降雨入渗对基坑开挖边坡稳定性影响分析.docVIP

降雨入渗对基坑开挖边坡稳定性影响分析

林廷松1，郑俊清2，黄福明2，3，韩同春2

(1．浙江大学建筑设计研究院，杭州310027；2．浙江大学岩土工程研究所，杭州310058；3.宁波市建筑设计研究院，宁波315012)

摘要：针对降雨入渗引起基坑变形失稳问题。以某放坡开挖基坑为例，建立一个考虑水力渗透系数特征曲线、土-水特征曲线以及修正的Mohr-Coulomb破坏准那么的非饱和土流固耦合有限元计算模型，进行雨水入渗下基坑开挖边坡渗流场和应力场耦合的数值模拟，得到降雨入渗过程的孔隙水压力场和含水率分布，在此根底上利用简化Bishop条分法进行边坡稳定平安系数计算。结果显示：降雨入渗对单一均质砂土边坡影响较大；上覆弱透水层能够有效减小降雨入渗对坡体表层及内部负孔隙水压力的影响，进而降低土体水平位移并提高边坡的稳定性。

关键词：降雨入渗；非饱和土坡；耦合分析；平安系数

中图分类号：TU560.4530文献标识码：A

Analysisontheinfluencesofrainfallinfiltrationsonstabilityofexcavationslop

LINTingsong1，ZHENGJunqing2，HUANGFuming2,3，HANTongchun2

(1．ArchitecturalDesignandResearchInstitute，ZhejiangUniversity，Hangzhou；310027，China；

2．InstituteofGeotechnicalEngineering，ZhejiangUniversity，Hangzhou310058，China；

3.NingboInstituteofArchitecturalDesign,Ningbo315012,China)

Abstract:Inordertosolvetheproblemofstabilityofexcavationslopunderrainfallinfiltration.Takingaslopeexcavationforexample,thispaperpresentsaflow-deformationcoupledfiniteelementanalysismodelofunsaturatedsoilwhichconsidershydraulicconductivitycurve,soil-watercharacteristiccurve,modifiedMohr-Coulombfailurecriterion.Thisanalysismodelisusedtoevaluatetheprocessofinfiltrationintoanunsaturatedslopeunderrainfallanditseffectonsoilslopebehavior,whichcanobtaintheprocessofrainfallinfiltrationmoisturedistributionofporewaterpressurefield.Basedonthis,theresultsofslopestabilitysafetyfactorcanbecalculatedbyusingthesimplifiedBishopmethod.Theresultsshowthat:therainfallinfiltrationhasagreatinfluenceonsinglehomogeneoussoilslope.Theoverlyingsemipermeablelayercaneffectivelyreducetheeffectsofrainfallinfiltrationonslopesurfaceandinternalofnegativeporewaterpressure,whichcanimprovethestabilityofthehomogenizingsoilslope.

Keywords:rainfallinfiltration;unsaturatedsoilslopes;coupledanalysis;stabilityfactor

引言

降雨引起边坡失稳的问题一直受到人们的关注。