考虑交叉管线影响的城市供水管网地震响应分析及震害评估

Seismic response analysis and damage assessment of urban water supply networks considering influences of crossing pipelines

以北京市某地区埋地供水管网为实例,通过直线型和交叉型典型管道二维有限元模型,系统分析了管道规格、接口形式、场地条件、地震动强度等级和地震动入射角等关键参数对管道接口轴向和转角变形的影响,得到了不同设防烈度地震动作用下该供水管网的损伤情况。基于国内外管道接口试验数据统计分析结果,确定了基于接口变形量的管道损伤判定准则,并用于不同管道接口类型地震损伤评价,建立了不同场地条件下典型管道接口地震损伤数据库。根据管道属性、场地信息和管道接口地震损伤数据库,基于GIS软件绘制管网地震损伤分布图。结果表明:相同烈度地震作用下,管线交叉处接口峰值变形量约为直管线接口的1.5倍~2.0倍,其中与法兰接口邻接的承插式接口存在峰值变形突变。罕遇烈度地震动作用下的管网地震损伤程度远高于设防烈度,且破坏多集中于Ⅳ类场地和管线交叉处。

Based on a buried water supply network in Beijing,the two-dimensional finite element models for the network are developed in this study.The influences of the critical parameters,such as the pipe diameter,joint type,site condition,intensity level of ground motion and incident angle of seismic wave,on the axial and bending deformations of pipe joints are systematically investigated,and the seismic damage status of the water supply network under different intensity levels of earthquakes is evaluated.Moreover,the criteria for damage assessment of the pipelines based on joint deformation are developed through the statistical analysis of the test results of the worldwide pipeline joints.These criteria are subsequently used for the seismic damage assessment of different types of pipeline joints.A seismic damage database of typical pipeline joints buried in different engineering sites is established.Finally,according to the pipeline properties,engineering site conditions and seismic damage database of typical pipeline joints,the seismic damage distribution maps of water supply networks are developed using the GIS.It is found that the peak deformations of the joints at the pipeline cross junctions are about 1.5 to 2.0 times those of the joints in a straight pipeline under the same intensity of earthquake ground motions.Besides,sudden changes of the peak seismic deformations occur at the push-on joints adjacent to the flange joints.The pipeline network suffers much more severe seismic damage under the considered maximum earthquake than under the design level of earthquake.The seismic damage mainly concentrates in the site classⅣand the cross junction of the pipelines.