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1、第34卷第1期防災(zāi)減災(zāi)工程學(xué)報(bào)Vo1.34No.12014年2月JournalofDisasterPreventionandMitigationEngineeringFeb.2O14地震作用下含軟弱夾層順層巖質(zhì)邊坡表面放大效應(yīng)研究馮志仁,劉紅帥,于龍(1.中國(guó)地震局地震工程與工程振動(dòng)重點(diǎn)實(shí)驗(yàn)室、中國(guó)地震局工程力學(xué)研究所,哈爾濱150080;2.黑龍江省水文地質(zhì)工程地質(zhì)勘察院,哈爾濱150040)摘要:為了研究地震作用下含軟弱夾層順層巖質(zhì)邊坡表面的放大效應(yīng),借用FLAC軟件,建立了含軟弱夾層順層巖質(zhì)邊坡動(dòng)力分析數(shù)值模型;在合理考慮地震動(dòng)輸入、邊界條件、網(wǎng)
2、格劃分與模型參數(shù)的基礎(chǔ)上,分析了地震動(dòng)峰值、頻率、持時(shí)以及初動(dòng)方向等因素影響下的邊坡表面放大效應(yīng)。研究結(jié)果表明:①地震動(dòng)峰值、頻率和初動(dòng)方向?qū)吰卤砻娣糯笮?yīng)的影響較顯著,而地震動(dòng)持時(shí)對(duì)邊坡表面放大效應(yīng)的影響微??;②隨著地震動(dòng)峰值的增加,放大效應(yīng)由軟弱夾層之上的坡面及坡頂面向坡肩點(diǎn)逐漸增大,坡肩點(diǎn)的放大效應(yīng)最大;③當(dāng)輸入地震動(dòng)頻率小于邊坡的自振頻率時(shí),邊坡表面加速度放大倍數(shù)較小,且頻率越小,放大倍數(shù)越小,當(dāng)輸入地震動(dòng)頻率大于邊坡的自振頻率時(shí),邊坡表面加速度放大倍數(shù)較大,且頻率越大,放大倍數(shù)亦越大。關(guān)鍵詞:軟弱夾層;巖質(zhì)邊坡;地震;加速度放大效應(yīng);數(shù)值模
3、擬中圖分類號(hào):P315文獻(xiàn)標(biāo)識(shí)碼:A文章編號(hào):1672-2132(2014)01—0096—05SurfaceAmplificationEffectofBeddingRockySlopewithWeakInterlayerunderEarthquakeFENGZhi—ren,LIUHong—shuai,YULong(1.KeyLaboratoryofEarthquakeEngineeringandEngineeringVibratoin;InstitueofEngineeringMechanics,ChinaEarthquakeAdministrati
4、on,Harbin150080,China;2.HydrogeologyandEngineeringGeologyProspectingInstituteofHeilongjiangProvince,Harbin150040,China)Abstract:Thispaperdealswiththesurfaceamplificationeffectofbeddingrockyslopewithweakinterlayerunderactionofearthquake.SoftwareFLAC00wasemployedtoestablishanumeri
5、calmodelwithconsiderationofearthquakeinput,boundarycondition,meshdivisonandmodelpa—rameters.Theeffectsofpeakvalue,frequency,durationandinitialdirectionofearthquakeonthesurfaceamplificationwereanalyzedanddiscussed.Theresultsshownthat,(1)thepeakval—ue,frequencyandinitialdirectiono
6、fearthquakegroundmotionplayasignificantroleinthesur—faceamplificationeffectofrockyslope,whilethedurationofearthquakeplayasmallrole.(2)Withincreaseofpeakvalueofgroundmotionandtheheightofslope。theamplificationfactorin—creased,especiallyinthetopcorner.(3)Whenthefrequencyofgroundmot
7、ionissmallerthanthenaturalvibrationfrequencyofslope,theamplificationfactorofsurfaceofslopedecrease.However,whenthefrequencyofearthquakeisgreaterthanthenaturalvibrationfrequencyofslope,theamplificationfactoriSgreaterandincreaseswithincreaseoffrequency.Keywords:weakinterlayer;rock
8、yslope;earthquake;accelerationamplificationeffe