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1、第36卷第7期巖土力學(xué)Vol.36No.72015年7月RockandSoilMechanicsJul.2015DOI:10.16285/j.rsm.2015.07.026移動(dòng)荷載作用下非均勻地基的動(dòng)力響應(yīng)分析1,211周鳳璽,曹永春,趙王剛(1.蘭州理工大學(xué)土木工程學(xué)院,甘肅蘭州730050;2.蘭州理工大學(xué)西部土木工程防災(zāi)減災(zāi)教育部工程研究中心,甘肅蘭州730050)摘要:基于線彈性動(dòng)力學(xué)理論,結(jié)合坐標(biāo)變換,建立了移動(dòng)荷載作用下非均勻彈性半平面地基的動(dòng)力控制方程,利用半解析法研究了移動(dòng)荷載作用下二維非均勻地基的動(dòng)力響應(yīng)問(wèn)題。采用傅里葉(Fourier
2、)級(jí)數(shù)展開(kāi),假設(shè)了響應(yīng)函數(shù)的級(jí)數(shù)形式,通過(guò)理論推導(dǎo)獲得了剪切模量隨深度任意變化的非均勻地基在移動(dòng)荷載作用下各物理量的解析表達(dá)式??紤]土體的剪切模量沿厚度方向按冪函數(shù)梯度變化,通過(guò)數(shù)值算例分析并討論了地基非均勻參數(shù)、荷載移動(dòng)速度以及地基表面的剪切模量等對(duì)地基力學(xué)響應(yīng)的影響規(guī)律,并與均質(zhì)地基的計(jì)算結(jié)果進(jìn)行了比較。數(shù)值結(jié)果表明:地基中各點(diǎn)的豎向位移隨著土體表面剪切模量和表征土體非均勻性的梯度因子的增大而減小,隨著荷載移動(dòng)速度的增大而增大。在移動(dòng)荷載作用下,非均勻地基與均勻地基的動(dòng)力響應(yīng)有著顯著的區(qū)別。關(guān)鍵詞:非均勻地基;移動(dòng)荷載;動(dòng)力響應(yīng);半解析法;傅里葉級(jí)數(shù)
3、中圖分類號(hào):TU435文獻(xiàn)標(biāo)識(shí)碼:A文章編號(hào):1000-7598(2015)07-2027-07Analysisofdynamicresponseofinhomogeneoussubgradeundermovingloads1,211ZHOUFeng-xi,CAOYong-chun,ZHAOWang-gang(1.SchoolofCivilEngineering,LanzhouUniversityofTechnology,Lanzhou,Gansu730050,China;2.WesternEngineeringResearchCenterofDisas
4、terMitigationinCivilEngineeringofMinistryofEducation,LanzhouUniversityofTechnology,Lanzhou,Gansu730050,China)Abstract:Basedonthetheoryoflinearelastodynamics,andcombinedwiththecoordinatetransformation,thedynamicgoverningequationsforahalf-planeinhomogeneoussubgradearedeveloped.Thed
5、ynamicresponseofatwo-dimensionalinhomogeneoussubgradesubjectedtomovingloadsisanalyzedbasedonasemi-analyticalmethod.UsingFourierseriesexpansion,andassumingtheseriesformofresponsefunction,theanalyticalexpressionsofvariousphysicalquantitiesaredevelopedfortheinhomogeneoussubgradesubj
6、ectedtomovingloads,inwhichtheshearmoduluscanarbitrarilychangewithdepth.Assumingtheshearmodulushasanexponentialdistributionwiththethickness,aparametricstudyispresentedtoillustratetheinfluenceofthefoundationsoilinhomogeneityandloadmovingvelocityaswellasshearmodulusatsubgradesurface
7、onthedynamicalresponseoffoundationsoils.Thecalculatedresultsarecomparedwiththeresponsesofahomogeneoussubgrade,showingthattheverticaldisplacementofsoildecreaseswiththeincreaseoftheshearmodulusatthesurfaceofsubgradeandtheinhomogeneousgradientindex,andincreaseswiththeincreaseofthelo
8、admovingvelocity.Underamovingload,thedyn