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Journal of mountain Science 2013年第3期10卷 370-377页

作者： WU Yan-hong LI Wei ZHOU Jun CAO Yang key laboratory of mountain surface processes and Ecological Regulation Chengdu Institute of Mountain Hazards and EnvironmentChinese Academy of Sciences

Gongga mountain, locates on the eastern edge of Tibetan Plateau of China, is the highest mountain in China except summits in Tibet. Only limited meteorological data on Gongga mountain have been published so far. Here we present the meteorological records from two stations, Moxi Station （at 1,621.7 m above sea level （a.s.1.）, 1992- 2010） and Hailuogou Station （at 2,947.8 m a.s.l., 1988-2010）, on the eastern slope of Gongga mountain. In the past two decades, the annual precipitation decreased while the annual mean temperature increased at Hailuogou Station. Both precipitation and temperature increased at Moxi Station. The precipitation variation on the eastern slope of Gongga mountain is influenced by both East Asian Monsoon and Indian Monsoon, so that the precipitation concentrated between May and October. The temperature variation on the eastern slope of Gongga mountain in the past two decades showed similar trends as that of the northern hemispheric and global. In the past two decades, the temperature increased o.35℃ and o.3℃/decade at Hailuogou Station and Moxi Station respectively, which was higher than the increase extents of northern hemispheric and global temperature. The most intense warming occurred at the first decade of 21St century. The winter temperature increased more at Hailuogou Station than at Moxi Station. A remarkable increase of temperature in March was observed with only a little precipitation at both high and low altitude stations.

关键词： Temperature Precipitation Variation Global change Gongga mountain

Case History of the Disastrous Debris Flows of Tianmo Watershed in Bomi County, Tibet, China: Some Mitigation Suggestions

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Journal of mountain Science 2014年第5期11卷 1253-1265页

作者： GE Yong-gang CUI Peng SU Feng-huan ZHANG Jian-qiang CHEN Xing-zhang key laboratory of mountain hazards and Earth surface processes / institute of mountain hazards and environment Chinese Academy of Sciences School of environment and Resources Southwest University of Sciences and Technology

Debris flows and landslides, extensively developing and frequently occurring along Parlung Zangbo, seriously damage the Highway from Sichuan to Tiebt(G318) at Bomi County. The disastrous debris flows of the Tianmo Watershed on Sept. 4, 2007, July 25, 2010 and Sept. 4, 2010, blocked Parlung Zangbo River and produced dammed lakes, whose outburst flow made 50 m high terrace collapse at the opposite bank due to intense scouring on the foot of the terrace. As a result, the traffic was interrupted for 16 days in 2010 because that 900 m highway base was destructed and 430 m ruined. These debris flows were initiated by the glacial melting which was induced by continuous higher temperature and the following intensive rainfall, and expanded by moraines along channels and then blocked Parlung Zangbo. At the outlet of watershed,the density, velocity and peak discharge of debris flow was 2.06 t/m3, 12.7 m/s and 3334 m3/s, respectively. When the discharge at the outlet and the deposition volume into river exceeds 2125 m3/s and 126×103 m3, respectively, debris flow will completely blocked Parlung Zangbo. Moreover,if the shear stress of river flow on the foot of terrace and the inclination angel of terrace overruns 0. 377 N/m2 and 26°, respectively, the unconsolidated terrace will be eroded by outburst flow and collapse. It was strongly recommended for mitigation that identify and evade disastrous debris flows, reduce the junction angel of channels between river and watershed, build protecting wall for highway base and keep appropriate distance between highway and the edge of unconsolidated terrace.

关键词： Debris Flow Characteristics Hazard Chain Formation Condition Tianmo Watershed

Characteristics of a Drainage Channel with Staggered Indented Sills for Controlling Debris Flows

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Journal of mountain Science 2014年第5期11卷 1242-1252页

作者： CHEN Xiao-qing YOU Yong CHEN Jian-gang HUANG Kai LI De-ji key laboratory of mountain hazards and Earth surface processes Chinese Academy of Sciences institute of mountain hazards and environment Chinese Academy of Sciences and Ministry of Water Conservancy

The characteristics of a new type of drainage channel with staggered indented sills for controlling debris flows were studied. The intermediate fluid in the non-viscous debris flow exhibited a helical movement, whereas the fluid near the sidewall had a stop-start movement pattern; the viscous debris flow exhibited a stable structure between the indented sills. The experimental results indicate that the mean velocity of the debris flow increased with increasing channel gradients, and the debris flow velocity was slightly affected by the angle of the sills. The average velocity of the non-viscous debris flow increased in the range of(0.5–1.5) interval between the indented sills, whereas the average velocity of the viscous debris flow increased initially and then decreased in the range of(0.75–1.25) interval between the indented sills. The depth of the non-viscous debris flow tended to gradually increase as the channel gradients increased, whereas the depth of the viscous debris flow gradually decreased as the channel gradients increased. When the discharge of the debris flow was constant, the angle and the interval between the indented sills had a slight effect on the depth of the viscous debris flow, whereas the depth of the non-viscous debris flow exhibited a different trend, as the sill angles and intervals were varied.

关键词： Debris flow Drainage channel Staggered indented sill Wenchuan earthquake

EXPERIMENTAL INVESTIGATION OF THE FAILURE OF CASCADE landSLIDE DAMS

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Journal of Hydrodynamics 2012年第3期24卷 430-441页

作者： NIU Zhi-pan XU Wei-lin LI Nai-wen XUE Yang CHEN Hua-yong State key laboratory of Hydraulics and mountain River Engineering Sichuan University Chengdu 610065China key laboratory-of mountain hazards and land surface processes and institute of mountain hazards andenvironment Chinese Academy of Sciences Chengdu 610041 China

This paper presents results of model tests for the landslide dam failure of a single dam and cascade dams in a sloping channel. The dams were designed to be regular trapezoid with fine sand. A new measuring method named the labeled line locating method was used to digitalize the captured instantaneous pictures. Under two different inflow discharges, the morphological evolution and the flow patterns during one dam failure and the failure of cascade dams were investigated. The results indicate that when the inflow discharge is large, the deformation pattern of the downstream dam is similar to that of the upstream dam, and both dams are characterized with the overtopping scour throughout the dam failure process. When the inflow discharge is small, the upstream dam is scoured mainly through a sluice slot formed by the longitudinal incision, and the downstream dam is characterized with the overtopping scour. The data set presented in this paper can be used for the validation of numerical models and provide a reference for the flood risk management of cascade landslide dams.

关键词： labeled lines locating method inflow discharge cascade landslide dam failure overtopping sloping flume

Types and Causes of Debris Flow Damage to Drainage Channels in the Wenchuan Earthquake Area

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Journal of mountain Science 2014年第6期11卷 1406-1419页

作者： CHEN Jian-gang CHEN Xiao-qing WANG Tao ZOU Yu-hua ZHONG Wei key laboratory of mountain hazards and Earth surface processes Chinese Academy of Sciences institute of mountain hazards and environment Chinese Academy of Sciences and Ministry of Water Conservancy

Debris flows are among the most common geological disasters in China,and have been particularly frequent in Sichuan Province since the Wenchuan earthquake on 12 May *** construction of debris flow drainage channels is a countermeasure used to distribute debris flow fans,and these channels play a critical role in the mitigation and prevention of damage resulting from debris *** field conditions,the useful life of drainage channels can be greatly shortened as a result of strong abrasions to the drainage structure caused by the debris *** investigations have shown that the types of damage to drainage channels include(a) erosion caused by hyper-concentrated silt flow,(b) impact fractures and foundation scour at the groundsills of the drainage channel,(c) destruction of the drainage channel outlet,and(d) destruction of the drainage channel caused by debris flow *** addition,based on the destruction of the drainage channel during the debris flow drainage process,a new type of drainage channel with energy dissipation components was proposed and applied in a steep,narrow gully for debris flow ***,design and engineering repair recommendations for drainage channels are provided as a reference for repairing the damage to the *** results can provide an important reference for the effective repair and optimal design of drainage channels.

关键词： Debris flow Drainage channel Damage type Wenchuan earthquake Geological disaster

Empirical-Statistical Models Based on Remote Sensing for Estimating the Volume of landslides Induced by the Wenchuan Earthquake

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Journal of mountain Science 2011年第5期8卷 711-717页

作者： FAN Jianrong LI Xiuzhen GUO Fenfen GUO Xiang key laboratory of mountain hazards and Earth surface processes Chinese Academy of Sciences Chengdu 610041 China Institute of Mountain Hazards and Environment CAS Chengdu 610041 China

The Wenchuan Ms 8.0 earthquake on May 12, 2008 induced a huge number of landslides. The distribution and volume of the landslides are very important for assessing risks and understanding the landslide - debris flow - barrier lake - bursts flood disaster chain. The number and the area of landslides in a wide region can be easily obtained by remote sensing technique, while the volume is relatively difficult to obtain because it requires some detailed geometric information of slope failure surface and sub-surface. Different empirical models for estimating landslide volume were discussed based on the data of 107 landslides in the earthquake-stricken area. The volume data of these landslides were collected by field survey. Their areas were obtained by interpreting remote sensing images while their apparent friction coefficients and height were extracted from the images unifying DEM (digital elevation model). By analyzing the relationships between the volume and the area, apparent friction coefficients, and the height, two models were established, one for the adaptation of a magnitude scale landslide events in a wide range of region, another for the adaptation in a small scope. The correlation coefficients (R2) are 0.7977 and 0.8913, respectively. The results estimated by the two models agree well with the measurement data.

关键词： 5.12 Wenchuan earthquake landslides Remote sensing Volume Estimation model

Characteristics of Earthquake-Triggered landslides and Post-Earthquake Debris Flows in Beichuan County

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Journal of mountain Science 2010年第3期7卷 246-254页

作者： ZHUANG Jianqi CUI Peng HU Kaiheng CHEN Xiaoqing GE Yonggang key laboratory of mountain hazards and land surface processes and institute of mountain hazards and environment Chinese Academy of Sciences Chengdu 610041 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Field investigations and aerial photography after the earthquake of May 12, 2008 show a large number of geo-hazards in the zone of extreme earthquake effects. In particular, landslides and debris flows, the geo-hazards that most threaten post-disaster reconstruction, are widely distributed. We describe the characteristics of these geo-hazards in Beichuan County using high-resolution remote sensing of landslide distribution, and the relationships between the area and volume of landslides and the peak-discharges of debris flows both pre- and post-earthquake. The results show： 1） The concentration （defined as the number of landslide sources per unit area： Lc） of earthquake- triggered landslides is inversely correlated with distance from the earthquake （DF） fault. The relationship is described by the following equation： Lc = 3.2264exp（-0.0831DF）（R2 = 0.9246）; 2） 87 % of the earthquake-triggered landslides were less than 15× 10^4 m2 in area, and these accounted only for 5o% of the total area; 84% of the landslide volumes were less than 60×10^4 m3, and these accounted only for 50% of the total volume. The probability densities of the area and volume distributions are correlated： landslide abundance increases with landslide area and volume up to maximum values of 5 ×10^4m2 and 30 ×10^4 m3, respectively, and then decreases exponentially. 3） The area （AL） and volume （VL） of earthquake-triggered landslides are correlated as described with the following equation： VL=6.5138AL1.0227 （R2 = 0.9231）; 4）Characteristics of the debris flows changed after the earthquake because of the large amount of landslide material deposited in the gullies. Consequently, debris flow peak-discharge increased following the earthquake as described with the following equation： Vpost = 0.8421Vprel-0972 （R2 = 0.9821）（Vpre is the peak discharge ofpre-earthquake flows and the Vpost is the peak discharge of post-earthquake flows）. We obtained the distribution of the landslides based on the above anal

关键词： 5.12 earthquake landslide Debris flow Magnitude Beiehuan County

Characteristics,Causes and Mitigation of Catastrophic Debris Flow Hazard on 21 July 2011 at the Longda Watershed of Songpan County,China

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Journal of mountain Science 2013年第2期10卷 261-272页

作者： GE Yong-gang CUI Peng GUO Xiao-jun SONG Guo-hu LIU Wei-ming key laboratory of mountain hazards and Earth surface processes Chinese Academy of Sciences institute of mountain hazards and environment Chinese Academy of Sciences University of Chinese Academy of Sciences

Debris flow is a common natural hazard in the mountain areas of Western China due to favorable natural conditions, and also exacerbated by mountainous exploitation activities. This paper concentrated on the characteristics, causes and mitigation of a catastrophic mine debris flow hazard at Longda Watershed in Songpan County, Sichuan Province, on 21 July 2011. This debris flow deposited in the front of the No.1 dam, silted the drainage channel for flood and then rushed into tailing sediment reservoir in the main channel and made the No.2 dam breached. The outburst debris flow blocked Fu River, formed dammed lake and generated outburst flood, which delivered heavy metals into the lower reaches of Fu River, polluted the drink water source of the population of over 1 million. The debris flow was characterized with a density of 1.87～2.15 t/m3 and a clay content of less than 1.63%. The peak velocity and flux at Longda Gully was over l0.0～10.9 m/s and 429.o～446.o m3/s, respectively, and the flux was about 700 m3/s in main channel, equaling to the flux of the probability of 1%. About 33o,ooorn3 solid materials was transported by debris flow and deposited in the drainage tunnel （120,000～130,000 m3）, the front of No.1 dam （100,000 m3） and the mouth of the watershed （l00,000～110,000 m3）, respectively. When the peak flux and magnitude of debris flow was more than 462 m3/s and 7,423 m3, respectively, it would block Fu River and produce a hazard chain which was composed of debris flow, dammed lake and outburst flood. Furthermore, the 21 July large-scale debris flow was triggered by rainstorm with an intensity of 21.2 mm/0.5 h and the solid materials of debris flow were provided by landslides, slope deposits, mining wastes and tailing sediments. The property losses were mainly originated from the silting of the drainage tunnel for flash flood but not for debris flow and the irrational location of tailing sediment reservoir. Therefore, the mitigation measures for mine debris flows

关键词： Debris Flow Characteristics Causes Mitigation Longda Watershed

Quantitative assessment of the impact of earthquakeinduced geohazards on natural landscapes in Jiuzhaigou Valley

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Journal of mountain Science 2019年第2期16卷 441-452页

作者： HU Xu-dong HU Kai-heng ZHANG Xiao-peng WEI Li TANG Jin-bo key laboratory of mountain hazards and Earth surface processes Chinese Academy of Sciences institute of mountain hazards and environment Chinese Academy of Sciences University of Chinese Academy of Sciences

Many natural landscapes that lie in high mountain regions are highly susceptible to geological hazards, and their values and integrity are strongly threatened by the hazards. A preliminary framework was proposed to undertake a quantitative assessment of the impact of earthquake-induced geological hazards on the natural landscapes. Four factors reflecting the aesthetic value, ecological value, integrity of landscapes were selected to assess their vulnerability. The impact of earthquake-induced geological hazards on the landscapes is quantitatively expressed as the product of their vulnerability and resilience. The assessment framework was applied to Jiuzhaigou Valley which was severely struck by the Ms 7.0 earthquake on August 8, 2017. Field survey, satellite image interpretation, high-resolution DEM and unmanned aerial vehicle(UAV) reconnaissance were used to retrieve the values of the assessment factors. Twenty seven World Heritage Sites in the valley strongly influenced by the earthquakeinduced geohazards were evaluated. The impact values of two sites of them(Sparking Lake and Nuorilang Waterfall) are up to 8.24 and 4.65, respectively, and their natural landscapes were greatly damaged. The assessment results show a good agreement with the actual damages of the heritage sites.

关键词： Natural landscapes assessment Jiuzhaigou earthquake Earthquake-induced geohazards World Heritage Sites

Allometric equations of select tree species of the Tibetan Plateau, China

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Journal of mountain Science 2017年第9期14卷 1889-1902页

作者： RAN Fei CHANG Rui-ying YANG Yang ZHU Wan-ze LUO Ji WANG Gen-xu key laboratory of mountain surface processes and Ecological Regulation Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China

The Tibetan forest is one of the most important national forest zones in China. Despite the potentially important role that Tibetan forest will play in the Earth?s future carbon balance and climate regulation, few allometric equations exist for accurately estimating biomass and carbon budgets of this forest. In the present study, allometric equations,both species-specific and generic, were developed relating component biomass(DW) to diameter at breast height(DBH) and tree height(H) for six most common tree species in Tibetan forest. The 6 species were Abies georgei Orr., Picea spinulosa(Griff.)Henry, Pinus densata Mast., Pinus yunnanensis Franch., Cypresses funebris Endl. and Quercus semecarpifilia Smith.. The results showed that, both DBH-only and DBH2 H based species-specific equations showed a significant fit(P<0.05) for all tree species and biomass components. The DBH-only equations explained more than 80% variability of the component biomass and total biomass, adding H as a second independent variable increased the goodness of fit, while incorporating H into the term DBH2 H decreased the goodness of fit. However, not all DBH-H combined equations showed a significant fit(P<0.05) for all tree species and biomass components. Hence, the suggested species-specific allometric equations for the six most common tree species are of the form ln(DW) = c + αln(DBH). The generalized equations of mixed coniferous component biomass against DBH, DBH2 H and DBH-H also showed a significant fit(P<0.05) for all biomass components. However, due to significant species effect, the relative errors of the estimates were very high. Hence, generalized equations should only be used when there are too many different tree species, or there is no species-specific model of the same species or similar growth form in adjacent area.

关键词： Tibetan forest Allometric models Species-specific Mixed coniferous forest Model evaluation