scholarly journals On snow stability interpretation of extended column test results

2020 ◽  
Vol 20 (7) ◽  
pp. 1941-1953 ◽  
Author(s):  
Frank Techel ◽  
Kurt Winkler ◽  
Matthias Walcher ◽  
Alec van Herwijnen ◽  
Jürg Schweizer
Keyword(s):  
Slope Stability ◽  
Large Data ◽  
Stability Assessment ◽  
Test Results ◽  
Column Test ◽  
Secondary Importance ◽  
Data Set ◽  
Detailed Classification ◽  
Stable Conditions ◽  
The Stability

Abstract. Snow instability tests provide valuable information regarding the stability of the snowpack. Test results are key data used to prepare public avalanche forecasts. However, to include them into operational procedures, a quantitative interpretation scheme is needed. Whereas the interpretation of the rutschblock test (RB) is well established, a similar detailed classification for the extended column test (ECT) is lacking. Therefore, we develop a four-class stability interpretation scheme. Exploring a large data set of 1719 ECTs observed at 1226 sites, often performed together with a RB in the same snow pit, and corresponding slope stability information, we revisit the existing stability interpretations and suggest a more detailed classification. In addition, we consider the interpretation of cases when two ECTs were performed in the same snow pit. Our findings confirm previous research, namely that the crack propagation propensity is the most relevant ECT result and that the loading step required to initiate a crack is of secondary importance for stability assessment. The comparison with the RB showed that the ECT classifies slope stability less reliably than the RB. In some situations, performing a second ECT may be helpful when the first test did not indicate rather unstable or stable conditions. Finally, the data clearly show that false-unstable predictions of stability tests outnumber the correct-unstable predictions in an environment where overall unstable locations are rare.

scholarly journals On the stability interpretation of Extended Column Test results

2020 ◽  
Author(s):  
Frank Techel ◽  
Kurt Winkler ◽  
Matthias Walcher ◽  
Alec van Herwijnen ◽  
Jürg Schweizer
Keyword(s):  
Slope Stability ◽  
Large Data ◽  
Stability Assessment ◽  
Test Results ◽  
Column Test ◽  
Secondary Importance ◽  
Data Set ◽  
Detailed Classification ◽  
Stable Conditions ◽  
The Stability

Abstract. Snow instability tests provide valuable information regarding the stability of the snowpack. Test results are key data used to prepare public avalanche forecasts. However, to include them into the operational procedures, a quantitative interpretation scheme is needed. Whereas the interpretation of the Rutschblock test is well established, a similar detailed classification for the Extended Column Test (ECT) is lacking. Therefore, we develop a 4-class stability interpretation scheme. Exploring a large data set of 1719 ECTs observed at 1226 sites, often performed together with a Rutschblock (RB) in the same snow pit, and corresponding slope stability information, we revisit the existing stability interpretations, explore the potential of a more detailed classification, and specifically consider the interpretation of cases when two ECTs were performed in the same snow pit. Our findings confirm previous research, namely that the crack propagation propensity is the most relevant result and that the loading step required to initiate a crack is of secondary importance for stability assessment. The comparison with the RB showed that the ECT classifies slope stability less reliably than the RB. In some situations, performing a second ECT may be helpful, when the first test did neither indicate rather unstable nor stable conditions. Finally, the data clearly show that false-unstable predictions of stability tests outnumber the correct-unstable predictions in an environment where overall unstable locations are rare.

Building Trust in Politics

2016 ◽  
pp. 127-157
Author(s):  
Michele Lobina ◽  
Marco Bottone
Keyword(s):  
Latin America ◽  
Latin American ◽  
Public Support ◽  
Large Data ◽  
Direct Impact ◽  
Data Set ◽  
Political Behaviour ◽  
The Public ◽  
Trust In Institutions ◽  
The Stability

This chapter studies the process of trust building in politics by using large data set on political behaviour in Latin America. The results yielded by developed models indicate specific elements as the most influential on the popular trust in institutions. These observed determinants were enclosed in five macro classes: cohesion of society; economic factors; electoral transparency; efficiency of judicial organs; and crime diffusion. The analysis of the public support in governments and parliaments revealed that certain variables have a direct impact on the stability of the Latin American democracies, while other factors merely determine the likelihood of a government's reappointment.

scholarly journals Machine-Learning-Based Classification Approaches toward Recognizing Slope Stability Failure

2019 ◽  
Vol 9 (21) ◽  
pp. 4638 ◽  
Author(s):  
Moayedi ◽  
Bui ◽  
Kalantar ◽  
Foong
Keyword(s):  
Machine Learning ◽  
Slope Stability ◽  
Nearest Neighbor ◽  
Support Vector ◽  
Sequential Minimal Optimization ◽  
Stability Assessment ◽  
K Nearest Neighbor ◽  
The Stability ◽  
Intelligent Models ◽  
Improved Support Vector Machine

In this paper, the authors investigated the applicability of combining machine-learning-based models toward slope stability assessment. To do this, several well-known machine-learning-based methods, namely multiple linear regression (MLR), multi-layer perceptron (MLP), radial basis function regression (RBFR), improved support vector machine using sequential minimal optimization algorithm (SMO-SVM), lazy k-nearest neighbor (IBK), random forest (RF), and random tree (RT), were selected to evaluate the stability of a slope through estimating the factor of safety (FOS). In the following, a comparative classification was carried out based on the five stability categories. Based on the respective values of total scores (the summation of scores obtained for the training and testing stages) of 15, 35, 48, 15, 50, 60, and 57, acquired for MLR, MLP, RBFR, SMO-SVM, IBK, RF, and RT, respectively, it was concluded that RF outperformed other intelligent models. The results of statistical indexes also prove the excellent prediction from the optimized structure of the ANN and RF techniques.

scholarly journals Geotechnical characteristics of unburnt colliery spoils after coal-recovery

2019 ◽  
Vol 262 ◽  
pp. 04006
Author(s):  
Tymoteusz Zydroń ◽  
Andrzej Gruchot ◽  
Eugeniusz Zawisza
Keyword(s):  
Slope Stability ◽  
Test Results ◽  
Coal Basin ◽  
Geotechnical Parameters ◽  
Coal Recovery ◽  
Geotechnical Characteristics ◽  
Upper Silesian Coal Basin ◽  
Materials Used ◽  
The Stability ◽  
Wave Passage

The aim of the study was to determine the geotechnical characteristics of the unburnt colliery spoils after coal-recovery from the dumping site of one of the mines of the Upper Silesian Coal Basin in Poland. Due to grain-size distribution of tested spoils their geotechnical properties were determined using medium-sized apparatuses. In order to verify the suitability of the studied spoils for the construction of hydraulic embankments, the seepage and stability calculations were conducted for models of hydraulic embankments including the effect of flood wave passage on stress conditions within the construction and their slope stability. The test results revealed, that the studied colliery spoils are characterized by favourable values of geotechnical parameters and they fulfil the requirements for soil materials used in the analysed type of constructions. The spoils are characterized by good compactibility, relatively low water permeability and average susceptibility to mechanical disintegration, which in the case of using this material for the construction of hydraulic embankments and using proper compaction technology, should reduce their susceptibility to weathering. The results of seepage and slope stability calculations for hydraulic embankments built of the studied spoils confirmed their suitability for that type of constructions, retaining the proper inclination of slopes, whereas the variant of embankment without sealing is safer from the stability viewpoint.

scholarly journals On the relation between avalanche occurrence and avalanche danger level

2019 ◽  
Author(s):  
Jürg Schweizer ◽  
Christoph Mitterer ◽  
Frank Techel ◽  
Andreas Stoffel ◽  
Benjamin Reuter
Keyword(s):  
Large Data ◽  
Swiss Alps ◽  
Data Sets ◽  
Snow Avalanches ◽  
Secondary Importance ◽  
Data Set ◽  
Avalanche Size ◽  
Wet Snow ◽  
Danger Level ◽  
Avalanche Danger

Abstract. In many countries with seasonally snow-covered mountain ranges warnings are issued to alert the public about imminent avalanche danger, mostly employing a 5-level danger scale. However, as avalanche danger cannot be measured, the charac-terization of avalanche danger remains qualitative. The probability of avalanche occurrence in combination with the ex-pected avalanche type and size decide on the degree of danger in a given forecast region (≳ 100 km2). To describe ava-lanche occurrence probability the snowpack stability and its spatial distribution need to be assessed. To quantify the rela-tion between avalanche occurrence and avalanche danger level we analyzed a large data set of visually observed ava-lanches from the region of Davos (Eastern Swiss Alps), all with mapped outlines, and compared the avalanche activity to the forecast danger level on the day of occurrence. The number of avalanches per day strongly increased with increasing danger level confirming that not only the release probability but also the frequency of locations with a weakness in the snowpack where avalanches may initiate from, increases within a region. Avalanche size did in general not increase with increasing avalanche danger level, suggesting that avalanche size may be of secondary importance compared to snowpack stability and its distribution when assessing the danger level. Moreover, the frequency of wet-snow avalanches was found to be higher than the frequency of dry-snow avalanches on a given day; also, wet-snow avalanches tended to be larger. This finding may indicate that the danger scale is not used consistently with regard to avalanche type. Although, observed ava-lanche occurrence and avalanche danger level are subject to uncertainties, our findings on the characteristics of avalanche activity may allow revisiting the definitions of the European avalanche danger scale. The description of the danger levels can be improved, in particular by quantifying some of the many proportional quantifiers. For instance, ‘many avalanches’, expected at danger level 4–High, means on the order of 10 avalanches per 100 km2. Whereas our data set is one of the most comprehensive, visually observed avalanche records are known to be inherently incomplete so that our results often refer to a lower limit and should be confirmed using other similarly comprehensive data sets.

Building Trust in Politics

2019 ◽  
pp. 641-664
Author(s):  
Michele Lobina ◽  
Marco Bottone
Keyword(s):  
Latin America ◽  
Latin American ◽  
Public Support ◽  
Large Data ◽  
Direct Impact ◽  
Data Set ◽  
Political Behaviour ◽  
The Public ◽  
Trust In Institutions ◽  
The Stability

This chapter studies the process of trust building in politics by using large data set on political behaviour in Latin America. The results yielded by developed models indicate specific elements as the most influential on the popular trust in institutions. These observed determinants were enclosed in five macro classes: cohesion of society; economic factors; electoral transparency; efficiency of judicial organs; and crime diffusion. The analysis of the public support in governments and parliaments revealed that certain variables have a direct impact on the stability of the Latin American democracies, while other factors merely determine the likelihood of a government's reappointment.

Stability Analysis of Highway Tunnel Portal Slope in Shiyan Area

2011 ◽  
Vol 368-373 ◽  
pp. 2824-2827
Author(s):  
Sheng Li Liu ◽  
Wen Guang Zhao ◽  
Yang Zhang ◽  
He Jie Gao ◽  
Fang Wei Fu
Keyword(s):  
Slope Stability ◽  
Natural State ◽  
Test Results ◽  
Highway Tunnel ◽  
Management Measures ◽  
Geological Conditions ◽  
Mechanism Of Landslide ◽  
The Stability ◽  
Rock Strata ◽  
Tunnel Portal

Under the control of the tow-Yun fracture, the geological conditions are complicated and the rock strata is broken in Shiyan area ,in the northwest of Hubei province, and the rock mass is weathered into fragment. When Highway is built in this area, a lot of tunnel portal slope and landslide problems will be met. To properly solve these problems, it is needed to analyze the slope stability and to propose appropriate management measures. In the paper, taken a highway tunnel portal slope in Shiyan area for example, a detailed research was made on the mechanism of landslide formation, and using laboratory soil test results and the simple Janbu method, the local and global slope stability is calculated. The results show that the slope is stable in natural state, and in heavy rains the stability coefficient is reduced quickly and the slope will be sliding. So the slope needs to manage and the rain water needs to control.

scholarly journals Systematic slope stability assessment through deformation field monitoring

2019 ◽  
Vol 92 ◽  
pp. 18009
Author(s):  
Yukun Wei ◽  
Anders B. Lundberg ◽  
Fredrik Resare
Keyword(s):  
Slope Stability ◽  
Measurement Data ◽  
Back Analysis ◽  
Field Measurements ◽  
Field Monitoring ◽  
Monitoring Data ◽  
Soil Parameters ◽  
Stability Assessment ◽  
Stability Of Slopes ◽  
The Stability

Field monitoring is frequently carried out during excavations and other geotechnical activities and provides additional information during the execution of a construction project. The interpretation of field monitoring data is often obscured by measurement noise and disturbance, and a systematic approach to assess both the quality and implications of the field monitoring data is very helpful in geotechnical practice. The possibility to infer practical conclusions from the field monitoring data depends on the type of field measurements, especially in monitoring of the stability of slopes. Pore pressure measurements can serve as a direct measurement of utilized soil strength for a slope, while deformation measurements are significantly more ambiguous and complicates the interpretation. The assessment of slope stability through field monitoring of deformations requires inverse or back analysis of the soil properties, followed by a forward analysis of the resulting slope stability. Such an inverse or back analysis is frequently influenced by non-uniqueness of the material properties and the stability of the measurement data. Systematic approaches to inverse or back analysis have been demonstrated in the scientific literature, but the practical use of these methods is not entirely straight-forward. The current paper presents a case study of systematic slope stability assessment through field measurements of deformations with a review of the field monitoring programme, numerical simulations of deformations, and a simplified approach to back analysis of the soil parameters. The excavation of a slope in an urban environment including layers of organic clay covered with highly heterogeneous gravel fill is used as an example of geotechnical back analysis. The aim is to elucidate some of the challenges in geotechnical back analysis while providing some practical solutions for practice.

scholarly journals Comparing the vibration of effects due to model, data pre-processing and sampling uncertainty on a large data set in personality psychology

2020 ◽  
Author(s):  
Simon Klau ◽  
Felix D. Schönbrodt ◽  
Chirag Patel ◽  
john Ioannidis ◽  
Anne-Laure Boulesteix ◽  
...  
Keyword(s):  
Large Data ◽  
Large Data Sets ◽  
Selective Reporting ◽  
Data Sets ◽  
Sample Sizes ◽  
Sampling Uncertainty ◽  
Data Set ◽  
Personality Psychology ◽  
Research Findings ◽  
The Stability

Researchers have great flexibility in the analysis of observational data. If combined with selective reporting and pressure to publish, this flexibility can have devastating consequences on the validity of research findings. We extend the recently proposed vibration of effects approach to provide a framework comparing three main sources of uncertainty which lead to instability in observational associations, namely data pre-processing, model and sampling uncertainty. We analyze their behavior for varying sample sizes for two associations in personality psychology. While all types of vibration show a decrease for increasing sample sizes, data pre-processing and model vibration remain non-negligible, even for a sample of over 80000 participants. The increasing availability of large data sets that are not initially recorded for research purposes can make data pre-processing and model choices very influential. We therefore recommend the framework as a tool for the transparent reporting of the stability of research findings.

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