【作者】 杨献波；

【导师】 程建川；

【作者基本信息】 东南大学 ， 道路与铁道工程， 2006， 硕士

【摘要】 在平面线形既定条件下,公路的纵断面优劣直接决定了土石方工程量,纵断面优化对减少工程投资有着直接的影响,对沿线自然环境和土壤保护也具有重要意义。通过对公路纵断面优化问题及其优化方法的比较分析,本文建立了基于遗传算法的纵断面优化模型,着力实现土方工程量作为优化目标的公路纵断面优化,以提高纵断面设计效率和质量。优化数学模型以计算土石方工程量作为优化目标,选择变坡点组合作为优化变量,在一定程度上解决了优化目标和变坡点里程关系隐匿情况下的变坡点里程和桩号同时优化的难题;在目标函数中引入填挖费用比系数,模型可以合理地体现设计者的填挖方倾向。针对纵断面优化问题,本文对遗传算法做了进一步的改进,初步解决了遗传算法在应用中的关键问题。在种群多样性评价的基础上,确定了选择、交叉和变异算子操作概率的自适应调整方法,对变异算子做了非一致性改进;通过数学实验分析,确定了以变坡点均分桩为期望的正态分布方式初始化纵断面线种群;针对遗传操作过程中纵断面线约束破坏的情况,提出了处理策略和约束修复方法。在遗传算法设计的基础上,本文编写完成了基于遗传算法的公路纵断面优化程序,并通过算例在不同条件下的优化成果初步验证了程序的有效性。更多还原

【Abstract】 After the highway horizontal alignment is fixed, the vertical alignment determination is the sensitive element of highway design. The vertical alignment has important implications not only on road construction costs but also with respect to disruption of natural landform and soil conservation. Optimizing the vertical alignment is very necessary in highway design. So, an evolutionary model using the improved genetic algorithms (GAs) has been developed in order to seek the most suitable solution for the earthwork cost objective. The model tries to increase the quality and efficiency of the vertical alignment design in the practice.In order to optimize the stake and elevation of grade change points simultaneously, this model chose the combination of grade change points as the decision variable during the optimizing process. With the calculated earthwork volume as the model objective, the fill-cut cost coefficient was created in the model to express the fill or cut trend in the vertical alignment design.Optimal vertical alignment analysis was made and some key problems during the GAs application were resolved primarily. According to the diversity evaluation of the population, the happening probability of selection operator, crossover operator and mutation operator was self-adjusted respectively during the population evolution and the mutation operator was non-uniform. The original grade change points were generated randomly by the normal distribution whose expectation was the corresponding average-stake value. As far as the constraint violation during optimal searching, the constraint processing strategy and method were also discussed in this paper.After the detailed design of the genetic algorithms, a highway vertical alignment optimal program using the improved genetic algorithms was achieved. And the program proved available to some extend by the optimal results of an example in different cases.更多还原