某河排污干管工程全长6000余m,埋设内径1.5m、外径1.8m钢筋混凝土承压企口型污水管道,埋设位置在现有河道中心一侧。该河道为游荡性河道,上游较宽,平均50m,下游较窄,平均10m。河床高低不平,且大部分为垃圾阻塞。河道两侧岸边无道路可行,也无临时材料堆放场地。该河枯水季节流量 A river drainage mains project of a total length of 6,000 m, buried diameter 1.5m, diameter 1.8m reinforced concrete pressure type mouth-type sewage pipe, buried in the existing center of the river side. The river is a wandering river, upstream wide, an average of 50m, the downstream narrow, an average of 10m. The river bed is rugged and mostly clogged with garbage. There is no road on both banks of the river and no temporary material storage site. The river is dry season traffic