共查询到20条相似文献，搜索用时 250 毫秒
1.
Visual simulation of landslide fluidized movement based on smoothed particle hydrodynamics 总被引：2，自引：2，他引：0
Earthquake-induced landslides can cause a large number of casualties and great economic loss. Presently, research methods
for studying landslides are largely based on a framework of solid mechanics. In this work, visualization software, known as
Visual SPH, is developed in Visual Basic 6.0, and can be used to analyze the fluidized movement of landslides based on smoothed
particle hydrodynamics (SPH). First, the accuracy of the software is verified through simulating a benchmark problem of a
dam-break. Then, fluidized movement analysis of the Tangjiashan landslide is carried out using this software. The simulation
derives plots of displacement versus time, reproduces the entire flow process of the Tangjiashan landslide, and determines
the run-out, which coincides exactly with the characteristics of flow-like landslides observed in the field. All of these
are essential in the design of supporting structures and site selection for reconstruction in earthquake-prone regions. 相似文献
2.
高速流动性滑坡运动距离远,破坏性强。这类滑坡在运动过程中常裹挟大量的松散物质,导致滑坡的体积和致灾范围增大,该现象被称为基底侵蚀效应。以往的研究指出基底侵蚀效应对这类滑坡的运动性有显著的影响,但却很少有研究考虑其对滑体性质的影响,以及如何对其进行量化。因此,本文基于动量守恒原理建立了考虑基底侵蚀效应的滑坡运动模型,利用有限差分法求解,并依据滑坡的侵蚀深度来计算侵蚀导致的滑坡性质变化。利用改进的模型对陕西泾河南岸的西庙店滑坡进行模拟分析。结果表明,滑坡运动可分为启动加速阶段（0~5 s）和运动减速阶段（5~14 s）。在启动加速阶段,基底侵蚀程度低,对滑体运动的影响较弱。而在运动减速阶段,基底侵蚀效应降低了滑带土强度,对该滑坡的运动产生了明显的促进作用,致使其发生远程运动。此外,对比考虑和不考虑基底侵蚀两种工况的模拟结果还发现,考虑这种影响时,模拟所得的运动范围及地形与实测吻合良好,而未考虑时模拟所得运动范围明显偏小。因此,本文的模型可对这类滑坡的运动过程进行更为有效的模拟。 相似文献
3.
滑坡涌浪是入水滑坡引起的一种次生灾害,其致灾范围远大于滑坡的运动区域,准确预测其演化过程是防治这类灾害的关键。现有预测模型多将滑体简化为刚体,而实际滑坡多表现出流态运动的特征。为更合理地描述滑体和涌浪的耦合运动,将滑体视为流态物质,在此基础上推导了滑坡与水体耦合运动的控制方程,利用有限差分法对控制方程求解,建立了一种可模拟流动性滑坡涌浪演化过程的动力学模型。使用该模型对三峡库区的龚家方滑坡涌浪的演化过程进行模拟,将模拟所得河道纵截面处的最大浪高值与实测值进行对比,结果表明最大浪高值出现在滑坡的主滑动方向,且最大浪高沿纵截面两侧快速衰减,模拟结果与实测吻合。 相似文献
4.
Statistical Analysis of Landslide Events in Central America and their Run-out Distance 总被引：3，自引：0，他引：3
Graziella Devoli Fabio V. De Blasio Anders Elverhøi Kaare Høeg 《Geotechnical and Geological Engineering》2009,27(1):23-42
Statistical analyses of landslide deposits from similar areas provide information on dynamics and rheology, and are the basis
for empirical relationships for the prediction of future events. In Central America landslides represent an important threat
in both volcanic and non-volcanic areas. Data, mainly from 348 landslides in Nicaragua, and 19 in other Central American countries
have been analyzed to describe landslide characteristics and to search for possible correlations and empirical relationships.
The mobility of a landslide, expressed as the ratio between height of fall (H) and run-out distance (L) as a function of the
volume and height of fall; and the relationship between the height of fall and run-out distance were studied for rock falls,
slides, debris flows and debris avalanches. The data show differences in run-out distance and landslide mobility among different
types of landslides and between debris flows in volcanic and non-volcanic areas. The new Central American data add to and
seem consistent with data published from other regions. Studies combining field observations and empirical relationships with
laboratory studies and numerical simulations will help in the development of more reliable empirical equations for the prediction
of landslide run-out, with applications to hazard zonation and design of optimal risk mitigation measures. 相似文献
5.
M. Pastor T. Blanc B. Haddad S. Petrone M. Sanchez Morles V. Drempetic D. Issler G. B. Crosta L. Cascini G. Sorbino S. Cuomo 《Landslides》2014,11(5):793-812
Hazard and risk assessment of landslides with potentially long run-out is becoming more and more important. Numerical tools exploiting different constitutive models, initial data and numerical solution techniques are important for making the expert’s assessment more objective, even though they cannot substitute for the expert’s understanding of the site-specific conditions and the involved processes. This paper presents a depth-integrated model accounting for pore water pressure dissipation and applications both to real events and problems for which analytical solutions exist. The main ingredients are: (i) The mathematical model, which includes pore pressure dissipation as an additional equation. This makes possible to model flowslide problems with a high mobility at the beginning, the landslide mass coming to rest once pore water pressures dissipate. (ii) The rheological models describing basal friction: Bingham, frictional, Voellmy and cohesive-frictional viscous models. (iii) We have implemented simple erosion laws, providing a comparison between the approaches of Egashira, Hungr and Blanc. (iv) We propose a Lagrangian SPH model to discretize the equations, including pore water pressure information associated to the moving SPH nodes. 相似文献
6.
To overcome the disadvantages of traditional flow analysis methods for liquefied soils that exhibit fluidization and large
deformation characteristics, Smoothed particle hydrodynamics (SPH) is adopted in this study to analyze the flow processes
of liquefied soils. Bingham model with the use of the Mohr–Coulomb yield criterion, the concepts of equivalent Newtonian viscosity,
and the Verlet neighbor list method are introduced into the framework of SPH to build an algorithm for the analysis of flowing
liquefied soils. This modeling involves a simulation of physical model test of flowing liquefied soils that can be compared
with numerical results. In addition, a shaking table test is selected from the literature for SPH analysis to verify the validation
of the SPH method and extend its applications. The SPH simulation can reproduce the flow processes of liquefied soils and
constrain estimates of the horizontal displacement, vertical displacement, and velocity of soils after liquefaction. According
to the dynamic behaviors of the materials involved, designs can be implemented to improve the seismic safety of structures. 相似文献
7.
We have developed a new approach for the numerical modeling of deformation processes combining brittle fracture and viscous flow. The new approach is based on the combination of two meshless particle-based methods: the discrete element method (DEM) for the brittle part of the model and smooth particle hydrodynamics (SPH) for the viscous part. Both methods are well established in their respective application domains. The two methods are coupled at the particle scale, with two different coupling mechanisms explored: one is where DEM particles act as virtual SPH particles and one where SPH particles are treated like DEM particles when interacting with other DEM particles. The suitability of the combined approach is demonstrated by applying it to two geological processes, boudinage, and hydrofracturing, which involve the coupled deformation of a brittle solid and a viscous fluid. Initial results for those applications show that the new approach has strong potential for the numerical modeling of coupled brittle–viscous deformation processes. 相似文献
8.
Small fast-moving flow-like landslides in volcanic deposits: The 2001 Las Colinas Landslide (El Salvador) 总被引：4，自引：0，他引：4
Fast-moving landslides are one of the most significant dangers deriving from slope instabilities. Landslides involving large volumes can develop in rock or debris avalanches with extreme mobility and enormous destructiveness. Nevertheless, a relevant number of casualties and damages derive from small, fast-moving landslides with flow-like behaviour.
The Las Colinas landslide occurred at Santa Tecla (El Salvador, Central America) during a strong earthquake. It slid off the northern flank of the Bálsamo ridge, and resulted in almost 500 casualties and can be considered one of the most destructive landslides ever known. Earthquake shaking was amplified by the rock mass and the steep ridge topography.
We collected original geological, geomorphological and geophysical data in the Cordillera del Bálsamo area. The involved materials, ranging from lapilli to tuff layers of different strength, have been mapped and characterized.
Slope stability analyses have been performed both under static and dynamic conditions through limit equilibrium and finite element methods.
Hazard zonation for this type of landslides requires the forecast of the movement velocity and final deposition area. We used a fully two-dimensional FEM model to simulate landslide spreading downslope. The developed code allows the use of different constitutive models and yield rules with the possibility to model and study internal deformation of the landslide mass, as well material entrainment and deposition. 相似文献
9.
坡顶堆载是人类工程活动诱发滑坡的主因之一。物质点法（MPM）属于一种无网格数值计算方法,它能够有效模拟滑坡大变形全过程物质行为与运动特征。文章基于线性形函数离散方法、MUSL求解格式及Drucker-Prager屈服准则,建立了可用于滑坡全过程模拟的单套单相物质点模型;通过对比干燥铝棒堆积物模拟砂堆失稳过程的基准试验结果,对模型有效性进行了验证。对堆载诱发型土质滑坡典型工况进行了物质点法全过程模拟,获得了滑坡全过程中典型时刻坡体形态、塑性应变分布以及控制点滑速演化趋势。结果表明:算例堆载诱发型土质滑坡属推移型滑坡,具有渐进性破坏特征,可分为坡顶压缩、局部蠕滑、加速滑动与减速滑动等四个阶段。参数分析结果亦表明,堆载诱发型土质滑坡前缘物质运动特征量均与堆载量间存在强正相关性、而与土体黏聚力及内摩擦角存在强负相关性。统计29种典型工况,分别建立了峰值滑动加速度、最大滑速、最大滑距及坡体最大动能等运动特征量与堆载量、土体黏聚力及内摩擦角之间的线性回归方程,可用于堆载诱发型土质滑坡致灾行为预测。 相似文献
10.
汶川八级地震滑坡高速远程特征分析 总被引：21，自引：3，他引：18
汶川地震触发的高速远程滑坡主要沿龙门山主中央断裂带汶川映秀安县高川北川县城平武南坝青川一线地震破裂带展布。由于获得了1.5g以上的抛掷加速度,具有明显的气垫效应,估计最大滑动速度一般大于70ms-1,滑动距离一般为滑体启动时长度的数倍甚至10多倍,堆积成坝形成多处堰塞湖,最大滑行距离达3.2km。本文重点解剖了位于地震破裂带南西段(初始震中)的汶川映秀牛圈沟滑坡碎屑流、位于地震破裂带中段的北川城西滑坡和位于地震破裂带北东段青川东河口滑坡碎屑流3个典型实例,认为具有如下特征:(1）岩性条件:母岩遭受长期构造动力作用,呈碎裂岩体,后期被强烈风化,岩体极为破碎;(2）抛掷效应:位于汶川地震主断裂带或附近,垂直加速度大于水平加速度,强地面运动持时长,岩体发生振胀和抛掷;(3）碰撞效应:上部滑坡体发生高位剪出和高位撞击,致使岩体碎屑化;(4）铲刮效应:撞击作用导致下部山体被铲刮,形成次级滑坡,为碎屑流体提供了足够展翼和抛洒物源体积;(5）气垫效应:碎屑化岩体快速抛掷导致下部沟谷空气迅速谷状圈闭和向下紊流,形成气垫效应,或者,在下部地形开阔地带压缩空气呈层流状态致使滑体凌空飞行。 相似文献
11.
Summary A quantitative procedure for hazard and risk assessment of large landslides that can develop as rock avalanches is discussed
in this paper. Reference is made to the IMIRILAND project, where a multidisciplinary methodology has been developed paying
particular attention to the landslide modeling process that leads to the quantification of the hazard, i.e. the prediction
of the occurrence probability, the involved area and the run-out velocity. The risk assessment methodology is exemplified
in the paper with reference to two cases: the Ceppo Morelli and Rosone landslides, both of which are located in the Italian
Western Alps. The results of these applications show that, despite the development of sophisticated 3D numerical methods,
many uncertainties still remain in the process of modeling large and complex landslides, related in particular to the definition
of the probability of failure and the rheological parameters to be used for the prediction of rock mass behavior. However
geo-mechanical models are found to be very valuable tools to verify, from a mechanical point of view, the assumptions introduced
through the geo-structural and geo-morphological analyses concerning the volume and the kinematics of the unstable mass, and
their role is fundamental for the determination of the involved area when mechanical parameters can be assumed with sufficient
reliability.
Author’s address: Marta Castelli, Politecnico di Torino – Dipartimento di Ingegneria Strutturale e Geotecnica, Corso Duca
degli Abruzzi 24, 10129 Torino, Italy 相似文献
12.
In the framework of the landslide susceptibility assessment, the maps produced should include not only the landslide initiation areas, but also those areas potentially affected by the traveling mobilized material. To achieve this purpose, the susceptibility analysis must be separated in two distinct components: (1) The first one, which is also the most discussed in the literature, deals with the susceptibility to failure, and (2) the second component refers to the run-out modeling using the initiation areas as an input. Therefore, in this research we present a debris flow susceptibility assessment in a recently burned area in a mountain zone in central Portugal. The modeling of debris flow initiation areas is performed using two statistical methods: a bivariate (information value) and a multivariate (logistic regression). The independent validation of the results generated areas under the receiver operating characteristic curves between 0.91 and 0.98. The slope angle, plan curvature, soil thickness and lithology proved to be the most relevant predisposing factors for the debris flow initiation in recently burned areas. The run-out is simulated by applying two different methods: the empirical model Flow Path Assessment of Gravitational Hazards at a Regional Scale (Flow-R) and the hydrological algorithm D-infinity downslope influence (DI). The run-out modeling of the 36 initiation areas included in the debris flow inventory delivered a true positive rate of 83.5% for Flow-R and 80.5% for DI, reflecting a good performance of both models. Finally, the susceptibility map for the entire basin including both the initiation and the run-out areas in a scenario of a recent wildfire was produced by combining the four models mentioned above. 相似文献
13.
Observation of shear zone development in ring-shear apparatus with a transparent shear box 总被引：1，自引：1，他引：1
Using a new ring-shear apparatus with a transparent shear box and video image analysis system, drained and undrained speed-controlled tests were conducted on coarse-grained silica sands to study the shear-zone formation process in granular materials. Velocity distribution profiles of grains under shear at various stages in the ring shear tests were observed through processing the video image by the Particle Image Velocimetry (PIV) program. Shear-zone thickness and type of shear mode (slide-like or flow-like) during shear were observed. Before reaching peak strength in low-speed and drained condition test, a comparatively major part of the sample in the upper shear box showed a velocity distribution profile of structural deformation and dilatancy behavior. After peak strength, the velocity profile changed into a slide-like mode and thereafter showed almost no change. In higher speed tests with drained and undrained conditions, an almost slide-like mode was observed, compared to low-speed test. Apparent shear-zone thicknesses of high-speed tests are thinner than low-speed tests. Unexpectedly, almost no difference was observed in the shear-zone thickness and mode of shear (slide or flow-like) between drained and undrained tests. This study was conducted as part of the International Programme on Landslides (IPL) M101 “Areal prediction of earthquake and rain induced rapid and long-traveling flow phenomena (APERITIF)” of the International Consortium on Landslides (ICL). These results will contribute to understanding the mechanism of shear-zone development in granular materials as a basic knowledge for disaster risk mitigation of rapid long run-out landslides. 相似文献
14.
15.
Liquefaction can result in the damage or collapse of structures during an earthquake and can therefore be a great threat to life and property. Many site investigations of liquefaction disasters are needed to study the large-scale deformation and flow mechanisms of liquefied soils that can be used for performance assessments and infrastructure improvement. To overcome the disadvantages of traditional flow analysis methods for liquefied soils, a soil–water-coupled smoothed particle hydrodynamics (SPH) modeling method was developed to analyze flow in liquefied soils. In the proposed SPH method, water and soil were simulated as different layers, while permeability, porosity, and interaction forces could be combined to model water-saturated porous media. A simple shear test was simulated using the SPH method with an elastic model to verify its application to solid phase materials. Subsequently, the applicability of the proposed SPH modeling method to the simulation of interaction forces between water and soil was verified by a falling-head permeability test. The coupled SPH method produced good simulations for both the simple shear and falling-head permeability tests. Using a fit-for-purpose experimental apparatus, a physical flow model test of liquefied sand has been designed and conducted. To complement the physical test, a numerical simulation has been undertaken based on the soil–water-coupled SPH method. The numerical results correspond well with the physical model test results in observed configurations and velocity vectors. An embankment failure in northern Sweden was selected so that the application of the soil–water-coupled SPH method could be extended to an actual example of liquefaction. The coupled SPH method simulated the embankment failure with the site investigation well. They have also estimated horizontal displacements and velocities, which can be used to greatly improve the seismic safety of structures. 相似文献
16.
物质点法（MPM）属于一种无网格数值计算方法,它可导入各种土体本构模型,考虑土体流固耦合行为,能够有效模拟土质滑坡大变形及超大变形。本文介绍了物质点法基本原理、控制方程与求解格式;基于5种物质点法的多孔介质表征模型,简要回顾了土质滑坡运动全过程物质点法模拟的最新研究进展。采用单套单相物质点模型,对深圳“12·20”人工堆填土滑坡全过程进行了物质点法模拟,使用了线性加载方式确定初始应力场,并使用了Drucker-Prager屈服准则弹塑性本构模型、GIMP算法与MUSL求解格式。模拟结果表明,该边坡发生失稳后,最大滑距达510m,滑坡范围纵向间距为1050m,最小滑坡角5.95°,均与观测结果相吻合。土体内部等效塑性应变区的演化趋势显示,滑坡机制为渐进式破坏,具体表现为:坡趾土体首先沿基岩界面发生剪切破坏,随后坡顶出现拉张裂隙,坡趾与坡顶塑性区分别沿基岩界面向坡体内部发育,形成贯通滑动面后滑动加速,超大变形出现。物质点法模拟滑坡运动全过程有助于理解滑坡致灾行为,可为滑坡防治提供参考。 相似文献
17.
Smoothed particle hydrodynamics (SPH) is a versatile technique which can be applied to single and multiphase flow through porous media. The versatility of SPH is offset by its computational expense which limits the practicability of SPH for large problems involving low Reynolds number flow. A parallel pore-scale numerical model based on SPH is described for modeling flow phenomena in porous media. Aspects of SPH which complicate parallelization are emphasized. The speed of the method is demonstrated to be proportional to the number of processors for test cases where load balance was achieved. The parallel algorithm permits the application of SPH to more complicated porous media problems than previously considered. For such problems, best performance is achieved when several soil grains are simulated by each processor. Finally, future applications of the method and possible extensions are discussed. 相似文献
18.
An assessment of the material point method for modelling large scale run-out processes in landslides 总被引：1，自引：1，他引：0
This paper demonstrates the predictive capabilities of a numerical model based on continuum mechanics for the simulation of run-out processes during landslides. It assesses a particle-based method that takes advantage of a double Lagrangian-Eulerian discretization and known as the material point method (MPM). Attention is given to the post-failure behaviour and, in particular, to the computation of important quantities such as run-out distance, maximum velocity and energy release. The MPM is a step forward in computational solid mechanics and has the potential to simulate large deformations such as those occurring during landslides. A validation is conducted based on simulations of two case studies of different scales, namely the Tokai-Hokuriku expressway failure in Japan and the Vajont landslide in Italy. The results show a very good agreement with field and other numerical observations. 相似文献
19.
甘肃永靖黑方台地区灌溉诱发型滑坡发育特征
及力学机制 总被引：1，自引：0，他引：1
水是诱发黄土滑坡最为积极的因素,以灌溉诱发型滑坡尤为典型.基于野外水工环地质综合调查,对黑方台地区灌溉渗透诱发滑坡的发育特征进行总结.通过分析特定孕灾地质条件下滑坡发育特征的差异,认为黄土滑坡形成的力学机制以滑移-压致拉裂-剪断型和蠕滑-拉裂-滑移型为主,而黄土-基岩滑坡以滑移-压致-拉裂型为主.滑移-压致拉裂-剪断型黄土滑坡为原位溯源后退扩展式,系灌溉水入渗后造成黄土饱和带厚度增大,不仅造成台缘周边地下水溢出带部位渗透压力增大,且抗剪强度显著弱化,从而在坡体自重作用下发生蠕滑剪切.锁固段突然破坏使滑坡快速启动,滑体冲击致早期饱水滑床产生液化,产生高位抛射,借助原始地形滑体加速运移形成高速远程运动.蠕滑-拉裂-滑移型黄土滑坡是黄土底部饱和带厚度较薄或灌溉入渗影响较小的地段,以后缘拉裂为主激发形成.渗灌溉水长期入渗造成下伏基岩顺倾泥岩层面软化泥化,从而在顺向坡段产生黄土-基岩顺层滑坡,该类滑坡以低速短程滑坡为主. 相似文献
20.
Assessing the hazard of potential landslides is crucial for developing mitigation strategies for landslide disasters. However, accurate assessment of landslide hazard is limited by the lack of landslide inventory maps and difficulty in determining landslide run-out distance. To address these issues, this study developed a novel method combining the InSAR technique with a depth-integrated model. Within this new framework, potential landslides are identified through InSAR and their potential impact areas are subsequently estimated using the depth-integrated model. To evaluate its capability, the proposed method was applied to a landslide event that occurred on November 3, 2018 in Baige village, Tibet, China. The simulated results show that the area with a probability of more than 50% to be affected by landslides matched the real trimlines of the landslide and that the accuracy of the proposed method reached 85.65%. Furthermore, the main deposit characteristics, such as the location of maximum deposit thickness and the main deposit area, could be captured by the proposed method. Potential landslides in the Baige region were also identified and evaluated. The results indicate that in the event of landslides, the collapsed mass has a high probability to block the Jinsha River. It is therefore necessary to implement field monitoring and prepare hazard mitigation strategies in advance. This study provides new insights for regional-scale landslide hazard management and further contributes to the implementation of landslide risk assessment and reduction activities.
相似文献