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1、第32卷第1期2015年1月公路交通科技JournalofHighwayandTransportationResearchandDevelopmentVoL32No.1Jan.2015doi:10.3969/j.issn.1002-0268.2015.01.008滾石沖擊荷載下墊層材料的動(dòng)力響應(yīng)研究向波1,何思明2,(1.四川省交通運(yùn)輸廳公路規(guī)劃勘察設(shè)計(jì)研究院,四JII環(huán)境研究所,四Jl莊衛(wèi)林1,王東坡2成都610041;2.中國(guó)科學(xué)院水利部成都山地災(zāi)害與成都610041)摘要:棚洞墊層結(jié)構(gòu)能有效地耗散滾石沖擊能
2、量,大幅度降低滾石沖擊力,是滾石防護(hù)棚洞設(shè)計(jì)的關(guān)鍵參數(shù)。本文以Hertz接觸理論為基礎(chǔ),考慮棚洞土墊層的彈塑性特性,運(yùn)用動(dòng)力有限元數(shù)值仿真技術(shù),研究了滾石法向沖擊荷栽下耗能墊層結(jié)構(gòu),分析了滾石沖擊速度、半徑對(duì)墊層土體動(dòng)力響應(yīng)規(guī)律的影響,為棚洞墊層結(jié)構(gòu)優(yōu)化設(shè)計(jì)提供理論依據(jù)。計(jì)算結(jié)果表明:按照完全彈性理論計(jì)算過高地估計(jì)了滾石沖擊力;滾石沖擊能量主要轉(zhuǎn)化為土墊層的塑性變形;土石墊層結(jié)構(gòu)能有效地吸收滾石沖擊能量,大大降低滾石對(duì)棚洞結(jié)構(gòu)的沖擊力。關(guān)鍵詞:道路工程;動(dòng)力響應(yīng);數(shù)值模擬;滾石;法向沖擊;彈塑性;回彈中圖分類號(hào):
3、TU435文獻(xiàn)標(biāo)識(shí)碼:A文章編號(hào):1002—0268(2015)01—0045—05ResearchonDynamicResponseofCushionunderRockfallImpactXIANGB01,HESi—min92,ZHUANGWei.1inl,WANGDong.p02(1.HighwayPlanning,SurveyandDesignResearchInstitute,SiehuanProvincialTransportDepartment,ChengduSichuan610041,China;2
4、.InstituteofMountainHazardsandEnvironment,ChineseAcademyofSciences,ChengduSichuan610041,China)Abstract:’rhecushionofrockshedcaneffectivelydissipateimpactenergyandgreatlyreduceimpactforceofrockfall,whichisthekeyparameterforoptimaldesigningofrockfallprotection.
5、Consideringtheelastic-plasticpropertyofthecushionmaterials,basedontheHertzcontacttheoryandusingthedynamicfiniteelementnumericalsimulationtechnology,westudiedtheenergydissipationcushionstructuresunderrockfallnormalimpactload,thenweanalyzedtheeffectofimpactvelo
6、cityandradiusofrockfallondynamicalresponseofcushion,whichprovidesatheoreticalbasisforstructureoptimizationdesignofcushionofrockshed.f11lecalculationresultshowsthat(1)thevalueofimpactforcecalculatedbycompleteelastictheoryisoverestimated;(2)theimpactenergyismai
7、nlyconvertedtoplasticdeformationofsoilcushion;(3)thecushionstructureCaneffectivelyabsorbtheimpactenergyofrockfallandgreatlyreducetherockfallimpactloadontherockshed.Keywords:roadengineering;rockfall;normalimpact;elastic·plastic;restitution;dynamicresponse;nume
8、ricalsimulation0引言滾石是個(gè)別塊石因某種原因從地質(zhì)體表面失穩(wěn)后經(jīng)過下落、回彈、跳躍、滾動(dòng)或滑動(dòng)中的一種或幾種組合運(yùn)動(dòng)方式沿坡面快速下移,最后在平緩地帶或障礙物附近靜止下來的一個(gè)動(dòng)力演化過程。當(dāng)滾石運(yùn)動(dòng)范圍內(nèi)有人類活動(dòng)或構(gòu)筑設(shè)施并引起一定損失時(shí),就構(gòu)成滾石災(zāi)掣1
9、。我國(guó)西部山區(qū)起伏陡峻,地質(zhì)條件復(fù)雜,構(gòu)造運(yùn)動(dòng)強(qiáng)烈,氣候復(fù)雜多變,山體破碎,導(dǎo)致滾石災(zāi)害頻發(fā),對(duì)