西藏帕隆藏布河谷崩塌滑坡、泥石流的分布规律

西藏帕隆藏布河谷崩塌滑坡、泥石流灾害严重。崩塌滑坡、泥石流的分布 ,因谷坡坡向的水热条件差异而导致坡向差异 ,因地貌发育和形态的沿程分异显现沿程差异 ,因其促发条件的差异又显现灾种差异。采用有序样品最优分割和方差分析等定量方法 ,揭示了崩塌滑坡、泥石流的差异性分布规律 :全河段可分为上游峡谷泥石流密集段 ,中游宽谷泥石流及崩塌滑坡较密集段 ,和下游、拉月曲峡谷崩塌滑坡、泥石流极密集段 ;北岸崩塌滑坡和泥石流比南岸数量多、规模大 ;崩塌滑坡有向下游增大增多之趋势。进而对道路平面选线原则提出了建议。

Differential distribution regularity of collapse-landslides and debris flows along Palong Zangbu River Valley in Tibet

Collapse-landslides and debris flows are main types of mountain disasters in Palong Zangbu river valley of Tibet. These disasters are large in scale and serious in harm-fulness to the valley. Differences of hydro-thermal conditions related to aspect of valley slope lead to differences distribution of the collapse-landslide and debris flows.Differences of the geomorphologic evolution and morphologic processes of the valley lead to distribution differences of the disasters along the river. Differences of growth conditions between collapse-landslides and debris flows lead to distribution differences of the two types of disasters. For control of mountain disasters and site selection of highways and railways along the river, distribution regularities of the collapse-landslides and debris flows with the above-mentioned differences are identified, by quantitative methods including orderly sample optimum cutting method and the variance analysis, method. These regularities are: (1) the whole river section (from Ranwu to Lulang) can be divided into: a) upstream gorge section with concentrateddistribution of debris flows, avalanches and debris cones; b) midstream broad valley section with more concentrated distribution of debris flows and collapse-landslides; and c)downstream gorge section and the tributary of Layue with extremely concentrated distribution of debris flows and collapse-landslides. (2) Quantities and scales of collapse-landslides and debris flows on the northern slope surpass those on the southern slope of the river valley. (3) The collapses and landslides have an increase tendency towards downstream and the debris flows have a decrease tendency in order of the downstream gorge section, the upstream gorge section and the midstream broad valley section. Further, some suggestions on site selection principle of road plane are advanced.