中巴喀喇昆仑公路冰川灾害

Glacier Geo-hazards along China- Pakistan International Karakoram Highway

中巴公路穿越西喀喇昆仑-喜马拉雅山系的冰缘地带,沿线冰川活跃,冰川消融与进退等引发各类地质灾害,严重损毁公路,危及公路安全。中巴公路灾害防治是中巴公路改扩建工程的目标,科学防灾减灾需要掌握中巴公路沿线冰川及冰川灾害的形成及发展规律。通过野外调查、定点观测、文献检索与遥感解译等研究手段发现,独特的地形地貌、丰沛的夏季降雪、险峻的地形落差、山地气候波动等环境因素孕育大量跃动型冰川,具有长期萎缩与间歇跃动、同期不同步、夏季累积型和悬冰川的活动特征。中巴公路沿线可区分为四大活动性冰川群,洪扎河谷(Hunza River)一带的帕苏幕士塔格山冰川群(Pasu Mustaghs)最为活跃。中巴公路冰川灾害可分为冰川灾害与冰川地质灾害两大类别,10个类型。其中,冰湖溃决、冰川泥石流的治理是工程上主要面临的防治问题。

The China-Pakistan International Karakorum Highway situates at the periglacial region through the Western Karakorum-Himalaya Mountain （Trans-Himalaya）. Along the Highway, flourishing glacier activities, such as glacier thaw, glacier advance and retreat, etc. contribute to occurrences of kinds of geological disasters, ruining the Highway and threating transport safety. The KKH reconstruction and extension project is targeted to geohazard prevention and control. Geohazard prevention and mitigation in a scientific approach rely on understanding of the KKH glaciers and related glaciated geohazards about their formation and development. Through field investigation, site observations, literature retrieval and review, remote sensing interpretation and other research approaehes, it is found that （ 1 ） the KKH is featured by the unique monsoon-effeeted periglaeial landforms, rich summer accumulated snow precipitation at peaks, extremes of precipitous valley relief, valley-localized glacier movements and the shifted contour extreme storms, which produces lots of surge glaciers with distinct behaviours characterized by perennial recession with unexpected surge, asynchronous movements for adjacent glaciers, summer accumulation type and outstanding hanging glacier activity. The glaciers along KKH could be zoned into 4 sections of active glacier group. The group of Pasu Mustaghs, near the Hunza River Valley, is currently the most threatening. The glaciated geohazards along KKH can be divided into 2 categories （glacier hazard and glacier geohazard） with 10 subcategories. Among them, glacial lake outburst, glacial debris flow are challenging most in engineering for prevention and mitigation.