长沙枢纽坝下Ⅱ级单线航道整治工程方案研究OACSTPCD

Due to the comprehensive impact of changes in the relationship between the Yangtze River and Dongting Lake and sand mining activities,the water level in the tail section of the Xiangjiang River downstream of the Changsha Dam has progressively decreased in recent years.During the dry season,the hazardous shoal represented by Wenjingtan can no longer meet the depth requirements of current Ⅱ-level waterway.In order to solve the problem of insufficient water depth in the low-water channel of Wenjingtan Section,a 2D numerical flow model of the long river section under the Changsha Dam was established.An improvement project plan for a Ⅱ-level and single-line channel under the Changsha Dam was carried out to analyze the distribution of water depth in the Wenjingtan Section and the low water levels upstream under the three-group plan of dredging the right branch of Wenjingtan Section,protecting the bottom of the left branch,and the combination of the bottom protection of the left branch and the dredging of the right branch.The research results show that after the implementation of the dredging plan for the right branch of Wenjingtan Section,the navigation water depth conditions have been optimized to meet the navigation depth requirements of Ⅱ-level waterways,but it will lead to a sharp deterioration in the low water level in the upper reaches of the Wenjingtan Section and the threshold water depth conditions downstream of the dam.After cooperating with the bottom protection plan for the left branch of Wenjingtan Section,the navigation depth conditions of the right branch of Wenjingtan Section have been further optimized.At the same time,the navigation water level along the upper reaches of Wenjingtan during the dry season has also increased overall,achieving the channel improvement objective.