The cutter suction dredger has the functions of dredging sand (soil, rock) and conveying mud, etc. It has high construction efficiency and adaptability, and is one of the most widely used engineering ships in dredging engineering. In recent years, with the gradual expansion of the construction scale of the port channel, the environmental protection requirements of the construction, the lack of soil source and other problems, the discharge distance of the construction of the blowing-fill engineering gradually increased, often beyond the normal transport range of the cutter suction dredger discharge distance. At present, for the long row discharge distance construction of the cutter suction dredger, the main method is to use the soil test excavation and the analysis of the dredge pump operating point, combined with the driver’s mastery of the equipment and experience to carry out the construction operation.

 

In practical projects, the construction of long discharge distance mainly reflects the following characteristics:

 

  • Transportation velocity changes slowly. Once the velocity is too low in construction, even lower than the critical velocity of the soil, the velocity can be increased after a long time of blowing water construction, resulting in a lower productivity and longer time.

 

  • The instrument display cannot reflect the overall pipeline transportation. Since the instrument sensors of the construction parameters of the cutter suction dredger are all installed on the pipeline and equipment on the ship, the mud discharge pipeline can only be controlled by the driver’s rough estimation and practical operation experience, but when the discharge distance is too long, the influence of pipeline transportation on the construction will gradually increase, and it is not enough to rely on the judgment of the driver.

 

  • The discharge pressure of the equipment is large. Because of the long discharge distance of the engineering pipeline and the large amount of mud in the pipeline, the driving force needed is larger, which leads to the increase of the pressure on the pipeline. The large increase of discharge pressure has a great threat to the safety of the dredge pump and the mud discharge pipeline, Sealing pumps may produce back filling, which cannot play a proper role in protecting the dredge pump shaft and lining plate.

 

  • Not all dredged soil can use the long discharge distance construction of the cutter suction dredger. Generally, the construction of the long discharge distance construction is not limited in the excavation, and whether the cutter suction dredger length discharge distance construction can be used depends on the actual factors such as critical velocity of the soil and the dredging pump capacity of the ship.

 

In addition, during the blowing-filling construction of the cutter suction dredger, because the distribution of underwater soil layer is not uniform and the soil quality is different at the same elevation, even if there are survey data, the change trend of soil distribution can only be roughly understood, and the specific excavation situation of the cutter at each position can not be accurately grasped. Therefore, in the construction of the cutter suction dredger mud pipeline, mud concentration is changing every moment, and the relative density of the slurry in the pipeline will fluctuate greatly during the operation of the cutter suction dredger such as reversing, anchoring and overturning truck. This requires the driver to make timely adjustment according to the change of parameters, so as to conduct dredging continuously and stably with high productivity. Within the normal range of discharge distance, the influence of the change of mud concentration on the overall pipeline can be eliminated within controllable time. Therefore, the construction control scheme can be drawn up according to the data displayed by the instrument on board, and timely adjustment can be made to ensure the continuous and stable construction.

 

By analyzing the working characteristics of long discharge distance, it can be seen that the construction difficulty of the cutter suction dredger under long discharge distance is different from that of the normal discharge distance, and it cannot provide more effective basis for the adjustment and optimization of the construction operation of cutter suction dredger under long discharge distance. Therefore, more targeted technology and construction basis should be adopted to ensure the safety and stability of construction.