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ID:52172390
大小:1.98 MB
页数:7页
时间:2020-03-23
《冻融循环作用下宽级配砾质土的渗透特性.pdf》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、JournalofEngineeringGeology工程地质学报1004-9665/2015/23(3)049807DOI:10.13544/j.cnki.jeg.2015.03.018冻融循环作用下宽级配砾质土的渗透特性王红雨唐少容邢毓航张学科(宁夏大学土木与水利工程学院银川750021)摘要针对西北地区特殊的气候条件和砾质土料源丰富的实际情况,提出采用宽级配砾质土代替黏土作为土工合成材料膨润土垫(GCls)的保护层共同构成垃圾填埋场复合防渗系统的构想。文中选取宁夏银川地区冲-洪积作用形成的天然砾质土料,经人工掺和制配成满足规范对GCls防渗垫保护层渗透系数要求的宽级配砾质土样,在实
2、验室对该土样进行了冻融循环作用下的渗透性能试验研究。结果显示,随着冻融次数的逐渐增加,土样的冻胀率逐渐变大,渗透系数也相应增大,经过12次冻融循环后,渗透系数约增大1~2个数量级;冻融循环初期,冻融作用对土样的影响最为剧烈,随着冻融循环次数的增加以及时间的延续,土样性状逐渐趋于稳定。由于宽级配砾质土对冻融循环作用的敏感性小于粉质黏性土,故采用宽级配砾质土作为Cls/GM的保护层共同组成填埋场复合防渗系统是值得期待的。关键词宽级配砾质土冻融循环渗透试验复合防渗系统中图分类号:TU411文献标识码:AHYDRAULICCONDUCTIVITYOFCOMPACTEDWIDEGRADINGGRAVEL
3、SOILSUNDERFREEZETHAWCYCLINGWANGHongyuTANGShaorongXINGYuhangZHANGXueke(CollegeofCivilandHydraulicEngineering,NingxiaUniversity,Yinchuan750021)AbstractThedesignconceptionofcompositelinersisconsistedofageomembrane(GM),geosyntheticclayliners(GCls)andcompactedgravelsoilsinlandfills.Thisconceptionisprese
4、ntedonthebasisoftheclimatecharacteristics,gravelsoilsmaterialrichinnature,andGClsthathavebeenexportedallovertheworldforvariousapplications.TheartificiallygradedgravelsoilsaretakenfromnaturalsedimentzoneforfloodalluvialatYinchuansuburbinNingxia.Thegravelsoilisfiguredouttomeettherequirementofpermeabil
5、itycoefficientthroughthecompactionandpenetrationexperiment.Thefrostheavingratioandhydraulicconductivityofgravelsoilsamplesaretestedunderfreezethawcyclinginthispaper.Thetestresultsindicatethatthefrostheavingratioincreasesasthenumberoffreezethawincreases.Asthenumberoffreezethawincreases,thepermea
6、bilitycoefficientalsoincreases.Thepermeabilitycoefficientisincreasedbyonetotwoordersofmagnitudeafter12cyclesoffreezingthawing.Atthebeginningoffreezethawcycle,ithasaninfluenceonthesoilsamples.Theinfluencetendstoberelativelystablestateasthenumberoffreezethawcyclesincreases.Thesensitivityofgravelsoi
7、lsunderfreezethawcyclingislessthanthatofthesiltclay.ItisacceptabletoundertakethelandfillcompositelinerswhichwillbecomprisedofGCls/GMandcompactedgravelsoilstogether.KeywordsCompactedgravelsoils,Freeze
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