Abstract

Hydraulic transport is the main form of sediment transport in dredging engineering. At present, the modeling of the dredge pump and the pipeline system is mostly based on the quasi-static matching of the pump’s performance characteristics. The influence of working parameter fluctuations and the feedback from redistribution of dredged materials are not considered when modeling the entire transport system. This leads to particular issues in the long-distance and high concentration sediment transportation. In this paper, based on the transport process of a cutter suction dredger in a certain construction project site, a long-distance pipeline transport dynamic theoretical model is established and validated by a large number of field test data. Firstly, the real-time concentration data, which are measured by the radioactive concentration meter located on the ship, are extrapolated to the whole pipeline by the Lagrange method. The accuracy of the extrapolated result is validated by the measured differential pressure data. Secondly, considering the pipeline parameters and soil parameters of medium and coarse sand in the project, the coefficient of friction resistance on each section of the pipeline is calculated by the revised Fei Xiangjun friction formula and the head loss of the whole pipeline are acquired. At the same time, according to the real-time concentration, rotation speed and flow rate of the dredging pump, the real-time pumping head is obtained. Finally, the slurry acceleration is calculated by Newton's second law, and the velocity of the slurry at the next moment is calculated. Subsequently, the real-time sediment suction volume is taken as the input parameter, and the concentration distribution, friction coefficient of the pipeline, slurry velocity and the pressure drop curve are recalculated for the next time step. The accuracy of the model is validated by comparing the measured data with the predicted data. It can be seen that the theoretical model is capable of simulating the macroscopic dynamic sediment transportation process in the long distance pipeline of the cutter suction dredger, and serves as a useful tool in the study of sediment transport system and flow assurance.

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