Abstract

Analysis of stability of river regime and riverbed in the bridge area as well as researches on river patterns is of great significance in construction of bridges. The river patterns and stability of river regime in the bridge area are the basis for the selection and layout of bridge position.

Dynamic state classification of bifurcated river patterns in the downstream of Yangtze River is helpful to the selection and layout of bridge positions. Researches show that the nodal reaches of bifurcated river pattern and the bifurcated river pattern with stable central islet in a river are of higher stability, the bifurcated river pattern with alternative central islet in a river, is less stable, and the bifurcated river pattern with central shoal in a river is the least stable. It is the basis for the selection and layout of bridge position at the near-estuary reach of Yangtze River.

Researches show that floods are the dominant dynamic force of alternate swinging evolution of bifurcated river pattern and riverbed topography at the near-estuary reach of Yangtze River. Practices show that artificial works in accordance with the law of river patterns can give full play to the stability of bifurcated rivers. The above is the directive thoughts for the selection of bridge position, layout of main span and maintenance of stable river regime after the construction of bridges at the near-estuary reach of Yangtze River.

Keywords: selection of bridge position, river pattern, river regime, stability, dynamic state classification