开挖膨胀土边坡坍滑的演化规律.pdf

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1、第30卷第7期公路交通科技Vol_3ONo．72013年7月JournalofHighwayandTransportationResearchandDevelopmentJu1．2013doi：10．3969／j．issn．1002—0268．2013．07．004开挖膨胀土边坡坍滑的演化规律杨和平，肖杰，程斌，赵文建(长沙理工大学特殊土工程研究所，湖南长沙410004)摘要：膨胀土路堑开挖一段时间后边坡坍滑是路基施工中常见现象且与坡高、坡率无直接联系。为探求其变形破坏演化过程以便实施有效工程处治，采用FLAc对广西百隆路百色膨胀土堑坡开挖过程进行模拟，获得新开挖边

2、坡的位移、应力、应变变化规律；通过强度折减法计算得到的安全系数随挖深增大而减小，但此时边坡是稳定的。此外采用FLAC热力学模块模拟边坡大气影响深度内的湿度场，再次分析获得经历干湿循环作用后其相应的位移、应力、应变变化规律，即边坡的失稳过程。对比工程实体修建时的现场观察与数值分析结果，发现两者基本吻合，由此总结并提出开挖膨胀土堑坡坍滑的4阶段变化规律及合理实施柔性支护的建议。关键词：道路工程；演化规律；堑坡开挖；膨胀土；边坡坍滑；FLAC；湿度场；柔性支护中图分类号：U416~14文献标识码：A文章编号：1002—0268(2013)07—0018—07Landsli

3、deEvolutionRegularityofExcavatedExpansiveSoilSlopeYANGHe—ping，XIAOjie，CHENGBin，ZHAOWen-jian(ResearchInstituteofSpecialSoilEngineering，ChangshaUniversityofScienceandTechnology，ChangshaHunan410004，China)Abstract：Theslidingofexpansivesoilcutslopeafterexcavationforaperiodoftimeisacommonapp

4、earanceduringconstructionofexpansivesoilsubgrade．Thisslidingisnotdirectlyrelatedtotheheightandratioofslope．Inordertofindouttheevolutionofitsdeformationandfailuretoimplementeffectiveengineeringtreatment，theFLACisusedtosimulatetheexcavationprocessofBaiseexpansivesoilcutslopeofBailongexpr

5、esswayinGuangxiandobtainitsregularitiesofdisplacement，stressandstrain．Thesafetyfactorofcutslopecalculatedbystrengthreductionmethodreduceswiththeincreaseofslopedepth，butitisstillstableafterthecomplicationofexcavation．Inaddition，thethermodynamicsmoduleofFLACisusedtosimulatethehumidityfie

6、ldofatmosphericeffectondepthofexpansivesoilslope，andgettheregularities(damage)ofthevariabilityofthedisplacement，stressandstrainofcutslopeafterwettinganddryingcycles．Thenumericalsimulationresultisbasicallyinaccordancewiththefieldobservationresultduringconstructionofthecutslope．Therefore

7、，thefour—stageevolutionregularityofslidingofexcavatedexpansivesoilcutslopeissummarizedandpresented，andthetechnologyofflexiblesupportingisreasonablyproposed．Keywords：roadengineering；evolutionregularity；cutslopeexcavation；expansivesoil；slopelandslide；FLAC；humidityfield；flexiblesupport殊