NUMERICAL MODELLING OF SCOUR IN THE RIVER TRAINING WORKS OF THE PADMA RIVER BRIDGE

摘要

A new 6.2 km long bridge designed for 148,000 m~3/s has been proposed over the Padma River in Bangladesh. Natural scoured depths in excess of 50 m have been observed at the proposed bridge site. A 11.3 km long river training work (RTW) has been proposed along the south bank to prevent the river from destroying the access road to the bridge and outflanking its right abutment. Physical model studies have shown that minimum bed levels at the south RTW can reach down to elevation -60 m (water surface at elevation +7.7 m). Erosion in a simplified version of the south RTW was studied numerically using the depth-averaged flow and sediment transport models Telemac2D-Sisyphe (T2D) and River2D-MORphology (R2D). Better agreement of scoured depths between the physical models and the numerical models was obtained by R2D (elevation -60 m) compared to T2D (elevation -50 m).