资源描述：
《土木工程类专业英文文献及翻译》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、PAVEMENTPROBLEMSCAUSEDBYCOLLAPSIBLESUBGRADESBySandraL.Houston,1AssociateMember,ASCE(ReviewedbytheHighwayDivision)ABSTRACT:Problemsubgradematerialsconsistingofcollapsiblesoilsarecom-moninaridenvironments,whichhaveclimaticconditionsanddepositionalandweatheringprocessesfavorabletot
2、heirformation.Includedhereinisadiscussionofpredictivetechniquesthatusecommonlyavailablelaboratoryequipmentandtestingmethodsforobtainingreliableestimatesofthevolumechangefortheseproblemsoils.Amethodforpredictingrelevantstressesandcorrespondingcollapsestrainsfortypicalpavementsubg
3、radesispresented.Relativelysimplemethodsofevaluatingpotentialvolumechange,basedonresultsoffamiliarlaboratorytests,areused.INTRODUCTIONWhenasoilisgivenfreeaccesstowater,itmaydecreaseinvolume,increaseinvolume,ordonothing.Asoilthatincreasesinvolumeiscalledaswellingorexpansivesoil,a
4、ndasoilthatdecreasesinvolumeiscalledacollapsiblesoil.Theamountofvolumechangethatoccursdependsonthesoiltypeandstructure,theinitialsoildensity,theimposedstressstate,andthedegreeandextentofwetting.Subgradematerialscomprisedofsoilsthatchangevolumeuponwettinghavecauseddistresstohighw
5、ayssincethebe-ginningoftheprofessionalpracticeandhavecostmanymillionsofdollarsinroadwayrepairs.Thepredictionofthevolumechangesthatmayoccurinthefieldisthefirststepinmakinganeconomicdecisionfordealingwiththeseproblemsubgradematerials.Eachprojectwillhavedifferentdesignconsideration
6、s,economiccon-straints,andriskfactorsthatwillhavetobetakenintoaccount.However,withareliablemethodformakingvolumechangepredictions,thebestdesignrelativetothesubgradesoilsbecomesamatterofeconomiccomparison,andamuchmorerationaldesignapproachmaybemade.Forexample,typicaltechniquesfor
7、dealingwithexpansiveclaysinclude:(1)Insitutreatmentswithsubstancessuchaslime,cement,orfly-ash;(2)seepagebarriersand/ordrainagesystems;or(3)acomputingoftheserviceabilitylossandamod-ificationofthedesignto"accept"theanticipatedexpansion.Inordertomakethemosteconomicaldecision,theamo
8、untofvolumechange(especiallynon-uniformvolumech
