scholarly journals Evaluating shear mobilization in rockfill columns used for riverbank stabilization

2009 ◽  
Vol 46 (8) ◽  
pp. 976-986 ◽  
Author(s):  
Marolo C. Alfaro ◽  
James A. Blatz ◽  
Wisam F. Abdulrazaq ◽  
Chang-Seok Kim
Keyword(s):  
Large Scale ◽  
Experimental Testing ◽  
Test Results ◽  
Lake Agassiz ◽  
Shearing Resistance ◽  
Glacial Lake Agassiz ◽  
The Stability ◽  
Rockfill Columns ◽  
The City

The major rivers within the City of Winnipeg are founded in glacial Lake Agassiz clay and silt sediments that have low shear strength. As such, riverbank instabilities are a common issue along many stretches of the rivers. The use of rockfill columns has become an increasingly utilized approach for stabilizing failing banks. Recent cases in Winnipeg have shown that movements can occur following installation of rockfill columns. Uncertainty regarding the magnitude of these movements that is required to mobilize shearing resistance in the rockfill columns has resulted in situations where the stability of riverbanks following remediation has been questioned. This has provided a need to improve our understanding about how much movement a stabilized slope must undergo before sufficient shear resistance of the rockfill column will be mobilized. The results of experimental testing conducted to assess the shear mobilization of rockfill column materials using a large-scale direct shear test apparatus are presented in this paper. The testing methodology is described along with the test results. The results show that the development of material specifications, construction, and placement methods and appropriate methods of analysis requires understanding of the stress–strain properties of the in situ soil and the rockfill material.

scholarly journals A Digital Framework to Predict the Sunshine Requirements of Landscape Plants

2021 ◽  
Vol 11 (5) ◽  
pp. 2098
Author(s):  
Heyi Wei ◽  
Wenhua Jiang ◽  
Xuejun Liu ◽  
Bo Huang
Keyword(s):  
Solar Radiation ◽  
Plant Species ◽  
Large Scale ◽  
Normal Growth ◽  
Adaptive Selection ◽  
Landscape Plant ◽  
Landscape Plants ◽  
The Stability ◽  
Stability And Accuracy ◽  
The City

Knowledge of the sunshine requirements of landscape plants is important information for the adaptive selection and configuration of plants for urban greening, and is also a basic attribute of plant databases. In the existing studies, the light compensation point (LCP) and light saturation point (LSP) have been commonly used to indicate the shade tolerance for a specific plant; however, these values are difficult to adopt in practice because the landscape architect does not always know what range of solar radiation is the best for maintaining plant health, i.e., normal growth and reproduction. In this paper, to bridge the gap, we present a novel digital framework to predict the sunshine requirements of landscape plants. First, the research introduces the proposed framework, which is composed of a black-box model, solar radiation simulation, and a health standard system for plants. Then, the data fitting between solar radiation and plant growth response is used to obtain the value of solar radiation at different health levels. Finally, we adopt the LI-6400XT Portable Photosynthetic System (Li-Cor Inc., Lincoln, NE, USA) to verify the stability and accuracy of the digital framework through 15 landscape plant species of a residential area in the city of Wuhan, China, and also compared and analyzed the results of other researchers on the same plant species. The results show that the digital framework can robustly obtain the values of the healthy, sub-healthy, and unhealthy levels for the 15 landscape plant species. The purpose of this study is to provide an efficient forecasting tool for large-scale surveys of plant sunshine requirements. The proposed framework will be beneficial for the adaptive selection and configuration of urban plants and will facilitate the construction of landscape plant databases in future studies.

Development of a high-efficiency and long-life 500W class H-Darrieus-type vertical axis wind turbine (VAWT) system using skin-spar-foam sandwich composite structure

2013 ◽  
Vol 20 (4) ◽  
pp. 383-394
Author(s):  
Changduk Kong ◽  
Haseung Lee
Keyword(s):  
Wind Turbine ◽  
Large Scale ◽  
High Efficiency ◽  
Vertical Axis ◽  
Small Scale ◽  
Test Results ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Structural Test ◽  
The City

AbstractSince the focus on the energy crisis and environmental issues due to excessive fossil fuel consumption, wind power has been considered as an important renewable energy source. Recently, several megawatt-class large-scale wind turbine systems have been developed in some countries. Even though the large-scale wind turbine can effectively produce electrical power, the small-scale wind turbine has been continuously developed due to some advantages; for instance, it can be easily built at a low cost without any limitation of location, i.e., even in the city. In case of small-scale wind turbines, the vertical axis wind turbine (VAWT) is used in the city despite having a lower efficiency than the horizontal axis wind turbine. Furthermore, most small-scale wind turbine systems have been designed at the rated wind speed of around 12 m/s. This aim of this work is to design a high-efficiency 500W class composite VAWT blade that is applicable to relatively low-speed regions. With regard to the aerodynamic design of the blade, parametric studies are carried out to decide an optimal aerodynamic configuration. The aerodynamic efficiency and performance of the designed VAWT is confirmed by computational fluid dynamics analysis. The structural design is performed by the load case study, initial sizing using the netting rule and the rule of mixture, structural analysis using finite element method (FEM), fatigue life estimation and structural test. The prototype blade is manufactured by hand lay-up and the matched die molding. The experimental structural test results are compared with the FEM analysis results. Finally, to evaluate the prototype VAWT including designed blades, the performance test is performed using a truck to simulate various ranges of wind speeds and some measuring equipment. According to the performance evaluation result, the estimated performance agrees well with the experimental test results in all operating ranges.

scholarly journals In-situ rock tests for fault gouge zone：A case in Fengman hydropower station, China

2021 ◽  
Vol 293 ◽  
pp. 03008
Author(s):  
Xinchuan Xu ◽  
Zhaoyue Yu ◽  
Fangfang Xue ◽  
Xiaogang Long ◽  
Xinyu Mao ◽  
...  
Keyword(s):  
Large Scale ◽  
Scientific Basis ◽  
Test Point ◽  
Actual Condition ◽  
Hydropower Station ◽  
Bearing Plate ◽  
Dam Site ◽  
Fault Gouges ◽  
The Stability

The existence of faults in the dam site area threatens the stability and safety of large-scale hydropower projects in China. The fault argillaceous zone is the worst kind of fault fracture zone, and the determination of its deformation and strength parameters is the key point of rock engineering investigation. In this study, the in-situ bearing plate test and direct shear test were carried out on the gouge zone of F67 fault in the dam site of Fengman Hydropower Station. The test results show that the deformation and shear law of each test point is good, which is basically consistent with the actual condition of the measured rock mass. However, due to the limited number of measurements, the results are limited in terms of macroscopic representation. The experimental results provide scientific basis for subsequent engineering design and further enhance the understanding of mechanical properties of fault gouges.

scholarly journals A chemo-enzymatic oxidation cascade to activate C–H bonds with in situ generated H2O2

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Simon J. Freakley ◽  
Svenja Kochius ◽  
Jacqueline van Marwijk ◽  
Caryn Fenner ◽  
Richard J. Lewis ◽  
...  
Keyword(s):  
Palladium Nanoparticles ◽  
Large Scale ◽  
Reaction Vessel ◽  
Enzymatic Oxidation ◽  
Catalytic Systems ◽  
In Situ Generation ◽  
Temperature And Pressure ◽  
The Stability ◽  
By Products

Abstract Continuous low-level supply or in situ generation of hydrogen peroxide (H2O2) is essential for the stability of unspecific peroxygenases, which are deemed ideal biocatalysts for the selective activation of C–H bonds. To envisage potential large scale applications of combined catalytic systems the reactions need to be simple, efficient and produce minimal by-products. We show that gold-palladium nanoparticles supported on TiO2 or carbon have sufficient activity at ambient temperature and pressure to generate H2O2 from H2 and O2 and supply the oxidant to the engineered unspecific heme-thiolate peroxygenase PaDa-I. This tandem catalyst combination facilitates efficient oxidation of a range of C-H bonds to hydroxylated products in one reaction vessel with only water as a by-product under conditions that could be easily scaled.

Moraine formation in northwestern Ontario: product of subglacial fluvial and glaciolacustrine sedimentation

1990 ◽  
Vol 27 (11) ◽  
pp. 1478-1486 ◽  
Author(s):  
David R. Sharpe ◽  
W. R. Cowan
Keyword(s):  
Large Scale ◽  
Silty Sand ◽  
Traditional View ◽  
Glacial Lake ◽  
Drainage Network ◽  
Lake Agassiz ◽  
Northwestern Ontario ◽  
Glacial Lake Agassiz ◽  
Transient Instability ◽  
Subglacial Meltwater

Long, arcuate, stratified end moraines in northwestern Ontario may represent major and rapid sedimentation events in glacial Lake Agassiz. Rapid lowering of the lake or lift of a marginal ice dam may have triggered widespread outbursts of subglacial meltwater which deposited these end moraines as coalesced or broad subaqueous lacustrine fans. Moraine cores are of undeformed gravel, sand, and silty sand that fine upward. Coarse beds are massive to weakly stratified. Large-scale cross-stratification may be present. Sandy rhythmic beds are laterally transitional to silt–clay rhythmites (varves). Similar facies occur in adjoining eskers.Moraine sediments have the expected characteristics of rapid deposition on subaqueous fans and, therefore, may not represent either prolonged sedimentation or stable ice margins. Rather, they may reflect rapid sedimentation associated with large discharges that induced transient instability in the drainage network and (or) surging prior to marginal sedimentation. This explanation for moraine formation questions the traditional view that large end moraines represent climatically controlled stillstands.

Application of Damage Rheology Model in Study on an Underground Cavern Group

2011 ◽  
Vol 90-93 ◽  
pp. 760-763
Author(s):  
Yin Ping Qi ◽  
Lv Xiang ◽  
Wei Shen Zhu
Keyword(s):  
Large Scale ◽  
Southwest China ◽  
Back Analysis ◽  
Great Depth ◽  
Underground Cavern ◽  
In Situ Stresses ◽  
The Stability ◽  
Damage Rheology ◽  
Hydropower Stations

A great number of large-scale hydropower stations are to be constructed in southwest China. Many of them feature great depth or high in situ stresses. In this paper, a coupled damage and rheology method is adopted for stability analysis of an underground cavern group with time effect to consider the rock deformation. Meanwhile, a new method considering the crackopening displacement is used for back analysis. The stability of the surrounding rock masses is then evaluated.

scholarly journals Laboratory data quality control: A new cost-effective approach

2018 ◽  
Vol 51 (5-6) ◽  
pp. 160-171
Author(s):  
Murat Aydos ◽  
Ahmet Nalbant ◽  
Yilmaz Vural
Keyword(s):  
Large Scale ◽  
Test Procedure ◽  
Laboratory Data ◽  
Reference Value ◽  
Cost Effective ◽  
Test Results ◽  
Data Quality Control ◽  
Control Data ◽  
The Stability ◽  
Working Point

In industrial and medical laboratories, prior to initiating the daily test procedure, the accuracy of the system is observed by measuring the reference control values. Measurements and test results may be below or above the reference value. Hence, the control data is employed in order to ensure that the test scores lie in the targeted range values, and the results obtained from the control data are evaluated via computer-based analysis. The results of the analysis have significant importance for control and improvement of process. Furthermore, the data to be analyzed may be the test results of a product as well as the measurement outcomes obtained from a laboratory. In this study, an algorithm named as Adaptive Precision Point Algorithm is proposed to evaluate the control data and to increase the stability by reducing the loss. In this schema, the contribution to the reduction of the total systematic error was observed by calculating the target working point and the Adaptive Precision Point deviations. Measurement outputs, in other terms the data, are processed in Adaptive Precision Point Algorithm. The algorithm determines a new adaptive working point for the incoming data by doing the required computations for precision working point. Moreover, the deviation between adaptive working point and the specified working point, which is defined according to the standards and rules, is calculated. By this way, adaptive working point is being utilized throughout the reduction of systemic errors. According to the results of the research, Adaptive Precision Point Algorithm eliminates the systematic errors on a large scale. The suggested algorithm provides results within the accepted quality deviation limits so it does not form a negativity in the understanding of quality. It is also observed that the algorithm sets a positive correlation between the minimized test results and reduction of time and material usage. Furthermore, the research and the algorithm offer a cost-effective solution. Consequently, the contribution and significance of the proposed algorithm can be understood in a better way by considering that it does not only maintain the quality limits but it also minimizes the cost and time spent during the testing of thousands of laboratory samples.

scholarly journals Experimental assessment of the ultimate performance and lateral drift behaviour of precast concrete building cores

2020 ◽  
Vol 23 (12) ◽  
pp. 2597-2613 ◽  
Author(s):  
Scott J Menegon ◽  
John L Wilson ◽  
Nelson TK Lam ◽  
Emad F Gad
Keyword(s):  
Cross Section ◽  
Large Scale ◽  
Experimental Testing ◽  
Precast Concrete ◽  
Composite Action ◽  
Lateral Drift ◽  
The Core ◽  
Concrete Building ◽  
Plate Connections

Precast concrete building cores are a widely used lateral load resisting system in low and mid-rise multi-storey buildings. However, despite their widespread use in countries like Australia or New Zealand, a very little research or experimental testing has been undertaken to assess their lateral drift behaviour. This article will present the findings and observations of a recent experimental testing programme into reinforced concrete precast building cores, which included three large-scale ‘box-shaped’ precast building core specimens. Adjacent panels in each specimen were connected together using welded stitch plate connections and then connected to foundation blocks on the top and bottom using grout tube connections. The results of the testing showed that the welded stitch plate connections were too flexible to allow full composite action to be developed in the cross-section, which meant the precast building core specimens were around 25% more flexible than an equivalent cast in-situ version. The testing also highlighted common detailing and construction deficiencies that can severely inhibit the ductility of the core.

scholarly journals Study and monitoring of the stability of a rock mass at the Dar-El-Oued tunnel, wilaya of Jijel – Algeria

2018 ◽  
Vol 149 ◽  
pp. 02069
Author(s):  
Chahra Yellas ◽  
Riad Benzaid ◽  
Mustapha Tekkouk
Keyword(s):  
Numerical Model ◽  
The State ◽  
Underground Structures ◽  
Surface Displacements ◽  
The Face ◽  
The Stability ◽  
National Road ◽  
The City ◽  
Good Agreement

The construction of a civil engineering work requires many preliminary studies as well as various calculation methods to give an assessment or a forecast of the state of the rock in place and the behavior of the structure in its real environment and under various conditions (construction phase, service and operating phase). The present work concerns the access zone of the Dar-El-Oued tunnel, located on the national road n°43 about 40 km West of the city of Jijel (northeastern Algeria). The geotechnical study of this tunnel was carried out following the classification methods relating to underground structures. Through the results of this study we have determined the influence of land pressures on the mechanical behavior of the ground, which allowed us to measure the state of stress in the rock and to make a comparison between the results of the measurements of convergence and that of numerical modeling. On the other hand, the influence of the velocity of vibration induced by explosive shots has been discussed in order to check the stability of the face as the digging progresses. From the results obtained, it can be said that the surface displacements of the soil are relatively small compared to those determined by the numerical model at the level of the vault and the slab. Note the good agreement between the results provided by our numerical model and those obtained in-situ.

Measurement and Characteristics Analysis of In Situ Stress in Expanding Area of Tao’er Coal Mine

2011 ◽  
Vol 90-93 ◽  
pp. 1732-1735
Author(s):  
Hu Jun He ◽  
Li Hui Sun ◽  
Sheng Rui Su ◽  
Shu Gang Wang ◽  
Ben Sheng Yang
Keyword(s):  
Coal Mine ◽  
Tectonic Stress ◽  
In Situ Stress ◽  
Parameters Optimization ◽  
Test Results ◽  
Support Design ◽  
Characteristics Analysis ◽  
Roadway Support ◽  
The Stability

In order to fully understand and correctly evaluate the stability of overlying strata and surrounding rock, in-situ stress of south main roadway, north main roadway and bypass in shaft station of expanding area, Tao’er coal mine was tested by KX-81-style triaxial stress gauge of hollow inclusion. The test results show that tectonic stress is main in in-situ stress of expanding area, Tao’er coal mine, horizontal principal stress is westeast distribution, 31.13-27.42MPa size, 27.42°-275° direction. Each stress state is not identical, vertical stress is basically slightly less than the weight of the rock covering on unit area. Application of measuring principle of in-situ stress and analysis of field measurement provide a reliable basis for roadway support design and parameters optimization in expanding area of Tao’er coal mine, ensure safety and smooth construction of roadway.

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