海洋液化地基中输水管道变形特性的振动台试验研究  

SHAKING TABLE TESTS TO INVESTIGATE THE DEFORMATION CHARAC-TERISTICS OF WATER PIPELINES IN MARINE LIQUEFIED FOUNDATIONS

作　　者：陈育民[1] 陈润泽 张坤贤 张喆 CHEN Yumin;CHEN Runze;ZHANG Kunxian;ZHANG Zhe(Hohai University,Nanjing 210024,China)

机构地区：[1]河海大学,南京210024

出　　处：《工程地质学报》2021年第6期1869-1877,共9页Journal of Engineering Geology

基　　金：国家自然科学基金面上项目(资助号:51679072,51879090,52179101).

摘　　要：埋地管道应用广泛,而在管道铺设过程中穿越的大范围可液化土层,面临着地震作用下管道液化上浮和变形破坏等风险。依托某临海火电站直埋管道工程,采用室内振动台模型试验方法,分析了海洋液化地基中输水管道的变形特性和动力响应,探究了砾石压重法和排水板加固法的抗液化效果。结果表明:海洋饱和砂土地基在动力荷载作用下发生液化,不同深度土层加速度出现不同程度的衰减,上部土层加速度衰减幅度最大且沿深度减小;不同土层中土体超孔压先快速上升达到峰值并维持稳定直至振动停止;在振动过程中,管道发生了明显上浮,且上浮速率逐渐降低,当振动停止时达到最大上浮位移;砾石压重法对于管道抗液化效果不佳,加速度和超孔压时程曲线与标准工况基本一致,中上层砂土出现明显液化现象,但超孔压峰值存在一定下降,且管道上浮与标准工况相比下降65.4%;而宽、窄排水板加固法效果更加显著,整体土层液化现象得到抑制,超孔压峰值与标准工况相比较小,且在振动期间持续降低,平均峰值与标准工况相比分别下降48.30%和38.91%,同时管道竖向位移与标准工况相比降幅均超过100%。在实际工程应用中,推荐使用排水板加固方案,同时需要选择适当的排水通道宽度。Buried pipelines are widely used,and the extensive liquefiable soil layers will lead to the problem of pipeline uplift and deformation damage during earthquakes.Based on the buried pipeline project,we analyzed the deformation characteristics and dynamic response of pipes in marine liquefied foundations,and investigated the anti-liquefaction effect of gravel layers and drainage panels.The main conclusions are as follows:the marine saturated sand foundation liquefies under the dynamic load,and the acceleration decay decreases with increasing depth.The excess pore pressure in different depth rises rapidly to the peak and remains stable until the vibration stops.During the vibration,the pipe floats significantly and the floating rate decreases gradually.The gravel layer method is not effective in anti-liquefaction of the pipe,and the acceleration and excess pore pressure are basically consistent with the standard working condition.The effect of wide or narrow drainage panels method are more significant,and the liquefaction phenomenon of the overall soil layer is suppressed.The peak excess pore pressure is smaller compared with the standard working condition,and the average peak value is reduced by 48.30%and 38.91%,respectively,while the vertical displacement of the pipe decreases by more than 100%compared with the standard working condition.In practical engineering applications,it is recommended to use the drainage panels to reduce the risk of foundation liquefaction,while the appropriate drainage panels width needs to be selected.

关 键 词：海洋液化地基 输水管道 变形特性 振动台试验 抗液化措施 

分 类 号：P751[交通运输工程—港口、海岸及近海工程]