边坡地震稳定性分析探讨
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摘要
传统的拟静力法和安全系数时程分析法在评价边坡地震稳定性时存在一定的局限性。在提出准确的评价边坡地震稳定性必需因素的基础上,建议对边坡地震稳定性分析方法重新进行分类。根据动力分析得到的边坡在地震作用下的破坏机制和破裂面的性质和位置,提出基于拉-剪破坏的动力时程分析法和强度折减动力分析法。第一种方法将FLAC计算得到破坏时刻的动应力施加到静力情况下边坡上,采用动力分析得到的拉-剪破裂面,结合极限平衡法求解边坡地震安全系数,是一种改进的动力有限元时程分析法;第二种方法考虑了拉-剪破坏的FLAC强度折减动力分析法,是完全动力的方法。最后通过算例分析验证了新方法的可行性,为边坡地震安全系数计算提供了一种新的思路。
There exist some limitations when evaluating the seismic stability of a slope by traditional pseudo-static method and time history analysis method for safety factor.Based on the necessary factors to evaluate the seismic stability of the slope accurately,the paper classifies the methods for analyzing the seismic stability of the slope.According to the failure mechanism and location and property of the fracture plane of the slope analyzed by the dynamic program FLAC,the paper presents the dynamic time history analysis method based on tensile-shear failure and the dynamic analysis method of strength reduction.The former is to impose the dynamic stress during the failure calculated by FLAC on the slope under static,then to work out the tensile and shear fracture plane and to calculate the safety factor of the slope by combining the limit equilibrium method.The latter considers the dynamic analysis method of FLAC strength reduction of tensile and shear failure.This method is a complete dynamic method.At last,the paper proves the feasibility of the new method by analyzing the calculation examples and provides a new idea for the calculation of safety factor of the slope.
There exist some limitations when evaluating the seismic stability of a slope by traditional pseudo-static method and time history analysis method for safety factor.Based on the necessary factors to evaluate the seismic stability of the slope accurately,the paper classifies the methods for analyzing the seismic stability of the slope.According to the failure mechanism and location and property of the fracture plane of the slope analyzed by the dynamic program FLAC,the paper presents the dynamic time history analysis method based on tensile-shear failure and the dynamic analysis method of strength reduction.The former is to impose the dynamic stress during the failure calculated by FLAC on the slope under static,then to work out the tensile and shear fracture plane and to calculate the safety factor of the slope by combining the limit equilibrium method.The latter considers the dynamic analysis method of FLAC strength reduction of tensile and shear failure.This method is a complete dynamic method.At last,the paper proves the feasibility of the new method by analyzing the calculation examples and provides a new idea for the calculation of safety factor of the slope.
引文
[1]刘红帅,薄景山,刘德东.岩土边坡地震稳定性分析研究评述[J].地震工程与工程振动,2005,25(1):164-171.
[2]GB50011-2001建筑抗震设计规范[S].
[3]Newmark N M.Effects of earthquakes on dams and embankments[J].Geotechnique,1965,15(2):139-160.
[4]刘汉龙,费康,高玉峰.边坡地震稳定性时程分析方法[J].岩土力学,2003,24(4):553-556.
[5]张伯艳,陈厚群,杜修力.拱坝坝肩抗震稳定分析[J].水利学报,2000(11):55-59.
[6]李育枢,高广运,李天斌.偏压隧道洞口边坡地震动力反应及稳定性分析[J].地下空间与工程学报,2006,2(5):738-743.
[7]唐洪祥,邵龙潭.地震动力作用下有限元土石坝边坡稳定性分析[J].岩石力学与工程学报,2004,23(8):1318-1324.
[8]李海波,肖克强,刘亚群.地震荷载作用下顺层岩质边坡安全系数分析[J].岩石力学与工程学报,2007,26(12):2385-2394.
[9]戴妙林,李同春.基于降强法数值计算的复杂岩质边坡动力稳定性安全评价[J].岩石力学与工程学报,2007,26(supp1):2749-2754.
[10]郑颖人,赵尚毅,张鲁渝.用有限元强度折减法进行边坡稳定分析[J].中国工程科学,2002,4(10):57-62.
[11]Zheng Yingren,Den Chujian,Tang Xiaosong,et al.Development of finite element limiting analysis method and its application in geotechnical engi-neering[J].Engineering Sciences,2007,3(5):10-36.
[12]赵尚毅,郑颖人,张玉芳.极限分析有限元法讲座Ⅱ有限元强度折减法中边坡失稳的判据探讨[J].岩土力学,2005,26(2):332-336.
[13]郑颖人,叶海林,黄润秋.地震边坡破坏机制及其破裂面的分析探讨[J].岩石力学与工程学报,2009,28(8):1714-1723.
[2]GB50011-2001建筑抗震设计规范[S].
[3]Newmark N M.Effects of earthquakes on dams and embankments[J].Geotechnique,1965,15(2):139-160.
[4]刘汉龙,费康,高玉峰.边坡地震稳定性时程分析方法[J].岩土力学,2003,24(4):553-556.
[5]张伯艳,陈厚群,杜修力.拱坝坝肩抗震稳定分析[J].水利学报,2000(11):55-59.
[6]李育枢,高广运,李天斌.偏压隧道洞口边坡地震动力反应及稳定性分析[J].地下空间与工程学报,2006,2(5):738-743.
[7]唐洪祥,邵龙潭.地震动力作用下有限元土石坝边坡稳定性分析[J].岩石力学与工程学报,2004,23(8):1318-1324.
[8]李海波,肖克强,刘亚群.地震荷载作用下顺层岩质边坡安全系数分析[J].岩石力学与工程学报,2007,26(12):2385-2394.
[9]戴妙林,李同春.基于降强法数值计算的复杂岩质边坡动力稳定性安全评价[J].岩石力学与工程学报,2007,26(supp1):2749-2754.
[10]郑颖人,赵尚毅,张鲁渝.用有限元强度折减法进行边坡稳定分析[J].中国工程科学,2002,4(10):57-62.
[11]Zheng Yingren,Den Chujian,Tang Xiaosong,et al.Development of finite element limiting analysis method and its application in geotechnical engi-neering[J].Engineering Sciences,2007,3(5):10-36.
[12]赵尚毅,郑颖人,张玉芳.极限分析有限元法讲座Ⅱ有限元强度折减法中边坡失稳的判据探讨[J].岩土力学,2005,26(2):332-336.
[13]郑颖人,叶海林,黄润秋.地震边坡破坏机制及其破裂面的分析探讨[J].岩石力学与工程学报,2009,28(8):1714-1723.
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