地震作用下可液化场地管道上浮动力响应及影响因素分析

地震作用下土体发生液化之后，由于超静孔隙水压力的产生和土体抗剪强度的降低，管道易发生上浮破坏。为研究管道上浮动力反应的影响因素，基于OpenSees有限元软件，通过目标反应谱和谱匹配等方法选取地震波，考虑不同管土特性和地震动特性，对地震作用下管道上浮动力反应进行了二维数值模拟。结果表明:土体相对密度、管径和管道埋深对管道上浮反应的影响较大，分别给出了土体相对密度、管径、管道埋深对管道上浮位移的影响规律及对应拟合公式；长持时地震动作用下，超静孔隙水压力消散较慢，管道上浮位移可达短持时地震动作用下管道上浮位移的2倍左右；近断层脉冲地震动作用下，管道上浮破坏和横向破坏两种破坏模式同时存在，且由于速度脉冲效应，管道横向破坏风险大于上浮破坏风险。

Influencing factors of seismic uplift response of buried pipelines in liquefiable soils

Pipelines buried in liquefiable sites would be damaged from uplift when subjected to earthquake due to excess pore water pressure generation and shear resistance reduction of soils. In order to investigate the influencing factors of the pipeline uplift responses，15 ground motion records are selected by matching the target response spectrum. Based on OpenSees platform，two-dimensional numerical simulations are carried out for dynamic response of pipelines under different soil and earthquake characteristics. The results indicate that the density ratio of soils，the diameter and buried depth of pipelines have a noticeable effect on the uplift response of pipelines. The influences of above factors are investigated with simple predictive models developed to evaluate the uplift displacement of pipelines. When subjected to a longer-duration ground motion，the excess pore pressure of liquefaction soils dissipates more slowly，and the mean uplift displacement of pipes is increased by up to 2 times. Under the excitation of the near-fault pulse-like ground motion，both the uplift and lateral deformations exist，yet the pipeline damage caused by the lateral deformation of soils is notably server that that caused by the uplift deformation.