scholarly journals On Dam Failure Induced Seismic Signals Using Laboratory Tests and on Breach Morphology due to Overtopping by Modeling

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2757
Author(s):  
Chi-Yao Hung ◽  
I-Fan Tseng ◽  
Su-Chin Chen ◽  
Zheng-Yi Feng
Keyword(s):  
Mass Movement ◽  
Dam Failure ◽  
Seismic Signals ◽  
Test Results ◽  
Erosion Process ◽  
Dam Breach ◽  
Hilbert Huang Transform ◽  
Hazard Reduction ◽  
Upstream Side ◽  
Factors Influencing

Dam models were constructed in an indoor flume to test dam breach failure processes to study the seismic signals induced. A simple dam breach model was also proposed to estimate hydrographs for dam breach floods. The test results showed that when the retrogressive erosion due to seepage of the dam continues, it will eventually reach the crest at the upstream side of the dam, and then trigger overtopping and breaching. The seismic signals corresponding to the failure events during retrogressive erosion and overtopping of the dam models were evaluated. Characteristics of the seismic signals were analyzed by Hilbert–Huang transform. Based on the characteristics of the seismic signals, we found four types of mass movement during the retrogressive erosion process, i.e., the single, intermittent, and successive slides and fall. There were precursor seismic signals found caused by cracking immediately before the sliding events of the dam. Furthermore, the dam breach modeling results coincided well with the test results and the field observations. From the test and modeling results, we confirmed that the overtopping discharge and the lateral sliding masses of the dam are also among the important factors influencing the evolution of the breach. In addition, the widening rate of the breach decreases with decreased discharge. The proposed dam breach model can be a useful tool for dam breach warning and hazard reduction.

Factors Influencing Nut Factor Test Results

2017 ◽  
Author(s):  
Warren Brown ◽  
Stewart Long
Keyword(s):  
Test Results ◽  
Bolted Joint ◽  
Factors Influencing ◽  
Applied Torque ◽  
Bolt Diameter ◽  
Joint Assembly

Nut Factor is used to establish a bolt load for a given applied torque in bolted joint assembly. In previous papers the effects of different factors influencing Nut Factor results were examined, which included the type of anti-seize, bolt and nut material, bolt diameter and amount of anti-seize applied. This paper examines those factors further and then includes additional factors which have been shown to have significant effect on the measured Nut Factor. The knowledge of these factors has been used to adjust the proposed ASTM specification for determining Nut Factor. It is also relevant to application in the field and to ensure that any testing conducted in a laboratory will be applicable in the field.

Features of Educational Motivation and Professional Identity of Russian and Indian Students at the Stage of Admission to the Master's School

2021 ◽  
pp. 31-35
Author(s):  
O. Potapov ◽  
Ritu Ritu
Keyword(s):  
Comparative Analysis ◽  
Professional Identity ◽  
Questionnaire Survey ◽  
Learning Motivation ◽  
Test Results ◽  
Factors Influencing ◽  
Two Samples ◽  
Educational Motivation ◽  
Indian Students

The article is devoted to the study of the peculiarities of educational motivation and professional identity of Russian and Indian students studying in Russia and intending to continue their studies in the magistracy. The use of a comparative analysis based on the test results for two samples, a questionnaire survey, showed the predominance of internal learning motivation and a higher level of professional identity of Indian students compared to students from Russia. The factors influencing the results of measuring educational motivation are indicated. General recommendations on the formation of optimal educational motivation and professional identity of future masters are given.

scholarly journals Impact resistance of external thermal insulation systems

2018 ◽  
Vol 163 ◽  
pp. 08004 ◽  
Author(s):  
Ewa Sudoł ◽  
Dawid Dębski ◽  
Renata Zamorowska ◽  
Barbara Francke
Keyword(s):  
Thermal Insulation ◽  
Impact Resistance ◽  
Experimental Program ◽  
Insulation Material ◽  
Test Results ◽  
Composite Systems ◽  
Factors Influencing ◽  
Insulation Systems ◽  
The Impact ◽  
Fibre Mesh

In the paper the results of an experimental program intended to determine factors influencing the impact resistance of the External Thermal Insulation Composite Systems (ETICS) were presented. For the research the systems based on polystyrene have been chosen. The insulation material was faced with a rendering consisting of base coat reinforced with standard or armored glass fibre mesh and silicone or silicone-silicate binders as finishing coats. The influence of various renderings components was evaluated with respect to resistance to hard body impact and resistance to hail. The test results were discussed in the context of the possible impact level on ETICS in use.

scholarly journals Rockfall induced seismic signals: case study in Montserrat, Catalonia

2008 ◽  
Vol 8 (4) ◽  
pp. 805-812 ◽  
Author(s):  
I. Vilajosana ◽  
E. Suriñach ◽  
A. Abellán ◽  
G. Khazaradze ◽  
D. Garcia ◽  
...  
Keyword(s):  
Particle Motion ◽  
Mass Movement ◽  
Seismic Energy ◽  
Quantitative Information ◽  
Volume Estimation ◽  
Seismic Signals ◽  
Energy Estimation ◽  
Time Frequency ◽  
On The Road ◽  
The Impact

Abstract. After a rockfall event, a usual post event survey includes qualitative volume estimation, trajectory mapping and determination of departing zones. However, quantitative measurements are not usually made. Additional relevant quantitative information could be useful in determining the spatial occurrence of rockfall events and help us in quantifying their size. Seismic measurements could be suitable for detection purposes since they are non invasive methods and are relatively inexpensive. Moreover, seismic techniques could provide important information on rockfall size and location of impacts. On 14 February 2007 the Avalanche Group of the University of Barcelona obtained the seismic data generated by an artificially triggered rockfall event at the Montserrat massif (near Barcelona, Spain) carried out in order to purge a slope. Two 3 component seismic stations were deployed in the area about 200 m from the explosion point that triggered the rockfall. Seismic signals and video images were simultaneously obtained. The initial volume of the rockfall was estimated to be 75 m3 by laser scanner data analysis. After the explosion, dozens of boulders ranging from 10−4 to 5 m3 in volume impacted on the ground at different locations. The blocks fell down onto a terrace, 120 m below the release zone. The impact generated a small continuous mass movement composed of a mixture of rocks, sand and dust that ran down the slope and impacted on the road 60 m below. Time, time-frequency evolution and particle motion analysis of the seismic records and seismic energy estimation were performed. The results are as follows: 1 – A rockfall event generates seismic signals with specific characteristics in the time domain; 2 – the seismic signals generated by the mass movement show a time-frequency evolution different from that of other seismogenic sources (e.g. earthquakes, explosions or a single rock impact). This feature could be used for detection purposes; 3 – particle motion plot analysis shows that the procedure to locate the rock impact using two stations is feasible; 4 – The feasibility and validity of seismic methods for the detection of rockfall events, their localization and size determination are comfirmed.

scholarly journals On the evaluation of yield stress of soils for debris flow analysis

2019 ◽  
Vol 92 ◽  
pp. 05002
Author(s):  
Carlos Besso ◽  
Tácio Mauro Pereira de Campos
Keyword(s):  
Debris Flow ◽  
Yield Stress ◽  
Mass Movement ◽  
Flow Analysis ◽  
Rheological Parameters ◽  
Test Results ◽  
Slump Test ◽  
Acceleration And Deceleration ◽  
Cheap Alternative ◽  
Set Up

Debris flow materials behave as a fluid, hence its analysis requires rheological parameters such as yield stress and viscosity. Yield stress is associated to the start and the end of the mass movement downhill in the sense that it denotes the yield transition from the creep to the flow regime, i.e., passage from solid to fluid state. This paper presents an experimental study of the yield stress of a colluvium from Rio de Janeiro, through its determination in a modified set-up of the slump test and in a rotational parallel plate rheometer. Tests were performed in five different water contents above its liquidity limit, providing a fairly good relationship between yield stress and water content. While slump test provides yield stress related to the beginning of the movement (acceleration), rheometer results are related to flow's outset and stoppage. As a result, the percentual differences between yield stresses associated with acceleration and deceleration were less than 5% in all testes, which is related to the low hysteresis effect in the flow curves obtained in the rotational rheometer. Comparing the two methodologies, it is proposed a correction from rheometer to slump test results. Results obtained are compared with data presented in other studies involving soil's yield stress, showing a good acceptance of the slump test results as a cheap alternative to rheometers.

Predict Research for Loss of Life Due to Dam Breach for Guangxi Luocheng Kama Reservoir

2011 ◽  
Vol 243-249 ◽  
pp. 3877-3882
Author(s):  
Rong Yong Ma ◽  
Xiang Chen ◽  
Lei Lei Yang ◽  
Xiao Qing Zhang
Keyword(s):  
Calculation Result ◽  
Dam Break ◽  
Dam Failure ◽  
Suitable Model ◽  
Actual Situation ◽  
Dam Breach ◽  
Loss Of Life ◽  
At Home

In this paper，the basic situation of Guangxi luocheng Kama reservoir and the potential dangers are introduced firstly, and then，different models often used to estimate the loss of life in dam failure at home and abroad are introduced and analysed.Based on the above, a suitable model for national actual situation is chosen to predict the loss due to this reservoir dam breach，and the severity according to the calculation result of assuming Kama reservoir dam-break is assessed. Finally, the relevant departments’s measures of rescuing and evacuating downstream masses etc. at danger in 2009 are proved to be correct，necessary and timely.

Une modélisation théorique nouvelle de la rupture par submersion d'une digue en terre et sa validation

2004 ◽  
Vol 31 (5) ◽  
pp. 797-812 ◽  
Author(s):  
N E Zerrouk ◽  
C Marche
Keyword(s):  
Numerical Model ◽  
Formation Process ◽  
Earth Dam ◽  
Dam Failure ◽  
Second Step ◽  
Dam Breach ◽  
Erosion Mechanism ◽  
Flow Hydraulics ◽  
Earth Fill

This paper presents the EROBAR numerical model on breach formation in earth-fill dams during an overtopping flow. Hydraulics of flow over an earth-fill dam is considered as the basis for the comprehension of the breach formation process. To this will be added the mastery of the erosion mechanism and of widening of the breach canal. As the breach formation process in an earth-fill dam is very complex, the EROBAR model was the object of a two-step formulation, with the two steps joined later. The first step deals with the flow hydraulics, vertical erosion, and longitudinal evolution of the profile of the dam. The second step introduces the widening of the breach, based on the instability of the breach slope. After the two formulations were joined and validated, the EROBAR model was applied to the experimental dyke, to several homogenous earth-fill dams with or without protection, and to zoned dams.Key words: dam failure, breach erosion, earth-fill dam breach, overtopped earth dam, numerical model.

Horizontal Capacity of Embedded Suction Anchors in Clay

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
S. Bang ◽  
K. Jones ◽  
Y. S. Kim ◽  
Y. Cho
Keyword(s):  
Analytical Solution ◽  
Model Test ◽  
Soil Type ◽  
Embedment Depth ◽  
Centrifuge Model Test ◽  
Test Results ◽  
Pullout Capacity ◽  
Direct Function ◽  
Centrifuge Model ◽  
Factors Influencing

The embedded suction anchor (ESA) is a type of permanent offshore foundation that is installed by a suction pile. The primary factors influencing the horizontal pullout capacity of an ESA include the loading point, the soil type, the embedment depth, and the addition of flanges. The main purpose of this study is to develop an analytical solution that is capable of estimating the horizontal pullout capacity of ESAs with the loading point being anywhere along its length with or without flanges. An analytical solution has been developed to estimate the horizontal pullout capacity of embedded suction anchors in clay seafloor. Validation has been made through comparisons with the centrifuge model test results. Results indicate that the horizontal pullout capacity of the embedded suction anchor in clay increases, reaches its peak, and then starts to decrease as the point of the load application moves downward. The effect of flanges on the horizontal pullout capacity is also found to be significant. The horizontal pullout capacity is a direct function of the loading point. The horizontal pullout capacity increases as the loading point moves downward and the maximum pullout capacity is obtained when the loading point is approximately at the mid-depth. The increase in horizontal pullout capacity can be significant, i.e., more than twice in magnitude when the maximum pullout capacity is compared with that associated with the loading point near the top or tip.

scholarly journals Parameter Measurements of Moving Gas Bubbles Using Image Tomography Title

2016 ◽  
Vol 21 (3) ◽  
pp. 5-14
Author(s):  
Mariusz Roland Rząsa
Keyword(s):  
Center Of Mass ◽  
Mass Movement ◽  
Measuring Method ◽  
Movement Trajectory ◽  
Bubble Shape ◽  
Test Results ◽  
Empirical Correlations ◽  
Movement Trajectories ◽  
Geometric Figures

Abstract The paper presents an idea of a new measuring method based on image tomography. This method focuses on registration of images of bubbles moving in two perpendicular directions. Two images are used for determination of the center of mass, movement trajectory and local velocities. Volume and area of bubbles are defined by using approximation of the bubble shape with the known geometric figures. The paper also presents the algorithm of reconstruction of the bubble shapes and movement trajectories, as well as exemplary test results. The obtained results were compared with empirical correlations in the published literature.

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