桃源枢纽船闸下游引航道中水期整治技术

Middle water period regulation technique for downstream approach channel of Taoyuan Hydro-junction ship lock

桃源枢纽船闸位于江心洲洲尾,中水期枢纽两侧同时泄流,船闸下游引航道及口门区段存在横流和泥沙淤积等碍航问题,有必要通过工程措施予以解决。采用定床水流和定床输沙试验,研究不同中水期整治方案下,船闸下游引航道及口门区的水流泥沙条件。结果表明:1)左侧疏浚区能有效平衡右侧疏浚区的侧向引流作用,疏浚区宽度越宽,河段横向流速和泥沙淤积量越小。相较于直立墙结构,斜坡式石笼坝导墙能够有效避免末端回流的形成,进一步减小口门区横向流速和泥沙淤积。2)沿下游引航道口门区及连接段左侧布置疏浚区,疏浚宽度等于1.5倍引航道宽度,疏浚底高程26.44 m,同时采用斜坡式石笼坝延长左侧导墙200 m,可较好解决中水期河段碍航问题。

The Taoyuan hydro-junction ship lock is located at the tail of the central bar. In the middle water period,the plunging flow is from both sides of the hydro-junction,which causes the problems of transverse current and sand deposition in the downstream approach channel and its entrance area of the ship lock. It is necessary to solve the problem through engineering measures. The fixed bed flow and fixed-bed sediment transport experiments are carried out to study the flow and sediment conditions in the navigation hindering reach under the different regulation work plans of the middle water period. The results show that: 1) The left dredged area can effectively balance the lateral drainage effect caused by the right dredged area. The wider is the width of the left dredged,the smaller are the transverse current velocity and the volume of the sand deposition in the reach. Comparing to the vertical wall construction,the ramp-style gabion dam can effectively avoid the reverse current formed at the end of the dam,so it further reduces the transverse current velocity and the volume of the sand deposition in the reach in the middle water period. 2) A dredging area is arranged along the entrance area of the downstream approach channel and the left side of the connecting section. The dredging width is equal to 1. 5 times the width of the approach channel,and the dredging bottom elevation is 26. 44 m. At the same time,the slope-type gabion dam is used to extend the left guide wall by 200 m,which can better solve the navigation-obstructing problem in the middle water period.