scholarly journals CALIBRATION OF DISTRIBUTED SHALLOW LANDSLIDE MODELS IN FORESTED LANDSCAPES

2010 ◽  
Vol 41 (3) ◽  
pp. 23 ◽  
Author(s):  
Gian Battista Bischetti ◽  
Enrico Antonio Chiaradia
Keyword(s):  
Slope Stability ◽  
Success Rate ◽  
Stability Index ◽  
Shallow Landslide ◽  
Space Distribution ◽  
Root Cohesion ◽  
Susceptibility Maps ◽  
Index Mapping ◽  
Forested Landscapes ◽  
The Stability

<p>In mountainous-forested soil mantled landscapes all around the world, rainfall-induced shallow landslides are one of the most common hydro-geomorphic hazards, which frequently impact the environment and human lives and properties. In order to produce shallow landslide susceptibility maps, several models have been proposed in the last decade, combining simplified steady state topography- based hydrological models with the infinite slope scheme, in a GIS framework. In the present paper, two of the still open issues are investigated: the assessment of the validity of slope stability models and the inclusion of root cohesion values. In such a perspective the “Stability INdex MAPping” has been applied to a small forested pre-Alpine catchment, adopting different calibrating approaches and target indexes. The Single and the Multiple Calibration Regions modality and three quantitative target indexes – the common Success Rate (SR), the Modified Success Rate (MSR), and a Weighted Modified Success Rate (WMSR) herein introduced – are considered. The results obtained show that the target index can 34 003_Bischetti(569)_23 1-12-2010 9:48 Pagina 34 significantly affect the values of a model’s parameters and lead to different proportions of stable/unstable areas, both for the Single and the Multiple Calibration Regions approach. The use of SR as the target index leads to an over-prediction of the unstable areas, whereas the use of MSR and WMSR, seems to allow a better discrimination between stable and unstable areas. The Multiple Calibration Regions approach should be preferred, using information on space distribution of vegetation to define the Regions. The use of field-based estimation of root cohesion and sliding depth allows the implementation of slope stability models (SINMAP in our case) also without the data needed for calibration. To maximize the inclusion of such parameters into SINMAP, however, the assumption of a uniform distribution of probability of the parameters must be overtaken. In small and steep catchments where there is an intrinsic susceptibility to instability phenomena, moreover, an additional class of low probability of instability (0.81)&lt;1.0) has been proposed to better discriminate the areas classified as unstable.</p>

scholarly journals SLOPE STABILITY ANALYSIS CONSIDERING WEIGHT OF TREES AND ROOT REINFORCEMENT

2019 ◽  
Vol 27 (4) ◽  
pp. 201-208
Author(s):  
Majid Lotfalian ◽  
Mehran Nasiri ◽  
Amir Modarres ◽  
Wei Wu
Keyword(s):  
Slope Stability ◽  
Soil Type ◽  
Soil Reinforcement ◽  
Tree Age ◽  
Stability Factor ◽  
Slope Stabilization ◽  
Root Reinforcement ◽  
Root Cohesion ◽  
The Stability ◽  
Old Trees

We study the effect of roots of alder trees on soil reinforcement and slope stabilization. Two types of soil, i.e. Marl and Clayey soils and alders of three ages are considered. The slope stability is studied according to the tree indices based on tree age and soil type. The effect of root reinforcement on slope stability is considered by an additional cohesion. The stability analyses are carried out by the FEM. We perform parameter studies considering tree age, soil type and surcharge. The results indicate that soil type is effective on cohesion. The results also showed that with increasing age of trees from 7 to 15 years, the amount of additional root cohesion increased and with the increase of the age of trees to 20 years this amount slightly decreased. Also, with regard to a constant slope geometry, the type of soil and the uniform surcharge pressure, 7-year-old trees have shown better performance in slope stabilization. It has been observed that as the age of alder trees grows, although the amount of additional root cohesion increases, however, due to increased surcharge pressure, the overall slope stability factor decreases.

scholarly journals Avaliação de Suscetibilidade a Movimentos de Vertente em Terraços Agrícolas pela Aplicação de Modelos Matemáticos de Base Física

2017 ◽  
Vol 33 ◽  
pp. 1
Author(s):  
Ana Faria ◽  
Carlos Valdir de Meneses Bateira ◽  
Sofia Oliveira ◽  
Joana Fernandes ◽  
Fernando Marques
Keyword(s):  
Stability Index ◽  
Shallow Landslide ◽  
Landslide Stability ◽  
Stability Model ◽  
Index Mapping

O artigo efetua a avaliação da suscetibilidade a deslizamentos, em terraços com talude em terra, no vale do Douro. São aplicados modelos matemáticos de base física: SHAllow Landslide STABility model e Stability INdex MAPping. Os modelos aplicados combinam os conceitos de talude infinito e, fluxo hidrológico em estado estacionário. Ambos os modelos, de suscetibilidade, utilizam as seguintes propriedades do solo: coesão, ângulo de atrito, peso específico do solo e espessura do solo. O SINMAP aplica ainda a coesão das raízes. Uma das principais diferenças entre os modelos refere-se à definição das áreas contributivas. O SHALSTAB utiliza o fluxo de direções múltiplas (MFD) e o SINMAP utiliza o fluxo de direções infinitas (D∞). A validação dos resultados foi realizada com base no inventário de deslizamentos, seguindo o método da matriz de contingência. Dos resultados obtidos, o SHALSTAB classifica corretamente 77% dos deslizamentos e o SINMAP 90% de deslizamentos. Contrariamente, o índice de falsos positivos do SHALSTAB é significativamente mais elevado (67%) enquanto o SINMAP apresenta (83%). No que se refere à relação entre os Índices de Verdadeiros Positivos e de Falsos Positivos o SHALSTAB apresenta um melhor balanço entre a predição dos deslizamentos e a dimensão das áreas definidas como instáveis com 1,14, relativamente a 1,09 apresentado pelo SINMAP.

The stability and collapse of lava domes: insight from UAS-derived 4D structure and slope stability models

2020 ◽  
Author(s):  
Brett Carr ◽  
Einat Lev ◽  
Loÿc Vanderkluysen ◽  
Danielle Moyer ◽  
Gayatri Marliyani ◽  
...  
Keyword(s):  
Slope Stability ◽  
Lava Domes ◽  
The Stability

ANALISIS KESTABILAN LERENG DINDING AKHIR DI PIT BARATLAUT PADA PENAMBANGAN BATUBARA DI PT. PUTERA BARA MITRA , KECAMATAN MENTEWE, KALIMANTAN SELATAN

KURVATEK ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 21-34
Author(s):  
Untung Wahyudi ◽  
Excelsior T P ◽  
Luthfi Wahyudi
Keyword(s):  
Slope Stability ◽  
Mining Operation ◽  
Subsurface Water ◽  
Mining System ◽  
Mine Site ◽  
Analysis And Design ◽  
The Stability ◽  
End Wall ◽  
Wall Slope ◽  
Mining Slope

PT. Putera Bara Mitra used open mining system for mining operation, Yet the completion of study on the end wall slope stability that  undertaken by geotechnical PT. Putera Bara Mitra in Northwest Pit and the occured a failure in the low wall on the 1st June 2012 led to the need for analysis and design the overall slope at the mine site. To analyze and design the overall slope, used value of the recommended minimum safety. The value was based on company for single slope SF ≥ 1.2 and SF ≥ 1.3 for overall slope. The calculation used Bichop method with the help of software slide v 5.0. Geometry improvements was done at the low slopes that originally single wall with a 30 m bench height and a slope 70° with SF = 0.781, into 4 levels with SF = 1.305. The analysis explained the factors that affect the stability of the low wall included the mining slope geometry, unfavorable drainase system, material stockpiles and seismicity factors. It was necessary to do prevention efforts to maintain the stability of the slope included the redesign to slope geometry, handling surface and subsurface water in a way to control slopes draining groundwater, vegetation stabilization using and monitoring slope using Total Station with Prism and Crackmeter to determine the movement of cracks visible on the surface. 

PENGARUH KECENDERUNGAN PERUBAHAN CURAH HUJAN TERHADAP LONGSOR

2018 ◽  
Vol 2 ◽  
pp. 325
Author(s):  
Deyana Lutfita Kanos
Keyword(s):  
Stability Index ◽  
Index Mapping

<p>Tanah longsor merupakan bencana geologi terbesar ke tiga dan seringkali terjadi di beberapa wilayah di Indonesia seperti Kabupaten Kebumen yang sering mengalami tanah longsor yakni memiliki 580 kejadian longsor tersebar di 247 titik selama 7 tahun terakhir dikarenakan letak geografis daerah tropis yang memiliki curah hujan tinggi hingga 4000 mm/tahun yakni pada 1984.  Sehubungan dengan perubahan iklim, terdapat prediksi kecenderungan perubahan curah hujan pemicu longsor terbagi dalam tiga kategori; 51–100 mm/hari, 71–140 mm/3 hari, dan 81–160 mm/5 hari diperhitungkan menggunakan metode Mann-Kendall yang ditempatkan berdasarkan wilayah Poligon <em>Thiessen</em>. Identifikasi potensi tanah longsor menggunakan metode <em>Stability Index Mapping</em> (SINMAP) dengan variabel kemiringan lereng, jenis tanah, dan curah hujan. Analisis spasial bertujuan untuk memaparkan kaitan antara kecenderungan perubahan curah hujan terhadap kejadian longsor. Kaitan antara kecenderungan perubahan curah hujan yang di <em>overlay</em> dengan kejadian longsor dan potensi longsor merupakan tujuan dari penelitian ini sehingga dapat terlihat bagaimana kecenderungan curah hujan di masa mendatang pada lokasi potensi dan rawan tanah longsor. Hasil analisis kecenderungan perubahan curah hujan menunjukkan bahwa terdapat peningkatan curah hujan yang signifikan di beberapa wilayah seperti Karanganyar dan menurun seperti di Rantewringin. Kejadian longsor dan potensi longsor tinggi di dominasi pada bagian utara dan barat daya Kabupaten Kebumen, potensi sedang di sekitar potensi tinggi, dan potensi rendah paling mendominasi.<strong></strong></p><p><strong>Kata kunci</strong>: subjek <em>Kecenderungan, Curah Hujan, Mann-Kendall, Thiessen, Longsor, SINMAP, Sistem Informasi Geografi, Overlay, Analisis Spasial, Kebumen</em></p>

A FORECAST OF PRODUCTIVE LONGEVITY OF HOLSTEIN COWS BY INDIRECT SIGNS

2020 ◽  
Author(s):  
З.С. САНОВА
Keyword(s):  
Correlation Coefficient ◽  
Aging Process ◽  
Direct Relationship ◽  
Stability Index ◽  
Age At First Calving ◽  
Group I ◽  
Predicted Values ◽  
The Stability ◽  
Relationship Of ◽  
The Relationship

В статье представлены материалы о взаимосвязи продолжительности продуктивного использования коров с характеристикой устойчивости к деградации, с возрастом отела и удоем. В исследованной, разнородной по происхождению, группе животных для прогноза продуктивного периода коров, обусловленного устойчивостью к деградации и возрастом первого отела, пригодно уравнение регрессии, аргументами в котором являются индекс устойчивости, возраст первого отела в первой и второй степенях. Коэффициент корреляции межу предсказанными значениями продуктивного периода и его фактическими величинами в I группе составляет 0,502, во II - 0,604. При этом крайние варианты прогнозируются со статистическими ошибками 5 мес при оценке индекса устойчивости по 2 лактациям и 4,1 мес по 3, а средние варианты, соответственно, 1,6 и 1,51 мес. Индекс устойчивости к процессу старения является важной характеристикой биологических особенностей коров, определяющий их продуктивное долголетие. Его оценка по первым 2 и 3 лактациям имеет прямолинейную связь с продуктивным периодом (r=0,4109 и r=0,5270), соответственно. Зависимость продуктивного периода от возраста первого отела криволинейная — с увеличением возраста первого отела сокращается срок продуктивного использования, при возрасте первого отела более 1400 дней срок продуктивного использования колеблется от 1,33 до 1,41 лактации. Коэффициент корреляции между этими характеристиками коров составляет - 0,2164 в I и - 0,2620 во II группах. The article presents materials about the relationship of the duration of productive use of cows with the characteristic of resistance to degradation, with the age of calving and milk yield. In the studied group of animals, which is heterogeneous in origin, the regression equation is suitable for predicting the productive period of cows due to resistance to degradation and the age of the first calving, the arguments of which are the stability index, the age of the first calving in the first and second degrees. The correlation coefficient between the predicted values of the productive period and its actual values in group I is 0.502, in group II - 0.604. At the same time, the extreme variants are predicted with statistical errors of 5 months when evaluating the stability index for 2 lactations and 4.1 months for 3, and the average variants, respectively, are 1.6 and 1.51 months. The index of resistance to the aging process is an important characteristic of the biological characteristics of cows, which determines their productive longevity. Its estimate for the first 2 and 3 lactations has a direct relationship with the productive period (r=0.4109 and r=0.5270), respectively. The dependence of the productive period age at first calving curvilinear with increasing age at first calving reduces the time to productive use, while age at first calving of more than 1400 days, the period of productive use ranges from 1.33 to 1.41 lactation. The correlation coefficient between these characteristics of cows is-0.2164 in I and-0.2620 in II groups.

Slope Stability Analysis under the Condition of Seepage

2012 ◽  
Vol 204-208 ◽  
pp. 241-245
Author(s):  
Yang Jin
Keyword(s):  
Finite Element Method ◽  
Shear Strength ◽  
Slope Stability ◽  
Negative Impact ◽  
Strength Reduction ◽  
Soil Slope ◽  
Failure State ◽  
Calculation Results ◽  
The Stability ◽  
Shear Strength Reduction

The stability of soil slope under seepage is calculated and analyzed by using finite element method based on the technique of shear strength reduction. When the condition of seepage or not is considered respectively, the critical failure state of slopes and corresponding safety coefficients can be determined by the numerical analysis and calculation. Besides, through analyzing and comparing the calculation results, it shows that seepage has a negative impact on slope stability.

Soil Strength Reduction Method Induced by Variation of Water Content

2012 ◽  
Vol 170-173 ◽  
pp. 847-852
Author(s):  
Peng Ming Jiang ◽  
Zhong Lei Yan ◽  
Peng Li
Keyword(s):  
Slope Stability ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Characteristic Curve ◽  
Strength Reduction ◽  
Actual State ◽  
Soil Slope ◽  
Simple Method ◽  
The Common ◽  
The Stability

As the complexity of unsaturated soil theory, and it must have a long test period when we study the unsaturated soils, so the conventional design analysis software does not provide such analysis, so we can imagine that such a slope stability analysis does not accurately reflect the actual state of the slope. Based on the known soil moisture content，this paper use the soil water characteristic curve and strength theory of unsaturated soil to calculate the strength reduction parameters of soil which can calculate the stability of the soil slope when using the common calculation method. It is noticeable that this method can be extended and applied if we establish regional databases for this simple method, and these databases can improve the accuracy of the calculation of slope stability.

scholarly journals The stability index of a cactus

1977 ◽  
Vol 24 (2) ◽  
pp. 170-183
Author(s):  
Douglas D. Grant ◽  
D. A. Holton
Keyword(s):  
Connected Graph ◽  
Stability Index ◽  
The Stability

AbstractWe show that ifGis a connected graph of ordernsuch that no line lies in more than one cycle (in other words,Gis a cactus of ordern), then the stability index ofGis one of the integers 0, 1,n−7,n−6,n−5,n−4 orn.

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