Runout Number: A New Metric for Landslide Runout Characterization

2021 ◽  
Vol 27 (4) ◽  
pp. 455-470
Author(s):  
Cory S. Wallace ◽  
Paul M. Santi
Keyword(s):  
Slope Angle ◽  
Measurement Methods ◽  
Washington State ◽  
Initial Slope ◽  
Landslide Area ◽  
Predictive Parameters ◽  
Landslide Mobility ◽  
Two Parameters ◽  
Landslide Runout ◽  
Mobility Measure

ABSTRACT Landslide runout has traditionally been quantified by the height-to-length ratio, H/L, which, in many cases, is strongly influenced by the slope of the runout path. In this study, we propose an alternative mobility measure, the unitless Runout Number, measured as the landslide length divided by the square root of the landslide area, which characterizes landslide shape in terms of elongation. We used a database of 158 landslides of varying runout distances from locations in northern California, Oregon, and Washington state to compare the two runout measurement methods and explore their predictability using parameters that can be measured or estimated using geographic information systems. The Runout Number better describes the overall runout for several landslide and slope geometries. The two mobility measures show very little correlation to each other, indicating that the two parameters describe different landslide mobility mechanisms. When compared to predictive parameters shown by prior research to relate to landslide runout, the two runout measurement methods show different correlations. H/L correlates more strongly to initial slope angle, upslope contributing area, landslide area, and grain size distribution (percent clay, silt, total fines, and sand). The Runout Number correlates more strongly to planimetric curvature, upslope contributing area normalized by landslide area, and percent sand. Although these correlations are not necessarily strong enough for prediction, they indicate the validity of both runout measurement methods and the benefit of including both numbers when characterizing landslide mobility.

Nonlinear dynamics of flexible links in planar parallel robots using a new beam element

2020 ◽  
Vol 26 (7-8) ◽  
pp. 475-489
Author(s):  
Mahdi Sharifnia
Keyword(s):  
Slope Angle ◽  
Main Idea ◽  
Parallel Robot ◽  
Beam Element ◽  
Parallel Robots ◽  
The Body ◽  
Inverse Dynamic ◽  
Two Parameters ◽  
Euler Bernoulli Beam ◽  
Similar Elements

In the present research, a previously presented beam element in planar static problems is extended to planar dynamic problems. As investigated in the previous work of the author, formulation of the presented Euler–Bernoulli beam element is simpler and the beam element more efficient than similar elements in large deflection problems. In the present element, the main idea is estimating the dimensions of the body in the deformed configuration, instead of estimating its absolute or relative positions. Therefore, two parameters, the length and slope angle of the beam centroid curve, are selected to be estimated by interpolating polynomials. To verify the efficiency of the element, obtained results for the flexible pendulum are compared with previous works. Because of the simple and efficient formulation of the element, it can be efficiently used for dynamic analysis of planar flexible linkages, and especially in flexible parallel robots, which are the main aims of the present research. Finally, the inverse dynamic of the flexible 3-RRR parallel robot is presented.

Recognition of Surface Roughness Based on Fractal Theory and the Microscopic Images

2012 ◽  
Vol 241-244 ◽  
pp. 3030-3033
Author(s):  
Zhen Zhen Guan ◽  
Ming Hui Ye ◽  
Xiao Chun Yin ◽  
Xiao He Luo
Keyword(s):  
Surface Roughness ◽  
Fractal Theory ◽  
Fractal Dimensions ◽  
Measurement Methods ◽  
Microscopic Images ◽  
Measuring Surface ◽  
Measurement Resolution ◽  
Measurement Results ◽  
Practical Engineering ◽  
Two Parameters

Values of surface roughness are usually unstable with conventional measurement methods because of the affection of measurement resolution and signal sampling, in order to make the measurement results reflect the practical engineering surface accurately, a new method of measuring surface roughness based on microscopic images and fractal theory is proposed. The microscopic images are acquired and pretreated, the structure function method is used to calculate the fractal dimension and fractal proportion coefficient, experiment results show that the fractal dimensions of tested samples with same making method are equal basically, while the fractal proportion coefficients are changed with different surface roughness, the two parameters can express the surface state preferably.

scholarly journals Effect of the Slope Angle and Its Classification on Landslide

2020 ◽  
Author(s):  
Seda Çellek
Keyword(s):  
Landslide Susceptibility ◽  
Slope Angle ◽  
Landslide Area ◽  
Advantages And Disadvantages ◽  
Definition Of ◽  
Landslide Maps ◽  
Selection Of

Abstract. The phase after the determination of the landslide area in landslide susceptibility studies is the selection of methods and parameters to be used. Approximately 1500 randomly selected publications show that it is necessary to select a parameter based on the area. Research has shown that the parameter of slope is greatly preferred. There is nearly consensus of opinion among researchers regarding the use of the parameter. The research included the definition of slope made by different researchers, the advantages and disadvantages of the use of the parameter, different classifications that are used, the formation intervals of landslides, their use together with other parameters, and its effect on the formation of landslides. Classifications were studied based on the slope values at which landslides. Generally, automatic slope classifications are used in the preparation of landslide maps. There isn’t standard in parameter maps. Therefore, there isn’t class range that is referenced when preparing slope maps. In this study, preferred class ranges and slope values where landslides occur were determined in the literature. 40 landslides area has been selected in Turkey. These were evaluated in the slope classes determined according to the literature. The results compared with the literature were found to be compatible.

scholarly journals Dormant landslides distributed in upper course of Sun Kosi Watershed and landslides induced by Nepal Gorkha Earthquake 2015

2018 ◽  
Vol 55 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Hiroshi Yagi ◽  
Kazunari Hayashi ◽  
Daisuke Higaki ◽  
Ching-Ying Tsou ◽  
Go Sato
Keyword(s):  
Large Scale ◽  
Slope Angle ◽  
Area Ratio ◽  
Slope Gradient ◽  
Landslide Area ◽  
Gorkha Earthquake ◽  
Augen Gneiss ◽  
Steep Slopes ◽  
Lower Slope ◽  
Dip Slope

This study detected 897 dormant landslides of deep-seated type in the upper course of the Sun Kosi Watershed. It also shows geology and slope gradient that are prone to cause deep-seated landslides in the Great Himalaya and Midland zones. The dormant landslides are predominantly distributed in geological areas of the Augen Gneiss, Benighat Slate, Robang Phyllite and the Kuncha Phyllite, considering both landslide area ratio and site number. Landslides of deep-seated type are also found prone to develop on dip-slope. Occurrence of landslides usually increases over 20 degrees of slope angle for each geological type, though the number of landslides in the phyllite area increases below 20 degrees. It is very clear that landslides in phyllite area are prone to occur from relatively lower slope angles compared to those occurring in quartzite, gneiss and the Sermathang Formation. Nepal Gorkha Earthquake 2015 caused 1804 landslides in this study area. Most of the earthquake-induced landslides are of shallow types that occurred just below break of slope, showing a shoulder shaped profile along the deep gorge. They are predominantly distributed on steep slopes in the geological areas of slate, gneiss and dolomite. None of the dormant landslides of large scale was activated by the earthquake.

scholarly journals Numerical evaluation on steep soil-nailed slope using finite element method

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Panyabot Kaothon ◽  
Kean Thai Chhun ◽  
Chan-Young Yune
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Evaluation ◽  
Factor Of Safety ◽  
Slope Angle ◽  
The Finite Element Method ◽  
Conventional Design ◽  
Two Parameters ◽  
Element Method

AbstractIn conventional design of soil-nailed slope, the nail parameters such as nail spacing (1–2 m), and nail inclination (10º–20º) have been recommended without considering any specific slope angle. Henceforth, this paper presents a numerical evaluation on the soil-nailed slope with flexible facing based on the finite element method in order to investigate the range of those two parameters with any size of nail head in various slope angles (45º, 55º, 65º, and 75º). Based on a minimum factor of safety (FSmin  =  1.5), the analysis results indicated that the suggested range of those parameters in the conventional specification was applicable in the slope angle of 45º and 55º with any sizes of nail head. Nevertheless, it was not practical for slope angle of 65º and 75º, which required the size of nail head at least 400  ×  400  ×  250 mm, with nail spacing less than or equal to 1.5 m, and nail inclination from 5º to 10º.

scholarly journals An evaluation of influential factors on landslide mobility during the 2008 Wenchuan earthquake

2014 ◽  
Vol 2 (1) ◽  
pp. 613-647 ◽  
Author(s):  
D. P. Guo ◽  
M. Hamada ◽  
C. He
Keyword(s):  
Wenchuan Earthquake ◽  
Rock Type ◽  
Multivariable Analysis ◽  
Slope Angle ◽  
Influential Factors ◽  
2008 Wenchuan Earthquake ◽  
The 2008 Wenchuan Earthquake ◽  
Landslide Volume ◽  
Geological Conditions ◽  
Landslide Mobility

Abstract. The 2008 Wenchuan earthquake triggered a huge amount of landslides along the Longmenshan thrust belt zone in southwest China. It is essential to evaluate the effects of numerous influential factors on landslide mobility, as a result of having seriously endangered the lives and properties along travel path. Hence, the relations between equivalent coefficient of friction (μ = Hmax / Hmax) and other six parameters of 46 landslides, such as three topographical factors, landslide volume, horizontal peak ground acceleration (PHA) and rock type, have been qualitatively analyzed by means of simplified plots and regressions. The quantitative effectiveness of each factor on landslide mobility was revealed by multivariable analysis and it was found that slope height, rock type, slope transition angle and landslide volume were more influential than slope angle and seismic acceleration. The statistical significance tests and predictive results both demonstrated that the empirical-statistical model of landslide mobility yielded a satisfactory agreement between observations and predictions, therefore, the presented model could be practically applicable in similar geological conditions as Wenchuan earthquake affected area.

Travel Distance Prediction of Landslides Triggered by the M8.0 Wenchuan Earthquake

2011 ◽  
Vol 71-78 ◽  
pp. 1736-1740 ◽  
Author(s):  
Xiu Zhen Li ◽  
Ji Ming Kong ◽  
Sheng Wei Li
Keyword(s):  
Wenchuan Earthquake ◽  
Slope Angle ◽  
Field Investigation ◽  
Travel Distance ◽  
Initial Slope ◽  
Factors Affecting ◽  
Runout Distance ◽  
Landslide Volume ◽  
Distance Prediction ◽  
Linear Correlations

Volume and slope are two important factors affecting the runout distance of landslides. Field investigation on 46 landslides triggered by the Wenchuan earthquake show that there are positive linear correlations between the logarithmic values of landslide volume and travel distance. And there is also a positive linear relationship between the equivalent friction coefficient and tangent value of initial slope angle for the landslides. On the basis, we obtained an empirical-statistic equation between the horizontal and vertical travel distance, the volume and initial slope angle. This can provide a basis for prediction of earthquake-induced landslides.

scholarly journals Landslides triggered by the 12 January 2010 Mw 7.0 Port-au-Prince, Haiti, earthquake: visual interpretation, inventory compiling and spatial distribution statistical analysis

2014 ◽  
Vol 2 (2) ◽  
pp. 1259-1331 ◽  
Author(s):  
C. Xu ◽  
J. B. H. Shyu ◽  
X.-W. Xu
Keyword(s):  
Spatial Distribution ◽  
Slope Angle ◽  
Slope Aspect ◽  
Haiti Earthquake ◽  
Number Density ◽  
Landslide Area ◽  
Seismic Landslides ◽  
Seismic Landslide ◽  
Area Percentage ◽  
Landslide Area Percentage

Abstract. The 12 January 2010 Port-au-Prince, Haiti, earthquake (Mw 7.0) triggered tens of thousands of landslides. The purpose of this study is to investigate the correlations of the occurrence of landslides and their erosion thicknesses with topographic factors, seismic parameters, and their distance from roads. A total of 30 828 landslides triggered by the earthquake covered a total area of 15.736 km2, distributed in an area more than 3000 km2, and the volume of landslide accumulation materials is estimated to be about 29 700 000 m3. These landslides are of various types, mostly belonging to shallow disrupted landslides and rock falls, but also include coherent deep-seated landslides and rock slides. These landslides were delineated using pre- and post-earthquake high-resolutions satellite images. Spatial distribution maps and contour maps of landslide number density, landslide area percentage, and landslide erosion thickness were constructed in order to analyze the spatial distribution patterns of co-seismic landslides. Statistics of size distribution and morphometric parameters of co-seismic landslides were carried out and were compared with other earthquake events in the world. Four proxies of co-seismic landslide abundance, including landslides centroid number density (LCND), landslide top number density (LTND), landslide area percentage (LAP), and landslide erosion thickness (LET) were used to correlate co-seismic landslides with various landslide controlling parameters. These controlling parameters include elevation, slope angle, slope aspect, slope curvature, topographic position, distance from drainages, lithology, distance from the epicenter, distance from the Enriquillo–Plantain Garden fault, distance along the fault, and peak ground acceleration (PGA). A comparison of these impact parameters on co-seismic landslides shows that slope angle is the strongest impact parameter on co-seismic landslide occurrence. Our co-seismic landslide inventory is much more detailed than other inventories in several previous publications. Therefore, we carried out comparisons of inventories of landslides triggered by the Haiti earthquake with other published results and proposed possible reasons of any differences. We suggest that the empirical functions between earthquake magnitude and co-seismic landslides need to update on the basis of the abundant and more complete co-seismic landslide inventories recently available.

scholarly journals Computation Method for the Settlement of a Vertically Loaded Pile in Sloping Ground

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Chong Jiang ◽  
Wen-yan Wu ◽  
Jia-li He ◽  
Lu-jie Chen
Keyword(s):  
Slope Angle ◽  
Friction Angle ◽  
Compression Modulus ◽  
Tangent Modulus ◽  
Computation Method ◽  
Sloping Ground ◽  
Stress Theory ◽  
Hyperbolic Curve ◽  
Pile Settlement ◽  
Two Parameters

Based on the hyperbolic curve tangent modulus method and the wedge stress theory, this paper proposes a calculation method for the settlement of a vertically loaded single pile in sloping ground. By establishing the relationship between the initial tangent modulus and the compression modulus of the slope soil, the tangent modulus of the slope soil is obtained combining with Mindlin-Geddes solution and Hansen formula, and the solution of the pile settlement in sloping ground is derived. Then, a series of numerical analyses are carried out to examine the feasibility of the proposed method. Finally, the effect of parameters is discussed in detail, including the slope angle, the distance of the pile from the slope crest, and the soil properties around the pile. The results show that the pile settlement will increase by increasing the slope angle or decreasing the distance of the pile from the slope crest, and the effect of the two parameters on the pile settlement is coupling-related. Besides, the compression modulus, cohesion, and internal friction angle of the soil around the pile are negatively related to the pile settlement and it is found that the compression modulus of the soil is the more influential parameter.

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