埋地管道的平稳随机振动

考虑地震时大地震动的相关性，导出了埋地管道轴向和横向随机振动响应的功率谱密度函数的解析式。实例计算表明，边界条件的影响仅限于管端附近。无论是轴向振动还是横向振动，埋地长管线的各阶固有频率均十分接近，出现了模态密集现象。由于有模态密集和较大的阻尼，模态之间的相互作用不可忽略。只要管段取得足够长，管中部应力就不随管段长度而变化。大地震动的空间相关性对管线随机振动影响很大，因此要慎重选取。ＣｌｏｕｇｈＰｅｎｚｉｅｎ给出的ＣＰ模型和胡聿贤给出的Ｈ模型都可用来计算埋地管道的随机响应。

Power spectral density functions of axial and lateral random vibrations are derived in consideration of correlation of the ground motion with earthquake. The results of instance computation show that the effect of boundary conditions is confined near to pipeline ends. The natural frequencies in various ranks of long buried pipeline for axial vibration and lateral vibration are close to each other, which shows modal concentrating. Because of the concentrated modals and high damping, the interaction among modals must be involved. The space correlation of ground motion having tremendous effects on the random vibration of buried pipeline should be selected cautiously. Clough\|Penzien (CP) model and Hu Yixians model can be utilized to calculate the random response of buried pipeline respectively, but the result of CP model is more reasonable.