文档摘要：北疆供水一期工程渠基膨胀土受环境影响力学特性衰减严重并导致渠坡发生滑动破坏现象,采用粉土质砂对膨胀土进行换填处理,运行一定年限后渠坡仍发生滑动破坏.为深入分析渠坡破坏机理,采用静压、吸水、饱和-脱水三种制样方法模拟换填渠道完建期、通水期、停水期粉土质砂换填料力学状态,通过开展直剪、压缩、电镜扫描试验,从宏-微观角度分析其力学特性规律及物理机制.研究结果表明:(1)宏观力学试验:不同制样方法试样随着含水率增加,c、φ、Es值整体呈现下降趋势,压缩指数呈上升趋势,回弹指数呈波动变化.随着含水率增加,吸水试样c、φ、Es值始终小于另外两种制样方法试样,静压与饱和-脱水试样c、φ、Es值之间的关系以最优含水率(ω=12.2％)为界限存在明显差异,当ω≤12.2％时,饱和-脱水试样c、φ、Es值高于静压试样;当ω＞12.2％时,静压与饱和-脱水试样c、φ、Es值无明显差异.(2)微观物理机制:受结合水膜、易溶盐、黏土矿物等因素的影响,粉土质砂经历吸水/饱和-脱水后孔径会发生扩张/收缩,相较于静压试样,吸水/饱和-脱水试样中、大孔隙占比增加/减少,小孔隙占比减少/增加,宏观上表现为c、φ、Es减小/增加,其中当ω＞12.2％时饱和-脱水试样只是微孔隙发生变化,因此宏观上与静压试样强度指标无明显差异.由此表明经历吸水或饱和-脱水后粉土质砂换填料孔隙结构变化复杂,强度不稳定,是渠坡发生滑动破坏的一个重要诱因.(3)函数关系预测:通过建立静压与吸水、饱和-脱水试样强度指标之间的函数关系,预测换填渠道不同时期粉土质砂力学指标大小及规律,得出静压试样与吸水、饱和-脱水试样c、Es值呈指数相关,中值呈线性相关;采用粉砂土对静压与饱和-脱水试样c、φ值间的关系进行验证,发现其函数形式与粉土质砂一致,表明这可能是砂土共有的性质.研究结果可为北疆供水一期工程粉土质砂换填渠道的安全运行提供参考.
Abstract：TheexpansivesoilofthecanalfoundationofthefirstphaseofthewatersupplyprojectinnorthernXinjiangisseriouslyattenuatedbytheenvironmentalinfluenceandleadstotheslidingdamageofthecanalslope.Inordertodeeplyanalyzethefailuremechanismofthecanalslope,threesamplepreparationmethodsofstaticpressure,waterabsorptionandsaturation-dehydrationwereusedtosimulatethemechanicalstateofsiltysandreplacementandfillerreplacementinthecompletionperiod,waterpassageperiodandwatershutdownperiodofthereplacementchannel,andthemechanicalpropertiesandphysicalmechanismofthechannelwereanalyzedfromthemacroandmicroperspectivesbycarryingoutdirectshear,compressionandelectronmicroscopescanningtests.Theresultsshowthat:(1)macroscopicmechanicaltest:withtheincreaseofmoisturecontent,thec,φandEsvaluesofthesampleswithdifferentsamplepreparationmethodsshowadownwardtrend,thecompressionindexshowsanupwardtrend,andthereboundindexfluctuates.Withtheincreaseofwatercontent,thevaluesofc,φandEsofthewaterabsorptionsamplesarealwayssmallerthanthoseoftheothertwosamplepreparationmethods,andtherelationshipbetweenthestaticpressureandthec,φandEsvaluesofthesaturated-dehydratedsamplesissignificantlydifferentwiththeoptimalmoisturecontent(ω=12.2％),andwhentheω≤12.2％,thec,φandEsvaluesofthesaturated-dehydratedsamplesarehigherthanthoseofthestaticpressuresamples.Whenω＞12.2％,therewasnosignificantdifferenceinthec,φandEsvaluesofthesamplesofthetwosamplepreparationmethods.(2)Microscopicphysicalmechanism:undertheinfluenceofboundwaterfilm,solublesalt,claymineralsandotherfactors,theporesizeofsiltysandwillexpand/shrinkafterwaterabsorption/saturation-dehydration.Comparedwiththestaticpressuresample,theproportionofmediumandlargeporesinthewaterabsorption/saturation-dehydrationsampleincreases/decreases,andtheproportionofsmallporesdecreases/increases.Macroscopically,c,φandEsdecrease/increase.Whenω＞12.2％,thesaturated-dehydratedsampleonlychangesthemicropores,sothereisnosignificantdifferenceinthestrengthindexbetweenthestaticpressuresampleandthesaturated-dehydratedsample.Thisindicatesthatthechangeofporestructureofsiltysandafterwaterabsorptionorsaturation-dehydrationiscomplexandthestrengthisunstable,whichisanimportantcauseofslidingfailureofcanalslope.(3)Predictionoffunctionalrelationship:Byestablishingthefunctionalrelationshipbetweenthestrengthindexofthesamplebythehydrostaticpressuremethodandtheothertwosamplepreparationmethods,thesizeandlawofthemechanicalindexofsiltysandindifferentperiodsofthereplacementchannelwerepredicted,anditwasconcludedthatthevaluescandEsvaluesofthestaticpressuresampleswereexponentiallycorrelatedwiththesamplesofwaterabsorptionandsaturation-dehydration,andtheφvalueswerelinearlycorrelated.Therelationshipbetweenstaticpressureandsaturation-dehydratedsamplescandφvalueswasverifiedbysiltysand,anditwasfoundthatitsfunctionalformwasconsistentwiththatofsiltysand,indicatingthatthismaybeacommonpropertyofsand.TheresearchresultscanprovideareferenceforthesafeoperationofthesiltysandreplacementchannelofthefirstphaseofthewatersupplyprojectinnorthernXinjiang.
作者：杨振杰 张凌凯Author：YANGZhenjie ZHANGLingkai
作者单位：新疆农业大学水利与土木工程学院,乌鲁木齐830052;新疆水利工程安全与水灾害防治重点实验室,乌鲁木齐830052
刊名：材料导报 ISTICEIPKU
Journal：MaterialsReports
年，卷(期)：2024, 38(z1)
分类号：TU411
关键词：粉土质砂 制样方法 含水率 力学特性 物理机制
Keywords：siltysand samplepreparationmethod watercontent mechanicalproperty physicalmechanism
机标分类号：TU4P642.21U416.1
在线出版日期：2024年7月4日
基金项目：不同制样方法条件下粉土质砂力学特性的试验研究[
期刊论文] 材料导报--2024, 38(z1)杨振杰 张凌凯北疆供水一期工程渠基膨胀土受环境影响力学特性衰减严重并导致渠坡发生滑动破坏现象,采用粉土质砂对膨胀土进行换填处理,运行一定年限后渠坡仍发生滑动破坏.为深入分析渠坡破坏机理,采用静压、吸水、饱和-脱水三种制样方...参考文献和引证文献
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关键词：粉土质砂,制样方法,含水率,力学特性,物理机制,
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