饱和黄土边坡的动力失稳机制研究
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摘要
通过对无限边坡的拟静态平衡分析和考虑饱和黄土在地震作用下动孔隙水压的增长规律,探讨了动孔隙水压对饱和黄土无限边坡地震期间和震后稳定状态的影响。分析表明,地震时孔隙水压累积导致的抗剪强度衰减会导致边坡发生永久变形,甚至导致整体滑动破坏或因黄土液化而发生流滑破坏。引入一个粘聚力界限值来区别黄土边坡的最终破坏模式,以及动孔压比的两个界限值来评价抗剪强度衰减对其破坏机制的影响。最后给出了此类边坡稳定状态的判别图,并建议了分析步骤。
Based on the pseudo-static equilibrium of infinite slope and the earthquake-induced pore water pressure of saturated loess,the effects of earthquake-induced pore water pressure on seismic and post seismic stability of saturated loess slopes were investigated.In loess slopes the shear strength reduction caused by pore water pressure might lead the slope to a permanent deformation,to a slide failure or to a flow failure if liquefaction condition were approached.A threshold value of the cohesion of loess was introduced to distinguish the eventual failure modes,and two threshold values of the earthquake induced pore pressure ratio were given to evaluate the effect of shear strength reduction on the slope failure mechanism.The results were presented in the form of stability charts and a procedure for the evaluation of the seismic stability condition was described.
Based on the pseudo-static equilibrium of infinite slope and the earthquake-induced pore water pressure of saturated loess,the effects of earthquake-induced pore water pressure on seismic and post seismic stability of saturated loess slopes were investigated.In loess slopes the shear strength reduction caused by pore water pressure might lead the slope to a permanent deformation,to a slide failure or to a flow failure if liquefaction condition were approached.A threshold value of the cohesion of loess was introduced to distinguish the eventual failure modes,and two threshold values of the earthquake induced pore pressure ratio were given to evaluate the effect of shear strength reduction on the slope failure mechanism.The results were presented in the form of stability charts and a procedure for the evaluation of the seismic stability condition was described.
引文
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[2]黄建梁,王威中,薛宏交.坡体地震稳定性的动态分析[J].地震工程与工程振动,1997,17(4):113–122.
[3]Sarma SK.Seismic stability of earth dams and embankments[J].Geotechnique,1975,25:743–761.
[4]刘忠玉,魏建东.饱和黄土边坡的动力稳定性分析[J].岩土力学,2005,26(2):198–202.
[5]刘公社,巫志辉.动荷载下饱和黄土的孔压演化规律及其在地基动力分析中的应用[J].工业建筑,1994,(3):40–44.
[6]王兰民,刘红玫,李兰,等.饱和黄土液化机理与特性的试验研究[J].岩土工程学报,2000,22(1):89–94.
[7]佘跃心,刘汉龙,高玉峰.饱和黄土孔压增长模式与液化机理试验研究[J].岩土力学,2002,23(4):395–399.
[8]刘汉龙,佘跃心,王兰民.强夯黄土地基液化试验研究[A].土动力学与岩土地震工程[C].刘汉龙.北京:中国建筑工业出版社,2002:218–223.
[9]杨振茂,赵成刚王兰民,等.饱和黄土的液化特性与稳态强度[J].岩石力学与工程学报,2004,23(22):3853–3860.
[10]钱家欢,殷宗泽.土工原理与计算(第二版)[M].北京:中国水利水电出版社,1996.
[2]黄建梁,王威中,薛宏交.坡体地震稳定性的动态分析[J].地震工程与工程振动,1997,17(4):113–122.
[3]Sarma SK.Seismic stability of earth dams and embankments[J].Geotechnique,1975,25:743–761.
[4]刘忠玉,魏建东.饱和黄土边坡的动力稳定性分析[J].岩土力学,2005,26(2):198–202.
[5]刘公社,巫志辉.动荷载下饱和黄土的孔压演化规律及其在地基动力分析中的应用[J].工业建筑,1994,(3):40–44.
[6]王兰民,刘红玫,李兰,等.饱和黄土液化机理与特性的试验研究[J].岩土工程学报,2000,22(1):89–94.
[7]佘跃心,刘汉龙,高玉峰.饱和黄土孔压增长模式与液化机理试验研究[J].岩土力学,2002,23(4):395–399.
[8]刘汉龙,佘跃心,王兰民.强夯黄土地基液化试验研究[A].土动力学与岩土地震工程[C].刘汉龙.北京:中国建筑工业出版社,2002:218–223.
[9]杨振茂,赵成刚王兰民,等.饱和黄土的液化特性与稳态强度[J].岩石力学与工程学报,2004,23(22):3853–3860.
[10]钱家欢,殷宗泽.土工原理与计算(第二版)[M].北京:中国水利水电出版社,1996.
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