Case history of the disastrous debris flows of Tianmo Watershed in Bomi County, Tibet, China: Some mitigation suggestions

Ge, Yong; Cui, Peng; Su, Fenghuan; Zhang, Jianqiang; Chen, Xingzhang

doi:10.1007/s11629-014-2579-2

Cited by 45 publications

(13 citation statements)

References 24 publications

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“…Assuming that the thickness of the ice debris cover is greater than that of the active layer of the permafrost, mass movement activity occurs only under specific topographic conditions and/or under the action of external meltwater sources or slope undercutting (Schomacker, 2008). However, there have been more than three large-scale debris flows took place in the Tianmo gully at July 25-31 (DF1) and September 5-8 (DF2) of 2010, September 4 of 2007 (DF3) (Ge et al, 2014), and all occurred during summer when temperature generally exceeded 25 °C (Figure 2). In summer 2020, several fresh debris flows were found in the Tianmo gully (Figure 1B), which can be concluded that it is highly likely that thawing can initiate mass movement activity here.…”

Section: Study Area and Sampling Locationmentioning

confidence: 99%

“…They propose that the presence of ice enhances soil mechanical properties, and ice debris mixtures deform little under low temperatures are generally more resistant than their components in alpine environments (Konrad and Morgenstern, 1980;Ting et al, 1983;Hivon and Sego, 1995). As temperature rises towards the thawing point, films of unfrozen water gradually form at the interface between ice and soil particles, glacial tills on the surface of steep slopes determines the evolution of slope collapse (Chamberlain et al, 1972;Zimmermann and Haeberli, 1992;Moore, 2014;Zhang et al, 2014). However, above findings are failure explain the conclusion that till provides the main source of materials for glacial debris flows.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Properties of Frozen Glacial Tills due to Short Periods of Thawing

Jiang

Wang

et al. 2021

Front. Earth Sci.

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Due to the warming climate, glacier retreat has left massive glacial tills in steep gullies; ice in the soil is prone to change phase resulting in the decrease of the ice strength and bonding of soil particles; collapse of thawing tills can lead to debris flows with disastrous consequences for geotechnical infrastructures. To improve our understanding of the mechanics of thawing glacial tills, we conducted unconsolidated–undrained direct shear tests on glacial tills from Tianmo gully on the southeastern Tibetan Plateau. Control specimens were not subjected to freeze–thaw action. A total of 648 specimens with three different dry densities, three initial water contents, and 18 thawing times were tested. Peak shear strength, peak stress to displacement ratio (0.857), and cohesion were the highest in frozen specimens. After a thawing time of 0.25 h, there was a marked decline in shear strength; maximum friction was 2.58, which was far below the value of cohesive strength. For thawing times of 0.25–4 h, peak strength varied little with thawing time, but cohesion decreased and internal friction angle increased with increasing thawing time. Our results indicate that thawing of the solid ice in the till during the initial phase of till thawing is the key control of peak till strength; the effect of ice on cohesion is greater during the initial phase of thawing and in loose tills. Moreover, frequent sediment recharge of gullies may be explained by the decrease of cohesion with increasing thawing time caused by short-term destruction of ice bonding.

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Section: Study Area and Sampling Locationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mechanical Properties of Frozen Glacial Tills due to Short Periods of Thawing

Jiang

Wang

et al. 2021

Front. Earth Sci.

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“…Given that rock avalanches (landslides) occur more often during the summer due to the higher temperatures and precipitation, loose deposits generally have favorable water content and pore fluid pressure conditions for the transformation of associated mass movements into debris flows ( see Iverson et al, 1997, 2011). The debris flows that occur under such circumstances usually have a much higher velocity than those stimulated by hydraulic processes and are therefore much more destructive (Chiarle et al, 2007; Deng et al, 2017; Ge et al, 2014; Wei et al, 2018). For example, the velocities of DFMC events that have occurred in the Rio Santa valley (Peru) and Tianmo Gully (China) were over 40m/s (as estimated using run-up and super-elevation geometry) (Evans et al, 2009; Ge et al, 2014; Mergili et al, 2018).…”

Section: Examples Of Dfmc Events From Literature and Their Causesmentioning

confidence: 99%

Debris flows originating in the mountain cryosphere under a changing climate: A review

Yao

Huang

et al. 2020

Progress in Physical Geography: Earth and Environment

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Debris flows originating in the mountain cryosphere (DFMC) are one of the most globally important, widely distributed mass flows (and natural geohazards) in mountain areas with a high altitude and/or high latitude. This is particularly the case in high mountain areas that have been undergoing rapid glacier retreat, permafrost degradation, and other melt/thaw related processes. As a consequence, the actual hazards and potential risks of DFMC have drawn increasing attention in the context of global climate change (i.e. a rising temperature and higher occurrence of strong precipitation events). Unlike debris flows at low elevations, where their occurrence is closely related to precipitation (intensity and duration), the breach of a DFMC event depends on precipitation and/or air temperature, which in turn influence melt/thaw processes, rending the formation mechanism much more complicated. Although research has been widely carried out on DFMC in past decades, there is still a long way to go before we have reached a complete understanding of the formation mechanism and triggering conditions. This review summarizes recent progress in the study of DFMC, including typical DFMC events and their causes, the failure mechanisms of rock (or ice-rock joints), the characteristics of moraine deposits, initiation through hydraulic erosion (entrainment), the relationship between DFMC initiation and meteorological conditions, and the slope stability of the mountain cryosphere under a changing climate. Several issues that should be addressed in future research are also discussed.

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“…In general, the total loss caused by such a multi-hazard chain is far greater than that caused by a single hazard (Chai et al, 1995;Xu et al, 2010;Chen et al, 2011;Ma and Kaiheng, 2013). Recent events, e.g., the 2007 and 2010 Tianmo debris flows (Ge et al, 2014;Deng et al, 2017) and the 2018 Sedongpu debris flows in southeastern Tibet (Hu K. et al, 2019), demonstrate that the multi-hazard chain may affect great spatial and temporal extents than a debris flow.…”

Section: Introductionmentioning

confidence: 99%

Multi-Hazard Chain Reaction Initiated by the 2020 Meilong Debris Flow in the Dadu River, Southwest China

Lan

Wang

et al. 2022

Front. Earth Sci.

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Delivery of large volumes of sediment by debris flows in a short time into rivers often initiates a hazardous chain reaction in alpine valleys. Predicting the multi-hazard chain’s evolution and intervening in its cascading effects by artificial countermeasures face major challenges due to the spatial and temporal variability of controlling factors. On June 17, 2020, a rainstorm-induced debris flow event with a volume of 2.4 × 105 m3 occurred in the Meilong catchment, Danba County, Sichuan Province, Southwest China, which triggered a debris flow–outburst flood–landslide hazard chain. Large amounts of sediment entered the Xiaojinchuan River and formed a barrier lake. The outburst flood and narrowed river flow eroded 2.76 × 106 m3 of deposits and reactivated the Aniangzhai landslide. Engineering measures were implemented to prevent the hazard, including dredging, rechanneling, and embankment construction. The deformation rate and acceleration of the landslide decreased from a peak of 75 mm/h to 8.74 mm/h and a peak of 16.46 mm/h2 to 0.13 mm/h2 before and after the engineering, respectively, according to measurements of a ground-based monitoring radar. Without the engineering measures, the factor of safety of the landslide would be reduced to 0.93, and a larger landslide dam hazard would occur if the foot were eroded by more than 17 m. The case and its successful engineering demonstrate that artificial intervention measures are effective in halting the cascading process of natural hazards.

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Case history of the disastrous debris flows of Tianmo Watershed in Bomi County, Tibet, China: Some mitigation suggestions

Cited by 45 publications

References 24 publications

Mechanical Properties of Frozen Glacial Tills due to Short Periods of Thawing

Mechanical Properties of Frozen Glacial Tills due to Short Periods of Thawing

Debris flows originating in the mountain cryosphere under a changing climate: A review

Multi-Hazard Chain Reaction Initiated by the 2020 Meilong Debris Flow in the Dadu River, Southwest China

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