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1、JournalofEngineeringGeology工程地質(zhì)學(xué)報(bào)1004-9665/2016/24(1)010207DOI:10.13544/j.cnki.jeg.2016.01.013西峰塬黃土的濕陷性研究①①②①吳光輝王家鼎馬威王延壽(①西北大學(xué)大陸動(dòng)力學(xué)國家重點(diǎn)實(shí)驗(yàn)室西安710069)(②昆明理工大學(xué)國土資源工程學(xué)院昆明650093)摘要采用雙線法對(duì)西峰塬原狀Q3黃土進(jìn)行增濕、減濕情況下的壓縮試驗(yàn)。分析了黃土的濕陷變形隨濕度及壓力的變化規(guī)律。利用SEM技術(shù)測(cè)試了黃土濕陷前后的微結(jié)構(gòu)變化,采用微結(jié)構(gòu)定量
2、化分析方法和分形分維集合方法分析了黃土試樣微觀孔隙的變化規(guī)律。結(jié)果表明:(1)黃土濕陷性的產(chǎn)生是構(gòu)成黃土架空孔隙的“剛性”結(jié)點(diǎn)變異導(dǎo)致。(2)同級(jí)壓力下超越濕陷率隨初始含水量的增加而變大;初始含水量在同一水平下,隨壓力的增加超越濕陷率逐漸變大。(3)黃土濕陷過程伴隨孔隙數(shù)量大幅增加,平均孔徑減小,孔隙面積縮小,大中孔隙數(shù)量驟降;孔隙結(jié)構(gòu)變得更加復(fù)雜。本文提出了黃土超越濕陷率的概念及受外界因素的影響規(guī)律,分析了非飽和黃土的濕陷機(jī)理,即水分和外力不同組合情況的濕陷性。關(guān)鍵詞濕陷變形SEM技術(shù)超越濕陷率微結(jié)構(gòu)架空孔隙+中
3、圖分類號(hào):P642.131文獻(xiàn)標(biāo)識(shí)碼:AUNIAXIALCOMPRESSIONANDSEMTESTSFORLOESSCOLLAPSIBILITYATLOESSPLATEAUOFXIFENG①①②①WUGuanghuiWANGJiadingMAWeiWANGYanshou(①NorthwestUniversity,StateKeyLaboratoryofContinentalDynamics,Xian710069)(②FacultyofLandResourcesEngineering,KunmingUniversi
4、tyofScienceandTechnology,Kunming650093)AbstractThebehaviorofundisturbedloessinthecaseofmoisteningordemoisteningisinvestigatedusingdoublelineuniaxialcompressiontestinthispaper.Thecollapsibledeformationrulesofcollapsibleloessareexaminedandanalyzed,duringthegrow
5、thprocessofhumidityandpressure.AndthemicrostructureofthesamplesaretestedusingSEMtechnique.Furthermorethemicrostructureofsamplesisanalyzedwithquantitativemethodandfractaltheory.Theresultsareshownthefollowings:(1)“Rigidnodefailure”oftrellisporescancausetheloessc
6、ollapsibility.(2)Watercontentofloesshasamarkedeffectonitscollapsibledeformation.Whenpressureissomevalue,itsexceedingcollapsibleprobabilitycanincreaseasmoisturecontentincreases.Similarly,thetestdatashowthatforloesswithconstantwatercontent,itsexceedingcollapsibl
7、eprobabilitycanincreasegraduallyaspressureincreases.(3)Theaveragenumberofporeofsampleobviouslyincreasesandtheporeareadecreasesafterthesampleiscollapsed.Thecollapseisaprocessthatsmallporeincreases,fractaldimensiondecreases,andcomplexityoftheporeincreases.Thecon
8、ceptoftheexceedingcollapsiblecoefficientisputforward.Ananalysisis收稿日期:2014-11-27;收到修改稿日期:2015-09-07.基金項(xiàng)目:國家自然科學(xué)基金(40972193,41372269),高等學(xué)校博士學(xué)科點(diǎn)專項(xiàng)科研基金(20116101130001)資助.第一作者簡介:吳光輝(1