可液化场地桥梁桩基改进m值法研究
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摘要
为了合理分析可液化场地桥梁桩基侧向承载力进行了改进m值法的研究。基于振动台试验和m值法,建立了桩-土相互作用体系有限元分析模型;引入反映可液化砂层侧向承载力衰减状态的孔压比指标值Ru;将不同时刻对应墩顶配重惯性力作为体系外部激励施加于墩顶;通过不断试算液化过程中砂土的m值,保证桩的弯矩计算值与试验值吻合较好。建立了考虑孔压比效应的砂土m值衰减因子p与Ru之间关系式。最后,推荐给出可液化场地桥梁桩基侧向承载性能分析的改进m值法。
A modified m-value method is studied,in order to reasonably analyze the lateral bearing capacity of bridge pile foundation in liquefiable ground.The FE analytical model of pile-soil interaction system is established based on shaking table test and the m-value method.The pore pressure ratio indicator is introduced to reflect the attenuation state of the lateral bearing capacity of liquefiable sand;and the inertial force,from the counter weights on the pier at different times,on the top of the pile as the external excitation is directly applied to pile-soil interaction system.The calculated pile bending moments are insured to be in good agreement with the recorded results through trying m-values of sand continualling during liquefaction.The relational expression between the attenuation factor p of m-value and the indicator is established.Finally,the modified m-value method is brought out and recommended to analyze the lateral bearing capacity of bridge pile foundation in liquefiable ground.
A modified m-value method is studied,in order to reasonably analyze the lateral bearing capacity of bridge pile foundation in liquefiable ground.The FE analytical model of pile-soil interaction system is established based on shaking table test and the m-value method.The pore pressure ratio indicator is introduced to reflect the attenuation state of the lateral bearing capacity of liquefiable sand;and the inertial force,from the counter weights on the pier at different times,on the top of the pile as the external excitation is directly applied to pile-soil interaction system.The calculated pile bending moments are insured to be in good agreement with the recorded results through trying m-values of sand continualling during liquefaction.The relational expression between the attenuation factor p of m-value and the indicator is established.Finally,the modified m-value method is brought out and recommended to analyze the lateral bearing capacity of bridge pile foundation in liquefiable ground.
引文
[1]Seed H B.Design problems in soil liquefaction[J].Journal of Geotechnical Engineering,1986,113(8):827-845.
[2]Finn W D L,Fujita N.Piles in liquefiable soils:seismic analysis and design issues[J].Soil Dynamics and Earthquake Engineering,2002,22:731-742.
[3]叶万灵,时蓓玲.桩的水平承载力实用非线性计算方法-NL法[J].岩土力学,2000,21(2):97-101.
[4]Taboada V.M,Dobry R.Centrifuge modeling of earthquake-induced lateral spreading in sand[J].Journal of Geotechnical and Geoenvironmental Engineering,1998,124(12):1195-1206.
[5]凌贤长,唐亮.液化场地桩基侧向响应分析中p-y曲线模型研究进展[J].力学进展,2010,40(3):250-262.
[6]李雨润,袁晓铭.液化场地上土体侧向变形对桩基影响研究评述[J].世界地震工程,2004,(2):17-22.
[7]王建华,冯士伦.液化土层中桩基水平承载特性分析[J].岩土力学,2005,26(10):1597-1601.
[2]Finn W D L,Fujita N.Piles in liquefiable soils:seismic analysis and design issues[J].Soil Dynamics and Earthquake Engineering,2002,22:731-742.
[3]叶万灵,时蓓玲.桩的水平承载力实用非线性计算方法-NL法[J].岩土力学,2000,21(2):97-101.
[4]Taboada V.M,Dobry R.Centrifuge modeling of earthquake-induced lateral spreading in sand[J].Journal of Geotechnical and Geoenvironmental Engineering,1998,124(12):1195-1206.
[5]凌贤长,唐亮.液化场地桩基侧向响应分析中p-y曲线模型研究进展[J].力学进展,2010,40(3):250-262.
[6]李雨润,袁晓铭.液化场地上土体侧向变形对桩基影响研究评述[J].世界地震工程,2004,(2):17-22.
[7]王建华,冯士伦.液化土层中桩基水平承载特性分析[J].岩土力学,2005,26(10):1597-1601.
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