中文摘要：

为了有效布设轨道交通网络，考虑可达性约束与轨道线网合理规模约束，建立了城市轨道交通网络布局优化的双层模型。该模型上层为一个多目标函数，其使得总出行时间最少，轨道交通线网总长度最少及总换乘次数最少；下层通过容量限制分配方法将客流在轨道交通线网上进行分配。算例结果表明，运用该双层模型可对所有可能的轨道交通线路进行筛选，并得到最优的线路网络布设方案。该模型可用于城市轨道交通规划中，对线路网络进行优化布局。

英文摘要：

For effective arrangement of urban rail transit lines, considering traffic zones being divided, the accessibility constraint and the constraint of the rail transit network＇s size, the bi-level programming model for urban rail transit network＇s layout was set up. The upper level of this model is a multi-objective function which is to minimize the total travel time and the total rail transit lines＇ length and the total transfer times, and the lower level of the model is a capacity-constrained traffic assignment model that describes passenger flow assignment on the rail transit network. The results of an illustration show that the reasonable rail transit lines can be selected from all possible lines and the optimal scheme of the rail transit network＇s layout can be obtained using this bi-level programming model. This model can be used in urban rail transit＇s planning for optimizing the rail transit network＇s layout.