OPTIMUM APPROACH TO DETERMINE THE COEFFICIENTS IN SEDIMENT-CARRYING CAPACITY FORMULA

摘要

Numerical simulation of sediment transport and bed erosion or deposition in rivers, estuaries and coastal waters has become an important approach in sediment research. Because sediment transport is very complex and unsteady, different mathematical models have been established on the basis of different principles, such as sheer stress and energy of water flow. In China, the sediment-carrying capacity formula based on water flow energy equilibrium is widely applied to numerical simulation and successfully used to solve sediment problems in many important engineering such as the Three Gorge project and the regulation of the deep navigation waterway in the Yangtze River Estuary. The sediment-carrying capacity of water flow means the maximum sediment load, carried by water flow. So it is very important to obtain the sediment-carrying capacity formula for developing sediment numerical models, and the key problem is to determine its coefficients in the best way. Directly based on the least square method, a new method called enumeration method is developed in this paper. This method is different from the conventional method in which regression analysis is made after logarithm is taken. The analysis of errors and comparison of results show that the coefficients determined by the enumeration method are reasonable and the formula is accurate in calculating the natural sediment-carrying capability of water flow. This method is simple and practical, and it is the most optimum approach to the determination of the coefficients in the sediment-carrying capability formula at present.