干湿循环条件下复合改良膨胀土的工程特性及微观机理研究

文档摘要：为研究粉煤灰(高钙)复合木质素纤维改良云南蒙自膨胀土的工程特性和微观机理,开展改良土的胀缩特性试验,并且在干湿循环条件下进行复合改良土的力学特性试验,结合改良前后微观结构和物相变化分析得出改良机理.试验表明:粉煤灰能降低膨胀土的膨胀率,单掺粉煤灰改良土胀缩率降低至无膨胀性水平,土体强度提升,黏聚力增幅显著,试样趋于脆性破坏,最佳掺量为20％.以最优粉煤灰掺量复合木质素纤维进行力学特性试验,复合改良土强度较单一改良土均有进一步提升,且强度随养护龄期延长而继续增加;土体内摩擦角随改良物掺入并无明显变化,基于素膨胀土上下微小波动,20％粉煤灰+1.0％木质素纤维为最佳复合改良配比.进行干湿循环试验后,试样无侧限抗压强度、抗剪强度和黏聚力均随干湿循环次数增加而减小,在前三次干湿循环中降幅较大,内摩擦角随干湿循环次数增加无明显规律变化.改良土强度在数次干湿循环过程中力学特性均优于膨胀土,其中复合改良抑制干湿循环破坏效果比单掺改良更好.结合微观试验结果可知,掺入粉煤灰后土体中生成了硅酸胶凝产物,该产物可填充土体中的孔隙,增加土体密实度,纤维掺入可抑制土体干湿循环过程裂隙发育.

Abstract：Inordertostudytheengineeringcharacteristicsandmicrocosmicmechanismofflyash(highcalcium)compositeligninfibermodifiedYunnanMengziexpansivesoil,carryouttheexpansionandcontractioncharacteristicstestoftheimprovedsoil,andconductthemechanicalpropertytestofthecompositeimprovedsoilundertheconditionofthedry-wetcycle,andcombinetheanalysisofthemicrostructureandphasechangesbeforeandafterimprovementtoobtaintheimprovementmechanism.Thetestshowsthat:flyashcanreducetheexpansionrateofexpansivesoil,theexpansionandshrinkagerateoftheimprovedsoilmixedwithflyashisreducedtothelevelofnoexpansion,thestrengthofthesoilbodyisimproved,thecohesionissignificantlyincreased,andthesampletendstobebrittle.Thebestdosageis20％.Usingbestdosageflyashtocompoundligninfibertocarryoutthemechanicalpropertytest,thestrengthofthecompound-improvedsoilisfurtherimprovedcomparedwiththesingle-improvedsoil,andthestrengthcontinuestoincreasewiththegrowthofthecuringage.Thefrictionangleinthesoildoesnotchangesignificantlywiththeadditionoftheimprovedsubstance.Basedontheslightfluctuationoftheplainexpansivesoil,20％flyash+1.0％ligninfiberisthebestcompositeimprovementratio.Afterthedry-wetcycletest,theunconfinedcompressivestrength,shearstrength,andcohesionofthesamplealldecreasedwiththeincreaseinthenumberofdry-wetcycles.Inthefirstthreedry-wetcycles,thedecreasewaslarger.Thefrictionanglehasnoobviouschangewiththeincreaseindryingandwettingcycles.Thestrengthoftheimprovedsoilisbetterthanthatoftheexpansivesoilintheprocessofseveraldry-wetcycles,andthecombinedimprovementisbetterthanthesingle-mixedimprovementininhibitingthedamageofthedry-wetcycle.Combinedwiththeresultsofmicroscopictests,itcanbeseenthatsilicicacidgellingproductsareformedinthesoilaftertheadditionofflyash,whichcanfillthesoil'sporesandincreasethesoil'scompactness.

作者：蔡祎   欧明喜   陈颖辉   李强   史伟中 Author：CAIYi   OUMingxi   CHENYinghui   LIQiang   SHIWeizhong
作者单位：昆明理工大学建筑工程学院,昆明650500云南工程勘察设计院集团有限公司,昆明650051
刊名：材料导报 ISTICEIPKU
Journal：MaterialsReports
年，卷(期)：2024, 38(z1)
分类号：TU443
关键词：云南膨胀土  粉煤灰(高钙)  木质素纤维  工程特性  微观结构  
Keywords：Yunnanexpansivesoil  flyash(highcalcium)  ligninfiber  engineeringcharacteristics  microstructure  
机标分类号：TU443U416.1TU502.3
在线出版日期：2024年7月4日
基金项目：干湿循环条件下复合改良膨胀土的工程特性及微观机理研究[
期刊论文]  材料导报--2024, 38(z1)蔡祎  欧明喜  陈颖辉  李强  史伟中为研究粉煤灰(高钙)复合木质素纤维改良云南蒙自膨胀土的工程特性和微观机理,开展改良土的胀缩特性试验,并且在干湿循环条件下进行复合改良土的力学特性试验,结合改良前后微观结构和物相变化分析得出改良机理.试验表明:...参考文献和引证文献
参考文献
引证文献
本文读者也读过
相似文献
相关博文

关键词：云南膨胀土,粉煤灰(高钙),木质素纤维,工程特性,微观结构,

2024-10-3 23:06 上传 干湿循环条件下复合改良膨胀土的工程特性及微观机理研究.pdf

文件大小:

22.14 MB

下载次数:

60

高速下载