剑潭—横沥河段航道升级措施及模型试验

Upgrading measures and model test of Jiantan to Hengli river section Channel

剑潭—横沥河段航道扩能工程河势弯曲、宽窄相间、滩多水浅、上下相连、输沙能力有限、人为采沙活动严重,工程整体性高且与河段联动效应强。根据滩险碍航特征和整体优化的原则,提出“疏浚为主、整疏结合、控制河势、稳定航槽”的整治原则,认为航槽应沿河道深泓布置,挖槽纵向采用变底坡设计,横向采用梯形断面或复式断面形式。应完善整治建筑物布置,适当束窄整治线宽度,并充分利用已有丁坝,新建丁坝和加长旧坝。开展定床物理模型试验与水流泥沙动床物理模型试验,分析改造后航道沿程水位、比降、流速的变化,明确航道泥沙的冲淤量,研究改造措施的合理性。结果表明,整治后航道沿程水位与比降下降,航道流速增加,年均淤积量为3.98万m3,改造措施合理可行。

The channel expansion project of Jiantan to Hengli river section is bend,and wide and narrow alternated.There are many shoals which are linked together.Sediment transport capacity of the river section is limited.Sand mining activities are very serious.So the project has high integrity and strong linkage effect with river section.According to the principle of obstruct features by rapids and overall optimization,the regulation principles of the dredging mainly,combination of renovation and dredge,controlling river regime,and stable trough are proposed.The navigation channel should be arranged along the channel deep line.Variable bottom slope design is adopted in longitudinal excavation.Trapezoid section or compound section is adopted in the transverse direction.The layout of regulation buildings should be improved.Width of regulation line should be narrow.The existing spur dikes should be fully used.New spur dikes should be built and old spur dikes should be extended.The fixed bed model test and sediment physical model test are carried out.The changes of water level,gradient and velocity along the channel after reconstruction are analyzed.The amount of erosion and deposition of channel sediment is determined,and the rationality of reconstruction measures is studied.The results show that after the regulation,the water level and gradient along the channel decrease,and the channel velocity increases.The average annual sedimentation volume is 39,800 m 3.The upgrading measures are reasonable and feasible.