地震研究

地震作用下桩土的相互作用一直都是抗震研究中的热点问题。基于2×2直、斜群桩振动台试验,利用OpenSees有限元软件进行不同频率正弦波输入下直、斜群桩的动力响应对比分析。结果表明:在正弦波作用下、直、斜群桩承台位移与加速度均被放大; 随着输入正弦波频率的增大,承台位移与加速度放大倍数均表现出增长趋势,并且直群桩承台的放大倍数大于斜群桩; 对于正弦波输入下的非液化砂土和饱和砂土的直、斜群桩工况,振动过程中土样的液化速度与输入正弦波频率成正相关。通过OpenSees软件进行数值模拟的计算结果与振动台试验结果吻合较好,验证了液化土中直、斜群桩动力响应数值模型的正确性。

The interaction between pile and soil under seismic action has always been a hot topics in the seismic research of geotechnical engineering.Based on vibration Tab.test of 2×2 straight and inclined group piles,the OpenSees finite element software is used to compare and analyze the dynamic response of straight and inclined group piles under different frequency sine wave input in this paper.The results show that under the action of sine wave,the displacement and acceleration of the pile caps are amplified in both the straight and the inclined group piles.With the increase of the frequency of input sine wave,magnification times of the displacement and acceleration show an increasing trend,and the magnification times of the pile cap under the condition of straight group piles is greater than that of the inclined group piles.With the input of sine wave,the liquefaction velocity of soil samples is positively correlated with the frequency of input sinusoidal wave during the vibration process of straight and inclined group piles in nonliquefied sand and saturated sand.The result of numerical simulation by OpenSees is in good agreement with the result of shaking Tab.test,which verifies the correctness of the numerical model of dynamic response of straight and inclined group piles in liquefied soil.

引言
1 振动台试验
2 数值模拟
3 振动台试验与数值模拟动力响应对比分析
4 结论

图1 直、斜群桩试验传感器布置图及试验现场图<br/>Fig.1 Layout diagram of tests sensors for straight and inclined piles and photos of test sites

图1 直、斜群桩试验传感器布置图及试验现场图
Fig.1 Layout diagram of tests sensors for straight and inclined piles and photos of test sites

图2 三维有限元数值分析模型<br/>Fig.2 Schematic diagram of 3D finite element numerical analysis model

图2 三维有限元数值分析模型
Fig.2 Schematic diagram of 3D finite element numerical analysis model

表1 砂土本构模型计算参数<br/>Tab.1 Calculation parameters of sand constitutive model

表1 砂土本构模型计算参数
Tab.1 Calculation parameters of sand constitutive model

表2 桩模型参数<br/>Tab.2 Pile model parameters

表2 桩模型参数
Tab.2 Pile model parameters

图3 三维桩-土界面连接示意<br/>Fig.3 Schematic diagram of 3D pile-soil interface connection

图3 三维桩-土界面连接示意
Fig.3 Schematic diagram of 3D pile-soil interface connection

图4 1.5 Hz正弦波非液化砂土的试验与模拟加速度(a)及位移(b)时程曲线<br/>Fig.4 Comparison of time history curves of the acceleration(a)and displacement(b) of non-liquefied sand under 1.5 Hz sine wave in test and simulation

图4 1.5 Hz正弦波非液化砂土的试验与模拟加速度(a)及位移(b)时程曲线
Fig.4 Comparison of time history curves of the acceleration(a)and displacement(b) of non-liquefied sand under 1.5 Hz sine wave in test and simulation

表3 不同频率正弦波下非液化砂土中直、斜群桩动力响应对比<br/>Tab.3 Comparison of dynamic response of straight and inclined piles in non-liquefied sand under different frequency sine wave

表3 不同频率正弦波下非液化砂土中直、斜群桩动力响应对比
Tab.3 Comparison of dynamic response of straight and inclined piles in non-liquefied sand under different frequency sine wave

表4 不同频率正弦波下饱和砂土中直、斜群桩动力响应对比<br/>Tab.4 Comparison of dynamic response of straight and inclined piles in saturated sand under different frequency sine wave

表4 不同频率正弦波下饱和砂土中直、斜群桩动力响应对比
Tab.4 Comparison of dynamic response of straight and inclined piles in saturated sand under different frequency sine wave

图5 1.5 Hz正弦波饱和砂土的试验与模拟加速度(a)及位移(b)时程曲线<br/>Fig.5 Comparison of time history curves of the acceleration(a)and displacement(b) of saturated sand under 1.5 Hz sine wave in test and simulation

图5 1.5 Hz正弦波饱和砂土的试验与模拟加速度(a)及位移(b)时程曲线
Fig.5 Comparison of time history curves of the acceleration(a)and displacement(b) of saturated sand under 1.5 Hz sine wave in test and simulation

图6 1.5 Hz(a),3 Hz(b),6 Hz(c)正弦波输入下直群桩试验与模拟的孔压时程对比<br/>Fig.6 The time history of hole pressure is compared with that of simulated pile group test with 1.5 Hz(a),3 Hz(b),6 Hz(c)sinusoidal wave input

图6 1.5 Hz(a),3 Hz(b),6 Hz(c)正弦波输入下直群桩试验与模拟的孔压时程对比
Fig.6 The time history of hole pressure is compared with that of simulated pile group test with 1.5 Hz(a),3 Hz(b),6 Hz(c)sinusoidal wave input

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备注

引言

1 振动台试验

2 数值模拟

3 振动台试验与数值模拟动力响应对比分析

4 结论

期刊信息