冰碛湖溃决危险区铁路沿河线方案评价方法

为建立青藏高原南缘冰碛湖溃决危险区铁路方案风险评价方法，首先，对青藏高原南缘74例冰碛湖溃决灾害实例溃决机制进行统计分析；在此基础上，针对冰碛湖溃决影响因素众多、关系复杂且具有高度不确定性的特点，利用多态贝叶斯网络建立了冰碛湖溃决概率预测模型；然后，以冰碛湖溃决危险区沿河线路工程为承灾体，综合冰碛湖溃决危险性评估与沿河线河谷地貌特征提出了各类风险区线路长度计算程式，建立了针对冰碛湖溃决危险性的铁路选线方案评价方法；最后，以中尼铁路跨喜马拉雅段的樟木、吉隆局部走向方案为例，说明评价方法的作业程式. 研究结果表明:樟木方案在冰碛湖分布区的线路长度小于吉隆方案，从选线角度属于线路短直方案，但樟木方案各风险区段线路总长超出吉隆方案约45%；从冰碛湖溃决风险角度，吉隆方案优于樟木方案. 

Evaluation Method of Railway Schemes Along Rivers in Risk Areas of Moraine-Dammed Lake Outburst

This study is aimed at risk assessments of railway schemes in moraine-dammed lake outburst risk areas in the southern Tibet Plateau. Based on the mechanism analysis of 74 outburst events in the study area, a multi-state Bayesian-Network prediction model is established considering the complex relationships among the influencing factors and high uncertainties of the outburst events. Taking the railway line engineering along rivers in moraine-dammed lake outburst risk areas as the hazard bearing body and combining the risk assessment of moraine-dammed lakes with geomorphological characteristics of the river valley, a calculation program of the railway scheme length in various risk areas and an evaluation system for railway schemes considering moraine-dammed lake outburst risk are proposed. In addition, the operation procedure of the proposed method is demonstrated taking the Zhangmu and Gyirong schemes of the China-Nepal railway as examples The results show that the Zhangmu scheme has a smaller route length in the moraine lake distribution area than the Gyirong scheme, and belongs to the short straight scheme from the perspective of route selection; however, the total length of the Zhangmu scheme in each risk area exceeds that of the Gyirong scheme by about 45%. Therefore, the Gyirong scheme is the better selection when considering the moraine lake outburst risk.