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1.
Nikos Gerolymos 《国际地质力学数值与分析法杂志》2010,34(4):383-407
A mathematical model is developed for the dynamic analysis of earthquake‐triggered rapid landslides, considering two mechanically coupled systems: (a) the accelerating deformable body of the slide and (b) the rapidly deforming shear band at the base of the slide. The main body of the slide is considered as a one‐phase mixture of Newtonian incompressible fluids and Coulomb solids sliding on a plane of variable inclination. The evolution of the landslide is modeled via a depth‐integrated model of the Savage–Hutter type coupled with: (a) a cyclic hysteretic constitutive model of the Bouc–Wen type and (b) Voellmy's rheology for the deformation of the material within the shear band. The original shallow‐water equations that govern the landslide motion are appropriately reformulated to account for inertial forces due to seismic loading, and to allow for a smooth transition between the active and the passive state. The capability of the developed model is tested against the Higashi–Takezawa landslide. Triggered by the 2004 Niigata‐ken Chuetsu earthquake, the slide produced about 100m displacement of a large wedge from an originally rather mild slope. The mechanism of material softening inside the shear band responsible for the surprisingly large run‐out of the landslide is described by a set of equations for grain crushing‐induced pore‐water pressures. The back‐analysis reveals interesting patterns on the flow dynamics, and the numerical results compare well with field observations. It is shown that the mechanism of material softening is a crucial factor for the initiation and evolution of the landslide, while viscoplastic frictional resistance is a key requirement for successfully reproducing the field data. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
2.
A shallow landslide erosion and sediment yield component, applicable at the basin scale, has been incorporated into the physically
based, spatially distributed, hydrological and sediment transport modelling system, SHETRAN. The component determines when
and where landslides occur in a basin in response to time-varying rainfall and snowmelt, the volume of material eroded and
released for onward transport, and the impact on basin sediment yield. Derived relationships are used to link the SHETRAN
grid resolution (up to 1 km), at which the basin hydrology and final sediment yield is modelled, to a subgrid resolution (typically
around 10–100 m) at which landslide occurrence and erosion is modelled. The subgrid discretization, landslide susceptibility
and potential landslide impact are determined in advance using a geographic information system (GIS), with SHETRAN then providing
information on temporal variation in the factors controlling landsliding. The ability to simulate landslide sediment yield
is demonstrated by a hypothetical application based on a catchment in Scotland.
Received: 30 October 1996 · Accepted: 25 June 1997 相似文献
3.
The literature review on discrete element (DEM) model analysis of jigging reveals that an idealized fluid behavior is assumed and the damping of the fluid motion across the mineral bed is generally ignored. A microscopic model based on the principles of Computational Fluid Dynamics (CFD) is used to simulate the liquid flow and stratification of coal particles with a wide size range and density distribution in jigging. Fluid motion is calculated by directly solving the Navier–Stokes equations. Coal particles are moved in a Lagrangian frame through the action of forces imposed by the fluid and gravity. Particle effects on fluid motion are fed back at each time step through calculating the velocity disturbance caused by the particle. Particle–particle and particle–wall collisions are also considered. The snapshots of particle configurations for the simulation of stratification in oscillating flow show that the model predicts the macroscopic behavior, such as segregation and stratification, of particles reasonably well. 相似文献
4.
Finite element simulation of impulse wave generated by landslides using a three-phase model and the conservative level set method 总被引：1，自引：1，他引：0
A numerical model has been developed using the finite element method for the simulation of impulse waves generated by landslides. The fluid-like landslide is modeled as a generalized non-Newtonian visco-plastic fluid. A three-phase flow model based on the incompressible viscous Navier–Stokes equations is solved using the finite element method to describe the motion of the three types of fluid in landslide. The conservative level set method is expanded to n-phase flow cases and employed to capture the interface of the three phases: air, water, and the landslide. The overall performance of the approach is checked by a number of validation cases: a Rayleigh–Taylor instability problem to illustrate the capability of the proposed method to deal with interface capturing, a benchmark test of a subaerial landslide generated by an impulse wave is carried out and compared with the published experimental data and numerical results, and finally, the 1958 Lituya Bay landslide generated impulse wave, and its results are compared against a scaled-down experiment and other published numerical results. It can be noted that the current model has an excellent ability to capture the complex phenomena that occurs during the whole process of the landslide-generated impulse wave, and considering the simplified treatment of the landslide and the numerical model, fairly good agreement between computed and experimental results has been observed for all simulation cases. 相似文献
5.
Soil flow and induced air blasts are of great harm to humanity, and historically they have caused a lot of damage to infrastructure.
However, these phenomena cannot be described by traditional analog modeling methods that limit their use in disaster prevention
efforts. Computational fluid dynamics (CFD) is an applied technique commonly used in a range of fields including the chemical
industry, and aircraft and automobile manufacturing, but little is reported on the use of this method to simulate flowing
soil in geotechnical engineering applications. The CFD method can effectively make up for the deficiency of normal calculation
methods in the analysis of soil flow and air blasts. This paper uses the FLUENT (version 6.3) CFD calculation software to
simulate the processes of soil flow and induced air blast changes during soil flow with an Eulerian air–soil two-phase model
included in a standard k-ε turbulence model. Velocity vectors of air blasts at different times during soil flow are obtained, and the characteristics
of turbulent flow can be found based on the velocity vectors. The numerical simulation techniques adopted in this paper captured
precise configurations of soil flow. The results show that the CFD method is especially suitable for simulating the process
of soil flow; hazard assessments can be implemented, and the performance of structures involved with disaster prevention can
be improved based on the numerical simulation of changing air blasts. 相似文献
6.
In this study, we tried to model the processes of moisture and heat transfers in the soil–vegetation–atmosphere system in
an integrated comprehensive way. The purpose of the study is to simulate profiles of soil water content and temperature at
root active zone (i.e., 0–50 cm), taking the root water uptake, soil evaporation, and canopy transpiration into account. The
water and heat transfer equations are solved by an iterative Newton–Raphson technique and a finite difference method is used
to solve the governing equations. Soil water content and soil temperature dynamics could be simulated rather accurately in
a cropped field on Loess Plateau area. The water and heat transfer flux predicted by the classical theory of Philip and de
Vries (Tans Am Geophys Union 38:222–232, 1957) slightly overestimated near the surface and underestimated at the deeper depths, as a result of the overestimated soil evaporation
at the top soil layer (0–10 cm) and underestimated crop canopy transpiration at the deeper depths (10–50 cm). Water content
tended to be underestimated for the entire profile at the soil surface (from 0 to 50 cm). Soil temperatures during the simulated
period was slightly overestimated in the nighttimes and underestimated in the daytimes, as a result of the underestimated
soil water content at the top soil layer (0–10 cm) and overestimated at the deeper depths (10–50 cm). Soil temperatures tended
to be underestimated for the entire profile at the soil surface (from 0 to 50 cm). While the sum of the water and heat regimes
yielded a much better match with the soil water content and soil temperature obtained from the field observations. The results
obtained show that the model coupled water and heat transfer is able to capture the dynamics of soil water content. 相似文献
7.
相似材料的研制是滑坡模型试验的关键。在相似材料的研究基础上,通过大量的配比试验,结合模糊综合评价法对不同配比材料的相似性进行比较,研制出同时模拟物理力学性能相似和渗流作用相似的水库型滑坡相似材料,这种材料由标准砂、滑体土、膨润土和水溶液混合而成。同时通过库水作用下滑坡模型试验评价该材料的相似效果,记录水位升降过程中坡内的孔隙水压力变化、渗流变化、滑面形态及裂缝形成发展过程。试验结果表明,库水对岩土体物理力学性质的弱化和坡内指向临空面的渗透压力是滑坡产生的主要诱发因素;水库型滑坡的破坏模式为有多级滑面的牵引式破坏;试验观测的浸润线与理论计算结果基本吻合。该相似材料的物理力学性能和渗流效果均能达到试验相似要求,模拟库水作用下滑坡变形破坏过程的效果良好,是一种比较理想的水库型滑坡模型相似材料。研究结果为进一步开展大型水库型滑坡模型试验提供了科学依据。 相似文献
8.
新疆伊宁县喀拉亚尕奇滑坡动力学特征研究 总被引：4，自引：4，他引：0
通过对高速远程黄土滑坡动力学特征的研究,提出黄土高速远程滑坡空间预测的模拟方法。以新疆伊宁县喀拉亚尕奇黄土滑坡为例,基于野外地质调查和无人机航拍影像图,结合滑坡研究区的工程地质条件,分析了该滑坡的基本特征和形成条件。研究发现,该滑坡的主要诱发因素是冰雪融水入渗,其孕灾模式主要为四个阶段:后缘拉裂阶段,黄土节理冻胀扩展阶段,融雪入渗失稳阶段,高速下滑阶段。同时利用Rapid模型对滑坡运动全过程进行模拟,计算得到滑坡运动持续时间为26 s,最大运动速度达到22 m/s,堆积体的平均厚度达到5 m等运动特征要素,结果表明Rapid模型可以较好的模拟分析黄土高速远程滑坡动力学效应,为黄土地区类似滑坡的成灾机理和动力学效应分析提供参考。 相似文献
9.
10.
Geomorphology and landslide susceptibility assessment using GIS and bivariate statistics: a case study in southern Italy 总被引：3，自引：2，他引：1
In this article, the results of a study aimed to assess the landslide susceptibility in the Calaggio Torrent basin (Campanian
Apennines, southern Italy) are presented. The landslide susceptibility has been assessed using two bivariate-statistics-based
methods in a GIS environment. In the first method, widely used in the existing literature, weighting values (Wi) have been calculated for each class of the selected causal factors (lithology, land-use, slope angle and aspect) taking
into account the landslide density (detachment zones + landslide body) within each class. In the second method, which is a
modification of the first method, only the landslide detachment zone (LDZ) density has been taken into account to calculate
the weighting values. This latter method is probably characterized by a major geomorphological coherence. In fact, differently
from the landslide bodies, LDZ must necessarily occur in geoenvironmental classes prone to failure. Thus, the calculated Wi seem to be more reliable in estimating the propensity of a given class to generate failure. The thematic maps have been reclassified
on the basis of the calculated Wi and then overlaid, with the purpose to produce landslide susceptibility maps. The used methods converge both in indicating
that most part of the study area is characterized by a high–very high landslide susceptibility and in the location and extent
of the low-susceptible areas. However, an increase of both the high–very high and moderate–high susceptible areas occurs in
using the second method. Both the produced susceptibility maps have been compared with the geomorphological map, highlighting
an excellent coherence which is higher using method-2. In both methods, the percentage of each susceptibility class affected
by landslides increases with the degree of susceptibility, as expected. However, the percentage at issue in the lowest susceptibility
class obtained using method-2, even if low, is higher than that obtained using method-1. This suggests that method-2, notwithstanding
its major geomorphological coherence, probably still needs further refinements. 相似文献
11.
水下滑坡是常见的地质灾害之一,为解决离散元PFC难以模拟水下流体环境的问题,提出采用计算流体力学OpenFOAM与离散元PFC耦合的计算方法。针对流固耦合中的尺度相似性问题,提出了适用于该耦合方法的相似性方法并验证了其可行性。通过典型案例分析了基于该耦合方法的水下滑坡动力学特性及堆积形态,并与单向耦合水下滑坡和陆上滑坡结果进行了对比。结果表明该耦合方法能够较好地模拟水下滑坡运动规律,主要表现为滑坡体前端厚度较大并呈椭圆面;水下滑坡运动过程和堆积形态与陆上滑坡差异较大,OpenFOAM-PFC双向耦合与单向耦合方法相比具有优越性。 相似文献
12.
The Zymoetz River landslide, British Columbia, Canada: description and dynamic analysis of a rock slide–debris flow 总被引：1，自引：0，他引：1
Scott McDougall Nichole Boultbee Oldrich Hungr Doug Stead James W. Schwab 《Landslides》2006,3(3):195-204
The Zymoetz River landslide is a recent example of an extremely mobile type of landslide known as a rock slide–debris flow. It began as a failure of 900,000 m3 of bedrock, which mobilized an additional 500,000 m3 of surficial material in its path, transforming into a large debris flow that traveled over 4 km from its source. Seasonal snow and meltwater in the proximal part of the path were important factors. A recently developed dynamic model that accounts for material entrainment, DAN3D, was used to back-analyze this event. The two distinct phases of motion were modeled using different basal rheologies: a frictional model in the proximal path and a Voellmy model in the distal path, following the initiation of significant entrainment. Very good agreement between the observed and simulated results was achieved, suggesting that entrainment capabilities are essential for the successful simulation of this type of landslide. 相似文献
13.
A rigorous finite volume model to simulate subaerial and submarine landslide-generated waves 总被引：5，自引：5，他引：0
This paper presents a new landslide-generated wave (LGW) model based on incompressible Euler equations with Savage-Hutter assumptions. A two-layer model is developed including a layer of granular-type flow beneath a layer of an inviscid fluid. Landslide is modeled as a two-phase Coulomb mixture. A well-balanced second-order finite volume formulation is applied to solve the model equations. Wet/dry transitions are treated properly using a modified non-linear method. The numerical model is validated using two sets of experimental data on subaerial and submarine LGWs. Impulsive wave characteristics and landslide deformations are estimated with a computational error less than 5 %. Then, the model is applied to investigate the effects of landslide deformations on water surface fluctuations in comparison with a simpler model considering a rigid landslide. The model results confirm the importance of both rheological behavior and two-phase nature of landslide in proper estimation of generated wave properties and formation patterns. Rigid slide modeling often overestimates the characteristics of induced waves. With a proper rheological model for landslide, the numerical prediction of LGWs gets more than 30 % closer to experimental measurements. Single-phase landslide results in relative errors up to about 30 % for maximum positive and about 70 % for maximum negative wave amplitudes. Two-phase constitutive structure of landslide has also strong effects on landslide deformations, velocities, elongations, and traveling distances. The complex behaviors of landslide and LGW of the experimental data are analyzed and described with the aid of the robust and accurate finite volume model. This can provide benchmark data for testing other numerical methods and models. 相似文献
14.
The August 27, 2014, rock avalanche and related impulse water waves in Fuquan,Guizhou, China 总被引：1，自引：1，他引：0
At about 8:30 p.m. on 27 August 2014, a catastrophic rock avalanche suddenly occurred in Fuquan, Yunnan, southwestern China. This landslide and related impulse water waves destroyed two villages and killed 23 persons. The impulse waves occurred after initiation of the landslide, caused by the main part of the slide mass rapidly plunging into a water-filled quarry below the source area. The wave, comprising muddy water and rock debris, impacted the opposite slope of the quarry on the western side of the runout path and washed away three homes in Xinwan village. Part of the displaced material traveled a horizontal distance of about 40 m from its source and destroyed the village of Xiaoba. To provide information for potential landslide hazard zonation in this area, a combined landslide–wave simulation was undertaken. A dynamic landslide analysis (DAN-W) model is used to simulate the landslide propagation before entering the quarry, while Fluent (Ansys Inc., USA) is used to simulate the impulse wave generation and propagation. Output data from the DAN-W simulation are used as input parameters for wave modeling, and there is good agreement between the observed and simulated results of the landslide propagation. Notably, the locations affected by recordable waves according to the simulation correspond to those recorded by field investigation. 相似文献
15.
Richard H. Guthrie Peter J. Deadman A. Raymond Cabrera Stephen G. Evans 《Landslides》2008,5(1):151-159
Landslide magnitude–frequency curves allow for the probabilistic characterization of regional landslide hazard. There is evidence
that landslides exhibit self-organized criticality including the tendency to follow a power law over part of the magnitude–frequency
distribution. Landslide distributions, however, also typically exhibit poor agreement with the power law at smaller sizes
in a flattening of the slope known as rollover. Understanding the basis for this difference is critical if we are to accurately
predict landslide hazard, risk or landscape denudation over large areas. One possible argument is that the magnitude–frequency
distribution is dominated by physiographic controls whereby landslides tend to a larger size, and larger landslides are landscape
limited according to a power law. We explore the physiographic argument using first a simple deterministic model and then
a cellular automata model for watersheds in coastal British Columbia. The results compare favorably to actual landslide data:
modeled landslides bifurcate at local elevation highs, deposit mass preferentially where the local slopes decrease, find routes
in confined valley or channel networks, and, when sufficiently large, overwhelm the local topography. The magnitude–frequency
distribution of both the actual landslides and the cellular automata model follow a power law for magnitudes higher than 10,000–20,000 m2 and show a flattening of the slope for smaller magnitudes. Based on the results of both models, we argue that magnitude–frequency
distributions, including both the rollover and the power law components, are a result of actual physiographic limitations
related to slope, slope distance, and the distribution of mass within landslides. The cellular automata model uses simple
empirically based rules that can be gathered for regions worldwide. 相似文献
16.
H. Y. Liu S. Q. Kou P.-A. Lindqvist C. A. Tang 《Rock Mechanics and Rock Engineering》2007,40(2):107-144
Summary A series of numerical tests including both rock mechanics and fracture mechanics tests are conducted by the rock and tool
(R–T2D) interaction code coupled with a heterogeneous masterial model to obtain the physical–mechanical properties and fracture
toughness, as well as to simulate the crack initiation and propagation, and the fracture progressive process. The simulated
results not only predict relatively accurate physical–mechanical parameters and fracture toughness, but also visually reproduce
the fracture progressive process compared with the experimental and theoretical results. The detailed stress distribution
and redistribution, crack nucleation and initiation, stable and unstable crack propagation, interaction and coalescence, and
corresponding load–displacement curves can be proposed as benchmarks for experimental study and theoretical research on crack
propagation. It is concluded that the heterogeneous material model is reasonable and the R–T2D code is stable, repeatable and a valuable numerical tool for research on the rock fracture process. 相似文献
17.
Landslides can block mountainous streams and form landslide dams to threaten downstream residents. It is necessary for reliable methods to predict landslide dam dynamic for risk assessment. In this paper, we present a two-layer model of Savage–Hutter type to simulate the dynamic evolution of landslide dam which take account of the erosion of river bed. The two-layer shallow water system is derived by depth-averaging the incompressible Navier–Stokes equations with the hydrostatic assumption integrated of the erosion model of river bed. The effect of excess pore water pressure is considered in the erosion process. A high order accuracy scheme based on Roe-type solver is used to discretize the present model. Finally, several numerical tests are performed to verify the stability of the algorithm and reliability of the model. Numerical results indicate that the erosion effect enhances the huge destructiveness of landslide and increase the possibility of river blocked by landslides. The impact of excess pore water pressure on erosion process should be considered. 相似文献
18.
Susana Torno Javier Toraño Mario Menéndez Malcolm Gent 《Environmental Earth Sciences》2011,64(1):73-83
A computational fluid dynamics (CFD) model has been developed to simulate the dispersion of dust generated in blasting located
in limestone quarries. This is a complex phenomenon that has been studied through the use of several digital video recordings
of blasts and dust concentration field measurements by ‘light scattering’ dust collectors. In addition, the subsequent simulation
of the dispersion of the dust cloud by means of multiphase CFD has also been studied. CFD calculations were carried out using
software Ansys CFX 10.0, through transitory models with Lagrangian particle models crossing an Eulerian air continuous phase.
This paper presents results obtained by model simulations where physical barriers are set close to the blasting, with the
aim of decreasing the dust cloud dispersal and the associated environmental impact. 相似文献
19.
文章采用DAN3D数值方法对深圳人工堆填体滑坡运动过程进行了模拟研究,探讨了深圳“12.20”滑坡远程动力成灾过程。通过研究得到以下几点结论:（1）滑坡后破坏运动主要分为两个阶段:前一阶段为滑源区内运动,体现了高孔隙水压力下滑剪切;后一阶段为在流通区和堆积区内运动,体现了高饱和度滑体流动（涌动）剪切。（2）饱水渣土滑坡远程流化运动分析中,摩擦模型适合模拟孔隙水压力作用下的滑源区渣土体的失稳下滑运动过程;宾汉姆模型适合模拟非牛顿流体饱和渣土体的流化剪切过程;摩擦-宾汉姆组合模型更适用于该类型滑坡全过程的反演运动分析。（3）深圳滑坡后破坏运动速度变化主要经历了“启动-加速-持速-减速”的运动过程,高含水渣土的固-流转化致使滑坡远程运动,并造成巨大伤亡损失。（4）模拟结果显示:堆积区平均堆积厚度为11 m,堆积范围为0.4 km 2,最大运动速度为30 m/s,最大速度发生于距滑坡后缘620 m处,堆积范围、堆积厚度和运动速度同滑坡实际值基本一致。上述研究思路和方法对城市地质中渣土滑坡灾害的危险区划和渣土场科学选址评估具有一定借鉴意义。 相似文献
20.
Large old landslides are common in the Three Gorges area. Baota landslide, a large rockslide, is one of the largest landslides
in the Three Gorges area. In the landslide body there are two terraces to be recognized. The two terrace deposits is not a
two-grade terrace, but mainly remnants left by an occurrence of Baota landslide. Optically stimulated luminescence (OSL) dating
suggests that the age of the terrace deposits is 38–32 kyr BP. The OSL ages along with other Thermoluminescence (TL) and Radiocarbon
(14C) ages support the conclusion that the Baota landslide was originally triggered by strong precipitation occurred in a warm
climate period of 30,000–40,000 years BP. 相似文献