低频率泥石流灾害及工程防治

重现期＞50 a的泥石流被定义为低频率泥石流。低频率泥石流灾害可能发生在生态环境良好的地区,并造成重大的财产损失和人员伤亡。低频率泥石流灾害具有需要大暴雨、特大暴雨、冰湖或水库(尾矿坝)溃决、火山爆发、冰雪融化、冰崩、雪崩、滑坡、地震等特殊因素激发,危害严重,难于预测预报等特点。低频率泥石流灾害应采取土木工程进行预防性治理,工程设计的要点是,在沟谷中布置坚固的大中型骨干拦挡工程,并保证有充足的拦淤库容。新型拦砂坝设计采用重力式结构,低坝群布置,浆砌石建造,在坝体上设置大孔口,具有工程投资小,就地取材,施工简单,有选择性地拦截泥沙,拦淤库容可以反复使用等优点,适合我国国情。

The Hazards and Engineering Control of Low Frequency Debris Flow

Low frequency debris flow is defined as that with return period of larger than 50 years. The most disas- ters have been caused by the low-frequency debris flows,which occur usually under heavy rain and rainstorm;break of ice lake and reservoir (tail mineral dams),volcanic eruptions,melted ice and snow,ice collapse,avalanche, landslides,earthquakes,and others alike. They also occur in good ecological conditions. The forecast of low-fre- quency debris flow is difficult and generally engineering measurements are necessary for prevention. In designing engineering works,the large and medium-sized dams of gravity types should be set in the gully with sufficient ca- pacity of storage. And deeper dams should be planned in group with coordinating function. The sediment can be se- lectively captured and the capacity of storage can be renewed. Dams are built in stone masonry with parallel holes for delivering water and fine content of sediment of the flow. Engineering system like this costs less and requires no special materials and techniques in construction.