Abstract:The scale of the renovated ship lock at Bailongtan has been greatly improved,but due to the curved river conditions in the downstream mountainous canyon,the layout of the ship lock is extremely difficult.By utilizing a 180 overall hydraulic physical model,the navigation flow conditions in the entrance area of the downstream approach channel are investigated,and measures to improve navigation conditions are proposed.The results show that after the confluence of flow discharged from the power station and the overflow dam,the continuous longitudinal contraction of the channel due to the narrowing effect of the diversion dike causes the flow to concentrate into a narrow and deep riverbed with persistently increasing dynamics.The sudden expansion of the channel behind the diversion dike leads to unfavorable flow patterns such as significant cross flows and back-flow in the entrance area of the approach channel,resulting in poor navigation conditions.By implementing engineering measures such as excavating high and steep slopes to widen the river channel,and widening the gorge’s high side slopes,creating permeable openings in the diversion dike,and installing permeable piles,the relative velocity gradient between the main flow and the entrance area can be significantly reduced.This effectively mitigates issues such as excessive cross-flow and back-flow,substantially improving navigation conditions.
