Sewer line construction
Sewer line construction As we know most of sewer lines are built so as to flow under gravity following the natural flow of it and in this case its laid to a gradient of 1:80 because of this gradient its cleansing velocity is induced. first of we must determine howfar this pipeline has to be laid ,that is 1Km.Then finding out the horizontal trace of pipeline and lines must be marked on the ground starting from the tail end or farther most downstream, marking the centerline alignment The setting out is carried out with the help of boning rod, sight rail and leveling instrument. In order to get the desired gradient at least 4 sight rails are used Sight rails should not be placed on top of the centerline of pipeline, if its so then its hard to excavate therefore it must be placed at a side(as shown in fig ). After that we should get the height of the offset sight rail using the leveling instrument thereafter excavation will commence. Respect to all sight rail