沿山脊走向长输油气管道强震动力响应特征

沿山脊走向的长输油气管道在我国西部山区常有分布，强震作用下其动力响应直接关系到管道的安全运营，实际管道工程建设中亟需相关研究结果提供指导。依托云南玉溪龙马槽村段此类输油管道工程，考虑山坡的工程地质特征，对管道与坡体进行整体三维数值建模，采用有限差分方法FLAC3D进行数值模拟，基于汶川地震波，计算得到了水平地震加速度峰值、震后等典型时刻的管道位移、轴力、剪力和弯矩及坡体稳定性等地震动力响应特征。结果表明，管道内力最大值出现于震后时刻，地震作用使管道轴力达到较高水平，而剪力与弯矩值的量级仅占最大轴力的约1%；竖向地震波对管道内力影响较小，管道受力的不利部位出现在其与断层交界附近。地震过程中管道水平方向存在较多的弹性变形，竖向则存在较多的塑性变形，管道累计变形是影响其内力的主要因素，管道内力最大值出现于震后时刻。 

Dynamic response charactertstics of long petroleum pipelines extending along mountain ridge under strong earthquake

There are many long petroleum pipelines extending along mountain ridges in the mountainous areas of western China.Dynamic responses of the pipelines under strong earthquake have significant effect on their safe service ability.It is necessary for the related investigations to provide guidance for practical construction of the pipeline projects.In terms of a typical section of this kind of oil pipelines at Longmacao village, Yusi, Yunnan, a pipeline-slope 3D numerical simulation model is established considering engineering geology conditions of the slope.Further, dynamic responses of the pipeline including its displacement, axial force, shear force and bending moment as well as overall stability of the pipeline-slope system are computed using FLAC3D program with inputting Wenchuan seismic wave, and the seismic responses at some typical moments such as the moment at peak value of the horizontal acceleration and after the earthquake are specifically obtained.The results show that internal forces of the pipeline reach their maximum values after the earthquake, and the axial force gets high level under strong earthquake but the shear force and bending moment are in small level with about 1% magnitude of the former.Besides, vertical seismic wave has little effect on internal forces of the pipeline, and the position of the maximum internal forces is near the intersection of the pipeline and fault.During strong earthquake, the pipelines appear mainly elastic and plastic deformation in the horizontal and vertical direction, respectively.The accumulated deformation is the major factor to influence internal forces of the pipelines, whose maximum occurs at the moment after the earthquake.