Yield Design of the Reinforced Embankment

2011 ◽  
Vol 368-373 ◽  
pp. 2804-2807
Author(s):  
Bing Zhang ◽  
Xiao Mou Wang
Keyword(s):  
Upper Bound ◽  
Design Approach ◽  
Stability Factor ◽  
Multiphase Model ◽  
Construction Process ◽  
Backfill Soil ◽  
Geotechnical Structures ◽  
The Stability ◽  
Kinematic Approach

A frequently used technique for improving the performance of geotechnical structures consists in incorporating into the backfill soil, during the construction process, regularly spaced thin reinforcing inclusions, called geotextile, geomembranes or geogrids. The stability of embankment, stabilized by reinforcing membranes, is investigated by means of a multiphase model developed in the framework of the yield design approach. By means of the kinematic approach, leading to upper bound estimates for the stability factor of the structure.

Stability of Slopes in Anisotropic, Nonhomogeneous Soils

1975 ◽  
Vol 12 (1) ◽  
pp. 146-152 ◽  
Author(s):  
W. F. Chen ◽  
N. Snitbhan ◽  
H. Y. Fang
Keyword(s):  
Upper Bound ◽  
Limit Analysis ◽  
Limit Equilibrium ◽  
Equilibrium Analysis ◽  
Stability Factor ◽  
Failure Plane ◽  
Limit Equilibrium Analysis ◽  
Stability Of Slopes ◽  
Upper Bound Technique ◽  
The Stability

The upper bound technique of limit analysis has been found to be very successful in analyzing the stability of cuttings in normally consolidated clays. However, most soils in their natural states exhibit some anisotropy with respect to shear strength, and some nonhomogeneity with respect to depth. It is difficult to obtain the solution based on the classical limit equilibrium analysis with the assumed noncircular failure plane with such soil properties included. This paper establishes an expression for the stability factor Ns, based on the upper bound technique of limit analysis which yields a close-formed solution for sections in which the following conditions are considered: (a) log-spiral failure-plane, through and below toe; (b) non-homogeneity; (c) anisotropy; and (d) general slope.

Determining the Norton’s Equivalent Model of Distribution System with Distributed Generation (DG) for Stability Analysis

2019 ◽  
Vol 12 (2) ◽  
pp. 190-198
Author(s):  
Sunny Katyara ◽  
Lukasz Staszewski ◽  
Faheem Akhtar Chachar
Keyword(s):  
Distributed Generation ◽  
Normal Condition ◽  
Distribution System ◽  
Distribution Networks ◽  
Equivalent Model ◽  
Stability Factor ◽  
Matlab Simulation ◽  
The Stability ◽  
Stability Issues

Background: Since the distribution networks are passive until Distributed Generation (DG) is not being installed into them, the stability issues occur in the distribution system after the integration of DG. Methods: In order to assure the simplicity during the calculations, many approximations have been proposed for finding the system’s parameters i.e. Voltage, active and reactive powers and load angle, more efficiently and accurately. This research presents an algorithm for finding the Norton’s equivalent model of distribution system with DG, considering from receiving end. Norton’s model of distribution system can be determined either from its complete configuration or through an algorithm using system’s voltage and current profiles. The algorithm involves the determination of derivative of apparent power against the current (dS/dIL) of the system. Results: This work also verifies the accuracy of proposed algorithm according to the relative variations in the phase angle of system’s impedance. This research also considers the varying states of distribution system due to switching in and out of DG and therefore Norton’s model needs to be updated accordingly. Conclusion: The efficacy of the proposed algorithm is verified through MATLAB simulation results under two scenarios, (i) normal condition and (ii) faulty condition. During normal condition, the stability factor near to 1 and change in dS/dIL was near to 0 while during fault condition, the stability factor was higher than 1 and the value of dS/dIL was away from 0.

scholarly journals Reliability Estimation of Reinforced Slopes to Prioritize Maintenance Actions

2021 ◽  
Vol 18 (2) ◽  
pp. 373
Author(s):  
Farshad BahooToroody ◽  
Saeed Khalaj ◽  
Leonardo Leoni ◽  
Filippo De Carlo ◽  
Gianpaolo Di Bona ◽  
...  
Keyword(s):  
Urban Areas ◽  
Evaluation Method ◽  
Likelihood Function ◽  
Reliability Estimation ◽  
Analytical Models ◽  
Geotechnical Structures ◽  
Reinforced Slopes ◽  
The Stability ◽  
Methods Analytical ◽  
Asset Managers

Geosynthetics are extensively utilized to improve the stability of geotechnical structures and slopes in urban areas. Among all existing geosynthetics, geotextiles are widely used to reinforce unstable slopes due to their capabilities in facilitating reinforcement and drainage. To reduce settlement and increase the bearing capacity and slope stability, the classical use of geotextiles in embankments has been suggested. However, several catastrophic events have been reported, including failures in slopes in the absence of geotextiles. Many researchers have studied the stability of geotextile-reinforced slopes (GRSs) by employing different methods (analytical models, numerical simulation, etc.). The presence of source-to-source uncertainty in the gathered data increases the complexity of evaluating the failure risk in GRSs since the uncertainty varies among them. Consequently, developing a sound methodology is necessary to alleviate the risk complexity. Our study sought to develop an advanced risk-based maintenance (RBM) methodology for prioritizing maintenance operations by addressing fluctuations that accompany event data. For this purpose, a hierarchical Bayesian approach (HBA) was applied to estimate the failure probabilities of GRSs. Using Markov chain Monte Carlo simulations of likelihood function and prior distribution, the HBA can incorporate the aforementioned uncertainties. The proposed method can be exploited by urban designers, asset managers, and policymakers to predict the mean time to failures, thus directly avoiding unnecessary maintenance and safety consequences. To demonstrate the application of the proposed methodology, the performance of nine reinforced slopes was considered. The results indicate that the average failure probability of the system in an hour is 2.8×10−5 during its lifespan, which shows that the proposed evaluation method is more realistic than the traditional methods.

Accuracy contours in (nT, λ) space in electrochemical digital simulations

1991 ◽  
Vol 56 (1) ◽  
pp. 20-41 ◽  
Author(s):  
Dieter Britz ◽  
Merete F. Nielsen
Keyword(s):  
Finite Difference ◽  
Linear Sweep Voltammetry ◽  
Stability Factor ◽  
Dimensionless Time ◽  
Simulation Techniques ◽  
Rational Algorithm ◽  
The Stability ◽  
Transport Problems ◽  
Current Approximation ◽  
Digital Simulations

In finite difference simulations of electrochemical transport problems, it is usually tacitly assumed that λ, the stability factor Dδt/δx2, should be set as high as possible. Here, accuracy contours are shown in (nT, λ) space, where nT is he number of finite difference steps per unit (dimensionless) time. Examples are the Cottrell experiment, simple chronopotentiometry and linear sweep voltammetry (LSV) on a reversible system. The simulation techniques examined include the standard explicit (point- and box-) methods as well as Runge-Kutta, Crank-Nicolson, hopscotch and Saul’yev. For the box method, the two-point current approximation appears to be the most appropriate. A rational algorithm for boundary concentrations with explicit LSV simulations is discussed. In general, the practice of choosing as high a λ value when using the explicit techniques, is confirmed; there are practical limits in all cases.

scholarly journals Spectrophotometric indicators of the stability of anthocyanin-containing extracts depending on the color of plant materials

2020 ◽  
Vol 31 (2) ◽  
pp. 88-92
Author(s):  
Vladimir Mikhailovich Koldaev ◽  
Artem Yurevich Manyakhin ◽  
Petr Semenovich Zorikov
Keyword(s):  
Hydrochloric Acid ◽  
Stability Factor ◽  
Plant Materials ◽  
Herbal Preparations ◽  
Violet Color ◽  
The Stability ◽  
Selection Of ◽  
Factor Coefficient ◽  
Anthocyanin Degradation

AbstractThis paper aims at spectrophotometric determination of changes in stability of extractable anthocyanins during drying of plant materials depending on their color. Raw and dried colored parts of 50 plant species from 25 families were used for the study. The extracts were prepared over 95% ethanol acidified with hydrochloric acid (pH ~ 1). The absorption spectra were registered within the range of 210 to 680 nm. The extinction variability factor, coefficient of intensity absorption relative and generalized stability factor were used to determine the anthocyanin degradation. The highest values of the stability factor were obtained for the extracts from fruit shells of burgundy or violet color within the range of 0.934±0.024 to 0.973±0.024, while the extracts from flower petals of the same care featured the stability factor that was 1.19 to 1.44 times less. The values of the stability factor of the extracts from black, red and blue materials are 1.15 to 1.19 times, 1.74 to 2.48 times and 4.65 to 4.84 times less respectively than those of the extracts from violet-burgundy materials. It is appropriate to apply the spectrophotometric factors of anthocyanins stability used in this study to selection of promising plants for industrial cultivation as material of anthocyanin-containing herbal preparations. The most stable anthocyanins are those of burgundy-purple and black fruits.

scholarly journals Qualifications for teachers and teachers of gifted students in Jeddah

2018 ◽  
Vol 2 (4) ◽  
Author(s):  
Ibtisam Rashad Abdullah Hameedah
Keyword(s):  
Random Sample ◽  
Gifted Students ◽  
Point Of View ◽  
Average Score ◽  
Stability Factor ◽  
Years Of Experience ◽  
Jeddah City ◽  
Study Population ◽  
Descriptive Approach ◽  
The Stability

This study aimed to identify the qualitative competencies of teachers and teachers of gifted students in Jeddah from their point of view and to indicate the extent of these competencies according to the variables of the study: gender, scientific qualification and years of experience. We have used the descriptive approach, as a questionnaire was developed to collect data, verified its validity and stability in the appropriate educational and statistical methods, and the value of the stability factor, Kronbach Alpha, (0.75). The study population is composed of all teachers and teachers of the gifted students in the schools of Jeddah city (70) teachers and teachers, a random sample was selected (40%). The results of the study showed that the qualitative competencies of teachers and teachers of gifted students came in a medium and an average score of (3.31) according to the Likert quintile scale. The results also showed that there were statistically significant differences between the estimations of the sample of the study of the qualitative competencies of teachers and gifted students in Jeddah For the sex variable, and the absence of differences attributed to the variable of scientific qualification, and years of experience.

scholarly journals Analysis of suspension bridge tunnel-type anchorage construction on the stability of surrounding rock

2020 ◽  
Vol 198 ◽  
pp. 02006
Author(s):  
Nana Li ◽  
Yongqiang Zhou ◽  
Yanqiang Zhao ◽  
Guiju Li
Keyword(s):  
Suspension Bridge ◽  
Surrounding Rock ◽  
Construction Process ◽  
Analysis Model ◽  
Stability Of Surrounding Rock ◽  
Numerical Software ◽  
Left And Right ◽  
Simulation Results ◽  
The Stability ◽  
The Right

In order to study the interaction between the left and right tunnels of suspension bridge tunnel-type anchorage, the finite difference numerical software is used to analyze the mechanical properties of the surrounding rock during the construction process. A numerical analysis model based on FLAC3D is established to analyze the stress, displacement and plastic zone changes of the surrounding rock of right tunnel anchor cavern during the construction of left tunnel anchor cavern. The right tunnel anchor cavern is excavated firstly, and then the left tunnel anchor cavern is excavated. The numerical simulation results show that the main displacement of the right tunnel occurs in the construction stage of the anchor plug body and the rear anchor cavern of the left tunnel. During the excavation of the left tunnel, the plastic zones of the left and right tunnel anchor caverns are only connected above the middle of the waist wall. Therefore, it is suggested that during the construction process, especially in the excavation stage of the anchor plug body and the rear anchor cavern, the area above the middle of the tunnel waist wall should be strengthened in time to ensure the construction safety.

Research on the Construction Technology of High Brick Chimney

2011 ◽  
Vol 255-260 ◽  
pp. 65-69
Author(s):  
Hua Feng Deng ◽  
Min Zhu ◽  
Jing Guo ◽  
Tao Lu
Keyword(s):  
Detailed Calculation ◽  
Construction Technology ◽  
Structural Members ◽  
Construction Process ◽  
Horizontal Cross Section ◽  
Transport Equipment ◽  
Work Surface ◽  
The Stability ◽  
Calculation Analysis ◽  
Technical Measures

Chimney is the building which is high but the horizontal cross section is small, so the high altitude work surface is small and difficult to construct, in which the stability of the scaffold and the safety of vertical transport equipment are especially important. For the serious problems arising in the prophase construction of the 50m chimney, double rows steel pipe scaffold was designed outside the chimney, and the vertical transportation uses the external grillage hoisting frame. Reformed the internal existing scaffold into pedestrian passage to separate people and material, and a detailed calculation analysis of the structural members such as scaffold, grillage hoisting frame and other structures was carried out. Large deformation, destabilization and other safety problems of the scaffold, grillage hoisting frame and other structures were not arising during the anaphase construction process, which indicates that the construction technical measures and calculation and analysis results are with important guiding significance to guarantee the smooth of the construction, and also can be referenced by other similar projects.

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