杨情情, 苏志满, 陈锣增, 黄丽娟. 2015: 冰屑对冰-岩碎屑流运动特性影响作用的初步分析. 工程地质学报, 23(6): 1117-1126. DOI: 10.13544/j.cnki.jeg.2015.06.012
    引用本文: 杨情情, 苏志满, 陈锣增, 黄丽娟. 2015: 冰屑对冰-岩碎屑流运动特性影响作用的初步分析. 工程地质学报, 23(6): 1117-1126. DOI: 10.13544/j.cnki.jeg.2015.06.012
    YANG Qingqing, SU Zhiman, CHEN Luozeng, HUANG Lijuan. 2015: FLUME TESTS ON INFLUENCE OF ICE TO MOBILITY OF ROCK-ICE AVALANCHES. JOURNAL OF ENGINEERING GEOLOGY, 23(6): 1117-1126. DOI: 10.13544/j.cnki.jeg.2015.06.012
    Citation: YANG Qingqing, SU Zhiman, CHEN Luozeng, HUANG Lijuan. 2015: FLUME TESTS ON INFLUENCE OF ICE TO MOBILITY OF ROCK-ICE AVALANCHES. JOURNAL OF ENGINEERING GEOLOGY, 23(6): 1117-1126. DOI: 10.13544/j.cnki.jeg.2015.06.012

    冰屑对冰-岩碎屑流运动特性影响作用的初步分析

    FLUME TESTS ON INFLUENCE OF ICE TO MOBILITY OF ROCK-ICE AVALANCHES

    • 摘要: 冰-岩碎屑流是一种发育在高寒山区、含固态水的特殊碎屑流,具有超强的运动性。冰屑对提高冰-岩碎屑流运动性至关重要,但对其认识仍较为不足。通过对2000年易贡滑坡的灾史资料分析和野外调查,指出易贡滑坡启动时携带冰川冰体、运动时铲刮含冰碎屑物,而且具有规模大、冲出距离远的运动特性,是典型的冰-岩碎屑流。进而引入斜槽实验模拟岩土体上覆冰川冰体失稳下滑的过程,验证调查发现的堆积体前端坑洞群问题,探讨冰-岩碎屑材料冲出距离与含冰量、冰屑岩屑粒径比的关系。研究发现,冰屑可能包裹在碎屑流前端并全程参与碎屑流运动,在停积后由于融化而在堆积体上形成坑洞。被包裹的冰屑能够提高冰-岩碎屑材料的冲出距离,但含冰量较大时冰屑可能由于黏结成团、不易进入碎屑流内部而导致冲出距离变小。由此归结得到,冰屑提高碎屑流冲出距离的一个重要前提为冰屑进入碎屑流内部,当冰屑与岩屑的粒径比越小时冰屑越容易进入。这项研究工作为认识冰屑影响提供了坑洞调查法和斜槽实验法,研究成果有助于更为深入地认识冰-岩碎屑流运动特性的冰屑影响机理,为预防冰-岩碎屑流的远程致灾提供科学依据。

       

      Abstract: Rock-ice avalanches in high-mountain regions can have an extremely high mobility and an enormous destructive potential. The influence of ice is of critical importance to enhance the mobility of rock-ice avalanches. However, the role of ice during the mass movement processes has not been systematically investigated and the mechanisms leading to the typically long run-out distances of such events are not well understood. Based on field investigation and historical data analysis of Yigong landslide occurred in April 2000,a conclusion is drawn that Yigong landslide is a typical rock-ice avalanche with a huge volume and an extremely long run-out, which involved ice or snow from the beginning of the movement or due to entrainment. A series of flume tests are conducted to reproduce the propagation of roc-ice avalanches and to explain a group of holes located on the front of deposit which are observed in the field. Furthermore, the run-outs of granular avalanches with different ice contents and size ratios of rock and ice particles are measured. The results show that ice particles are possibly involved in the front mass of granular avalanches on their whole movement. Then they melt when the avalanches deposit. It is the possible cause of the formation of the holes in the deposit. The involved ice particles can enhance the mobility of rock-ice avalanches. However, the length of run-out would not increase but decrease in the condition of large ice contents due to the ice cohesive action which makes the ice particles become large ones and difficult to enter into granular avalanches. It is concluded that the entrainment of ice particles into the mass of granular avalanches plays an important role in enhancing the mobility. The smaller size ratio of ice and rock particles, the easier the ice particles entered into granular avalanches. This work contributes to a better understanding of the role of ice in enhancing the mobility of rock-ice avalanches, and also to provide a scientific guidance in preventing the hazards.

       

    /

    返回文章
    返回