Bishop法的简化计算假设对边坡安全系数的影响
|
摘要
应用条分法计算边坡安全系数时,为方便运算,会对某些计算条件做出简化。本文以简化Bishop法作为安全系数求解方法,通过设计的比较方案,讨论了条块重心简化、地震力施加方式简化对安全系数的影响,还分析了竖向地震力施加方向的问题。研究结果表明:①条块重心简化对安全系数的影响极小,可以忽略;②地震力施加方式简化时,误差总体上随着边坡坡率变小、滑弧圆心角变大而逐渐减小,随着坡高变高、地震设计烈度变大而增大,粘聚力和内摩擦角的变化对误差基本不产生影响;③竖向地震力方向的选取主要与地震设计烈度相关,在同一地震烈度下,坡高改变了施加方向改变时的参数临界值。
It is common to simplify some calculation conditions when applying slice method to calculate the factor of safety of a slope.In this paper,the influences of the simplification of slice gravity center and seismic load imposition on the factor of safety are discussed by several design projects via the Bishop method.The applied direction of vertical seismic load is also considered.The results show that:(1)The influence of the simplification of slice gravity center on safety factor can be neglected.(2)When considering the simplification of the imposition of seismic load,the deviation generally decreases with slope ratio reducing and central angle increasing of the slip surface.On the contrary,the increase of the height of the slope and the design earthquake intensity has negative effects on the deviation.Besides,the variation of cohesion and internal frictional angle has little influence on deviation.(3)The selection of vertical seismic force direction mainly depends on designed seismic intensity.The slope height further affects the critical parameter values of direction changing at the same earthquake intensity level.
It is common to simplify some calculation conditions when applying slice method to calculate the factor of safety of a slope.In this paper,the influences of the simplification of slice gravity center and seismic load imposition on the factor of safety are discussed by several design projects via the Bishop method.The applied direction of vertical seismic load is also considered.The results show that:(1)The influence of the simplification of slice gravity center on safety factor can be neglected.(2)When considering the simplification of the imposition of seismic load,the deviation generally decreases with slope ratio reducing and central angle increasing of the slip surface.On the contrary,the increase of the height of the slope and the design earthquake intensity has negative effects on the deviation.Besides,the variation of cohesion and internal frictional angle has little influence on deviation.(3)The selection of vertical seismic force direction mainly depends on designed seismic intensity.The slope height further affects the critical parameter values of direction changing at the same earthquake intensity level.
引文
[1]陈祖煜.土质边坡稳定分析—原理、方法、程序[M].北京:中国水利水电出版社,2003.Chen Z Y.Soil Slope Stability Analysis—Theory、Methods and Programs[M].Beijing:China Water-Power Press,2003.
[2]Dancan J M.State of the art:limit equilibrium and fi-nite-element analysis of slopes[J].Journal ofGeotechnical Engineering,1996,122(7):577-596.
[3]SL203-97,水工建筑物抗震设计规范[S]
[4]SL386-2007,水利水电工程边坡设计规范[S]
[5]JTJ044-89,公路工程抗震设计规范[S]
[6]张鲁渝,郑颖人.扩展简化Bishop法的取距中心对安全系数的影响[J].岩土力学,2004,25(8):1239-1243.Zhang L Y,Zheng Y R.Effect of moment axis onsafety factors by extended simplified Bishop method[J].Rock and Soil Mechanics,2004,25(8):1239-1243.
[7]陈昌富,杨宇,龚晓南.基于遗传算法地震荷载作用下边坡稳定性分析水平条分法[J].岩石力学与工程学报,2003,22(11):1919-1923.Chen Ch F,Yang Y,Gong X N.Horizontal slicemethod of slope stability analysis under seismic loadbased on genetic algorithm[J].Chinese Journal ofRock Mechanics and Engineering,2003,22(11):1919-1923.
[8]沈振中,崔娟,任华春.土石坝抗震稳定性分析的极限平衡水平条分法[J].南水北调与水利科技,2011,9(3):145-149.Shen Zh Zh,Cui J,Ren H Ch.Quasi-static limit equi-librium horizontal slice method for seismic stabilityanalysis ofearth-rock dam[J].South-North Water Di-version and Water Science&Technology,2011,9(3):145-149.
[2]Dancan J M.State of the art:limit equilibrium and fi-nite-element analysis of slopes[J].Journal ofGeotechnical Engineering,1996,122(7):577-596.
[3]SL203-97,水工建筑物抗震设计规范[S]
[4]SL386-2007,水利水电工程边坡设计规范[S]
[5]JTJ044-89,公路工程抗震设计规范[S]
[6]张鲁渝,郑颖人.扩展简化Bishop法的取距中心对安全系数的影响[J].岩土力学,2004,25(8):1239-1243.Zhang L Y,Zheng Y R.Effect of moment axis onsafety factors by extended simplified Bishop method[J].Rock and Soil Mechanics,2004,25(8):1239-1243.
[7]陈昌富,杨宇,龚晓南.基于遗传算法地震荷载作用下边坡稳定性分析水平条分法[J].岩石力学与工程学报,2003,22(11):1919-1923.Chen Ch F,Yang Y,Gong X N.Horizontal slicemethod of slope stability analysis under seismic loadbased on genetic algorithm[J].Chinese Journal ofRock Mechanics and Engineering,2003,22(11):1919-1923.
[8]沈振中,崔娟,任华春.土石坝抗震稳定性分析的极限平衡水平条分法[J].南水北调与水利科技,2011,9(3):145-149.Shen Zh Zh,Cui J,Ren H Ch.Quasi-static limit equi-librium horizontal slice method for seismic stabilityanalysis ofearth-rock dam[J].South-North Water Di-version and Water Science&Technology,2011,9(3):145-149.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心