南平蔡源滑坡泥石流成灾特点及灾后反思

THE CHARACTERISTICS AND EXPERIENCE OF LANDSLIDE AND DEBRIS FLOW DISASTER IN CAI YUAN VILLAGE,NANPING CITY

在花岗岩风化强烈地区,即使在植被茂密的自然山坡,持续强降雨阈值达到一定程度,易引发群发性滑坡泥石流,形成灾害链。这些滑坡多是表层土质滑坡,具有突发性,滑面多呈直线型,位于残坡积层与全-强风化界面之间。滑动前变形迹象不明显,一旦启动迅速成为高速滑坡,形成所谓"气垫效应",能跨越沟坎,运行距离较远,其前缘冲击波能摧毁一切,造成严重灾难。滑体在沟谷洪水作用下转化为泥石流,形成二次灾害。区域性大面积群发性地质灾害的产生,使抢险救灾工作难于开展,从灾害发生到抢险救灾结束,整个过程给我们留下很多经验、教训和启示。

A large number of disaster chain of landslide and debris flow have been caused by the strong rainfall threshold easily in the weathered granite strong area, even in the dense vegetation of natural slopes zone. The charcteristic of surface soil landslide include linear sliding surface between the eluvial slope wash and highly weathered interface, with sudden formation. Lanslide cause serious destroy disaster in the leading edge by the formation o{ ＂ air cushion effect＂ with once started quickly high-speed and previous unclear sliding deform- ation signs. Landslide transform to debris flow by the effect of the flood disaster in the val- ley. The rescue and relief work is difficult to carry out for the large regional group of geolog- ical hazards. The experience and indoctrination have procured from the whole process of the disaster deformation to the subsequent rescue.