帕隆藏布流域低频泥石流的成因机制分析——以倾多镇抄布隆巴泥石流为例

Characteristics and Geneses of Low Frequency Debris Flow along Parlongzangbo River Zone: Take Chaobulongba Gully as an Example

2017年8月3日西藏波密县倾多镇抄布隆巴暴发泥石流,此前70余年未暴发过泥石流,作为帕隆藏布流域典型的低频泥石流,对其成因进行分析,为大量的冰川融水使位于沟源处的大量冰水堆积体处于饱和状态,使土体内部摩擦系数大大降低,黏聚力急剧减小,超过土体稳定性临界点突然发生溃决及大规模崩滑,致使沟道内堆积的大量冰水堆积物进入沟道形成泥石流。并采用形态实测法和称重法等方法计算其流量、流速及重度。通过分析抄布隆巴泥石流的成因,对帕隆藏布流域低频泥石流的成因进行了探讨,并得出了帕隆藏布流域低频泥石流大部分以冰川型泥石流为主,且预测区域内泥石流沟将进入新一轮活跃期,具多频次、多成因、规模不等的暴发趋势。

On August 3,2017,an outbreak of debris flow occurred in Dundo Town,Bomi County,Tibet.No debris flow occurred in the past 70 years.As a typical low-frequency debris flow in the Palongzangbo Basin,the causes of the outbreak were analyzed through on-site investigation.A large number of glacial melting water saturated the ice-water accumulation at the source of the gully.The internal friction coefficient and cohesion of the soil were greatly reduced,and the sudden collapse and large-scale landslides occurred beyond the critical point of soil stability,resulting in a large number of ice-water deposits accumulated in the ditch entering the ditch to form debris flow.The flow rate,velocity and gravity were calculated by the method of morphological measurement and weighing method.Based on the analysis of the causes of the debris flow in Chaobulongba,the causes of the low-frequency debris flow in Palongzangbu Basin were discussed.It is concluded that most of the low-frequency debris flows in Palongzangbu Basin are glacial debris flows,and that the debris flow gullies in the region will enter a new active period with multiple frequencies,multiple causes and different scale storms.Trend.