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1、戈壁碎石土地基原状土掏挖基础抗拔试验探究摘要：在甘肃和新疆的7个试验场地完成了40个戈壁碎石土地基原状土扩底掏挖基础抗拔试验，得到了基础抗拔荷载位移特性。结果表明，上拔荷载作用下，戈壁碎石土地基掏挖基础具有良好的抗拔承载性能，荷载位移曲线呈大致相同变化规律，可分为扩大端土体被压密的弹性阶段、土体剪切变形至塑性区贯通的弹塑性阶段、滑动面形成至破坏的3个特征阶段。根据基础荷载位移曲线，采用双切线交法确定了试验基础极限上拔承载力。基于土体滑移线场理论和Mohr-Coulomb强度准则，引入抗拔土体圆弧滑动面假设，推导了戈壁掏挖扩底基
2、础的抗拔承载力理论计算公式，并将试验结果与理论计算结果进行了对比分析。关键词：戈壁；碎石土；掏挖扩底基础；抗拔；输电线中图分类号:TU411文献标志码：A文章编号：1674-4764(2012)04-0024-07FieldTestAnalysisonBelledPierFoundationsunderTensileLoadinGravelGobiLUXianlongl,2,QIANZengzhen2,TONGRuimingl,ZHENGWeifengl(1.TransmissionandTransformationEngin
3、eeringResearchDepartment,ChinaElectricPowerResearchInstitute,Beijing100192,P.R.China；2.SchoolofEngineeringandTechnology,ChinaUniversityofGeosciences,Beijing100083,P.R.China)Abstract：Fortyfull-scalefieldtestswereconductedonbelledpierfoundationsatsevengravelGobisitesi
4、nGansuprovinceandXinjiangUygurAutonomousRegioninChina.Theupliftload-displacementresponseofbelledpierfoundationsingravelGobialmostfollowedthesamepatternandpresentedthree-phasebehaviors・Undertensileload,theonsetofthecurveusuallystartedfromtheelasticlinearpartresulting
5、fromthecompressionandcompactionofgravelGobiabovetheenlargedbase・Andconsequently,withtheoccurreneeandfurtherdevelopmentofaplasticzonearoundthefoundation,theupliftload-displacementcurveturnedintoanelasto-plasticstage・Finally,theformationofwholerupturesurfacebroughttot
6、heentireshearingdamageofGobisoil.Theultimateupliftbearingcapacitieswereobtainedbyusingtheslope-tangentmethodforalltestfoundations・Basedonthetheoryoflimitingequilibrium,theMohr-Coulombyieldingcriterionandslip-linefieldmethod,thecirclearcrupturesurfaceboundaryconditio
7、nwasintroduced.AndthetheoreticalcalculationequationtodeterminetheultimateupliftbearingcapacityofthebelledpierfoundationingravelGobiwasobtained.ThetheoreticalresuItswerecomparedwiththoseofthetestsandtheyturnedoutingoodagreement.Keywords：Gobi；gravelsoil；belledpierfoun
8、dation；uplift；transmissionline戈壁是粗砂、砾石覆盖在硬土层上的荒漠地形，在中国西北地区广泛分布。随着电网建设的发展，越来越多的输电线路需经过戈壁滩地区。杆塔基础作为输电线路的重要组成部分，其造价、工期和劳动消耗量在整个工程中占很大比重。杆塔基础具
