冲淤变动型沟谷泥石流防治结构及计算   总被引：10，自引：0，他引：10  

王蓉  翁其能  陈洪凯 《山地学报》2001,(Z1)

本文以平川沟泥石流为例 ,基于对冲淤变动型沟谷泥石流基本特性的分析 ,遵循“以泄为主、导排结合”的防治原则 ,提出了有效治理此类泥石流的汇流 #速流结构 ;运用地基梁计算理论对速流槽进行了力学分析计算 ,比较详细地进行了汇流槽侧墙、锚固桩的内力计算。  相似文献   

西藏易贡滑坡物质运动全过程数值模拟研究     

柴贺军  王士天  许强  黄润秋  范相德 《地质灾害与环境保护》2001,12(2):1-3,82

2000年4月9日20时05分，西藏波密县易贡乡发生的大型山体崩滑，造成极大危害。在野外调查基础上，运用离散单元法模拟该崩滑体破坏、运动的全过程，此次灾害为扎木弄沟源头的山体崩塌，振动引起沟内崩坡积物发生沙土液化而随崩塌体一起运动，形成高速碎屑流的破坏运动机制，与实际情况较为吻合。  相似文献   

新一轮二滩电站库区遥感调查   总被引：1，自引：0，他引：1  

王治华  王晓红 《中国地质灾害与防治学报》2001,12(1):60-66

新一轮二滩电站库区遥感调查是在我国前20年滑坡、泥石流遥感调查技术方法基础上的一次革新。本文介绍了革新方法的数据源、工作平台、技术流程、及人机交互与自动分类相结合的遥感解译方法，并对获得的工作区滑坡、泥石流的数量、分布、特性及它们的环境背景作简要分析。  相似文献   

The Llullaillaco volcano, northwest Argentina: construction by Pleistocene volcanism and destruction by sector collapse     

J. P. Richards  M. Villeneuve 《Journal of Volcanology and Geothermal Research》2001,105(1-2)

Llullaillaco is one of a chain of Quaternary stratovolcanoes that defines the present Andean Central Volcanic Zone (CVZ), and marks the border between Chile and Argentina/Bolivia. The current edifice is constructed from a series of thick dacitic lava flows, forming the second tallest active volcano in the world (6739 m). K–Ar and new biotite laser ⁴⁰Ar/³⁹Ar step-heating dates indicate that the volcano was constructed during the Pleistocene (≤1.5 Ma), with a youngest date of 0.048±0.012 Ma being recorded for a fresh dacite flow that descends the southern flank. Additional ⁴⁰Ar/³⁹Ar measurements for andesitic and dacitic lava flows from the surrounding volcanic terrain yield dates of between 11.94±0.13 Ma and 5.48±0.07 Ma, corresponding to an extended period of Miocene volcanism which defines much of the landscape in this region. Major- and trace-element compositions of lavas from Llullaillaco are typical of Miocene–Pleistocene volcanic rocks from the western margin of the CVZ, and are related to relatively shallow-dipping subduction of the Nazca plate beneath northern Chile and Argentina.Oversteepening of the edifice by stacking of thick, viscous, dacitic lava flows resulted in collapse of its southeastern flank to form a large volcanic debris avalanche. Biotite ⁴⁰Ar/³⁹Ar dating of lava blocks from the avalanche deposit indicate that collapse occurred at or after 0.15 Ma, and may have been triggered by extrusion of a dacitic flow similar to the one dated at 0.048±0.012 Ma. The avalanche deposits are exceptionally well preserved due to the arid climate, and prominent levées, longitudinal ridges, and megablocks up to 20-m diameter are observed.The avalanche descended 2.8 km vertically, and bifurcated around an older volcano, Cerro Rosado, before debouching onto the salt flats of Salina de Llullaillaco. The north and south limbs of the avalanche traveled 25 and 23 km, respectively, and together cover an area of approximately 165 km². Estimates of deposit volume are hampered by a lack of thickness information except at the edges, but it is likely to be between 1 and 2 km³. Equivalent coefficients of friction of 0.11 and 0.12, and excess travel distances of 20.5 and 18.5 km, are calculated for the north and south limbs, respectively. The avalanche ascended 400 m where it broke against the western flank of Cerro Rosado, and a minimum flow velocity of 90 m s⁻¹ can be calculated at this point; lower velocities of 45 m s⁻¹ are calculated where distal toes ascend 200 m slopes.It is suggested that the remaining precipitous edifice has a high probability for further avalanche collapse in the event of renewed volcanism.  相似文献   

Empirical predictors of annual bed load travel distance,and implications for salmonid habitat restoration and protection     

Timothy J. Beechie 《地球表面变化过程与地形》2001,26(9):1025-1034

Measurements of annual travel distance (L_b) of bed load sediment at 16 locations in Alaska, the intermountain USA, west coast USA and Scotland are strongly correlated with bankfull channel width (r² = 0·86, p < 0·001). Travel distance of particles is probably limited by trapping in bars, which have a longitudinal spacing proportional to channel width. Increased abundance of woody debris reduces bar spacing and may reduce L_b. Longer cumulative duration of bed load transporting flows in a year appears to increase L_b. Other predictors of annual travel distance such as stream power per unit length, drainage area and bankfull discharge were less well correlated with L_b (r² ranging from 0·27 to 0·51). Stream power per unit bed area, basal shear stress and slope were not significantly related to L_b (r² < 0·05). Most correlations were improved when regressions were limited to data from the west coast USA. Travel distance estimates can be used to help identify reaches that may take longer to recover from large, short‐term increases in sediment supply. Published in 2001 by John Wiley & Sons, Ltd.  相似文献   

Distorted Froude‐scaled flume analysis of large woody debris     

Nicholas P. Wallerstein  Carlos V. Alonso  Sean J. Bennett  Colin R. Thorne 《地球表面变化过程与地形》2001,26(12):1265-1283

This paper presents the results of a movable‐boundary, distorted, Froude‐scaled hydraulic model based on Abiaca Creek, a sand‐bedded channel in northern Mississippi. The model was used to examine the geomorphic and hydraulic impact of simplified large woody debris (LWD) elements. The theory of physical scale models is discussed and the method used to construct the LWD test channel is developed. The channel model had bed and banks moulded from 0·8 mm sand, and flow conditions were just below the threshold of motion so that any sediment transport and channel adjustment were the result of the debris element. Dimensions and positions of LWD elements were determined using a debris jam classification model. Elements were attached to a dynamometer to measure element drag forces, and channel adjustment was determined through detailed topographic surveys. The fluid drag force on the elements decreased asymptotically over time as the channel boundary eroded around the elements due to locally increased boundary shear stress. Total time for geomorphic adjustment computed for the prototype channel at the Q₂ discharge (discharge occurring once every two years on average) was as short as 45 hours. The size, depth and position of scour holes, bank erosion and bars created by flow acceleration past the elements were found to be related to element length and position within the channel cross‐section. Morphologies created by each debris element in the model channel were comparable with similar jams observed in the prototype channel. Published in 2001 John Wiley & Sons, Ltd.  相似文献   

Assessment of Debris-Flow Hazards of Alluvial Fans   总被引：1，自引：0，他引：1  

Okunishi  Kazuo  Suwa  Hiroshi 《Natural Hazards》2001,23(2-3):259-269

A strategy is presented for the assessment ofdebris-flow hazards on alluvial fans on the basis ofa case study carried out on the southern foot of astratovolcano named Mt. Yatsugatake. Transformation ofcommercial forests into a golf course was planned ata corner of the Kikkakezawa fan. The case studyinvolves an assessment of hazards due to debris flowsof different magnitudes and their recurrenceintervals. The environmental conditions for therecurrence of these debris flows are discussed as wellas the extent of the areas affected by them. In orderto generalize the case study, concepts of hazardpotential, hazard and risk for debris flows onalluvial fans are established. Accordingly, the hazardpotential is the possible hazards at any location onan alluvial fan in an indefinitely long time period,which can be assessed on the basis of hydrological andother geoscientific investigations. Hazards associatedwith a particular land use can be evaluated on thebasis of the hazard potential considering the locationand the time period associated with the land use. Riskcan be further assessed considering the life styles inthis land and the social conditions.  相似文献   

新疆岩石·岩屑·水系沉积物元素背景平均值   总被引：3，自引：0，他引：3  

杜佩轩  田素荣 《物探与化探》2001,25(2):117-122

论证了中国丰度及地壳表层物质成分研究的必要性和重要性，利用区域地球化学勘查所提供的高精度分析数据，经严格统计计算，发表新疆地区其一级构造单元表层岩石、岩屑、水系沉积物的39种元素背景平均值。  相似文献   

四川龙门山南段东缘泥石流     

朱平一  罗德富 《山地学报》1996,(4)

当地断裂众多，岩体破碎，崩塌滑坡遍布，加之是强震带和川西大暴雨中心区，相对高度３００—３５００ｍ，泥石流形成条件极为充分．泥石流沟汇水面积小，沟床比降陡，主沟长度短．绵竹汉旺后山泥石流综合治理后，可成为一个示例．  相似文献   

泥石流监测预警站的组建     

陈景武  陈精日 《山地学报》1992,(1)

泥石流监测预警站利用的是泥石流预警报系统,以便对泥石流进行监测后,作出泥石流预警报。泥石流预警报系统由三个子系统组成,这就是:1.暴雨类泥石流预报子系统;2.泥石流地声报警子系统;3.泥石流规模报警子系统。三个子系统分别用在泥石流监测预警站所属的雨量、地声、泥位三类泥石流监测点上。泥石流预警报系统由中国科学院东川泥石流观测研究站在蒋家沟研制而成,1985年底通过鉴定,获1986年度中国科学院科学技术进步三等奖。  相似文献