磨子沟泥石流物源特征及易发性分析

文章结合磨子沟沟域的现场调查资料,在总结其基本形态特征的基础上,对泥石流物源进行分类,以明确该泥石流沟可能存在的风险,为后续的预测和治理提供关键依据,具有重要的现实意义.从地形地貌上看,磨子沟流域内相对高差大,地形陡峻,沟谷纵坡较大,有利于泥石流物质的汇集和成灾;从物源条件上看,泥石流的固体物源类型有崩滑型、沟道型、坡...     

新宾草盆小学后沟泥石流易发程度数量化评判

研究了新宾县草盆小学后沟工程地质条件及泥石流发育特征,分析了地形地貌、固体物源和水动力条件等影响泥石流的内外因素,并对各项影响因子进行了数量化评判,划分了地质灾害影响区,预测了地质灾害的发展趋势,提出了设置谷坊拦砂节流和排水沟疏导分流的泥石流防治建议。     

云南本屋宅箐泥石流沟特征及危险性评价

文章以云龙县宝丰乡福利村本屋宅箐泥石流沟为研究对象,在现场实地调查的基础上,阐述泥石流沟特征、类型、成因、发展趋势,并对该泥石流沟的危险性进行了评价。该泥石流的形成受地质、地形、气象水文及人类活动等综合因素的影响,前期降雨使固体物质分散汇入沟床积累,属于崩塌+滑坡型、沟谷泥石型、中型、高频、发展期稀性泥石流。目前,福利村本屋宅箐流域固体物源丰富,降雨集中,水源充沛,溯源侵蚀作用强烈,物源区滑坡、沟岸坍塌发育,谷坡稳定性差,泥石流的发展有增强趋势。本次采用成都山地所刘希林于1996年提出的单沟泥石流危险度评价方法对该泥石流沟的危险性进行评价,单沟泥石流危险度H单=0604,按照分级标准,福利村本屋宅箐泥石流沟属高度危险泥石流沟。     

大渡河某泥石流沟形成机制及其工程效应研究

结合大渡河某泥石流沟发生的大规模泥石流灾害，阐述了泥石流的发育历史，对该泥石流沟各功能区进行了详细的工程地质调查分析，研究了该泥石流沟形成机制及带来的工程效应影响，指出应防范泥石流的发生，从而减小对沟口桥梁及公路的影响。     

雅安漫哈沟泥石流形成机理及防治建议

通过对四川省雅安市石棉县漫哈沟的现场调查,从地形地貌、物源、水源等基本条件入手,分析了漫哈沟泥石流的特征与形成机理,并提出了专门针对漫哈沟泥石流物源丰富、堆积区建筑物密集、沟口过流断面狭窄的特点的防治建议。     

5.12地震引发潜在泥石流灾害的调查评价——以四川省德阳绵竹市龙形沟泥石为例

"5.12"地震形成的滑坡崩塌为泥石流提供了丰富的固体松散物质,严重威胁到交通、民房和安置点等的安全[1、2],成为灾区重建的重大隐患。本文以四川省绵竹市龙形沟泥石流为例,讨论5.12地震引发潜在泥石流地质灾害的调查评价方法。龙形沟流域属高山峡谷地貌,呈叶状,支沟众多,主沟未暴发过泥石流,但"5.12"地震后,现场调查发现流域内多达9条支沟暴发了泥石流。本文针对该类潜在泥石流沟谷的特点,在野外工作的基础上,分析其易发程度和发展趋势,计算其容重、流速、流量和冲击力等特征参数,对该类潜在泥石流沟谷的调查和防治具有一定实际意义。     

怒江州贡山县从尼泥石流形成条件与诱发机理

在查阅资料、现场调查与理论分析的基础上,对怒江州贡山县从尼泥石流形成条件、基本特征与诱发机理开展了分析与研究。研究结果表明:从尼泥石流沟目前属发展期泥石流沟,应加强监测与预警预报。     

甲学沟泥石流发育特征及防治建议

甲学沟泥石流属暴雨一沟谷型稀性泥石流,历史上曾多次爆发泥石流,对下游居民和公路造成危害。在对甲学沟实地跟踪调查的基础上,将泥石流沟划分为形成区、形成流通区、堆积区三个分区。研究该泥石流沟的地质环境条件及发育特征,查明泥石流的成因机制,有针对性的提出防治措施,对类似地质灾害的评价及治理具有一定的借鉴意义。     

格地罗沟高频泥石流特征及成因机制研究

格地罗泥石流沟位于四川省凉山州盐源县境内,为典型高山区沟谷型高频率稀性泥石流,据调查访问,格地罗沟每年均发生1~3次小型泥石流或含高泥沙的洪水,平均每10年就会发生一次一定规模的泥石流。该泥石流形成区流域面积较小,沟道较短,但物源极其丰富,在暴雨时期易发生泥石流,在川西地区具有一定的代表性。本文从泥石流的流域特征、水源条件、物源的启动与转化等方面,采用现场调查、遥感解译等手段研究了该沟发生高频泥石流的成因机理。     

汶川县绵虒镇磨子沟泥石流灾害特征分析

2013年7月10日,汶川县境内都汶高速两侧暴发多处泥石流灾害,磨子沟为其中一条泥石流沟。磨子沟泥石流冲出固体物质高达41.75×104m3,淹没了沟口G213草坡4号桥及道路,以及沟口克约村4组殷家坝安置点房屋42户,造成260余人无家可归,经济损失极大。由于本次泥石流灾害发生在汛期,是降雨作用的结果,研究其形成原因,对进一步认识汶川县内泥石流发育特征具有重要的意义。本文根据现场调查,从物源条件、地形条件和降雨条件分析了泥石流的形成原因,并分析了泥石流的成因机制,以及泥石流运动特征,最后提出了防治方案建议等。     

未确知测度理论在东川泥石流危险性评价中的应用

将未确知测度理论应用到东川泥石流沟危险性评价中。根据实际工程地质条件,选取12个泥石流危险性影响因子作为评价指标,制定评价指标的危险性分级标准。根据未确知测度理论建立泥石流危险性评价指标的单指标测度函数,然后运用层次分析法计算各评价指标的权重,得到泥石流危险性的综合测度函数,最后使用置信度识别准则对泥石流危险性等级进行判定。将该方法应用于云南省东川地区12条泥石流沟,结果表明,该方法的判定结果比经典方法更符合实际,证明了该方法的合理性。     

Numerical assessment of the impeding effect of check dams in the Hongchun debris flow gully,Sichuan Province,China

To mitigate potential damage from debris flows, numerous check dams have been constructed in thousands of debris flow gullies all over the world. However, the efficiencies of these check dams are largely unknown because they are normally designed based on empirical methods. This paper presents an assessment of the impeding effect of check dams constructed in the Hongchun debris flow gully in Sichuan Province, China by using an improved finite difference model. Compared with other models, the improved model can consider both the impeding effect of check dams and bed entrainment. We analyzed the impeding effect of these check dams on different initial scales of debris flows. The results show that these check dams perform quite well in constraining bed entrainment downstream of the gully. The average velocity, peak discharge, and final scale of a debris flow in the gully can be substantially reduced by constructed check dams. The impeding effect is sufficient when the initial volume of the debris flow is less than 1.5 times that of the catastrophic debris flow event that occurred in this gully on 14 August 2010. This study improves our understanding of the influence of check dams on the dynamic and bed entrainment processes of debris flows. The model adopted in this study can be a robust tool to quantify the efficiencies of existing check dams and provide reasonable guidance in the design of check dams in debris flow gullies.

     

The geomorphological comparison of two debris flows and their triggering mechanisms

 The paper reports on debris flows in the Tungmen and Hoser areas of Taiwan, triggered by Typhoon Ofelia on 23 June 1990 and Typhoon Herb at the end of July 1996 respectively. The intense rainfall resulted in large volumes of debris being eroded from the valleys. The village of Tungmen was almost totally destroyed by in excess of 100,000 m³ of material which was moved by the 1990 debris flow while the 1996 typhoon was responsible for the movement of almost 1.5 million m³ of material, 80% of which extended to the confluence area of the two side gullies and the Hoser River. Attention is drawn to the change in shape of the valley sides from generally V-shaped prior to the debris flow to U-shaped following the storms. A comparison of aerial photographs as well as field data was used to define the main topographical effects of the 1990 storm (Tungmen) and 1996 event (Hoser). A study of the discontinuity pattern within the valleys emphasised the significance of toppling and gravity slumping of material in the sides of the valleys in producing large quantities of debris which, in heavy storm conditions, can flow down the gullies. Laboratory tests were used to simulate the effect of saturation on the materials. These indicated that in their saturated state they would easily become unstable. Received: 1 December 1999 · Accepted: 11 January 2000     

G212线陇南段泥石流发育成因及其时空分布特征分析

 首先通过前人研究以及野外调查,深入分析研究区所处的工程地质环境,包括地质构造、地层岩性、工程地质岩组、地形地貌、新构造运动、降雨、植被以及人类活动等。其次,在充分认识本区泥石流发生机制的基础上,通过对研究区典型泥石流沟的实地调查,结合工程地质环境,综合分析研究区泥石流分布的空间特征与时间特征。空间上集中分布于白龙江干流及其一级支流岷江和北峪河三个流域;时间上的分布特征体现在日时段、月时段及年代时段3个方面,其中月时段主要分布在7,8月份。研究结果对拟建国道212的选线,灾害抢险的制定、救灾和抗灾的途径和措施以及泥石流时空分布特征分析理论的发展等具有一定的指导与借鉴意义。     

甘肃临泽县地质灾害类型及特征

甘肃省张掖市临泽县是河西走廊地质灾害最为发育的县区之一.通过实地测量、调查评价和综合研究等手段,在概述县域自然地理条件及地质背景的基础上,县域内已有的地质灾害共30处,其中泥石流沟29条主要集中分布于祁连山和合黎山山前与走廊平原的过渡带,尤其是北部合黎山山前连片分布;崩塌1处为斜坡坡度65°的独山子崩塌.从地形条件、物...     

谷坊在泥石流防治中的作用--以云南蒋家沟2条支沟的对比为例

泥石流灾害严重威胁其影响区人民的生命和财产安全,但是泥石流灾害可以通过诸如控制侵蚀等工程措施来预防或者减轻。谷坊正是能够在泥石流形成区对泥石流灾害进行有效防治的工程措施之一。在野外实地调查的基础上,运用构造地质、工程地质、岩土力学等理论和方法,对比云南蒋家沟泥石流的2个主要支沟——门前沟(有谷坊布设)和多照沟(没有谷坊布设)在沟床纵坡降、沟谷两侧斜坡稳定性及泥石流侵蚀速率等3个方面的差异,来说明谷坊工程能够有效抬高泥石流侵蚀基准面,降低泥石流沟谷回淤段沟床纵坡及由此带来的泥石流流速的降低和能量的耗散,固定沟床、稳定岸坡、促进植被生长,最终达到防治泥石流的目的。此外,还讨论了谷坊设计时需要注意的几点问题。     

Une méthodologie d'analyse et de cartographie de l'aléa "initiation de laves torrentielles" – application au torrent du Bragousse (France)

Debris flows may result in personal injury or loss of life as well as damage to constructions. The economic consequences of such events are important, and likely to become more so with increasing urbanisation. In this paper, "debris flow" is defined as a viscous flow of saturated materials at high velocities of up to 20?m/s in channels. These materials have a high concentration of solids such that their dynamics may be considered at the interface between mechanical and hydraulic flow. The occurrence of a debris flow results from a number of interrelated factors including topography, geology, geomorphology and hydrogeology. The triggering factor is most often water, frequently a violent rainstorm. In order to identify the initiation mechanisms, it is necessary to have a knowledge of the environmental situation in the particular catchment area. Clearly, this will involve an understanding of: (1) the catchment area and its geological conditions; (2) the climatic characteristics of the locality and the nature of the materials in the source area; (3) the pattern of such events in the past. In order to obtain such an understanding, a dual approach of field and laboratory work was considered appropriate. Twelve catchment areas in the northern and southern French Alps were studied to assess the significance of the three aspects mentioned above. The study of numerous debris flow deposits sampled in these catchment areas suggested two types of debris flows: those with a cohesive matrix and those with a granular matrix. In the field, they were categorised on the basis of a morphological consideration of the area as well as according to the texture and grain size of the material in the flow. In the laboratory, granulometric tests were used. In addition, the granulometric and geotechnical characteristics of the source areas were compared with those of the debris flow materials. The grain size distribution appears to be an important factor in determining the likelihood that the source area materials would be moved by violent storms and from a debris flow. From tests undertaken on the <20?mm fraction, superficial deposits with between 16 and 40% of the particles of <50?μm seemed to be most likely to result in debris flows. This paper discusses the fieldwork undertaken from the upper catchment area down to the channel of a debris flow. Each mechanism is described with an analysis of the geological and topographical contexts, the extent of the movement and the hydrological processes that lead to the initiation of a debris flow. On the basis of this, maps have been produced to show the potential for the initiation of a debris flow. Five criteria were chosen to define the debris-flow hazard: (1) slope angle; (2) nature of the geological formation and hydrogeological characteristics; (3) slope erodability and instability; (4) grain size; (5) available volumes of superficial deposits present in the source area. These five indices form the global index. The maps show the spatial distribution of the hazard and can be useful in determining the most appropriate remedial/protective works to be undertaken in zones of the greatest risk.     

The December 1999 Cervinara landslides: further debris flows in the pyroclastic deposits of Campania (southern Italy)

In December 1999, numerous landslides similar to those that had previously struck neighbouring parts of the Campania area occurred above the town of Cervinara. One of these landslides reached the town, causing the death of six persons and considerable damage. The landslides involved the 1 to 2 m thick pyroclastic mantle which overlies the carbonate hill slopes and took the form of a debris flow, although in the early stages debris slide/debris avalanche movement occurred along the 39° slope with further debris flows developing along gullies. Hydrological analyses indicated that the landslides were associated with a storm of exceptional characteristics. However, the rains do not satisfactorily explain this event, particularly as the December 1968 storm, which had similar features to that of December 1999, did not trigger similar landslides. The paper discusses the geomorphological and hydrological characteristics of the area and highlights the importance of the trackways cut into the hillsides. It is concluded that the recent landslides of Cervinara – and other similar landslides in the Campania area – may be partly due to man-made changes along the slopes. Electronic Publication