三峡树坪滑坡动力学的有限元模拟     

赵永红  王航  邓凯  李小凡 《岩石学报》2016,32(7):2217-2224

三峡工程是迄今为止最大的水利工程,对库区滑坡灾害的监测和机制研究一直是重要的研究课题。本文利用Terra SAR-X的强度图进行相关计算,求解出2009年5月20日至8月5日期间三峡树坪滑坡的形变场。该形变场特征和树坪滑坡体的地形特征吻合甚好,位移大小、方向和三峡大学对滑坡体的野外观测结果基本吻合。以此高精度位移场为外部约束,结合野外观测资料对滑坡体介质力学性质进行分类并选取边界条件,利用有限元方法对滑坡活动进行动力学计算模拟。计算过程中对滑坡体的滑动面形状、因降雨引起材料参数变化和三峡水库水位等因素分别反演和调整,得出符合其变形和发展过程的滑坡动力学特征。发现软弱带的物性参数决定滑坡体总体滑动量,滑坡体的物性参数决定位移分布的峰值位置。在确定了滑坡动力学特征之后,进一步讨论降雨和库区水位下降对滑坡产生的贡献权重,得出降雨是树坪滑坡的决定因素。  相似文献   

滑坡监测数据处理回归模型分析及探讨     

张纯志 《测绘与空间地理信息》2016,(8)

主要介绍了滑坡监测的技术和方法,并通过万源市太平镇某滑坡监测实践,阐述了在地形复杂、观测条件恶劣的山区进行滑坡监测时,基准监测点选择、监测网布设、数据处理的方法。最重要的是用线性回归方程分析监测数据,为科学治理提供可靠的依据。  相似文献   

Volcanism and archipelagic aprons in the Marquesas and Hawaiian Islands     

P. E. Filmer  M. K. McNutt  H. F. Webb  D. J. Dixon 《Marine Geophysical Researches》1994,16(5):385-406

Geophysical observations demonstrate that the archipelagic apron surrounding the Marquesan hot-spot volcanoes is derived almost entirely from mass wasting processes. Seismic reflection and refraction data constrain the volume of the apron sediments to approximately 200,000 km³, with thicknesses reaching over 2 km in the deep portions of the moat near the edge of the volcanic edifice. Seismic velocities average 4 to 5 km s^–1 in the sediments, and 6 km s^–1 at the top of the underlying basement. Single channel seismic profiles show acoustically chaotic cores in the sediments of the apron, which are interpreted as debris flows from mass wasting events. We deduce that the apron is formed by catastrophic collapses that may involve volumes over 100 km³ tens to hundreds of times during the lifetime of a volcano. Comparison with similar data from the Hawaiian Islands yields the result that the total volume of volcanics and their derived sediments along the strike of the chains is only slightly smaller for the Marquesas, implying comparable eruption rates. However, the ratio of sediment to surface volcanic load is much larger for the latter, leading to an overfilled moat in the Marquesas and an underfilled moat at Hawaii. The much larger size of the Hawaiian islands can be explained as the combined effects of a higher thermal swell, loading a stiffer elastic plate, and proportionately less mass wasting.  相似文献   

Modelling the effect of land management interventions and climate change on sediment loads in the Manawatū–Whanganui region     

Les Basher  Raphael Spiekermann  John Dymond  Alex Herzig  Ella Hayman  Anne-Gaelle Ausseil 《新西兰海洋与淡水研究杂志》2020,54(3):490-511

ABSTRACT

SedNetNZ is used to model the effect of erosion control undertaken under the Sustainable Land Use Initiative (SLUI) and predict the effect of climate change on sediment load in the Manawatū–Whanganui region. Sediment load in 2004 is estimated at 13.4?Mt?yr^?1; by 2018, ≈5000?km² of land had farm plans implemented and annual sediment load reduced by 6.2% of the 2004 load. If SLUI stops at the 2018 level of implementation, by 2038 it is predicted to achieve a 15.7% reduction in annual sediment load. If SLUI continues to implement farm plans, 7949?km² of land will be treated by 2043 and annual sediment load could be reduced by a further 14.7%. Climate change is predicted to substantially increase sediment loads. By 2043 annual sediment load for the region is predicted to increase, compared to 2004, by between 8.3 and 23.7%. However, this can largely be offset by SLUI works. By 2090 an annual sediment load increase of between 53 and 224% due to climate change is predicted. The results suggest climate warming may dominate changes in sediment load in the future.  相似文献   

A numerical procedure for predicting rainfall‐induced movements of active landslides along pre‐existing slip surfaces     

Michele Calvello  Leonardo Cascini  Giuseppe Sorbino 《国际地质力学数值与分析法杂志》2008,32(4):327-351

A numerical model to predict landslide movements along pre‐existing slip surfaces from rainfall data is presented. The model comprises: a transient seepage finite‐element analysis to compute the variations of pore water pressures due to rainfall; a limit equilibrium stability analysis to compute the factors of safety along the slip surface associated with transient pore pressure conditions; an empirical relationship between the factor of safety and the rate of displacement of the slide along the slip surface; an optimization algorithm for the calibration of analyses and relationships based on available monitoring data. The model is validated with reference to a well‐monitored active slide in central Italy, characterized by very slow movements occurring within a narrow band of weathered bedrock overlaid by a clayey silt colluvial cover. The model is conveniently divided and presented in two parts: a groundwater model and a kinematic model. In the first part, monthly recorded rainfall data are used as time‐dependent flow boundary conditions of the transient seepage analysis, while piezometric levels are used to calibrate the analysis by minimizing the errors between monitoring data and computed pore pressures. In the second part, measured inclinometric movements are used to calibrate the empirical relationship between the rate of displacement along the slip surface and the factor of safety, whose variation with time is computed by a time‐dependent stability analysis. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Accounting for soil parameter uncertainty in a physically based and distributed approach for rainfall‐triggered landslides          下载免费PDF全文

E. Arnone  Y. G. Dialynas  L. V. Noto  R. L. Bras 《水文研究》2016,30(6):927-944

In this study we propose a probabilistic approach for coupled distributed hydrological‐hillslope stability models that accounts for soil parameters uncertainty at basin scale. The geotechnical and soil retention curve parameters are treated as random variables across the basin and theoretical probability distributions of the Factor of Safety (FS) are estimated. The derived distributions are used to obtain the spatio‐temporal dynamics of probability of failure, in terms of parameters uncertainty, conditioned to soil moisture dynamics. The framework has been implemented in the tRIBS‐VEGGIE (Triangulated Irregular Network (TIN)‐based Real‐time Integrated Basin Simulator‐VEGetation Generator for Interactive Evolution)‐Landslide model and applied to a basin in the Luquillo Experimental Forest (Puerto Rico) where shallow landslides are common. In particular, the methodology was used to evaluate how the spatial and temporal patterns of precipitation, whose variability is significant over the basin, affect the distribution of probability of failure, through event scale analyses. Results indicate that hyetographs where heavy precipitation is near the end of the event lead to the most critical conditions in terms of probability of failure. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

基于SPOT5遥感影像的浅层滑坡体自动提取方法     

杨树文  谢飞  韩惠  冯光胜 《测绘科学》2012,(1):71-73,88

本文在前人研究的基础上,对浅层滑坡体的提取方法进行了改进。首先利用改进的MSAVI算法提取SPOT5影像中的裸地信息,进而对提取的结果进行去阴影、坡度筛选、形态学滤波、栅-矢转换、面积和顺坡性筛选,并基于改进的多峰直方图阈值自动选取算法实现了滑坡体信息的自动提取。经过实验比较表明,改进的方法既有效地去除非滑坡体等干扰信息,又真正实现了滑坡体信息的自动提取,从而极大地提高了已发生滑坡体的识别、提取效率和精度。  相似文献   

Evolution stages of large deep-seated landslides at the front of a subalpine meridional chain (Maritime-Alps, France)   总被引：1，自引：0，他引：1  

Swann Zerathe  Thomas Lebourg 《Geomorphology》2012,138(1):390-403

Studying long term-evolution of gravitational slope evolution is a key to understanding deep-seated landslide processes. This paper deals with three large Deep-Seated Landslides (DSLs) at a front of a subalpine meridional chain, on the “La Marbrière” slope near the town of Grasse (Alpes-Maritimes, France). The geological framework controlling the stability and morphology of the DSLs is associated with thick and tamped Triassic layers of mudstone with gypsum overlain by highly faulted Jurassic limestone. Gravitational deformation affects the entire slope, involving a movement of about 1.1 × 10⁸ m³ of rock material. It creates large disturbances in landscape morphology, such as scarps, counter-slope scarps, trenches and other typical gravitational morpho-structures. Geomorphological mapping coupled with deep electrical resistivity tomography (ERT) reveals a strong correlation between these morpho-structures and inherited brittle tectonic features. This observation relies on spatial and geometrical relations (on the surface and at the depth of more than 150 m, checked by ERT) between the most persistent fault and the gravitational morpho-structures. The specific distribution of the morpho-structures on the basis of their morphological typologies and variations in the stage of evolution of three DSLs provides an interpretation of their kinematics during the last 400 ka. It appears that soft substratums combined with inherited persistent anisotropies are key factors in the development of the DSLs. Indeed, outflow of mudstone due to the lithostatic pressure imposed by individual limestone compartments has led to general slope subsidence. Then, a progressive toppling of a rock mass may have led to the catastrophic rock collapse along bedding planes.The evolution of the DSLs can be divided into three distinct stages represented by three zones: a young collapse stage (zone 1), a pre-collapse stage (zone 2) and an old mature stage (> 400 ka, zone 3). As the DSLs occur on the same slope and in the same geological context, this area offers interesting perspectives for understanding factors controlling the long-term gravitational evolution of slopes.  相似文献   

降雨型浅层滑坡的变形预测模型   总被引：1，自引：0，他引：1  

李德心  何思明 《山地学报》2012,(3):342-346

滑坡是边坡被某些诱发因素激发失稳产生滑动的一种地质现象。它是地质灾害的主要类型,尤其以降雨滑坡数量最多,其中浅层滑坡分布最广。通过对降雨型浅层滑坡的变形进行分析,建立了基于功能原理的滑坡一维运动方程,并结合太沙基固结原理,研究滑坡运动过程中孔隙水压力的消散,揭示了滑坡从运动-停止的动力演化过程,构建了降雨型浅层滑坡的位移预测模型,并以都江堰塔子坪滑坡为例进行分析,通过mathmatic给出了滑坡运动的速率、位移与降雨量的量化关系式。  相似文献   

运用历史航照及地形图建置数值地形资料并探讨1941年草岭山崩之地形演育(英文)     

陈秦妃  张国桢  詹瑜璋  郭志禹 《福建地质》2010,29(Z1)

<正>In tectonically active mountain belts such as the Taiwan(Fig.1a),frequent landslides affect the stability of mountain slopes,and landslides favour river erosion of disrupted masses.In the climatic and geodynamic context of Taiwan with heavy rainfall,approximate typhoon frequency of 3 -5 per year,rapid uplift of～5-10 mm yr~(-1) and strong denudation rate.Landslides are among the most common earthquake induced secondary effects and are causing huge damage to  相似文献