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一、前言供水管线穿越河道工程造价在很大程度上取决于管线的敷设方法。以往当采用铸铁管时,常根据河床断面将穿越管道分成几段,用弯头联结起来,如图1所示,当采用钢管时,则将几段焊接成折线。这样不仅穿越管道构造复杂,加工麻烦,而且组装工作须在管道就位之后进行,势必导至工期延长。此外,这种方法不能使管线与河底断面更好地吻合,因而使土方工程量大大增加,投资亦随之增加。
I. INTRODUCTION The cost of water supply pipeline crossing rivers depends largely on the laying method of the pipeline. In the past, when cast iron pipes were used, the crossing pipe was often divided into several sections according to the cross-section of the river bed, and they were joined together with an elbow. As shown in Fig. 1, when the steel pipe was used, several sections were welded into a fold line. In this way, not only is the construction of the pipelines complicated and processing is troublesome, but also the assembly work must be carried out after the pipelines are in place, which will inevitably lead to an extension of the construction period. In addition, this method does not allow the pipeline to better conform to the bottom section of the river, thus greatly increasing the amount of earthwork and increasing the investment.