1.Water depth of construction areas
On navigable rivers, vessels frequent traffic, or there are large wind waves on the approach channel of the seaport and estuarine port. if the construction area has enough water depth, there are waters at both ends for the dredger to turn head and throw mud (or conditions for blowing to land), can choose a self-propelled trailing suction hopper dredger. Because the self-propelled trailing suction hopper dredger can dig, load, transport, and unload itself. Single ship operation is flexible and has the strongest wind resistance. In the construction section of the water, depth is small can not be loaded for construction, can cast the first side, benefits flow construction.
When the discharge yard can be selected on the land or waters near the construction area, the cutter suction dredger or the dredging pump chain bucket dredge can be selected, equipped with appropriate water and land discharging equipment, or an elevated long slot chain bucket dredger. This kind of construction combination can self-excavating, self-transporting, self-unloading, and the excavation, lifting, transportation, and processing work can be carried out simultaneously and continuously, with the highest utilization rate of working hours. Dredge pump and elevated long-groove chain bucket dredgers are rarely used now, and cutter suction dredger is widely used because of its great advantages, and its economy is better than any other construction combination.
2. Dig-and-blow combination
There is no soil treatment condition near the construction area, but within the range of water depth available for tugs and barges traffic, within the scope of the optional to dredge underwater or on land, according to engineering condition and quantity, can choose chain bucket or single bucket dredger, equipped with the proper number of tug barges for them (or self-propelled barge) can take underwater dredging within an appropriate distance (should not be commonly more than 10 kilometers, too expensive if too far), or equipped with dredgers for blowing on the land or in deep water. This method is known as a dig-and-blow combination.
Small construction can also use grab (grab dredger or modified land excavator), belt conveyor, or manual unload the soil from the mud barge or flat barge on the land. (trucks can also be equipped on land. Buckets do long-distance processing). The bucket chain dredger has a good excavation, which is suitable for underwater construction projects with high-quality requirements, such as foundation trench or wharf berth, etc. The grab dredger is especially suitable for excavation near buildings, small foundation trench, dams, and underwater obstacle treatment. Bucket dredgers are used for geology that is particularly solid and other types of dredgers are difficult to dig or under other specific conditions.
3. Soil treatment
Soil treatment method is often an important prerequisite to determine the construction combination of a dredging project, for the purpose of the excavation of the dredging projects should also from the comprehensive utilization of the soil, if the project owner needed, try to adopt the blow-and-fill method, In addition to the cutter suction dredger construction combination, other construction combinations adopt the blow-and-fill method, which often cost more, resulting in lower profits or losses. It is necessary to select the construction combined with the best comprehensive benefit from a long-term perspective and comprehensive consideration and comparison.