![]() ![]() At the lower end of the suction pipe a special designed suction mouth, the so-called draghead is loosening the sediment with the help of water jets and / or teeth. At the locating where the sediment is extracted the suction pipes are lowered to the seabed. A TSHD is a vessel equipped with one or two suction pipes. In that case the sediment is transported in the hopper (cargo hold) of the dredge. With increasing distance (in dredging practice typically from 10 – 100 km) trailing suction hopper dredges (TSHD) are often employed. Production limiting factors are available pumping power and minimum pressure at the suction inlet of the pump.įor relative short distance sediment is transported by hydrotransport in most cases. The flow regime typically encountered is therefore heterogeneous. The largest part of the sediment dredged is used as building material and is therefore not fine grained. Combined with dilatant behavior this leads to large negative pore pressure or even cavitation of pore water.Īlthough Vertical Transport can be performed mechanically (for instance with a grab dredge), in most cases a hydraulic mechanism is used using (submerged) centrifugal pumps. Deformation rate is very large during excavation. Soil mechanical parameters as friction angles and permeability as well as fluid mechanical properties as viscosity, and settling velocities play an important role. The phase change can be regarded as dynamic soil mechanics or high concentrated slurry flow. In both cases sediment is transformed from a solid into a fluid state in a very short time. The Excavation can be mechanically or hydraulically.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |