闽清县丽星村坡面型泥石流特征分析及防治建议

2016年7月9日,受台风“尼伯特”的影响,福建省福州市闽清县池园镇丽星村发生2处坡面型泥石流,推毁坡脚1栋土木房,造成直接经济损失约50万元,在强降雨等条件的诱发下,易再次发生泥石流,严重危及坡脚居民的生命财产安全。通过收集研究区基础资料,开展详细的地面调查及现场勘查,查明2处坡面型泥石流的规模、运动特征、物源条件以及泥石流发生的主要影响因素和未来的发展趋势,提出斜坡坡面修建完善的排水沟、加强坡面排水、泥石流沟谷处加强坡面绿化的防治建议,为后续泥石流治理工作提供参考依据。     

坡面型泥石流治理过程中土体变形机制宏细观研究

 试验利用“锚杆–护坡”模拟“锚杆固定大面积护坡”进行坡面型泥石流治理试验,研究坡面型泥石流“锚杆–护坡”治理过程中土体变形的宏细观机制。试验观测表明在“锚杆–护坡”治理下坡体未发生分层滑动,坡体位移场分析中出现了潜在的圆弧状薄弱面,坡体形成类似于黏土的小位移圆弧滑移趋势。采用可视化细观测试系统从细观尺度研究坡面型泥石流“锚杆–护坡”治理下土体的变形机制。细观分析可知,试验过程中,颗粒下沉并在坡体底部积聚,坡体下层细颗粒含量增加,上层以粗颗粒为主,导致坡体上部面积孔隙率大于底部,坡体结构由不同粒径颗粒均匀分布变为“底部细颗粒沉积密实,上层粗颗粒骨架稳定”的相对稳定结构。试验研究表明：“锚杆–护坡”的滤水固土作用,改变坡体的变形机制和结构,减小坡面型泥石流的发生几率,为坡面型泥石流的工程治理提供参考。     

映（秀）-日（隆）旅游公路沿线泥石流灾害及防治对策

阐述了映（秀）-日（隆）旅游公路沿线泥石流的类型、分布规律及特征，泥石流的类型是坡面型、沟谷型、冰雪型泥石流，系统地分析了泥石流形成的基本因素——地质条件、地貌条件、水源条件和人为因素．介绍了泥石流对公路的危害，提出了合理的防治措施，为公路设计及施工建设提供了依据。     

西藏高原地区灾害特点分析

结合西藏高原地区的自然环境特点,介绍了该地区常见的地质灾害类型,并分析了该地区滑坡、泥石流、地震、雪灾等灾害的成因机理,为西藏高原地区的房屋建造与灾害防治工作提供了依据。     

广西德保县地质灾害的形成条件及影响因素

德保县是广西地区地质灾害最为严重的县(市)之一,地质灾害类型主要有滑坡、危岩、崩塌、泥石流、地面塌陷、不稳定斜坡等。为了查明德保县地质灾害发育的地质环境条件和地质灾害类型,分析灾害的形成条件及影响因素,在德保县1∶5万地质灾害详细调查的基础上,通过实地踏勘,共核查了全县现有各类地质灾害396处。分析研究表明,该区地质灾害的形成条件主要与该区的地形地貌、岩土体类型、地质构造、降雨、地下水、人类活动等息息相关,而降雨和人类工程活动等因素则是形成地质灾害的重要影响因素。开展广西德保地区各类地质灾害的形成条件与影响因素研究,对该地区的地质灾害监测预警和防治工作具有重要意义。     

吉隆口岸美多当千泥石流基本特征及形成条件

受尼泊尔4.25地震的影响,西藏自治区吉隆口岸地区新增了大量的泥石流物源,成为该区严重的地质灾害隐患,。美多当千泥石流即为发育于该区的一条较为典型的泥石流。对美多当千泥石流的沟域平面特征、纵坡降特征进行研究,对其形成条件进行分析,发现该泥石流的发与当地地形地貌、物源条件和水源条件关系密切。这一研究成果对该地区泥石流防治具有一定的理论指导意义和实用价值。     

热河沟泥石流成因机制分析

受汶川地震的影响,西南地区地质灾害近来年频繁发生,尤其是泥石流灾害。在地震作用下,有更多的松散物源参与泥石流的运动,加大了泥石流的危害性和暴发频率。本文收集了热河沟的地质、气象和水文等资料,通过分析该沟的地形、物源和水源条件来分析泥石流的形成过程,结合现场调查取证来综合分析泥石流的形成机制,为泥石流的治理提供更为可靠的依据。分析表明,热河沟泥石流的成因机制为"暴雨-溃决"型。     

热河沟泥石流成因机制分析

受汶川地震的影响,西南地区地质灾害近来年频繁发生,尤其是泥石流灾害。在地震作用下,有更多的松散物源参与泥石流的运动,加大了泥石流的危害性和暴发频率。本文收集了热河沟的地质、气象和水文等资料,通过分析该沟的地形、物源和水源条件来分析泥石流的形成过程,结合现场调查取证来综合分析泥石流的形成机制,为泥石流的治理提供更为可靠的依据。分析表明,热河沟泥石流的成因机制为"暴雨-溃决"型。     

坡面泥石流冲击能量计算的探讨

在暴雨或特大暴雨激发下常成群发生的坡面泥石流爆发突然、破坏力强,危害极大。基于窄板沟坡面泥石流现场调查、试验与分析,结合现有的部分泥石流冲击能量计算公式,探索使用考虑坡面折减系数的能量转化守恒方法,对泥石流的流速、冲击能量等进行了计算,并给出了明洞破坏特征的简要分析。结果初步表明,现有的部分泥石流冲击能量计算公式对沟谷型泥石流适用性更好,对坡面型泥石流有一定的局限性。建议可将考虑坡面折减系数的能量转化守恒方法作为坡面泥石流冲击能量计算的一种补充方式,为今后类似区域的防灾减灾积累一定的经验。     

北京市延庆区石窑村南地沟泥石流特征及发展趋势预测

本文以北京市延庆区石窑村南地沟泥石流为研究对象,通过野外调查与GIS统计分析,研究该流域降雨条件、地形地貌和沟道条件、物源条件等形成条件特征,针对流域内松散堆积物转换,开展了流域分区特征分析;通过14个因子分析,建立了该泥石流的发育阶段识别模型,对其发展趋势进行了预测;利用单沟泥石流堆积区公式开展了最大危险区预测研究,提出相应的防治措施建议。研究表明:石窑村南地沟泥石流内松散堆积物动储量达18.36×10~4 m~3,物源类型划分为冲洪积物源、残坡积物源、人工堆积物源和崩滑塌物源4种,其中残坡积所占比重最大。该泥石流属于暴雨-沟谷型-支沟群发型、中易发泥石流,泥石流发展阶段处于发育期,最大危险区面积为0.413 km~2,对沟口堆积区的石窑村及村民的生命财产安全造成威胁,建议采用局部物源平整与疏理排导渠相结合的综合治理措施。本文为该区地质灾害防治提供基础依据。     

松潘县东龙沟泥石流形成条件与动力学特征分析

汶川"5·12"大地震引发了大量的次生地质灾害.这些次生地质灾害阻断交通,堵塞河流,对灾区人民的生命财产安全形成了严重威胁,并为灾区过渡性安置和灾后重建工作遗留重大的安全隐患.本文在分析四川省地震灾区松潘县东龙沟泥石流基本特征的基础上,通过对形成泥石流的地形、水源、物源三个基本条件进行了深入论述,计算了泥石流的重度、流...     

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、物质条件、降雨条件以及人类日益工程建设活动等方面研究表明,较大的沟床纵坡降比和流域面积、丰富的松散固体物质和短时间聚集的充足水源(多是有暴雨形成)是形成区内泥石流的基本条件。崩塌(不稳定斜坡)于公路沿线的人工开挖坡度大于60°的边坡地带。临泽县地质灾害具有不均匀性、突发性、周期性。该研究为县域地质灾害防灾减灾提供科学依据。     

浙江诸暨市地质灾害分布特征及内在控制因素

文章根据已有的地质灾害资料,对诸暨市地质灾害发生与分布特征进行了较系统的总结。玄武岩和变质岩分布区地质灾害最为易发,其次是细碎屑岩,地质构造对地质灾害的发生有着很大的控制作用,滑坡主要发生在中等坡(15°~30°),崩塌主要发生在陡坡与急坡(30°)。根据地质环境条件,将诸暨市地质灾害区域分为2个中易发区、5个低易发区。     

北京洪水峪泥石流形成条件探讨

洪水峪泥石流、沟内崩塌、不稳定斜坡等不良地质现象发育。该沟内煤矸石、沟道物源丰富,上游汇水面积大,沟道纵坡降较大,在强降雨沟道径流冲刷作用下,极易发生揭底起动而形成泥石流灾害。在雨季,支沟常有少量泥沙、块石冲出,阻塞进山道路,淤塞河道,引起原有坝体损毁,威胁居民生命财产安全。通过对以往资料的综合整理,结合现场调查,对洪水峪泥石流形成的诸多条件进行了分析,以期对该区泥石流的防治与预测起到参考作用。     

模糊综合评判法在建筑边坡地灾评估中的应用

根据深圳市某新建住宅小区场地内的建筑边坡特点,由影响边坡危险性的主要因素组建成评价指标体系,利用模糊综合评判方法,建立了建筑边坡危险性预测模型,计算出各边坡危险性判别指数,评价出其地质灾害危险性,并提出了相应的地质灾害防治措施建议。     

基于GIS的广西北流市地质灾害易发性分区评价

以北流市为例,利用地质环境要素对地质灾害易发性进行评价,并通过MapGIS软件实现可视化。选取了地质灾害发育密度、地貌类型、自然斜坡坡度、工程地质岩组、残坡积土层厚度、人类活动强度、多年平均降雨量7个影响地质灾害易发性的地质环境因素,建立了地质灾害易发性评价指标体系和评价方法,并对研究区进行了评价,依据预测分区指标计算,研究区地质灾害高易发区总面积为1185. 37 km~2,占全市总面积的49%;地质灾害中易发区总面积为1027. 76 km~2,占全市总面积的41%地质灾害低易发区总面积为243. 50 km~2,占全市总面积的10%。     

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.     

Characteristics and dynamic analysis of the February 2021 long-runout disaster chain triggered by massive rock and ice avalanche at Chamoli,Indian Himalaya

A massive rock and ice avalanche occurred on the western slope of the Ronti Gad valley in the northern part of Chamoli, Indian Himalaya, on 7 February 7, 2021. The avalanche on the high mountain slope at an elevation of 5600 m above sea level triggered a long runout disaster chain, including rock mass avalanche, debris avalanche, and flood. The disaster chain had a horizontal travel distance of larger than 17,600 m and an elevation difference of 4300 m. In this study, the disaster characteristics and dynamic process were analyzed by multitemporal satellite imagery. The results show that the massive rock and ice avalanche was caused by four large expanding discontinuity planes. The disaster chain was divided into five zones by satellite images and field observation, including source zone, transition zone, dynamic entrainment zone, flow deposition zone, and flood zone. The entrainment effect and melting water were recognized as the main causes of the long-runout distance. Based on the seismic wave records and field videos, the time progress of the disaster was analyzed and the velocity of frontal debris at different stages was calculated. The total analyzed disaster duration was 1247 s, and the frontal debris velocity colliding with the second hydropower station was approximately 23 m/s. This study also carried out the numerical simulation of the disaster by rapid mass movement simulation (RAMMS). The numerical results reproduced the dynamic process of the debris avalanche, and the mechanism of long-runout avalanche was further verified by parametric study. Furthermore, this study discussed the potential causes of disaster and flood and the roles of satellite images and seismic networks in the monitoring and early-warning.     

滑坡治理抢险工程设计探讨

边坡滑坡是一种常见的地质灾害,对工程建设的危害很大,轻则影响施工、道路的正常运行,重则破坏建(构)筑物和交通设施。只有对边坡滑坡形成的主要原因进行分析,才能更好的做到滑坡的防治工作。以云南昆明市呈贡新区二期市政道路建设项目设计某合同段左侧边坡滑坡治理抢险工程施工为例,对产生滑坡原因进行了分析,提出了相应的工程整治措施。