说明当管道掩埋于河床下时，河床粒径大小对管道附近床面冲刷坑的形成影响较

It shows that when the pipeline is buried under the river bed, the size of the river bed has little effect on the formation of scour pits on the bed surface near the pipeline. At this time, the pipeline is in a state of being less affected by the river.

It is explained that when the pipe is buried under the riverbed, the size of the riverbed particle size has less effect on the formation of the bed surface flushing pit near the pipe. At this point, the pipeline is in a state that is less affected by the river.

The results show that when the pipeline is buried under the river bed, the riverbed particle size has little influence on the formation of scour pits near the pipeline. At this time, the pipeline is in the state of less affected by the river.<br>