饱和黏性土坡的地震稳定状态研究
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摘要
通过对无限边坡的拟静态平衡分析,探讨了动孔压对饱和黏性土无限边坡的地震稳定状态的影响.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,对某些黏性土也可因液化而发生流滑破坏.引入一个黏聚力界限值来区别此类边坡的最终破坏模式,以及两个界限动孔压比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, the effects of earthquake-induced pore water pressure on seismic stability conditions of saturated cohesive soil slopes are investigated with reference to the infinite slope scheme. In these slopes, the shear strength reduction caused by pore water pressure bulid-up may lead the slope to a permanent deformation, to a slide failure or to a flow failure for some cohesive soils because of liquefaction. A threshold value of the cohesion of soil is introduced to distinguish the eventual failure modes, and two threshold values of the earthquake induced pore pressure ratio are introduced to evaluate the effect of shear strength reduction on the slope failure mechanism. The results are given in the form of stability charts and a procedure for the evaluation of the seismic stability condition is described.
Based on the pseudo-static equilibrium of infinite slope, the effects of earthquake-induced pore water pressure on seismic stability conditions of saturated cohesive soil slopes are investigated with reference to the infinite slope scheme. In these slopes, the shear strength reduction caused by pore water pressure bulid-up may lead the slope to a permanent deformation, to a slide failure or to a flow failure for some cohesive soils because of liquefaction. A threshold value of the cohesion of soil is introduced to distinguish the eventual failure modes, and two threshold values of the earthquake induced pore pressure ratio are introduced to evaluate the effect of shear strength reduction on the slope failure mechanism. The results are given in the form of stability charts and a procedure for the evaluation of the seismic stability condition is described.
引文
[1]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.
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[3]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.
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[5]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.
[6]钱家欢,殷宗泽.土工原理与计算[M].第2版.北京:中国水利水电出版社,1996.
[2]BIONDI G,CASCONE E,Maugeri M,et al.Seismic re-sponse of saturated cohesionless slopes[J].Soil Dynamicand Earthquake Engineering,2000,20(2):209~215.
[3]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.
[4]SARMA S K.Seismic stability of earth dams and embank-ments[J].Geotechnique,1975,25(6):743~761.
[5]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.
[6]钱家欢,殷宗泽.土工原理与计算[M].第2版.北京:中国水利水电出版社,1996.
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