高山峡谷区沿河公路泥石流灾害易损性评价指标与模型

As highways passing through the alpine-gorge areas with high elevation difference and complex geological conditions, their route, alignment, subgrade, bridging and tunneling are all under the influence of debris flows. It is even worse for those section located at the river valley, since that is the hazardous area of debris flow. In this research, we take the typical riverside highway in the alpine-gorge areas in western China as study object, analyze the spatial relation and dynamic connection between the highways and debris flows, and discuss hazard characteristics of debris flows and destructions of highway caused by debris flows. Furhermore, through systematically analyzing the random exposure process of mobile hazard-affected objects and the structural and functional vulnerability of the infrastructures (fixed hazard-affected objects) by using the methods of environment conditions analysis, field investigation, RS interpretation, actual monitoring, numerical simulation and mathematical analysis, we setup a system that could interpret the vulnerability of those highways, construct quantificational evaluation model, map out highway vulnerability zonaton and develop its methodology. Based on above researches, we analyze the vulnerability feature of riverside highways, finally provide scientific support to the line route selection, hazard mitigation design of road infrastructure, disaster risk prediction and management of the highways affected by debris flows in the alpine-gorge areas.

我国西部高山峡谷区，地势高差显著，地质条件复杂，泥石流广泛发育，严重影响着区内公路的线路走向、局部定线、路基工程、桥隧设计等，位于河谷段的线路，更是处于泥石流灾害危险区。项目选取我国西部典型高山峡谷区沿河公路为研究对象，采用环境背景分析、线路考察、遥感调查、野外监测、数值模拟与数理分析等手段，分析泥石流与沿河公路的空间关系、动力联系及致灾特征，定量描述公路移动承灾体的随机暴露过程，系统研究公路构筑物的结构功能易损性，建立基于公路构筑物和移动承灾体易损特性的高山峡谷区沿河公路易损性定量指标体系和综合评价模型，并制作公路易损性评价分区图，以此分析沿河公路易损性特征，为高山峡谷区公路避灾选线、工程减灾设计、灾害风险预测与管理提供科学依据。

受青藏高原强烈隆升的影响，我国西部高山峡谷区地形陡峻，地质条件复杂，加上气候变化极端暴雨天气增加的叠加影响，区内泥石流灾害广泛发育，严重影响着道路线路展布、路基和上下边坡的稳定，位于河谷段的线路，更是处于泥石流灾害危险区。公路易损性研究是道路灾害风险预测的关键环节，也是道路防灾减灾的核心问题。针对目前关于公路构筑物与移动承灾体易损性研究的不足，本项目选定川藏公路沿河路段为典型研究对象，开展泥石流与沿河公路的动力联系及致灾特征、公路构筑物的易损性分析与评价指标、移动承灾体暴露概率与易损性评价指标、沿河公路易损性评价模型等内容的研究工作，从敏感性、结构特性、功能影响等方面分析公路构筑物抗御灾害能力、灾后使用性能、灾后恢复能力等易损特性，运用随机过程模型，定量分析公路移动承灾体的随机暴露过程，建立了考虑公路构筑物和移动承灾体的公路易损性定量指标体系；利用多因子综合分析法，建立高山峡谷区沿河公路易损性评价模型，计算评估区公路易损度，结合GIS技术与易损性制图方法，制作公路易损性分区图，形成高山峡谷区沿河公路易损性定量评价方法。在此基础上，项目对受常年受泥石流威胁的川藏公路西曲河段进行公路易损性评估及实证研究，结果表明：评估结果与该路段泥石流危害公路情况相吻合；项目提出的公路易损性指标体系具与评价模型具有可移植性，可以应用于类似的泥石流多发区；项目研究结果可为高山峡谷区公路避灾选线、工程减灾设计、灾害风险预测与管理提供科学依据。