饱和砂土地基上边坡地震动力离心模型试验研究
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摘要
地震液化导致地基土体强度丧失往往对土工建筑物安全造成严重威胁。为借助动力离心模型试验研究地震液化对边坡稳定性的影响,该文采用粘度50 cs的硅油作为孔隙流体,通过二步抽真空法制作具有饱和地基的边坡模型,利用不规则任意波作为地震输入进行动力离心模型试验,研究了饱和地基边坡的动力响应、动孔压变化以及坡底液化和滑坡等规律。试验表明:地震中超静孔压有明显增长,地震结束后超静孔压逐渐消散;边坡不同位置超静孔压比明显不同;饱和地基部分液化导致边坡刚度减小和土体阻尼增大从而使边坡土体的加速度明显减小。
The effect of liquefaction on the global dynamic stability of a soil slope needs to properly evaluate in the liquefiable soil zone.A experimental system was developed with the subgrade of a slope saturated using silicon oil which has 50 times the viscosity of water in a rectangular rigid container with de-airing.Then,the dynamic centrifuge tests were performed to investigate the seismic behavior of the slope with the excess pore pressures at typical positions measured during the excitation of an irregular input earthquake motion.Analysis of the liquefaction of the saturated subgrade and its effect on the slope behavior revealed that the characteristic distribution of the slope response acceleration developed during the process of the accumulation and dissipation of the excess pore pressure.The subgrade liquefaction reduces the slope stiffness and the acceleration of the upper slope.
The effect of liquefaction on the global dynamic stability of a soil slope needs to properly evaluate in the liquefiable soil zone.A experimental system was developed with the subgrade of a slope saturated using silicon oil which has 50 times the viscosity of water in a rectangular rigid container with de-airing.Then,the dynamic centrifuge tests were performed to investigate the seismic behavior of the slope with the excess pore pressures at typical positions measured during the excitation of an irregular input earthquake motion.Analysis of the liquefaction of the saturated subgrade and its effect on the slope behavior revealed that the characteristic distribution of the slope response acceleration developed during the process of the accumulation and dissipation of the excess pore pressure.The subgrade liquefaction reduces the slope stiffness and the acceleration of the upper slope.
引文
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[2]Hayashi H,Nishikawa J,Taniguchi K.Seismic behavior ofroad embankment[C]//Centrifuge 98.Rotterdam,1998:243-248.
[3]Lee F H,Schofield A N.Centrifuge modeling of sandembankments and islands in earthquakes[J].Geotechnique,1988,38(1):45-58.
[4]Zeng X,Arulanandan K.Modeling lateral sliding of slopedue to liquefaction of sand layer[J].Journal of GeotechnicalEngineering,1995,121(11):814-816.
[5]王年香,章为民.混凝土面板堆石坝动态离心模型试验研究[J].岩土工程学报,2003,25(4):504-507.WANG Nianxiang,ZHANG Weimin.Dynamic centrifugemodel test for concrete face rock fill dam[J].ChineseJournal of Geotechnical Engineering,2003,25(4):504-507.(in Chinese)
[6]Madabhushi S P G,Haigh S K,Subedi B R.Seismicbehavior of steep slopes[C]//Balkema,ed.Proc PhysicalModeling in Geotechnics-ICPMG’02.Rotterdam,2002:489-494.
[7]于玉贞,邓丽军,李荣建.砂土边坡地震动力响应离心模型试验[J].清华大学学报(自然科学版),2007,47(6):789-792.YU Yuzhen,DENG Lijun,LI Rongjian.Centrifugemodeling test of the seismic response behavior of a sand slope[J].J Tsinghua Univ(Sci&Tech),2007,47(6):789-792.(in Chinese)
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