长江中游典型河段岸滩稳定性评价研究

Bank stability evaluation on typical reach of middle reaches of Changjiang River

岸滩稳定是岸线开发利用的前提。针对局部岸滩稳定性缺乏系统量化评估方法的问题,引入层次分析法-综合指数法,分析了来水来沙、边界条件对岸滩稳定的影响,构造了以近岸泥沙输移、主流摆动、边坡形态、河道形态及近岸泥沙组成(各因子权重占比分别为34.3%,25.7%,23.0%,9.9%,7.1%)为评价因子的岸滩稳定性评估层次模型,明确了各因子对应量化指标及稳定性综合指数的计算方法。模型在长江中游典型河段——武汉河段中下段的应用结果表明:该河段内顺直河道与分汊河道交界附近岸段稳定性相对较差,河道进出口、节点位置岸段稳定性相对较好,且右岸总体稳定程度大于左岸。提出的综合指数能较好地识别河道两岸不同位置的稳定程度,评估方法简单、可靠,可供其他类似河段评估应用。

Bank stability is the premise of shoreline resources utilization.Aiming at the problem of lacking comprehensive quantitative evaluation methods for bank stability,this paper introduced the Analytic Hierarchy Process(AHP)-comprehensive index method to analyze the influence of water,sediment,boundary conditions on bank stability.A bank stability evaluation hierarchical model which includes near-shore sediment transport,mainstream swing,bank slope,channel shape,and near-shore sediment composition(the weights of each factor were 34.3%,25.7%,23%,9.9%and 7.1%respectively)was constructed,and the quantitative index corresponding to each factor and the calculation method for the comprehensive stability index were clarified.The application results of the model in the typical reach(middle and lower reaches of the Wuhan Reach)showed that the stability of the bank near the junction of the straight river and the branched river was relatively poor,the stability of the bank at the entrance and narrowed section of the reach was relatively high,and the overall stability of the right bank was greater than that of the left bank.The comprehensive index can better reflect the stability degree of different bank sections,and the evaluation method was simple and reliable,which can be applied in other similar river reaches.