Browsing by Author "uba, Bantayehu"

Now showing 1 - 1 of 1
  • No Thumbnail Available
    Item
    The Unsaturated Shear Strength and Swelling Charac Teristics of Expansive Soils of Arbaminch
    (Addis Ababa University, 2011-06) uba, Bantayehu; Seged, Hadush (PhD)
    InEthiopia,somanyresearchesweredoneoncharacterizingexpansivesoilsofseveraltownsbutonlyasinglestudy,doneonAddisAbabaexpansivesoil,existsontheunsaturatedshearstrengthbehaviorofexpansivesoils.ThepresentstudyaddressesexaminingtheexpansivesoilsinArbaMinch–atownwithagreatportionofitsterraincoveredbythesamesoilbutnotconsideredinpreviousstudies.Alaboratory-testingprogramwasplannedandcarriedoutonundisturbedsoilsamplestakenfrom10differentlocationsinthetownforswellingpressuretesting;andamongthese,onepitwasallottedforunsaturatedshearstrengthstudy. Thelaboratorytestresultsrevealedthattheswellingpressurerangesfrom74.53to571.29kPa,SpecificGravityfrom2.63to2.80,PlasticityIndexfrom49to77%,ShrinkageIndexfrom81to117%andFreeSwellfrom94.0to165.0%.Themeasuredswellingpressuresandthegeotechnicalparametersdeterminedfromidentificationtestsareusedtoassessthevalidityofalreadydevelopedexpressionsbyvariousresearcherstothesiteunderstudyandnewmodels,thatrelateswellingpressurewithindexandphysicalproperties,aredevelopedusingSPSS16.0forwindowssoftware. Theresultsfromunsaturatedshearstrengthtestsperformedwitha50kNmodifieddoublewalltriaxialmachineonanundisturbedsamplesettingmatricsuctiontobe100kPa,150kPaand200kPaforaneffectiveconsolidationpressureof200kPahaveclearlyindicatedthesaturatedcasetoyieldsmallershearstrengththantheunsaturatedone.Themaximumdeviatorstressshowedtoincreasefrom107.61kPato174.35kPawithanincreaseinmatricsuctionbuttheshapeofthestress-straindiagramremainedidentical.