目前国内有较多船闸改扩建,由于布置受限,常采用多线船闸共用引航道的布置格局,多座船闸充、泄水引起的引航道内的非恒定流更加复杂,对船舶航行安全造成了较大影响。以现状葛洲坝三江引航道双线船闸为例,基于二维N-S方程数学模型,系统地探讨了不同泄水组合运行条件下共用引航道内水流波动特性、流速变化及叠加规律。结果表明:错时泄水时,后泄水船闸产生的正向流与先泄水船闸产生的反向流在引航道相遭遇会引起共用引航道内反向流速减小;相较单线船闸,双线泄水时,共用引航道内水位波峰增值随错时时间先大后小至零不变,波谷差值先正后负再不变,且在错时12~22 min泄水时,引航道内波谷更小;错时泄水时,首周期内波峰呈线性相加特性,而波谷在特定错时时间内叠加效应与相加特性差异不大。研究结果可为优化改扩建后的双线或者多线船闸共用引航道的通航水流条件、保障通航安全以及葛洲坝航运扩能工程提供参考。

[Objective] Shared approach channels were formed during the reconstruction and expansion of ship locks due to limited spatial conditions. This study focuses on the complex unsteady flow induced by water discharge from multi-line ship locks and its impact on navigation safety. Taking the double-line ship locks of the Sanjiang approach channel at the Gezhouba Project as the research object, this study systematically investigates the superposition patterns of flow fluctuations and flow velocity variations within the shared approach channel under different water discharge combinations using a mathematical model. The objective is to reveal the hydrodynamic response characteristics of the shared approach channel during coordinated operation of multi-line ship locks, thereby providing a theoretical basis for optimizing the operation scheduling of multi-line ship locks, improving navigation flow conditions, and enhancing navigation safety. [Methods] Based on the N-S equations for two-dimensional incompressible flow, a two-dimensional hydrodynamic mathematical model covering the downstream area of the Gezhouba Project and the Sanjiang approach channel was established. The model was validated using measured hydrological data and showed good accuracy and reliability. By setting different water discharge combination scenarios, various operation modes were simulated, including simultaneous discharge and staggered discharge of the double-line ship locks. The water level fluctuation process, flow velocity distribution, and their variation patterns within the shared approach channel were analyzed. Special attention was given to the staggered discharge conditions, under which the spatiotemporal interactions and response characteristics of the fluctuations generated by successive discharges were investigated. The superposition characteristics of wave crests and troughs and their effects on the flow regime within the shared approach channel were further examined. [Results] Under staggered water discharge conditions, the forward flow generated by the later-discharging ship lock met the reverse flow produced by the earlier-discharging ship lock within the approach channel, which significantly reduced the reverse flow velocity in the shared approach channel and was beneficial to ship navigation control. Compared with single-line ship lock discharge, during double-line ship lock discharge, the increment of water level wave crests in the approach channel first increased and then decreased with increasing staggered time, and finally tended to remain unchanged at zero. The difference in wave troughs was positive at first and then became negative, and ultimately tended to remain stable. When the double-line ship locks discharged with a staggered time of 12-22 minutes, smaller wave troughs occurred in the approach channel, which were favorable for ship navigation. In terms of wave superposition, the wave crests in the first cycle exhibited a pronounced linear superposition characteristic. Under specific staggered discharge conditions, the superposition effect of wave troughs showed only minor differences from the results of linear superposition, whereas nonlinear characteristics were observed at other staggered times. In addition, different discharge combinations produced distinct effects on the longitudinal flow velocity distribution along the shared approach channel. Significant variations in velocity gradients and flow directions were observed, particularly in the lock gate area and the middle section of the approach channel. [Conclusion] Staggered water discharge can regulate the reverse flow velocity within the approach channel and can further reduce wave troughs in the shared approach channel within specific staggered time intervals. The findings provide guidance for optimizing the layout of shared approach channels for existing and reconstructed multi-line ship locks, formulating reasonable discharge timing schemes, and mitigating the adverse effects of complex flow conditions on navigation safety. The results also offer scientific reference for improving navigation flow conditions in the Gezhouba navigation capacity expansion project and similar hydraulic hubs.