Taking a dredging project in a foreign country as an example，we analyze the construction data on transporting slightly weathered rocks by the 1 m diameter dredging pipelines of the self-propelled heavy-duty cutter suction dredger “Tiankun Hao”.Then，we calculate the head and efficiency of the dredge pump under the given working condition，obtain the relationships of density and flow velocity with friction coefficient，and give the recommended values of the soil conversion coefficient and the experimental coefficient.The results show that the technology，by giving full play to the characteristics of the heavy-duty cutter suction dredger that it can directly excavate and transport the slightly weathered rocks by pipelines，improves the construction efficiency on the basis of saving costs and protecting the environment and thereby ensures that the project is completed on time.