基于IAHP-IRMO法的既有路基挡土墙评估指标权重确定

Determination of index weights for assessment of existing subgrade retaining walls based on IAHP−IRMO method

在既有路基挡土墙安全评估中,评估指标权重的确定非常重要。目前,挡土墙评估指标权重的确定大多采用确定型的层次分析法,忽略了评估指标不确定性和模糊性的影响。为了准确反映评估指标权重的不确定性和模糊性,通过分析评估指标权重计算方法,采用区间层次分析法(IAHP)构造区间数判断矩阵来确定既有路基挡土墙评估指标的权重。针对区间数判断矩阵中求解权重方法的不足,引入相离度的概念,建立单目标优化模型。将模型中的目标函数作为适应度函数,运用改进径向移动算法(IRMO)进行全局优化搜索,并对IRMO算法中的惯性权重递减模型wk进行改进。采用的曲线递减模型能提高全局优化搜索能力,从而获得评估指标的最优权重。对2个不同算例与其他方法进行对比分析,并结合工程实例进行验证计算。结果表明:IRMO算法运用于区间数判断矩阵权重优化搜索具有稳定性和高效性,能够有效减小不确定性带来的影响,搜索速度快、收敛效率高、搜索结果更为稳定、客观、合理。IAHP−IRMO法应用于既有路基挡土墙评估指标权重计算方面具有可行性、有效性与准确性。工程实例得出的安全评估结果与现场实际情况较为符合,该方法能够广泛应用于铁路、公路等既有路基挡土墙的安全评估指标权重确定,为挡土墙安全评估提供依据。

In the safety assessment of existing subgrade retaining walls,the determination of evaluation index weights was particularly important.At present,the weight of evaluation index of retaining wall was mostly determined by the analytic hierarchy process(AHP),ignoring the influence of uncertainty and ambiguity of evaluating index.To accurately reflect the uncertainty and ambiguity of evaluation index weights,the interval analytic hierarchy process(IAHP)was used to construct the interval number judgment matrix by analyzing the calculation method of evaluation index weight.The weights of existing subgrade retaining wall evaluation indexes were determined.To address the shortcomings of the weight determination means in the interval number judgment matrix,the deviation was introduced to establish a single-objective optimization model.With the model objective function as the fitness function,the optimal weights were obtained by using the improved radial movement optimization(IRMO)algorithm.To improve the performance of global optimization,a curved decreasing inertia weight wk was applied in IRMO algorithm.The verification calculation was carried out by analyzing two different arithmetic cases and a certain engineering example.The results indicate that the IRMO algorithm has stability and efficiency in calculating the weight of interval number judgment matrix and can effectively reduce the impact of uncertainty.The IRMO algorithm has the advantages with fast optimization speed,high convergence efficiency,and the search results are more stable,objective and reasonable.The IAHP−IRMO method is feasible,effective and accurate to determine evaluating index weight calculation of existing subgrade retaining wall.The safety assessment results obtained from the engineering examples are consistent with the actual situation on site.The IAHP−IRMO method is widely used for determining the safety assessment index weights of existing subgrade retaining walls such as railways and highways,and it provides a basis for retaining wall safety assessment.