考虑地震效应的阻滑桩加固土坡简化分析方法
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摘要
利用拟静力概念,将塑性极限分析运动学定理与抗剪强度折减技术相结合,建立地震条件下土坡的极限平衡状态方程,以此确定土坡的屈服加速度系数与临界安全系数及相应的潜在破坏模式;进而对于在给定的荷载条件下不能满足抗震稳定性要求的土坡,考虑采用阻滑桩加固方式,根据桩侧有效土压力的合理分布模式导出极限平衡状态时桩侧抗力的解析式,以此进行土坡加固中阻滑桩的简化设计.通过一定的变动参数计算与对比分析,探讨了水平地震加速度系数对阻滑桩侧向极限抗力与最优加固位置的影响.研究表明:考虑地震效应的阻滑桩最优加固位置处于边坡坡脚处,因为较小的加固力就能使边坡达到设计的安全系数值;地震加速度系数对阻滑桩所需提供的加固力有明显影响,且地震加速度系数越高则影响越显著.
Based on the kinematic method of limit analysis and the reduction technique of shear strength,the equation for expressing the critical limit-equilibrium state of slope subjected to earthquake loads is formulated and is employed to define the yield acceleration factor,the overall safety factor and the corresponding critical failure mechanism for a slope within the framework of the pseudo-static approach.For the slope with stabilizing piles,the analytical expression is also derived and the stabilizing force supplied by piles is solved by mathematical optimization technique,which will be used in the structural design of pile.Several results are presented in order to illustrate the influence of seismic forces on the stabilizing force and the optimum location of pile placement.The research shows that the optimal location of the stabilizing piles against landslide in various earthquake acceleration coefficient cases examined is near the toe of the slope,where the force provided by the piles to achieve the design safety factor takes the lowest value.It also shows the effect of earthquake acceleration coefficient on dimensionless stabilizing force is remarkable,especially under high earthquake acceleration coefficients.
Based on the kinematic method of limit analysis and the reduction technique of shear strength,the equation for expressing the critical limit-equilibrium state of slope subjected to earthquake loads is formulated and is employed to define the yield acceleration factor,the overall safety factor and the corresponding critical failure mechanism for a slope within the framework of the pseudo-static approach.For the slope with stabilizing piles,the analytical expression is also derived and the stabilizing force supplied by piles is solved by mathematical optimization technique,which will be used in the structural design of pile.Several results are presented in order to illustrate the influence of seismic forces on the stabilizing force and the optimum location of pile placement.The research shows that the optimal location of the stabilizing piles against landslide in various earthquake acceleration coefficient cases examined is near the toe of the slope,where the force provided by the piles to achieve the design safety factor takes the lowest value.It also shows the effect of earthquake acceleration coefficient on dimensionless stabilizing force is remarkable,especially under high earthquake acceleration coefficients.
引文
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[8]CHEN J,YIN J H,LEE C F.Upper bound limitanalysis of slope stability using rigid finite elementsand nonlinear programming[J].Can Geotech J,2003,40(8):742-752
[9]CHEN W F.Limit Analysis and Soil Plasticity[M].Amsterdam:Elsevier Science,1975
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[11]年廷凯,栾茂田,杨庆.考虑各向异性效应的阻滑桩加固土坡稳定性[J].大连理工大学学报,2005,45(6):858-865(NIAN Ting-kai,LUAN Mao-tian,YANG Qing.Stability analysis of soil slopes stabilized by pilesconsidering effect of soil anisotropy usingupper-bound method of limit analysis[J].J DalianUniv Technol,2005,45(6):858-865)
[12]唐焕文,秦学志.实用最优化方法[M].大连:大连理工大学出版社,2000
[13]AUSILIO E,CONTE E,DENTE G.Stabilityanalysis of slopes reinforced with piles[J].Comput and Geotech,2001,28(5):591-611
[14]HASSIOTIS S,CHAMEAU J L,GUNARATNEM.Design method for stabilization of slopes withpiles[J].J Geotech and Geoenviron Eng,ASCE,1997,123(4):314-323
[15]铁道部第二勘测设计院.抗滑桩设计与计算[M].北京:中国铁道出版社,1983:1-37.
[2]CHANG C J,CHEN W F,JAMES T P.Seismicdisplacements in slopes by limit analysis[J].JGeotech Eng,ASCE,1984,110(7):860-875
[3]江见鲸,宋昆仑,傅德炫.土建工程实用计算程序选编[M].北京:地震出版社,1992
[4]殷跃平.长江三峡工程库区滑坡防治工程设计与施工技术规程[M].北京:地质出版社,2001
[5]潘家铮.建筑物的抗滑稳定和滑坡分析[M].北京:水利出版社,1980
[6]SARMA S K.Stability analysis of embankments andslopes[J].Geotechnique,1973,23(3):423-433
[7]栾茂田,金崇磐,林皋.非均布地震荷载作用下土坡的稳定性[J].水利学报,1990(1):65-72
[8]CHEN J,YIN J H,LEE C F.Upper bound limitanalysis of slope stability using rigid finite elementsand nonlinear programming[J].Can Geotech J,2003,40(8):742-752
[9]CHEN W F.Limit Analysis and Soil Plasticity[M].Amsterdam:Elsevier Science,1975
[10]GRIFFITHS D V,LANE P A.Slope stabilityanalysis by finite elements[J].Geotechnique,1999,49(3):387-403
[11]年廷凯,栾茂田,杨庆.考虑各向异性效应的阻滑桩加固土坡稳定性[J].大连理工大学学报,2005,45(6):858-865(NIAN Ting-kai,LUAN Mao-tian,YANG Qing.Stability analysis of soil slopes stabilized by pilesconsidering effect of soil anisotropy usingupper-bound method of limit analysis[J].J DalianUniv Technol,2005,45(6):858-865)
[12]唐焕文,秦学志.实用最优化方法[M].大连:大连理工大学出版社,2000
[13]AUSILIO E,CONTE E,DENTE G.Stabilityanalysis of slopes reinforced with piles[J].Comput and Geotech,2001,28(5):591-611
[14]HASSIOTIS S,CHAMEAU J L,GUNARATNEM.Design method for stabilization of slopes withpiles[J].J Geotech and Geoenviron Eng,ASCE,1997,123(4):314-323
[15]铁道部第二勘测设计院.抗滑桩设计与计算[M].北京:中国铁道出版社,1983:1-37.
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