1. The buried depth of the pipeline should be determined according to factors such as the degree of freezing, the external load and the intersection of other pipelines. Under normal circumstances, the buried depth can be 0.2 meters below the freezing line, and meet the following conditions: When the pipe diameter is greater than 100mm, the minimum buried depth of the pipe top is 1.20 meters.
2. The bottom width of the design groove is generally 0.5 m of the outer diameter of the pipe, and the excavation slope (i) is determined according to the soil condition, and the groove cross-sectional view is drawn.
3. Ductile iron castings are the same as other pipes. The head loss along the uniform flow is also hf=λ/dv2/2g. The difference is only “λ” (hydraulic friction coefficient), that is, the head loss can be localized according to the original cast iron pipe. Resistance loss calculation. In the design, when it is expected that there is a possibility of a sudden change in the flow rate of the water body, the water hammer pressure should be considered and can be calculated according to the relevant formula of hydraulics.