台风暴雨型泥石流启动机制
Initiating Mechanism of Typhoon-Triggered Debris Flow

台风暴雨型泥石流指由台风暴雨直接激发的泥石流.通过回归分析发现泥石流集聚爆发时间与最大1 h雨强出现时间几乎同步，传统的泥石流启动理论难以很好地解释这种现象.在分析该类泥石流启动过程的基础上，采用二维极限平衡分析模型从斜坡稳定性角度分析泥石流形成区斜坡在短历时强降雨过程中的破坏过程，认为在台风影响前期斜坡处于地下水渗流阶段，随着降水不断入渗坡体，土体基质吸力逐渐减少，有效应力下降.起关键作用的是出现超大短历时雨强，斜坡出现显著地表径流，其切向拖拽力一定程度上增加了斜坡的下滑力，从而加速其失稳破坏.这较好地解释了上述同步启动现象.最后，通过统计分析发现流域支沟启动比例与泥石流启动效率相关.
Typhoon-triggered debris flow refers to the debris flow that was triggered by typhoon storm. By regression analysis, it is found that debris flow multi-outbreak and the huge rainfall intensity were almost synchronizing, but traditional debris flow initiating theory can hardly explain this phenomenon. On the basis of analyzing the initiating process of typhoon-triggered debris flow, a two-dimension limit equilibrium analytic model was introduced to analyze the failure process of the slope in the forming area of the debris flow watershed in terms of stability, while the huge rainfall intensity in short duration come along. It is supposed that in the early stage of the typhoon influence, the slope was on the underground water seepage stage, as the water infiltrated into the slope, the matric suction in the soil reduced, and effective stress descended. The huge rainfall intensity in short duration played a pivotal role; notable overland runoff appeared on the slope surface, the sliding force of the slope was expanded by the shearing force of the overland runoff fand the slope failed more quickly. It explained the synchronizing phenomenon well. Finally, through statistical analysis, it was found that the debris flow initiating efficiency is relevant to the proportion of the tributary ditch initiating