基于北江大堤布设固定大断面及水文监测资料,分析西南历史险段河道演变特征；结合平面二维水、沙数学模型,进一步预测河道滩槽演化趋势,分析岸滩稳定性,评估整治工程防治效果。研究表明,整治工程实施后:① 新沙洲左汊岸滩基本稳定,近年来略有淤积；② 枯、中、洪水期左汊的分流比均呈减小的趋势；③ 典型洪水过程条件下,抛石防护平台与河槽结合部位易发生冲刷,冲刷幅度约为0.6～1 m。西南历史险段经过整治,险情基本得到控制,由于该河段洪峰流量大,深槽迫岸,仍需结合河势特征,加强日常监测与防护,确保大堤安全。
Based on the fixed large cross-section and hydrological monitoring data of The North River Grand Levee, this paper analyzes the evolution characteristics of Xi'nan Dangerous Section; combined with the plane two-dimensional water and sand mathematical model, it further predicts the erosion and deposition trend in the reach, analyzes the stability of the bank, and evaluates the control effect of the regulation engineering measures. The results show that:(1) the shoal of the left branch of xinshazhou is basically stable and slightly silted up in recent years;(2) the diversion ratio of the left branch is decreasing in dry, medium and flood periods;(3) under the typical flood process of 06.7, the joint of riprap protection platform and river channel is prone to scour, with a scour range of 0.6-1m. After the renovation of the historical dangerous section, the dangerous situation has been basically controlled. Due to the large flood peak flow and the deep channel pressing the bank, it is still necessary to strengthen the daily monitoring and protection in combination with the characteristics of river regime to ensure the safety of the levee.