Survey of dredging works
1.1 Purpose of survey
The different design of the project (from feasibility study to construction drawings and even construction organisation design) stage, the purpose and requirements of the investigation are not the same. Each design stage must have sufficient, reliable original information as a basis, the purpose of the survey is to obtain this information.
Dredging project investigation is to obtain the correct natural conditions and construction organisation conditions through various means (methods and ways), to provide a detailed and reliable basis for the design, construction and management of dredging project.
1.2 Requirements of survey work
In principle, the survey work should be carried out according to different design stages, from the whole to the local, according to the procedure, step by step.
Survey work should adhere to the scientific attitude of seeking truth from facts and serious work style, timely and accurate survey information.
1.3 survey content
The object of dredging is the sediment of underwater riverbed, it is very important to master the soil characteristics of dredging sediment to choose the right type of ship and improve the efficiency of dredging. Dredging activities are carried out in different natural environments such as coasts, estuaries, rivers, lakes, reservoirs, etc., with different hydrological and meteorological conditions. Mastering different hydrological and meteorological data is very important for the correct selection of dredger ship type, selection of mud throwing area, construction technology and construction time, safe operation and safe deployment of dredger, and careful arrangement of production. Coasts, estuaries, rivers and other alluvial seabed, riverbed and the water column in the sediment with the movement of the water flow, the interaction of the formation of different riverbed topography, and with the flow of water within the year of the cyclical changes in the river seabed topography is still in the constant adjustment of the changes. Mastery of coastal sediment, estuaries and rivers and other areas of sediment movement characteristics and riverbed change law for the correct choice of construction methods, construction technology, mud throwing area location, estimate the amount of dredging back to the dredging is essential, more important to the maintenance of dredging.
1.About the natural conditions, the main introduction: meteorological, hydrological, soil quality, topography and so on four (see table 3.1.1-1), about the movement of sediment and other knowledge please refer to the relevant manuals.
2. Regarding the conditions of construction organisation, there are mainly eight items as follows.
(1) the berth of the construction vessel, anchorage, pipeline equipment storage site, shipyard ship repair capacity and surface lifting, transport equipment and so on.
(2) Relevant regulations of local navigation and environmental protection departments.
(3) construction ship transfer route navigation conditions, cross-stream buildings (lines) of the clearance, water depth and so on.
(4) construction area about the river cables, pipelines, hydraulic buildings, underwater obstacles, as well as explosives, etc. and their affiliation.
(5) the type, number and frequency of ships passing through the construction area and the interference with the construction.
(6) The impact of the underwater mud disposal area on the dredging of harbours and waterways, aquatic resources and aquaculture, etc., as well as the land area of the blown-in area and the drainage channel.
(7) Traffic, post and telecommunications, medical and health care, living facilities, supply, rental of auxiliary vessels and employment of local labour in the construction area.
