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采用以广义Biot固结原理和Pastor-Zienkiewicz Mark-Ⅲ广义塑性本构模型为基础的动力有限元分析方法,研究了U形碎石排水对液化土中地下管线上浮的减灾效果及机理.U形排水带由2个竖向1个横向排水层构成.通过参数分析,讨论了竖向排水带宽度、竖向排水带与管线的距离、水平排水带厚度、排水碎石渗透系数等因素对地震时管线上浮位移的影响.研究结果表明:采用基于广义塑性本构模型的动力有限元分析方法可以很好地模拟地震时地下管线发生的上浮现象;在管线周围设置U形排水带明显降低了管线的上浮位移;排水带渗透系数对管线上浮位移的影响较大;合理地设计排水带的几何尺寸和渗透系数可有效地控制管线的上浮位移.
The dynamic finite element analysis method based on the generalized Biot consolidation principle and the Pastor-Zienkiewicz Mark-Ⅲ generalized plastic constitutive model is used to study the effect and mechanism of U-shaped gravel drainage on the floating of underground pipeline in liquefied soil. The drainage strip consists of two vertical drainage layers, one horizontal drainage layer.According to the analysis of parameters, the factors such as the vertical drainage width, the distance between the vertical drainage and the pipeline, the horizontal drainage zone thickness and the drainage macroscopical permeability coefficient are discussed. The results show that the dynamic finite element method based on the generalized plastic constitutive model can well simulate the floating phenomenon of the underground pipeline during the earthquake and the U-shaped drainage channel around the pipeline can obviously reduce the pipeline’s Floating displacement; the permeability coefficient of drainage belt has a great influence on the floating displacement of the pipeline; the rational design of the geometric size and permeability coefficient of the drainage belt can effectively control the floating displacement of the pipeline.