Study on Lateral Spreading of Gravel Piles Ground under Earthquake
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摘要: 基于OpenSees有限元软件建立液化场地-碎石桩动力相互作用模型和液化自由场地模型,将两类模型的场地孔隙水压力和侧向位移反应进行对比分析,揭示碎石桩加固液化场地机理及规律,并分析场地倾角和碎石桩渗透系数对碎石桩抵抗液化自由场地侧向位移的影响规律。研究结果表明,渗透性较高的碎石桩可加快孔隙水压力的消散,减弱场地液化程度,进而减小场地侧向位移;当场地倾角较大时,随着场地倾角的持续增大,碎石桩抵抗液化自由场地侧向位移的效果逐渐减弱;碎石桩渗透系数较小时,提高碎石桩渗透系数可显著减小液化场地侧向位移,当渗透系数增至一定程度时,碎石桩渗透系数对液化场地侧向位移的影响较小。Abstract: Based on the OpenSees Finite Element Software, a liquefied site-gravel pile dynamic interaction model and a liquefied free field model were established. The pore water pressure and lateral displacement responses of the two types of models were compared and analyzed to reveal the reinforcement mechanism and law of the gravel pile in the liquefied site. The effects of the site inclination and the gravel pile permeability coefficient on the resistance of the gravel pile to lateral displacement of the liquefied free field were also analyzed. The research results show that gravel piles with higher permeability can accelerate the dissipation of pore water pressure, reduce the degree of site liquefaction, and therefore decrease the lateral displacement of the site. When the site inclination is high, the effect of the gravel pile on resisting the lateral displacement of the liquefied free field gradually weakens with the continuous increase of the site inclination. When the permeability coefficient of the gravel pile is low, increasing the permeability coefficient of the gravel pile can significantly reduce the lateral displacement of the liquefied site. When the permeability coefficient reaches a certain level, the influence of the permeability coefficient of the gravel pile on the lateral displacement of the liquefied site becomes small.
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Key words:
- Liquefiable site /
- Gravel piles /
- Earthquake effects /
- Numerical simulation /
- Lateral displacement
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表 1 模型材料参数
Table 1. Model material parameters
参数 松砂 密砂 碎石桩 密度/(t·m−3) 1.7 2.0 2.14 参考剪切模量$ \text{/kPa} $ 60 000 110 000 128 000 参考体积模量$ \text{/kPa} $ 160 000 240 000 240 000 摩擦角ɸ/rad 31.0 35.0 43.3 八面体峰值应变 0.1 0.1 0.1 参考围压/kPa 101 101 101 压力系数 0.5 0.5 0.5 剪胀角ɸPT/rad 31.0 26.0 36.5 剪缩参数c1 0.087 0.028 0.028 剪缩参数c3 0.180 0.005 0.005 剪胀参数d1 0 0 0 剪胀参数d2 0.17 0.17 0.17 屈服面数 20 20 20 渗透系数/( m·s−1) 0.000 50 0.000 01 0.100 00 -
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