汶川震区桃关沟2013-07-10泥石流成灾机理

摘要

For the giant debris flow caused by heavy rainfall in Taoguan gully, in Wenchuan earthquake area on July 10th,2013. Field investigation and experiments were made to analyze the loose materials,rainfall,and terrain conditions of the Taoguan gully,and study the process of startup flow and deposition of the debris flow. The result shows that the damage of the rock mass triggered by earthquake in the gully is the root cause of such frequent debris flow after the earthquake. Its mechanism is actually the startup and superposition of loose materials from collapse and landslides,and deposits on slopes and in the gully. From the development trend,the Taoguan debris flow is now on a high-frequency developmental stage,and the possibility of breakout of large scale debris flows still exists.%针对2013年7月10日持续强降雨导致汶川震区桃关沟暴发特大型泥石流，通过现场勘查和试验，分析了桃关沟泥石流暴发的物源、降雨和地形条件，研究了泥石流的起动、流通和堆积过程。研究结果表明，地震对沟域内岩土体的震动破坏是震后泥石流频繁暴发的根源，其成灾机理体现出崩滑物源、坡面物源和沟道物源三者的启动及相互叠加，从发展趋势看，桃关沟泥石流正处于高频发育阶段，仍存在暴发大规模泥石流的可能性。