Joint Estimation Of Silty-sand Sudden Siltation In The Open Channel With Wind Duration And Equivalent Wind Speed

With the high speed development of economy in China, the requirement of choosing the site of the sea ports and navigation channels increases. There are many silty-sand beaches in our coastline, which accounts for the third of the appropriate site for building port. However, silty-sand beaches have the characteristics’small wind causes small deposition; big strong wind causes sudden siltation’. A strong wind could bring catastrophic loss. For example, a strong wind sprang up at Huanghua Port in2003, the sedimentation of the waterway is9.7million cubic meters and dredging material is difficult to remove, which severely influences the normal construction and operations.Mechanisms of siltation are complex, affected by many factors. Most of the formula for silty-sand calculation is semi-empirical methods; so far there is less appropriate formula for calculating siltation of channel. Based on the’effective energy of wind’method, formula for silty-sand sedimentation is proposed, using the ’black box’theory, the calculation process is generalized, then the relationship between the sedimentation and effective energy of wind is established, which makes complex problem simplified.In this paper, some parameters of sedimentation formula are analyzed by statistical method, in order to validate rationality. The concept of’equivalent wind speed’is deduced, and the two-dimensional joint probability model of wind speed and wind duration is established. In consideration of Single factor statistical analysis and Joint environmental conditions, the return value of sudden siltation volumes for silty-sand beaches is estimated, which will provide design parameters to channel engineering design and port construction. The main content of this paper is as follows:(1) To collect wind data, wave data and sediment data, based on the concept of effective energy of wind, an empirical formula is set up to forecast the volume of silty sand sudden siltation, and the coefficients of the equations are determined by using observed data.(2) In order to verify the rationality of the formula, the power of the wind scale and their relationship with the volume of silty-sand sudden siltation is set up by the method of correlation analysis.(3) Determine the wind energy in the contribution rate of the volume of silty-sand sudden siltation with the idea of principal component analysis, which achieves the aim of dimension reduction on condition that the amount of information is enough.(4) Optimize effective wind formula and calculate the predicted value for sedimentation and its confidence interval. Meanwhile confirm the most influence causes by which scale of the wind in sediment deposition process.(5) The concept of equivalent wind speed is proposed. With two dimension respectively logarithm normal, two dimension Gumbel distribution and two dimension Weibull distribution, fit the distribution of the wind speed and wind duration, estimate the return values of siltation volumes for engineering design.