| Bridges abound in roads, railways and cities, and play an important role in daily production and life. The destruction of bridge will bring disastrous consequences. Local scour around bridge pier is the main cause of bridge damage. So the research on bridge scour is of great significance. Water flow and sediment motion around bridge pier is very complex. There are many factors in local scour around bridge pier. The related researches are widely performed and lots of great results are obtained by domestic and foreign scholars. But many existing disputes still need to be further studied.Based on the previous research, this thesis emphatically studied the relation between the non-uniformity of bed material and local scour around bridge pier by generalized physical model tests. First, flow structure around bridge pier was observed and its effect on the scour was analyzed. Main cause was investigated for approaching the mechanism of local scour around bridge pier. Second, an experiment with model sediment of different particle size was conducted to analyze the development rule of scour hole in the course of scouring and the influence law of particle size on local scour around bridge pier. Then, an experiment with non-uniform model sediment was conducted. The non-uniformity of bed material was proved to be an important factor on local scour around bridge pier and the relation curve was put forward. Last, an experiment with layered riverbed was conducted to analyze the relationship between local scour around bridge pier and different depth distribution of layered structure. The latter was regarded as non-uniformity of riverbed with depth. |
