横向非一致激励下非均匀场地中埋地管道的振动台试验研究
Shaking table tests on buried pipelines in inhomogeneous soil under transverse non-uniform excitation
-
摘要: 为研究非均匀场地中大直径埋地管道在横向非一致激励下的地震反应,开展了埋地管道的多台阵振动台模型试验,分析了在不同地震动强度作用下埋地管道的加速度、应变响应规律。研究结果表明:均匀场地和非均匀场地中管道在横向一致、非一致激励下的加速度反应基本上服从于周围土体的加速度反应,管道主要产生了纵向弯曲变形;在横向一致激励较高加载等级下,场地变化过渡区的管道峰值应变相对较大,相比于均匀场地,非均匀场地中最大峰值弯曲拉应变高30%左右,在非一致激励作用下,非均匀场地中管道最大峰值弯曲拉应变反而低30%左右;在横向非一致激励较高加载等级下,均匀土中管道的应变响应比一致激励作用下增大两倍左右,非均匀土中管道的应变响应变化不明显。试验结果可为穿越非均匀场地大直径埋地管道的抗震设计提供参考。Abstract: A series of multi-point shaking table tests are conducted on model pipelines to investigate the seismic response of pipelines buried in inhomogeneous soil under transverse non-uniform seismic excitation. The acceleration and strain response laws of the buried pipelines under different ground motion intensities are analyzed. The main conclusions are as follows: the acceleration response of the pipelines is basically subjected to the acceleration response of the surrounding soil under uniform and non-uniform excitation. The buried pipelines mainly exhibit longitudinal bending deformation. Under the higher uniform seismic excitation, the peak strain of the pipelines in the transient zone where the soil properties change in the inhomogeneous soil model is larger than that in the homogeneous soil model. The maximum peak strain is basically about 30% higher than that in the homogeneous soil, However, the maximum strain peak is basically about 30% lower than that in homogeneous soil under non-uniform excitation. The strain response of the pipelines in homogeneous soil under the higher non-uniform seismic excitation is almost twice as large as that under uniform excitation, but then the strain response of the pipelines in inhomogeneous soil does not change significantly. The test results can provide a reference for the seismic design of large-diameter buried pipelines passing through inhomogeneous soil sites.