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1.
The paper first recalls briefly a methodological framework to assess landslide hazard and risk analysis in terms of predisposition, triggering andrevealing factors. This framework, that reflects the mechanisms involved in the landslide, is based on the Geotechnical Characterisation of slope movements proposed by Vaunat et al. (1994) and Leroueil et al. (1996). The Geotechnical Characterisation can be schematized by a 3-D matrix having the following axes: types of movement; types ofmaterial; and the four stages of movement: pre-failure, failure, post-failure andreactivation. For each relevant element of this 3-D matrix, there is a characterisationsheet including: the controlling laws and parameters, the predisposition factors, thetriggering or aggravating factors, the revealing factors and the consequences of the movement. The paper focuses afterwards on the post-failure stage, which generallyis the most destructive, and on the mobility index. It is shown that this laterindex can be described as the product of sub-indices associated with failure, brittlenessof the material, ability of the soil to develop pore pressures, geometry of the moving soil mass and characteristics of the terrain. It is also shown how these aspectscan be incorporated into the Geotechnical characterisation of slope movements. This seems to provide a rational basis for examining slope movements at the post-failure stage and assessing associated risks. 相似文献
2.
Christian Weiler 《Surveys in Geophysics》1995,16(5-6):671-679
For the purposes of a thesis at the Institute of avalanche and torrent control at the university of agriculture in Vienna a comparison of two avalanche-models, a hydraulic one from Voellmy/Salm/Gubler and a statistical one from Laatsch/Zenke/Dankerl with exemplary exactly known avalanches of Tyrol and Switzerland was started in 1993. The result of this work was that both models failed by the calculation of avalanches with high recurrence intervals (over 300 years). For the calculation of avalanches with recurrence intervals under 300 years the results of both models are regular. The conclusion is that a combination of two models i.e. a hydraulic one improved by statistical calculations will be the best. 相似文献
3.
汶川大地震触发了多处高速远程滑坡,导致了大量的人员伤亡及财产损失。其中,东河口滑坡是这次地震触发的最为典型的高速远程滑坡之一,同时也是目前备受关注、争论颇多的滑坡之一。野外调研结果表明,该滑坡的成因和动力特征主要包括震裂溃屈、水平抛射、碎屑流化和振动液化等4个方面。为了对该滑坡滑动过程中的振动液化这一动力特征进行模拟再现,在东河口滑坡体上采集了具有代表性的滑带土作为试验样品,并以该地震时的实测地震波作为动力输入,利用目前国际上最先进的DPRI环剪试验机,对滑坡滑动过程中的振动液化现象进行了一系列环剪试验研究。结果表明,地震作用过程中,发生在滑坡潜在滑面上的振动液化现象是导致高速远程滑坡产生的一个重要因素;伴随着振动液化过程,滑体的剪切强度迅速降低并产生逐渐增大的剪切位移,为高速远程滑坡的形成提供了条件 相似文献
4.
This paper presents forward simulation with MassMov2D code and sensitivity analysis of run out resulting from different scenarios of potential failure of a 40 million m3 active rockslide hanging above the village of Trafoi, in South Tyrol (Italy). Five scenarios of potential failure zones were identified, with the larger one being the failure of the entire rock slide. Forward simulations showed that the consequences for the Trafoi village would be potentially destructive. A parametric sensitivity analysis was carried out in order to increase the significance of risk assessment. Results obtained by varying friction and turbulent coefficients showed quite unequivocally that although the variability of the run out might be quite large it does not change risk scenarios significantly except in the smaller case of failure. This confirms the usefulness of forward simulations even if they might be affected by uncertainties related to the impossibility to retrieve optimised parameters. 相似文献
5.
Flow behaviour of the submarine glacigenic debris flows on the Bear Island Trough Mouth Fan, western Barents Sea 总被引：3，自引：0，他引：3
Using 3·5 kHz high-resolution seismic data, gravity cores and side-scan sonar imagery, the flow behaviour of submarine, glacigenic debris flows on the Bear Island Trough Mouth Fan, western Barents Sea was studied. During their downslope movement, the sediments within the uppermost part of the debris flows (<3 m) are inferred to have been deformed as a result of the shear stress at the debris–water interface. Thus, the uppermost part of the flow did not move downslope as a rigid plug. If present, a rigid part of the flow was located at least some metres below the surface. At c . 1000 to at least 1600 m water depth, the debris flows eroded and probably incorporated substrate debris. Further downslope, the debris flows moved passively over substrate sediments. The hypothesis of hydroplaning of the debris flow front may explain why the debris flows moved across the lower fan without affecting the underlying sediments. Detailed morphological information from the surface of one of the debris flow deposits reveals arcuate ridges. These features were probably formed by flow surge. Hydroplaning of the debris flow front may also explain the formation of flow surge. The long runout distance of some of the large debris flows could be due to accretion of material to the base of the debris flow, thereby increasing in volume during flow, and/or to hydroplaning suppressing deceleration of the flow. 相似文献
6.
A prediction model for horizontal run-out distance of landslides triggered by Wenchuan earthquake 总被引：1，自引：0，他引：1
The peak ground acceleration (PGA), the volume of a sliding mass V, the height of a mountain H L and the slope angle θ of a mountain are four important parameters affecting the horizontal run-out distance of a landslide L. Correlations among them are studied statistically based on field investigations from 67 landslides triggered by the ground shaking and other factors during the Wenchuan earthquake, and then a prediction model for horizontal run-out distance L is developed in this study. This model gives due consideration to the implications of the above four parameters on the horizontal run-out distance L and the validity of the model is verified by the Donghekou and Magong Woqian landslides. At the same time, the advantages of the model are shown by comparing it with two other common prediction methods. The major findings drawn from the analyses and comparisons are: (1) an exponential relationship exists between L and log V, L and log H L, L and log PGA separately, but a negative exponential relationship exists between L and log tanθ, which agrees with the statistical results; and (2) according to the analysis results of the relative relationship between the height of a mountain (H) and the place where the landslides occur, the probabilities at distances of 2H/3-H, H/3-2H/3, and 0-H/3 are 70.8%, 15.4%, and 13.8%, respectively, revealing that most landslides occurred at a distance of H/2-H. This prediction model can provide an effective technical support for the prevention and mitigation of landslide hazards. 相似文献
7.
Yi Rui 《Marine Geodesy》2019,42(3):246-262
Submarine debris flows have a significant impact on offshore and coastal facilities. The unique characteristics of submarine debris flows involve large mass movements and long travel distances over very gentle slopes. To improve our insight and knowledge of the basic mechanism behind submarine debris flows, an analytical model was derived for the mobility of submarine debris flows. This model takes into account the mass change of debris flows induced by deposition, stagnation pressure, and the topography of the depositional area. One case study on the Palos Verdes debris flow proves its ability to predict the run-out distance of a submarine debris flow to a reasonable level of accuracy. On the gentle slopes, the submarine debris flow progressively loses mass due to deposition, which in turn influences the flow velocity. In addition, the results show that the slope angle and spreading angle of the debris depositional zone play important roles in the sliding process. 相似文献
8.
永宁高速公路K117滑坡路段原为在泥质粉砂岩单斜地层内开挖2级形成的路堑边坡,开挖后产生典型平面滑动,在中部滑床形成长约25m的滑动槽,产生最远达35m的远程滑距,其成因机制复杂。本文在对滑坡基本特征及孕育过程开展详细调查研究的基础上,采用节理有限单元法对该滑坡经路堑开挖导致高位坍滑、刷方变更后触发高速远程滑塌、滑塌后壁残留滑体牵引松动,以及对其实施卸载、支挡回填及锚固的治理过程开展数值模拟,再现了该滑坡孕育发展全过程及其稳定性演化规律;分析了该边坡破坏的平面滑动机构及滑动面的物理力学特征,论述了该类滑坡启动高速远程滑动的开挖松弛致滑机理和裂隙充水致滑机理,最后提出了预测及治理该类滑坡的6点建议。研究表明,在单斜地层开挖路堑,使顺倾向软弱结构面临空暴露时,可能诱发边坡整体卸荷松弛,产生较大的不平衡滑坡推力,而卸荷松动产生的张裂隙导致滑坡对降雨入渗十分敏感,不平衡力和裂隙水压力的共同作用可迅速剪断滑面,伴随势能向动能的转化,产生高速远程滑动。 相似文献
9.
高速远程滑坡因其突发性、剧烈性、高速性、远程性等特点对人员和财产造成重大危害,是中国最严重的地质灾害类型之一,研究其灾变过程对中国防灾减灾具有重要的意义。DAN-W是基于拉格朗日有限差分法建立的动力模拟方法,反演模拟碎屑流运动过程,更适合高速远程滑坡的模拟分析。笔者以哀牢山地区芭蕉树滑坡为研究对象,研究芭蕉树滑坡的基本特征,利用DAN-W软件建立芭蕉树滑坡的计算模型,分析滑坡的灾变过程,依据滑坡特征考虑滑坡分区和铲刮效应,将滑动路径分为3段:滑源段、铲刮段、堆积段进行模拟计算;结果显示:滑坡前缘最大速度为26 m/s,后缘最大速度为30 m/s,后缘最大速度发生在剪出口位置,最大滑距为420 m,滑动14 s后滑体基本滑离剪出口,至运动30 s时停止滑动。所得结果与实际情况吻合度高。 相似文献
10.
东河口滑坡－碎屑流高速远程运移机制探讨 总被引：8，自引：0，他引：8
摘 要 青川东河口滑坡－碎屑流是5.12汶川大地震触发的典型高速远程滑坡,滑坡自高程1300m处开始滑动,总滑程约2400m,致使780余人遇难。野外调研结果表明,该滑坡自启动到最终静止,分别经历了滑坡启动阶段、重力加速阶段、圈闭气垫效应飞行阶段、撞击折返阶段及长距离滑动堆积阶段五个重要动力过程,最终抵达下寺河左岸的红花地村并形成堰塞湖。文中通过对该高速远程滑坡－碎屑流的地质背景及形态特征进行剖析认为,东河口滑坡启动区的断层破碎带、局部凸起地形以及力学性质较差的千枚岩、板岩的存在,对该滑坡的启动均有着显著影响;滑坡体在运行一段距离后是否可以继续保持高速远程滑动,除了有利的地形外,滑体滑动路径上坡体堆积物的含水状态是促使该滑坡成为高速远程滑坡碎屑流的重要原因之一。 相似文献