强震作用下土质边坡永久变形的简易评价方法和影响因素分析
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摘要
通过将地震作用下边坡动孔隙水压力与液化抵抗率的简便关系式代入基于Newmark法的边坡永久位移计算式中,建立考虑动孔隙水压力影响的边坡永久位移简便计算方法。此外,基于此简便计算方法和拟静力法研究边坡坡比、坡高、地下水位变化、地震强度和频谱特性对边坡永久位移和安全系数的影响规律。研究发现,地下水对地震作用下边坡永久位移和安全系数的影响显著,在进行边坡稳定性分析时,地下水的影响不容忽略。实际计算中不考虑竖向加速度影响时,计算的结果偏小,会过高的评估边坡的稳定性。边坡坡高对边坡永久位移和安全系数的影响比坡比的影响更为显著。远场地震(T1-II-1)对边坡的永久位移和安全系数的影响要大于近场地震(T2-II-1)。最后采用非线性回归拟合方法,得到考虑动孔隙水压力影响的边坡永久位移与安全系数的关系式,通过求解边坡的安全系数,能快速计算出边坡的永久位移,对边坡基于性能的抗震设计理念的实施具有重要的参考价值。
Pluging the relation between the pore water pressure and liquefaction resistance rate into calculation formula of the permanent displacement of slope based on Newmark method, a simple calculation method of the permanent displacement is established. The influence laws of slope ratio, height, underground water level, earthquake magnitude and seismic spectrum characteristics on permanent displacement and safety factor of the slope are studied. The results show that the influence of groundwater on permanent displacement and safety factor under earthquake is significant, which could not be neglected for the stability analysis of slope. If the vertical acceleration is not considered, the stability of slope will be overestimated. The influence of slope height on permanent displacement and safety factor is greater than the slope rate. The permanent displacement values under far field earthquakes(T1-II-1) are greater than that under near-field earthquake(T2-II-1). Finally using nonlinear regression fitting, the relation between the safety factor and permanent displacement considering the influence of groundwater are obtained. The permanent displacement of slope can be quickly solved by solving the safety factor and generating into the equation, which provides reference for the seismic design based on the performance.
Pluging the relation between the pore water pressure and liquefaction resistance rate into calculation formula of the permanent displacement of slope based on Newmark method, a simple calculation method of the permanent displacement is established. The influence laws of slope ratio, height, underground water level, earthquake magnitude and seismic spectrum characteristics on permanent displacement and safety factor of the slope are studied. The results show that the influence of groundwater on permanent displacement and safety factor under earthquake is significant, which could not be neglected for the stability analysis of slope. If the vertical acceleration is not considered, the stability of slope will be overestimated. The influence of slope height on permanent displacement and safety factor is greater than the slope rate. The permanent displacement values under far field earthquakes(T1-II-1) are greater than that under near-field earthquake(T2-II-1). Finally using nonlinear regression fitting, the relation between the safety factor and permanent displacement considering the influence of groundwater are obtained. The permanent displacement of slope can be quickly solved by solving the safety factor and generating into the equation, which provides reference for the seismic design based on the performance.
引文
[1]Newmark N M.Effects of earthquakes on dams and embankments[J].Geotechnique,1965,15(2):139-160
[2]Ausilio E,Conte E,Dente G.Seismic stability analysis of reinforced slopes[J].Soil Dynamics and Earthquake Engineering,2000,19(3):159-172
[3]Kim J M,Sitar N.Probabilistic evaluation of seismically induced permanent deformation of slopes[J].Soil Dynamics and Earthquake Engineering,2013,44:67-77
[4]Chang C J,Chen W F,Yao J T P.Seismic displacements in slopes by limit analysis[J].Journal of Geotechnical Engineering,1984,110(7):860-874
[5]林宇亮,杨果林.不同压实度路堤边坡的地震残余变形特性[J].中南大学学报:自然科学版,2012,43(9):3631–3637(Lin Yuliang,Yang Guolin.Seismic residual deformation behavior of embankment slopes of different compaction degrees[J].Journal of Central South University:Science and Technology,2012,43(9):3631–3637(in Chinese))
[6]董建华,朱彦鹏.地震作用下土钉支护边坡永久位移计算方法研究[J].工程力学,2011,28(10):101-103(Dong Jianhua,Zhu Yanpeng.Permanent displacement assessment of slope protected by soil nailing retaining wall under earthquake[J].Engineering Mechanics,2011,28(10):101-103(in Chinese))
[7]徐光兴,姚令侃,李朝红.地震作用下土质边坡永久位移分析的能量方法[J].四川大学学报:工程科学版,2010,42(5):286-291(Xu Guangxing,Yao Lingkan,Li Chaohong.Energy method for evaluating earthquake induced permanent displacement of soil slopes[J].Journal of Sichuan University:Engineering Science Edition,2010,42(5):286-291(in Chinese))
[8]日本道路協会.道路橋示方書·同解説[M].東京:日本道路協会:丸善(発売),1996(in Japanese))
[2]Ausilio E,Conte E,Dente G.Seismic stability analysis of reinforced slopes[J].Soil Dynamics and Earthquake Engineering,2000,19(3):159-172
[3]Kim J M,Sitar N.Probabilistic evaluation of seismically induced permanent deformation of slopes[J].Soil Dynamics and Earthquake Engineering,2013,44:67-77
[4]Chang C J,Chen W F,Yao J T P.Seismic displacements in slopes by limit analysis[J].Journal of Geotechnical Engineering,1984,110(7):860-874
[5]林宇亮,杨果林.不同压实度路堤边坡的地震残余变形特性[J].中南大学学报:自然科学版,2012,43(9):3631–3637(Lin Yuliang,Yang Guolin.Seismic residual deformation behavior of embankment slopes of different compaction degrees[J].Journal of Central South University:Science and Technology,2012,43(9):3631–3637(in Chinese))
[6]董建华,朱彦鹏.地震作用下土钉支护边坡永久位移计算方法研究[J].工程力学,2011,28(10):101-103(Dong Jianhua,Zhu Yanpeng.Permanent displacement assessment of slope protected by soil nailing retaining wall under earthquake[J].Engineering Mechanics,2011,28(10):101-103(in Chinese))
[7]徐光兴,姚令侃,李朝红.地震作用下土质边坡永久位移分析的能量方法[J].四川大学学报:工程科学版,2010,42(5):286-291(Xu Guangxing,Yao Lingkan,Li Chaohong.Energy method for evaluating earthquake induced permanent displacement of soil slopes[J].Journal of Sichuan University:Engineering Science Edition,2010,42(5):286-291(in Chinese))
[8]日本道路協会.道路橋示方書·同解説[M].東京:日本道路協会:丸善(発売),1996(in Japanese))
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