珠三角分汊河道险段形成机理及整治措施初探

珠江三角洲河网区河道受径流、潮汐动力双重作用，汊道分流随径流潮汐动力变化而变化，险段形成机理较单一河道复杂，传统治理方案易改变汊口两侧河道的分流比，影响整治效果。在分析了典型分汊险段附近河床演变特征的基础上，分析险段水动力特性，研究了其形成机理，并对各种整治防护措施进行对比试验。结果表明，模袋混凝土方案不改变汊道分流，不增加相邻河道泄流压力，且其整体性、适应性和高抗冲性避免了险段所在岸坡及河床的冲刷，可起到防护岸坡与堤脚的作用。该整治方案可为相关分汊河道险段治理提供借鉴。

Research on pitch formation mechanism of braided river in Pearl River Delta and harnessing measures

The river channel in the Pearl River Delta is influenced by the dynamics of runoff and tide, the diversion ratio of the braided river changes with the joint dynamics of runoff and tide, so the formation mechanism of pitch is more complex than that in a single channel. The effect of traditional control scheme would be affected because the river diversion ratio at branch mouth changes easily. Based on the analysis of the riverbed evolution characteristics of typical braided pitch, the hydrodynamic characteristics are discussed, and the pitch formation mechanism is revealed. The various regulation protection measures are studied by physical model experiments. The result shows that the mold bag concrete scheme doesn′t change the diversion ratio nor increase the discharge pressure on adjacent channel. The pitch in the bank and riverbed can be protected from scouring by the integrity, adaptability and high impact resistance of the scheme, which can protect the bank and levee toe.