南京市拟建过江隧道河段河床极限冲刷深度研究

Study onmaximum scouring depth at riverbed of proposed cross-river tunnel section in Nanjing City

河道稳定性和可能的极限冲刷深度是影响工程建设的主要限制因素。以长江南京河段拟建过江隧道为研究对象,结合近年来的水沙运动特征变化和河道演变,通过河工模型试验预测了不同水文条件下的河床极限冲刷深度,并与数学模型计算结果进行比较与分析。结果表明:①数学模型与河工模型所得结果基本一致。②在不利水文条件下,河床普遍受冲刷。左侧主深槽流速较大,潜洲左缘发生崩退情况;右槽河床冲刷幅度较大,潜洲的不稳定加剧了对右槽河床的冲刷。研究结果可为在该河段进行过江隧道选址提供重要的参考依据。

The stability of the river channel and the possible maximum scouring depth are the main limiting factors affecting the construction of the cross-river project.Aiming at the proposed cross-river tunnel in the Nanjing reach of the Yangtze River,we analyzed the characteristics of flow and sediment movement and the river channel evolution in recent years,based on this,the maximum scouring depths of river bed under different hydrological conditions were predicted by model test,and the results were compared with that of mathematical model test.The results showed that the results of the two models were relatively consistent.Under the unfavorable hydrological conditions,the riverbed is generally scoured,the velocity of the main deep channel on the left side is large and there is a collapse in the left side of submerged sandbar.The scouring range of the right channel riverbed is large and the instability of the submerged sandbar intensifies the erosion of the right channel riverbed.The research results can provide important reference for the location selection of the cross-river tunnel.