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1.
Understanding the triggering mechanism and possible kinematic evolution of a reactivated landslide in the Three Gorges Reservoir 总被引：2，自引：0，他引：2
More than 5000 landslides or potential landslides have been induced in the Three Gorges Reservoir (TGR) region since the impoundment in 2003, which have caused great damage and remain a huge threat to the dam and people living in the reservoir area. Understanding the deformation characteristics and failure mechanism of the landslides can be helpful in stability evaluation and landslide prediction. The primary aim of this study is to research the characteristics of the landslide motion and its relationships with environmental triggers, taking the Quchi landslide, a large, slow-moving, reactivated landslide in the TGR region, as an example. The instability clearly showed visible signs of movements since 2002, and after that, the slope has been experiencing persistent deformation. By combining 4 years of meteorological, hydrological data with displacement measurements from open fractures, deep boreholes, and surface points, as well as in situ observations, this paper reports the geological and geotechnical investigations performed to define the movement. The deformation is believed to be governed by reservoir water levels, while the precipitation has a minor effect. Seasonally, the slope movement has a very distinctive pattern with large deformation starting abruptly right after reservoir drawdown in June and lasting into late summer (September). Then there is a rapid transition to constant deformation (almost no displacement) as the reservoir level rises. The slope displacements appear to gradually increase every year, which suggests very high possibility of the large and overall failure of the slide. Both monitoring results and geomorphological observations have highlighted that the two active slide masses Q1 and Q2 would probably collapse in different kinematic evolution modes, i.e., the multistage failure and whole sliding motion. 相似文献
2.
Maria Serafina Barbano Giovanna Pappalardo Claudia Pirrotta Simone Mineo 《Natural Hazards》2014,73(3):1587-1607
A new dataset of landslides, occurred in a tectonically active region, has been analysed in order to understand the causes of the slope instability. The landslides we have dealt with took place along the volcanic rock cliff of S. Caterina and S. Maria La Scala villages (eastern Sicily, Italy), a densely inhabited area located on the eastern margin of Mt. Etna, where some seismogenic faults, locally named Timpe system, slip during moderate local earthquakes and also move with aseismic creep mechanisms. The results show that landslides are triggered by heavy rainfalls, earthquakes and creep fault episodes. Indeed, they occur along discrete fault segments, exhibiting a combination of both brittle failure, indicated by the earthquake occurrence, and aseismic creep events. The analysis of seismicity occurred on the Timpe fault system has shown that the active Acireale fault, in its southernmost segment, is subject to an aseismic sliding, which increases after the stick–slip motion in the nearby faults. Therefore, aseismic creep seems to concur in the predisposition of a rock to fail, since strains can increase the jointing of rock masses leading to a modification in the slope stability. Understanding the factors concurring to the slope instability is a useful tool for future assessments of the landslide hazard in densely settled areas, located on a volcanic edifice, such as Etna that is slowly sliding seawards, and where active faults, seismicity and heavy rains affect the deeply fractured slopes. 相似文献
3.
水库库区地形地质和水位地质条件复杂,蓄水后受降雨和库水位变动影响容易产生滑坡、崩塌等次生地质灾害,严重威胁水库安全运行和附近居民安全. 本文依托层次分析法,以某蓄水水库为研究对象,在充分收集其地形地质和水文条件资料的基础上,选取地形地貌、地层岩性、坡度、坡向、地灾点密度、地灾点面积、降雨、库水变动幅度和地震强度等9个致滑因子,构建评价矩阵和滑坡危险性计算评价方法. 依据评价成果划分4个滑坡危险性等级,借助MapGIS软件生成库区潜在滑坡危险性分区图. 该分区图与遥感解译的库区滑坡体分布点高度吻合,验证了评价模型的合理性. 相似文献
4.
中等倾角岩层顺向坡,受坡体结构和岩体物理力学性质控制,多存在变形、崩塌、滑坡等工程地质问题,常常会诱发大规模的地质灾害。该类斜坡潜在滑动面不直接出露地表,一般具有变形机制复杂、隐蔽性强和危害大的特点,是滑坡领域关注与研究的重点。拖担水库大坝左岸为一古滑坡,在水库扩建开挖过程中,诱发古滑坡体复活。在分析古滑坡工程地质条件的基础上,结合地质勘察和变形监测结果,研究了其变形特征及形成机制。研究结果表明:①左岸古滑坡具有岩层倾角“上陡下缓”、滑体底部存在反倾坡内的剪切破碎带、滑床岩体产生弧状弯曲的特点;②古滑坡体为一基岩顺层滑坡,滑动模式为“滑移（弯曲）—剪断”型,其变形破坏过程包括三个阶段:弯曲隆起阶段、滑移剪出阶段和扰动变形阶段;③该类斜坡变形破坏后,坡体易沿“上陡下缓”的椅型软弱层面发生二次滑动,滑坡控制关键是对下部变形区的保护。 相似文献
5.
Mechanism for the rapid motion of the Qianjiangping landslide during reactivation by the first impoundment of the Three Gorges Dam reservoir, China 总被引：10，自引：6，他引：4
Fawu Wang Yeming Zhang Zhitao Huo Xuanming Peng Shimei Wang Shintaro Yamasaki 《Landslides》2008,5(4):379-386
The first impoundment of the Three Gorges Dam reservoir in China started from a water surface elevation of 95 m on June 1,
2003 and reached 135 m on June 15, 2003. Shortly after the water level reached 135 m, many slopes began to deform and some
landslides occurred. The Qianjiangping landslide is the largest one; it occurred on the early morning of July 14, 2003 and
caused great loss of lives and property. Field investigation revealed that, although failure occurred after the reservoir
reached 135 m, the stability of the slope was already reduced by preexisting sheared bedding planes. To study the mechanism
of the rapid motion of this reactivated landslide, two soil samples were taken from a yellow clay layer and a black silt layer
in the sliding zone, respectively, and a series of ring shear tests were conducted on the samples. One series of ring shear
tests simulates the creep deformation behavior, while the other series simulates different shear rates. Conclusions drawn
from analysis of the ring shear tests indicate that the mechanism of the rapid motion of the reactivated landslide was caused
by the rate effect of the black silt layer during the motion phase after the creep failure. The yellow clay layer did not
play any important role in the rapid motion in the 2003 event. 相似文献
6.
7.
2019年9月14日11时,受多日降雨影响,甘肃省定西市通渭县常家河镇小庄村发生大规模黄土滑坡,体积约800万m3。滑坡造成部分农田、公路及阳坡大桥损毁,直接经济损失约2 347.2万元。在对滑坡现场进行大量地面调查的基础上,通过无人机航拍、现场测绘、走访调查和数值模拟等手段对滑坡的变形破坏特征进行了分析,并在此基础上探讨了其成因机制。结果表明:斜坡体是在震裂、蠕变、软化、水动力等多种条件下按照一定的先后顺序由稳态逐步演化至失稳;该滑坡的失稳演化过程和灾变机制可以概括为原始斜坡(黄土、泥岩二元层状结构)-地震触发(滑坡堆积体、坡体震裂损伤)-蠕变弱化(层间剪切带、裂缝和落水洞扩展)-降雨激发(滑带软化、泥化,水压力作用)-失稳滑动(滑面贯通)5个阶段;由于长期的蠕变和雨水的渗透冲蚀,坡体上的落水洞和地下暗河十分发育,且是控制本次滑坡边界的关键因素;滑坡后缘和前缘变形剧烈,中部变形相对稍弱,推断该滑坡为受地形及地下水作用控制明显的牵引-推移式复合滑坡。 相似文献
8.
近年来由于受极端强降雨天气的影响,宁镇地区山前缓坡发生多起中型-大型滑坡地质灾害,主要表现为间歇性蠕滑,规模较大,而滑移距离较小,一般小于30 m,该类滑坡严重威胁附近居民的生命和财产安全,造成巨大的经济损失和严重不良社会影响。为此,本文针对这一典型山前缓坡新型滑坡地质灾害,运用岩体结构控制论和优势面理论对其滑坡体地层结构及滑动机理进行研究,结果表明滑坡主要发生在山前缓坡地段,滑坡体具有特殊的地层结构及水文地质特性,受到强降雨作用时,在坡体内容易产生暂时性承压水,在其浮托力的作用下缓坡主要产生顶托破裂和剪切破坏,并随降雨产生间歇性蠕滑。 相似文献
9.
水动力型滑坡是指在冰川融雪、降雨、水位变动、地表径流及地下水活动等水动力因素驱动下而发生的斜坡岩土体失稳灾害。西南地区是水动力型滑坡尤其是库区滑坡的高发区,其失稳破坏直接威胁到人类的生命财产和基础设施的安全,且有可能造成深远的次生灾害,提升水动力型滑坡灾害的监测预警、综合防控与应急处置水平极为迫切。水动力型滑坡易发于松散堆积层、破碎岩体、软岩以及含有软弱夹层的斜坡等地层,地质环境、水文活动以及人类活动干扰等因素的长期作用在水动力型滑坡的孕育过程中起着关键作用。斜坡在各种不利因素的持续交替作用下,逐渐产生变形破坏,稳定性不断降低并趋于极限失稳状态,最终在短期水文条件的改变下而导致整体失稳破坏。斜坡失稳后的滑坡动力过程非常复杂,尤其是特大型高位滑坡,在运动过程中可能会产生强烈的冲击破碎和沿程侵蚀铲刮现象,导致滑坡运动性态的改变和堆积方量的增大,水的存在会加剧滑坡沿程侵蚀铲刮作用以及导致运动性态向流态化转变而造成更远的运动距离和更广的致灾范围。水动力型滑坡是一个复杂的系统性问题,不同地质结构和水动力条件的滑坡变形破坏过程存在很大差异,远距离非接触式滑坡早期识别与监测技术以及基于人工智能和大数据且具备自主学习的滑坡预报预警方法是未来重要发展方向。水动力型滑坡防治涉及到工程建设、经济民生、社会等多方面因素,需要综合运用工程措施和非工程措施。在未来水利水电工程建设过程中,应重视库区滑坡的危害性,复建设施的修建应尽可能远离库区滑坡影响区。 相似文献
10.
The determination of statistical and deterministic hydrological landslide-triggering thresholds 总被引：25，自引：0，他引：25
Mark T. J. Terlien 《Environmental Geology》1998,35(2-3):124-130
Hydrological landslide-triggering thresholds separate combinations of daily and antecedent rainfall or of rainfall intensity
and duration that triggered landslides from those that failed to trigger landslides. They are required for the development
of landslide early warning systems. When a large data set on rainfall and landslide occurrence is available, hydrological
triggering thresholds are determined in a statistical way. When the data on landslide occurrence is limited, deterministic
models have to be used. For shallow landslides directly triggered by percolating rainfall, triggering thresholds can be established
by means of one-dimensional hydrological models linked to the infinite slope model. In the case of relatively deep landslides
located in topographic hollows and triggered by a slow accumulation of water at the soil-bedrock contact, simple correlations
between landslide occurrence and rainfall can no longer be established. Therefore real-time failure probabilities have to
be determined using hydrological catchment models in combination with the infinite slope model.
Received: 15 October 1997 · Accepted: 25 June 1997 相似文献
11.
低速滑坡的缓慢活动特征受其滑带岩土的蠕变行为控制。但是,新生型低速滑坡和复活型低速滑坡滑带岩土的蠕变行为显然分属于峰前状态和残余状态下的蠕变行为。两种状态下滑带岩土蠕变行为有何差异,国内外尚无明确认识。为此,本文以取自两个典型巨型低速滑坡——甘肃舟曲泄流坡滑坡和锁儿头滑坡滑带的含角砾黏性土为研究对象,分别采用直接剪切蠕变试验和直剪反复剪后的直剪蠕变试验方法,对比研究了峰前状态和残余状态下黏性土的剪切蠕变行为。研究发现,峰前状态和残余状态下,黏性土剪切蠕变均呈现阶段性,各阶段转换的临界剪应力均与正应力水平和角砾含量正相关。但是,峰前状态下黏性土蠕变具有明显的稳定蠕变阶段;残余状态下黏性土蠕变缺失这一阶段;前者加速蠕变临界剪应力大于后者、但小于峰值强度,后者加速蠕变临界剪应力略微大于残余强度。两种状态下,黏性土蠕变行为差异的根本原因在于土体内部的不同结构。 相似文献
12.
2D viscoplastic finite element modelling of slow landslides: the Portalet case study (Spain) 总被引：3，自引：1，他引：2
J. A. Fernández-Merodo J. C. García-Davalillo G. Herrera P. Mira M. Pastor 《Landslides》2014,11(1):29-42
This paper proposes a hydro-geomechanical finite element model to reproduce the kinematic behaviour of large slow landslides. The interaction between solid skeleton and pore fluids is modelled with a time dependent u–p w formulation and a groundwater model that takes into account recorded daily rainfall intensity. A viscoplastic constitutive model based on Perzyna’s theory is applied to reproduce soil viscous behaviour and the delayed creep deformation. The proposed model is applied to Portalet landslide (Central Spanish Pyrenees). This is an active paleo-landslide that has been reactivated by the construction of a parking area at the toe of the slope. The stability analysis reveals that, after the constructive solutions were undertaken, the slope is in a limit equilibrium situation. Nevertheless, time-dependent analysis reproduces the nearly constant strain rate (secondary creep) and the acceleration/deceleration of the moving mass due to hydrological changes. Overall, the model reproduces a 2-m displacement in the past 8 years that coincides with in situ monitoring data. The proposed model is useful for short- and mid-term predictions of secondary creep. However, long-time predictions remain uncertain, stability depends strongly on the position of the water table depth and new failures during tertiary creep due to soil temporal microstructural degradation are difficult to calibrate. 相似文献
13.
Micro-sheeting of granite and its relationship with landsliding specifically after the heavy rainstorm in June 1999, Hiroshima Prefecture, Japan 总被引：1，自引：0，他引：1
M. Chigira 《Engineering Geology》2001,59(3-4):219-231
Certain types of granite in mountainous areas are microscopically sheeted to a depth of 50 m due to unloading under the stress field that reflects slope morphology. Micro-sheets generally strike parallel to major slope surfaces and gently dip downslope, forming cataclinal overdip slopes. The cataclinal overdip slope accelerates creep movement of micro-sheeted granite, which in turn loosens and disintegrates granite via the widening or neoformation of cracks, probably in combination with stress release, temperature change, and changes in water content near the ground surface. The surface portion of micro-sheeted granite is thus loosened with a well-defined basal front, which finally slides in response to heavy rain. Innumerable landslides of this type occurred in Hiroshima Prefecture, western Japan, following the heavy rainstorm of 29 June 1999. Following such landslides, the weathering of micro-sheeted granite exposed on the landslide scar recommences, setting the stage for future landslide. 相似文献
14.
綦江县土台镇滑坡是重庆市的重点地质灾害点之一.1998年9月5～6日,滑坡体发生了大规模的变形破坏,造成的直接经济损失高达100万元.本文通过成因机制分析,对土台镇滑坡的稳定性进行了定性评价,并对各种状态下的滑坡稳定性进行了系统的定量计算,认为该滑坡体总体是稳定的,但在前缘和东侧陡坡地带斜坡处于准极限平衡状态,具有发生次级滑坡的可能. 相似文献
15.
甘肃南部坪定-化马断裂带滑坡变形特征及其防治 总被引：1，自引：0，他引：1
以坪定-化马断裂带泄流坡滑坡为例,通过野外调查和变形监测资料分析,深入剖析了断裂带滑坡变形特征和形成机理,提出了断裂带滑坡的防治方法和治理措施。断裂带滑坡一般为大型—巨型滑坡,由多个次级滑坡体组成,历史上曾多次活动。变形监测资料表明,泄流坡滑坡变形目前处于匀速蠕变阶段,呈现蠕滑-塑流拉裂-土（石）流的变形破坏特点。断裂破碎带及其现今活动为滑坡长期蠕滑变形提供了物质基础,而降雨是滑坡体失稳下滑的主要诱发因素。断裂带滑坡按岩性可归类为松散堆积层滑坡。因此,对断裂带滑坡的防治应以防为主,以治为辅,即开展滑坡变形实时监测和群测群防,辅以滑坡表面排水、坡脚压载等措施,以减缓或防止泄流坡滑坡再次形成灾害。 相似文献
16.
Nonlinear Evolutionary Mechanisms of Instability of Plane-Shear Slope: Catastrophe, Bifurcation, Chaos and Physical Prediction 总被引：1，自引：0，他引：1
Summary. A cusp catastrophe model is presented and the necessary and sufficient conditions leading to landslides are discussed. The
sliding surface is assumed to be planar and is a combination of two media: medium 1 is elastic-brittle or strain-hardening
and medium 2 is strain-softening. The shear stress-strain constitutive model for the strain-softening medium is described
by the Weibull’s distribution law. This paper is a generalization and extension of the paper by Qin et al. (2001b), in which
the shear stress-strain constitutive model for medium 2 was described by a negative exponent distribution; a special case
of the Weibull’s distribution law. It is found that the instability of the slope relies mainly on both the stiffness ratio
of the media and the homogeneity index and that a new role of water is to enlarge the material homogeneity or brittleness
and hence to reduce the stiffness ratio. A nonlinear dynamic model (also called a physical forecasting model), which is derived
by considering the time-dependent behavior of the strain-softening medium, is used to study the time prediction of landslides.
An algorithm of inversion on the nonlinear dynamic model is suggested for seeking the precursory abnormality and abstracting
mechanical parameters from the observed series of a landslide. A case study of the Jimingsi landslide is analysed and its
nonlinear dynamic model is established from the observation series of this landslide using the suggested model and the algorithm
of inversion. It is found that the catastrophic characteristic index |D| shows a quick rise till reaching an extremely high peak value after the slope evolves into the tertiary creep, and subsequently
approaches a zero value prior to instability, which can be regarded as an important precursory abnormality index. By taking
into account the evolutionary characteristic of the slope being in the secondary creep, a simplified nonlinear dynamic model
is proposed for studying the properties of bifurcation and chaos. It is shown that the emergence of chaos depends on the mechanical
parameters of the sliding-surface media. 相似文献
17.
渭河中游宝鸡-扶风段北岸塬边集中发育大型黄土滑坡,体积超过1 000×104 m3的滑坡达58处。在区域活动断裂调查、地球物理勘察、典型斜坡结构与构造调查基础上,研究了大型滑坡结构及其形成机理。研究表明：渭河北缘活动断裂以地堑式结构控制北坡塬边斜坡的地貌,主断裂面倾向南,倾角平均为68°,而次级断面结构组合控制斜坡结构,影响塬边大型黄土滑坡结构;塬边主断裂面与多个大型黄土滑坡后缘滑壁一致,断裂最大下挫距离7.1 m,影响大型滑坡的形态及发生过程;活动断裂呈地堑式结构,局部次级断面控制塬边多级滑动面的结构及其演化过程,如杨家村滑坡,局部滑坡剪出受断裂结构控制,剪出口角度可达72°,大部分剪出口未受到断裂面影响,角度平均为23°;三门组黏土岩黏粒体积分数超过35%,塑限平均值为23,是滑坡的层间剪切带;降雨诱发老滑坡复活是目前新滑坡发育的主要形式,大量的老滑坡形成于0.009 Ma BP二级阶地侵蚀期,而古滑坡形成于0.13 Ma BP三级阶地侵蚀期。 相似文献
18.
岩溶山区特殊的地质结构导致崩塌、滑坡等地质灾害时常发生,带来了严重的人员伤亡和经济社会损失。研究岩溶山区崩滑灾害特征,建立相应的变形破坏地质模式,对于岩溶山区崩滑灾害风险防控与治理工程具有重要理论意义与指导价值。文章以典型地质灾害形成演化过程为例,在系统地分析研究区典型崩滑灾害地质背景、影响因素、动力学与运动学特征的基础上,提出了岩溶山区崩滑灾害变形破坏地质模式,得出以下主要结论:（1）影响崩滑成灾基本因素（崩滑灾害体势能、岩溶结构面、岩组结构、斜坡地貌和斜坡结构）、影响因素（水文地质条件、工程活动、地震、降雨）和变形运动特征（运动形式和变形机制）三个方面,据此建立了岩溶山区崩滑灾害地质分类指标体系。（2）结合研究区特征对模型体系里面的每个要素进行系统分析,崩滑灾害的发生是各个要素相互组合、相互作用的结果。（3）总结了研究区内5种典型崩滑地质模式:高势能反倾降雨型高速远程滑坡—碎屑流模型、高势能斜倾视向采矿型高速远程崩滑灾害模型、超高势能横向陡倾地震型高速远程滑坡、高势能采矿型高速崩塌—碎屑流模型、低势能差异风化崩塌模型。为后续开展物理模拟、数值模拟、稳定性计算和变形破坏预测等工作奠定基础。下一步将更加深入全面地建立研究区的崩滑灾害模式,并进行崩滑灾害的危险性分级工作。 相似文献
19.
In Nepal, people live in widely spread settlements in the fragile Himalayan terrains, and suffer more from landslides than from any other type of natural disaster. The small-scale rainfall-triggered landslides in the Lesser Himalaya of Nepal are generally shallow (about 0.5 to 2.5 m) and are triggered by changes in the physical property of soil layers during rainfall. The relation between landslides and slope hydrology has received little attention in Himalayan landslide research. Thus, this paper deals with the probability of slope failure during extreme rainfall events by considering a digital elevation model (DEM)-based hydrological model for soil saturation depth and an infinite slope stability model. Deterministic distributed analysis in a geographic information system (GIS) was carried out to calculate the probability of slope failure. A simple method of error propagation was used to calculate the variance of the safety factors and the probability of failure. When normally distributed failure probability values were checked against existing landslides, it was found that more than 50% of the pixels of existing landslides coincided with a high calculated probability of failure. Although the deterministic distributed analysis has certain drawbacks, as described by previous researchers, this study concluded that the calculated failure probability can be utilised to predict the probability of slope failure in Himalayan terrain during extreme rainfall events. 相似文献
20.
Xingang Wang Yueping Yin Jiading Wang Baoqin Lian Haijun Qiu Tianfeng Gu 《Landslides》2018,15(7):1377-1389
The rock masses of hydro-fluctuation belt experience seepage pressure following impoundment in the Three Gorges Reservoir; its creep behaviors are significant for reservoir bank slopes. To study the creep behaviors under seepage pressure (0, 1.45, and 1.75 MPa), we performed creep tests using representative landslide sandstone in the Three Gorges Reservoir and investigated the sandstone creep behaviors under the coupling effects of seepage pressure and stress. Previous researches on rocks have usually regarded the creep constitutive parameter as a constant; however, in this study, a nonlinear, nonstationary, plastic-viscous (NNPV) creep model which can describe the curve of sandstone creep tests is proposed. The rock-creep parameters under three levels of seepage pressure were identified, and theoretical curves using the NNPV model agreed well with the experimental data, indicating that the new model cannot only describe the primary creep and secondary creep stages under varying seepage pressures but also, in particular, perfectly describes the tertiary creep stage. Finally, the sensitivity of the NNPV model parameters is analyzed, and the result shows that the nonstationary coefficient α and the nonlinear coefficient m are main parameters affecting the tertiary creep stage. 相似文献