The Studies On Integral Technology Of Canal Scour & Sediment In North Nenjiang Conveyance Project (NNCP) Of Heilongjiang Province

The North Nenjiang Conveyance Project of Heilongjiang (NNCP) is located in the central of Song-Nen plain of Heilongjiang province, in the north longitude 126?-128?and east latitude 46?- 48?. The project is a integral large water conveyance project which mainly supplies water to Daqing oil field, chemistry industries, drinking water for people live near the conveyance canal and irrigates some farmlands. Since 1976, the project v.as completed and put in operating, it has made great social, economical and bio-ecolog:cal benefit. It has taken play an important rule. During 20 years operating, NCP has great change because of the erosion and sediment, specially the cross section enlarged, generally width enlarged 5-6 meters than normal section. The maximal exceeded more than 20 meters. For a multi-purpose conveyance project, the conduit capacity is a most important factor. Although the canal conduit capacity does not change very much than design discharge, the canal erosion due to many years scour already damaged the canal stability. Therefore, taking efficient measures should protect the canal.By means of prototype observation, analysis and numerical model the author analyzed the canal scour and sediment process, the different scour and sediment affected on the discharge and affected on materials movement in different cross sections of the canal. By means of prototype observation, analysis with materials and theories, and laboratory test, the author deeply analyzed the causes and procedure of canal cross section erosion, and obtained eight causes which resulted the canal deform including flow, seepage, runoff, collapse of bank, dry effect, human activity, wave flush, frozen, and then stressed to discuss the frozen process.Through theoretically analysis and comparing, the dissertation proposed the integral measures to renovate NCP, analyzed the principle of the measures, method and procedures. All of measures have been tested in test site. The general renovation principle is taking various measures according to the local conditions, such that: 1. For flow erosion, must take measure to control water flow and soil moving following the flow course. In the canal with sand moving balance and stable bed, may keep the current status; For the sediment canal which seriously reduced discharge, may properly clean sediment; For the seriously scoured canal, such as curved canal, should lining the canal. 2. For seepage, should take drainage. 3. For flushing canal by slop runoff, must build the cut off ditch. 4. For collapse erosion, should make gradual side slop and lining the bank of canal. 5. For frozen erosion the good measure is to cut slop and lining with coarse gravel; meanwhile, adjust the canal operating to less the frozen. 6. For slightly erosion canal, can plant trees and grass on the dyke to prevent the lateral erosion. 7. Following development of the new construction materials, the new technology is also used in NCP. For selecting the practical and economical method to protectthe canal, the new protection methods such as chemical solid materials lining, buried membrane lining and plantation bank protection have been tested in the project.