Study on Jet Dredging Technology

摘要

According to the Yellow River hydrology state, massive silt deposits in main watercourse of the reservoir. It is difficult for density current appears naturally because of low velocity. As a result , it seems necessary to agitate and transport the sediment on the reservoir bottom to the dam artificially, after which, the sediment before the dam will be brought to the downstream by high velocity flow occurred in the water regulation duration. As the depth of water is high and the silting — up rate is big in the Xiaolangdi reservoir, the cost on the equipment is quite high if using the common machinery dredging method, and the energy consumption is high. The jet dredging unit has the simple structure, reliable performance, high wearability, and can work freely without any limit on water depth. According to the internal and foreign engineering experience, the project of cleaning the silt on the bottom of Xiaolangdi reservoir is proposed. In the project, the bottom silt will be disturbed and sucked by the jet dredging unit and be discharged out of the reservoir to the downstream through the discharge hole of silt. According to design theory of jets flow, the simulation test installment has been designed and carried out. The experiment and the computed result indicate a set of jet dredging system may suck silt 5 t/s , the biggest water depth it can work is 80 m, and its unit energy consumption is 0. 156 kWh/t.