沟谷灾害链演化模式与风险防控对策（特约稿）

沟谷灾害链是近期才引起学界关注的灾害类型，也是川藏铁路交通廊道建设和运营中面临的巨大挑战。本研究提出了沟谷灾害链的定义及组成要素，通过分析大量已发生沟谷灾害链事件，总结了沟谷灾害链的特性与类型、归纳出常见沟谷灾害链的演化模式、探讨了影响沟谷灾害链的关键物理过程，提出了沟谷灾害链的风险评估及防控对策新思路，取得了以下结论：1）沟谷灾害链由潜在孕灾体、原生灾害、次生灾害（系列）和承灾体构成，具有时间相接、空间相连、因果关联、链式演进的典型特性；根据原生灾害类型可将沟谷灾害链分为滑坡灾害链、泥石流灾害链和冰湖灾害链3个大类和11个小类，这些演化模式可以通过三个关键过程（崩塌/滑坡-碎屑流/泥石流、滑坡/泥石流堵江-堰塞湖、堰塞湖/冰湖溃决）组合得到；2）沟谷灾害链的形成包含两种模式，一是原生灾害体的物理力学性质在运动中发生改变而形成次生灾害，二是原生灾害改变次生灾害体的形成条件进而诱发次生灾害；3) 沟谷灾害链的风险评估要同时关注原生灾害的起动机制和次生灾害的链生机制，要强化潜在灾害链物源的准确识别，加强对灾种转化过程的科学认识，量化灾种转化机制和临界条件，构建灾害链全过程数值模拟评估方法，开展未来情景下沟谷灾害链的演进过程和风险评估；4）沟谷灾害链的防控研究在目前仍处于起步阶段，应在提高对沟谷灾害链科学认识的基础上，建立完善的沟谷灾害链早期识别、监测预警、模拟评估、应急处置、工程治理、应急避险和风险管理综合治理体系。

Evolution Models, Risk Prevention and Control Countermeasures of the Valley Disaster Chain (Invited Contribution)

The valley disaster chain has recently attracted the attention of academics, which is also a huge challenge in the construction and operation of the Sichuan-Tibet railway transportation corridor. This research gives the definition and components of the valley disaster chains. By review valley disaster chain events that have occurred, the characteristics of the valley disaster chain were summarized, and their evolution models were summarized. The key factors that affecting the valley disaster chain were also discussed. Then, the risk assessment system, prevention, and control countermeasures of the valley disaster chain were proposed. The conclusions were obtained as follows: 1) The valley disaster chain is composed of potential disasters, primary disasters, secondary disasters (or series), and disaster-bearing bodies. Their typical characteristics were summarized as time continuity, spatial continuity, causality, and chain evolution. Based on the primary disasters, the valley disaster chain can be divided into 3 categories and 11 sub-categories, including landslide disaster chains, debris flow disaster chains, and glacial lake disaster chains, which can be formed by a combination of three key processes (collapse/landslide-clastic flow/debris flow, landslide/debris flow blocking the river, and dammed /glacial lake outburst). 2) The formation of the valley disaster chain includes two modes. One is that the physical and mechanical properties of the primary disaster mass changed during movement to form secondary disasters, the other is that the primary disaster body changes the boundary of the secondary disaster body that induces secondary disasters. 3) The risk assessment of the valley disaster chain should pay attention to both the initiation mechanism of the primary disaster and the chain generation mechanism of the secondary disasters. It is suggested to strengthen the identification accuracy of the source of the potential disaster, develop the scientific understanding of the disaster transformation process, and quantify the disaster transformation mechanisms and critical conditions, establish a numerical simulation and evaluation method for the valley disaster chain, and carry out the evolution process and risk assessment of the valley disaster chain under future scenarios; 4) The prevention and control of the valley disaster chain is still in its infancy and should be improved based on the scientific understanding of the disaster chain. A comprehensive system for early identification, monitoring and early warning, simulation evaluation, emergency response, engineering governance, emergency avoidance, and risk management of the valley disaster chain is needed in the future.