西藏帕隆藏布河谷崩塌滑坡、泥石流的分布规律

西藏帕隆藏布河谷崩塌滑坡、泥石流灾害严重。崩塌滑坡、泥石流的分布 ,因谷坡坡向的水热条件差异而导致坡向差异 ,因地貌发育和形态的沿程分异显现沿程差异 ,因其促发条件的差异又显现灾种差异。采用有序样品最优分割和方差分析等定量方法 ,揭示了崩塌滑坡、泥石流的差异性分布规律 :全河段可分为上游峡谷泥石流密集段 ,中游宽谷泥石流及崩塌滑坡较密集段 ,和下游、拉月曲峡谷崩塌滑坡、泥石流极密集段 ;北岸崩塌滑坡和泥石流比南岸数量多、规模大 ;崩塌滑坡有向下游增大增多之趋势。进而对道路平面选线原则提出了建议。     

汶川地震区绵远河流域泥石流形成区的崩塌滑坡特征

2008年汶川地震以后,四川省绵竹市清平乡表面覆盖了大量松散堆积物,这些物源在震后的几年中易受到暴雨激发,导致大量浅层崩塌、滑坡的形成,尤其在泥石流形成区。研究泥石流形成区崩塌、滑坡特征,有助于分析滑坡向泥石流转化的特点。2010-08-13绵远河流域发生强降雨致使数十条沟暴发泥石流,在统计了研究区内20条沟泥石流形成区内的386个崩塌、滑坡后,利用野外调查及高精度遥感影像,将386个崩塌、滑坡全部解译,并利用GIS分析统计出崩塌、滑坡在坡度、坡向、高程、沟道纵坡降、地层岩性、沟壑密度因子上的分布特征,得出在海拔1 700～2 400 m范围内崩塌、滑坡密度最大;坡度是影响崩塌、滑坡分布的重要因素,随着坡度的增加密度也越来越大,>70°时极易失稳;滑坡的方向垂直于发震断层明显多于平行于发震断层;纵坡降在500‰～600‰的区间内崩塌、滑坡大量分布;石炭系灰岩出露的地层容易产生大量崩塌、滑坡,尤其在下硬上软的岩层上面;在微度水土流失的区域,崩塌、滑坡分布集中,因此要加强该区域的监测预警。     

“4·20"芦山地震崩塌滑坡与公路危险性评价——以宝兴县省道S210沿线为例

以芦山地震重灾区宝兴县境内省道S210沿线为研究区,利用高分辨率航片,对沿线地震诱发崩塌滑坡进行判识,并通过分析地形、地层岩性及震中距等因子,探讨公路沿线崩塌滑坡的分布规律,进而利用确定性系数和频率比例法对地震诱发崩塌滑坡的易发性进行评价,最终通过沿线崩塌滑坡易发性分析结果对道路断道的危险性进行评价.研究结果发现:省道S210沿线芦山地震造成的坡面破坏以中小型崩塌为主,高程集中在750～1 500 m,坡度多位于30°～60°,且位于西、南西和北西坡向的崩塌滑坡较多,岩性以硬岩和软硬相间岩层为主,研究区距震中19～21 km的距离为崩塌滑坡集中分布区域.崩塌滑坡高易发区和较高易发区主要位于研究区的北段,南段公路同侧也有分布,较低和低易发区位于中段宽谷路段.     

浙江省泥石流形成及成灾特点

浙江地处我国东南沿海,近几年频繁遭受泥石流等山地灾害的危害。由于所处地理地质和气候环境,发育的泥石流有其独特的地域特征。从泥石流的发育特征、形成过程等探讨了浙江泥石流形成的机理,分析了其成灾特点。结果表明,浙江省泥石流为滑坡、崩塌转化型泥石流,泥石流的形成机理及过程主要为:强降雨下滑坡、崩塌发生,持续强降雨使得滑坡、崩塌松散物流化从而形成泥石流。滑坡、崩塌转化型泥石流在流域特征上表现为形成区坡度大,易发滑坡、崩塌,水力条件充分等。泥石流灾害具有低频性、群发性、并发性、突发性、夜发性、危害大等特点。     

仁博高速公路新增崧岭互通立交项目地质灾害危险性评估研究

针对仁博高速公路新增崧岭互通立交项目施工中可能引发的地质灾害问题,本文进行了评估。研究结果表明:拟建区域工程建设形成了大量的路堑边坡崩塌/滑坡、基坑(涵洞)崩塌、路堤边坡崩塌/滑坡和鱼塘岸边坡崩塌/滑坡等,对工程施工不利。识别出地质灾害危险性大区5处和危险性中等区7处,为进一步确定治理方案提供了基础。     

汶川地震触发的绵远河流域崩塌滑坡的特征

利用地震后ALOS影像自动提取了汶川地震重灾区绵远河流域内的崩塌滑坡,结合野外调查共确定地震触发崩塌滑坡1 073处,面积48.5 km2.其中分布最广、数量最多的是浅层崩滑体;同时由于地震力作用强烈,触发了许多深层、高速、远程滑坡,并形成了大量的滑坡堰塞湖.汶川地震诱发的第二大滑坡文家沟滑坡就位于流域内,该滑坡是本次地震中滑动距离最远的滑坡.地震导致大量的碎屑物质堆积在沟道内或悬挂在斜坡上,为泥石流的发生提供了有利条件.基于GIS的统计分析表明,地震滑坡的空间分布主要受发震断层的控制,流域内的崩塌滑坡受到了映秀-北川断裂和江油-都江堰断裂的双重影响,主要分布于两断裂上盘的一定范围内;地层岩性影响着地震滑坡的类型,岩浆岩、白云岩等硬岩主要发育浅层崩滑体,而上硬下软的地层多发生大型滑坡;大部分崩塌滑坡都发生在海拔1 000～2 000 m的高程内;坡度是崩塌滑坡发生的主要控制因素之一,大部分崩塌滑坡发生在25°～55°的范围内;坡向对滑坡的分布也有一定的影响,背靠震源(发震断层)方向的斜坡比面向震源(发震断层)方向更容易发生滑坡.     

南水北调西线一期工程滑坡崩塌体稳定性评价

南水北调西线工程的主要目标是解决西北、华北地区缺水问题。在现有资料和工作深度的基础上,对工程区滑坡崩塌体的稳定性进行了评价研究。研究表明：在整个工程区,库区内崩塌最为发育,滑坡较少;在不同的库区,岸坡的变形呈现出空间不均匀性。崩塌堆积体主要发生在碎裂（松散）岩质岸坡地段,分布于库区的崩塌堆积体中,稳定和基本稳定的占崩塌堆积体总数的25％,潜在不稳定的占崩塌堆积体总数的50％;分布于库区的滑坡堆积体中,潜在不稳定或不稳定的滑坡数量较多。     

芦山地震重灾区崩塌滑坡易发性评价

2013-04-20 T08:02,四川省芦山县发生7.0级大地震,地震诱发了大量的次生山地灾害.在芦山、宝兴、天全三个地震重灾县6651.35 km2的区域内,采用震后遥感影像解译并结合野外调查的方法,共解译出1379处崩塌(含落石)滑坡.应用GIS技术,建立了芦山地震诱发崩塌滑坡灾害及相关地形、地质空间数据库,分析了岩性、断层、地震动加速度、高程、坡度等5个因素与崩塌滑坡分布的关系,应用崩塌滑坡数量百分比这一标准来分别衡量每个因素中各个级别对崩塌滑坡的影响程度;然后使用层次分析法对这5个参数进行权重分析;在GIS平台下对这些参数进行综合分析,以此将研究区内的崩塌滑坡按易发程度分为极高易发区、高易发区、中易发区、低易发区4类,极高易发区与高易发区面积约2149.89 km2,占研究区总面积的32.32％.     

黄土丘陵区地质灾害规模参数幂律相依性研究

对滑坡、崩塌和不稳定斜坡等地质灾害规模参数幂律相依性进行定量研究,拓展了规模参数之间幂律相依性的研究范围。研究结果发现:1地质灾害规模参数的幂律相依性不仅存在于体积与面积之间,而且存在于面积与长、面积与宽等参数之间;2幂指数可以作为间接反映区域地质灾害或者不同类型地质灾害的宏观特征表征谱;3体积与面积关系式的幂指数分布为不稳定斜坡滑坡崩塌;面积与长关系式的幂指数分布为崩塌滑坡不稳定斜坡。面积与宽关系式的幂指数的分布为滑坡崩塌不稳定斜坡。     

泥石流源地土体应力应变特性对降雨响应过程的分析——以蒋家沟泥石流为例

根据对蒋家沟泥石流源地的崩塌、滑坡、散流坡,在旱季与雨季不同时段,降雨入渗后的土壤含水状况观测,以及泉水季节性变化,详细分析了泥石流源地崩塌、滑坡、散流坡土体的应力应变特性对降雨的响应过程差异.在雨季滑坡临空面和滑坡体内的土体含水量分别为6.67%、4.8%,滑坡活动主要是通过前缘剪出口崩塌方式补给下方沟床.崩塌体由于土体结构极为松散,在雨季该土体含水量通常高达8.85%～16%,使其土体的抗剪强度(C、φ)处于极限应力状态,一旦遇到降雨浸润和冲刷,迅速触变液化,转化为高浓度泥石流的侵蚀产沙过程.     

小湾水电站库区新民坝子滑坡稳定性研究

水库库区形成以后,由于水位的上升变动往往触发相当数量的坍塌和滑坡,对库岸稳定性造成严重影响.以小湾水电站库区新民坝子滑坡为例,在岸坡地质条件及变形破坏特征调查的基础上,对其变形破坏机制和稳定性进行分析和评价,得出其变形破坏方式为前缘一后缘逐级后退式失稳模式,且现状处于欠稳定状态;通过概化其地质模型,采用FLAc3D数值模拟手段进行流固耦合分析,得出水位上升至调查水位1 160 m高程和正常蓄水位1 240 m高程时的岸坡稳定性状况,计算结果表明蓄水至1 240 m高程后岸坡存在产生较大规模失稳的可能.这对类似库岸滑坡的调查分析具有一定参考意义.     

福建水口水电站库区的塌岸问题

从环境地质角度,对水口库区的塌岸问题,即库岸再造现象进行监测研究,并对塌岸发展的最终宽度,稳定时间历程进行预测,为水电工程移民安置,库区开发建设提供借鉴。     

三峡库区的新构造应力场及其对库岸滑坡滑动优势方向的影响*

新构造应力场在研究区域边坡稳定性及地表水土流失等方面具有重要作用。该文用地貌学方法——Scheidegger法,研究了三峡库区的新构造应力场及其与库岸滑坡滑动的优势方向问题。库岸滑坡发育的优势方向主要与新构造应力场的Maxl剪切带密切相关。     

灌溉诱发突发性黄土滑坡机理研究

系统揭示黑方台突发性黄土滑坡物理力学机理,对滑坡防治具有重要的作用。自上世纪六十年代年黑方台常年的农业灌溉诱发了大量20~40 m厚的饱和突发性黄土滑坡。本研究在野外调查的基础上,通过分析滑坡的变形破坏特征,针对分布范围广、危害性较大的突发性黄土滑坡,利用室内GDS三轴试验和模型试验,分析研究了饱和黄土的应力应变特性及突发性黄土滑坡的力学机制。三轴试验结果表明,当围压小于300 kPa时,饱和黄土可产生完全液化,并处于流塑状态;当围压大于300 kPa时,饱和黄土仅产生部分液化,仍具有一定的抗剪强度。饱和黄土的应力—应变模式均表现为强烈的应变软化—剪缩型,并具有一定的稳态特性。模型试验表明突发性黄土滑坡的变形破坏过程可大致分为底部浸水饱和—毛细水上升—持续蠕动变形—突发性破坏4个阶段。斜坡发生突发性破坏时,孔隙水压力激增,但总应力仍大于孔隙水压力,黄土滑坡发生部分液化,饱和黄土仍具有一定的强度,为突发性黄土滑坡发生提供了应力和能量积累的力学条件。研究从有效应力原理的角度阐述了突发性黄土滑坡的力学机理,可以为滑坡的防治治理提供一定的理论依据。     

Landslide Soils and Geomorphology in Bridger-Teton National Forest,Northwest Wyoming

Active landslides are evident throughout Bridger-Teton National Forest (BTNF), and northwestern Wyoming has one of the highest landslide densities in the country. Land use changes and increased demands for infrastructure challenge BTNF personnel to better understand landslide processes in order to make informed land management decisions. Despite recent population growth in the region, research on landslide phenomena is lacking. In this study, soil and geomorphic properties related to landslide occurrence were studied at 18 landslides in the BTNF. Landslides were categorized as active or inactive based on geomorphic features. Landslide soil characteristics including texture, shrink-swell potential, clay mineralogy, and horizonation were compared on active and inactive landslides. The results indicate that soil characteristics related to the degree of soil formation are different on active and inactive landslides. Soil characteristics such as plasticity, shrink-swell potential, and clay mineralogy influence slope stability and were distinctly different on active and inactive landslides, especially in C horizons. This study shows that soil characteristics and slope geomorphic properties may be useful for assessing landslide frequency. Our results support a hypothesis that landslide occurrence in the BTNF is related to weathering of soil and unconsolidated material, which affects clay mineralogy.     

湘赣浙紫色土的类型与分布特点

湘赣浙紫色土主要分布在沅江、湘江、赣江、信江、衢江流域几个NE或NNE向平行排列的紫色丘陵盆地内,出露上白垩统一下第三系红色碎屑岩,可见中丘中谷、低丘宽谷和缓丘带坝三类地形,分布不同风化程度的成土风化壳和紫色土类型。三省酸性紫色土和中性紫色土比例较大,达73％,比四川盆地多38—39％。     

岷江上游汶川-较场段滑坡稳定性的神经网络评判及其堵江可能性浅析

在滑坡的变形迹象研究的基础上,采用Ｂ－Ｐ神经网络模型对岷江上游汶川－较场河段内２８个典型滑支的稳定性进行评判,评判结果表明：目前岷江上游汶川－较场河段内共有１０个滑坡处于不稳定状态,在降雨、地震和人类工程活动等诱发因素作用下容易发生滑坡堵江。     

Aspects of landslide activity in the Mercantour Massif and the French Riviera, southeastern France

Landslides pose serious hazards in the Mercantour Massif and the French Riviera in southeastern France. The context for landslide development is a particularly favourable one, both in terms of the geomorphic and structural setting of this Alpine region, and of the climatic, hydrologic and seismic factors that trigger such failures. High mountain relief and steep slopes constitute a very favourable setting for failures affecting massive basement rocks and a very heterogeneous sedimentary cover whose resistance has been weakened by weathering, tectonic stresses, and cambering due to gravity. Among trigger factors, the important appears to be the precipitation regime. Rainfalls are commonly concentrated into short high-intensity downpours or into bursts of sustained falls over periods of several days, leading to soil saturation and lubrication of potential failure planes. Snowmelt also contributes to these lubrication processes. Earthquakes affecting this region are also a potentially important landslide trigger. However, while a lot of work has been done on the relationship between extreme climatic events and landslide activity, much less is known of the trigger effects of earthquakes.Both the background factors that promote landslide development and the factors that trigger such failures are discussed within a time frame of landslide development. Progressive changes in soil strength due to weathering, rock cambering and shattering processes lead to long-term reduction in resistance. Superimposed on these progressive changes are episodic triggerings related to rainfall and snowmelt episodes or earthquakes. Landslides may occur as shallow, low-volume “one-time” events or may be part of a progressive long-term failure. The former generally affect unconsolidated or clay-rich sedimentary rocks, especially on the coastal hillslopes of the French Riviera. A notable exception of a major, voluminous “one-time” event was the submarine landslide of the Var Delta in 1979. This landslide, like numerous other smaller subaerial landslides onland, was largely a result of human activities. This landslide occurred following extensive modification of the Var Delta and, notably, reclamation of the steep, fine-grained delta front. Deforestation, quarrying, urbanisation and road network developments are various ways in which human activity has destabilized the coastal hillslopes, favouring the development of numerous shallow landslides following each episode of heavy rainfall.Progressive landslides on the upper hillslopes of the Mercantour Massif have developed over long time spans (order of 10¹ to 10⁵ yrs) and have involved more complex interactions between lithological controls, slope characteristics and trigger factors. The Collelongue and Bois de Malbosc landslides have evolved into now stable failures buttressed by resistant migmatitic diorites or amphibolites. The more voluminous and well monitored Clapière landslide is a relatively simple rotational landslide of the toe-failure type. This active landslide poses a serious to inhabitants and infrastructure in the Tinée Valley. The importance of continued field monitoring, modelling and mapping of landslides and their hazards is emphasised.     

金沙江其宗河段河谷演化及其工程效应

金沙江其宗河段实地调研揭示:该河段共发育Ⅳ级阶地,其中Ⅳ级阶地卵砾石比Ⅲ级阶地的风化程度强得多;测年显示Ⅳ级阶地形成年代距今约80～90 ka,Ⅲ级阶地形成距今仅40～50 ka,取自zk204钻孔下部炭化木的14C测年为45 ka,这表明Ⅳ级阶地形成后,河谷一直下切到基覆界面,回填加积至现今Ⅲ级阶地的高度,然后又重新下切,形成Ⅲ级、Ⅱ级及Ⅰ级阶地,在形成程式上与川西河谷演化有较为明显的差异.由于河床覆盖层中、下部形成于晚更新世,具有超固结效果,不但承载力高而且不具有液化性.