandJingyanginShaanxiProvinceiscarriedout,theboundwatercontentandlimitaredetermined.ThethicknessoftheboundwaterfilmofloessisestimatedbasedontheHalseyequation,thesuctionisclassifiedacco
6、rdingtotheoccurrencestateofthewaterintheloess,andthesoil-watercharacteristiccurveofthewaterisobtainedwiththeKelvinequation.Firstly,theboundwatercontentofZhengningandJingyangloessisdeterminedbyisothermaladsorption,whichshowsthatthewatercontentoftheadsorbedboundwaterofZhengningloessisconc
7、entratedinthe4%-9%range,theboundaryhumidityofthestrongboundwaterandtheweakboundwaterisRH=0.90,theboundaryhumidityofJingyangloessisRH=0.59.Thedifferencebetweenthetwoismainlycausedbythedifferenceinclaymineralcontentandparticlesizegradation.Thestructureofloesshaslittleinfluenceont