The use of ductile iron pipe and rubber ring interface has the following advantages:
① Ductile iron pipes have high elongation, and the bearing pressure of K9 series pipes can reach 6MPa;
② Ductile iron pipes are not easy to produce electrical corrosion due to their high resistance, and they are connected with rubber sealing rings with insulation function, so they have electrical corrosion resistance, and have obvious advantages in application in tunnel sections filled with various stray currents;
③ Ductile iron pipe has good fatigue strength, good casting performance, low cost and convenient production;
④ The outer surface of nodular cast iron pipe is sprayed with zinc and asphalt paint, and the inside can be lined with cement, which can not only improve its performance, but also protect the water quality, so it can adapt to the underground humid environment and extend the service life of the pipe;
⑤ Ductile iron pipe construction is flexible, and the pipe joint can be deflected, so it is very convenient to install in the tunnel section of the subway curve section.
