scholarly journals Three-Dimensional Modeling of Spatial Reinforcement of Soil Nails in a Field Slope under Surcharge Loads

2013 ◽  
Vol 2013 ◽  
pp. 1-12
Author(s):  
Yuan-de Zhou ◽  
Kai Xu ◽  
Xinwei Tang ◽  
Leslie George Tham
Keyword(s):  
Field Test ◽  
Strong Dependence ◽  
Three Dimensional ◽  
Soil Nails ◽  
Spatial Reinforcement ◽  
Three Dimensional Modeling ◽  
Stability Of Slopes ◽  
Numerical Predictions ◽  
The Stability ◽  
Loose Fill

Soil nailing has been one of the most popular techniques for improving the stability of slopes, in which rows of nails and a structural grillage system connecting nail heads are commonly applied. In order to examine the spatial-reinforcement effect of soil nails in slopes, a three-dimensional (3D) numerical model has been developed and used to back-analyze a field test slope under surcharge loading. Incremental elastoplastic analyses have been performed to study the internal deformation within the slope and the development of nail forces during the application of top surcharge loads. Different treatments of the grillage constraints at nail heads have been studied. It is shown that the numerical predictions compare favorably with the field test measurements. Both the numerical and the field test results suggest that soil nails are capable of increasing the overall stability of a loose fill slope for the loading conditions considered in this study. The axial force mobilization in the two rows of soil nails presents a strong dependence on the relative distance with the central section. With the surcharge loads increased near the bearing capacity of the slope, a grillage system connecting all the nail heads can affect the stabilizing mechanism to a notable extent.

Three-dimensional seismic stability of slopes reinforced by soil nails

2020 ◽  
Vol 127 ◽  
pp. 103768 ◽  
Author(s):  
Tao Yang ◽  
Jin-Feng Zou ◽  
Qiu-Jing Pan
Keyword(s):  
Three Dimensional ◽  
Seismic Stability ◽  
Soil Nails ◽  
Stability Of Slopes

scholarly journals Autosomal Dominant Gyrate Atrophy-Like Choroidal Dystrophy Revisited: 45 Years Follow-Up and Association with a Novel C1QTNF5 Missense Variant

2021 ◽  
Vol 22 (4) ◽  
pp. 2089
Author(s):  
Ulrich Kellner ◽  
Nicole Weisschuh ◽  
Silke Weinitz ◽  
Ghazaleh Farmand ◽  
Sebastian Deutsch ◽  
...  
Keyword(s):  
Autosomal Dominant ◽  
Late Onset ◽  
Three Dimensional ◽  
Missense Variant ◽  
Clinical Aspects ◽  
Gyrate Atrophy ◽  
Three Dimensional Modeling ◽  
Long Term Follow Up ◽  
The Stability

We present a long-term follow-up in autosomal dominant gyrate atrophy-like choroidal dystrophy (adGALCD) and propose a possible genotype/phenotype correlation. Ophthalmic examination of six patients from two families revealed confluent areas of choroidal atrophy resembling gyrate atrophy, starting in the second decade of life. Progression continued centrally, reaching the fovea at about 60 years of age. Subretinal deposits, retinal pigmentation or choroidal neovascularization as seen in late-onset retinal degeneration (LORD) were not observed. Whole genome sequencing revealed a novel missense variant in the C1QTNF5 gene (p.(Q180E)) which was found in heterozygous state in all affected subjects. Haplotype analysis showed that this variant found in both families is identical by descent. Three-dimensional modeling of the possible supramolecular assemblies of C1QTNF5 revealed that the p.(Q180E) variant led to the destabilization of protein tertiary and quaternary structures, affecting both the stability of the single protomer and the entire globular head, thus exerting detrimental effects on the formation of C1QTNF5 trimeric globular domains and their interaction. In conclusion, we propose that the p.(Q180E) variant causes a specific phenotype, adGALCD, that differs in multiple clinical aspects from LORD. Disruption of optimal cell-adhesion mechanisms is expected when analyzing the effects of the point mutation at the protein level.

Stability Analysis for Slopes of Maerdang Hydropower Station with the Three-Dimensional Limit Equilibrium Method

2013 ◽  
Vol 275-277 ◽  
pp. 1427-1430
Author(s):  
Yi Sheng Huang ◽  
Jian Lin Li
Keyword(s):  
Stability Analysis ◽  
Limit Equilibrium ◽  
Three Dimensional ◽  
Limit Equilibrium Method ◽  
Hydropower Station ◽  
Stability Of Slopes ◽  
Equilibrium Method ◽  
The Face ◽  
The Stability ◽  
The Right

Firstly analyzed the stability of blocks with block theory and secondly evaluated the stability of blocks with three-dimensional limit equilibrium method and finally evaluated the whole stability of slopes. Stability analysis for the slope of Maerdang hydropower station shows that natural slopes which belong to the upstream of Hadehei ditch on the right bank will not occur wedge slide, tailrace slopes of hydropower station have not sliding slopes searched which are in potential slide, if taking some measures to reinforce the stability of man-made slopes on the face rock-fill hub, which may meet the demand of the specification.

The Motion Simulation and Analysis of Reinforced Flip Device Based on UG NX7.5

2012 ◽  
Vol 625 ◽  
pp. 155-158
Author(s):  
Jun Sun ◽  
Wei Zhu ◽  
Hai Lun Tang ◽  
Long Tian ◽  
Wei Liu
Keyword(s):  
Three Dimensional ◽  
Operating Parameters ◽  
Optimized Design ◽  
Motion Simulation ◽  
Working Process ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Cutting Machine ◽  
Modeling Software ◽  
The Stability

In this article, we research on the flip device of steel cutting machine, doing kinematics analysis to the discharging mechanism, calculating the operating parameters of the mechanism and optimizing the operating parameters of the flip device. With the using of three-dimensional modeling software UG NX7.5, reinforced flip device is precisely modeled, and all parts it concluded are assembled together, then whole mechanism kinematical simulation is carried out. The optimum flip angle of the unloading mechanism is obtained through the study of the Simulation results. By analyzing the displacements, velocity, acceleration and other data of unloading rack at any moment in the working process, the optimized design of discharging mechanism is given. Finally, the stability of discharging mechanism is analyzed.

On the stability of the decelerating laminar boundary layer

1984 ◽  
Vol 138 ◽  
pp. 297-323 ◽  
Author(s):  
Mohamed Gad-El-Hak ◽  
Stephen H. Davis ◽  
J. Thomas Mcmurray ◽  
Steven A. Orszag
Keyword(s):  
Boundary Layer ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Velocity Profiles ◽  
Hairpin Vortices ◽  
Boundary Layer Equations ◽  
Numerical Predictions ◽  
Layer Flow ◽  
Lift Off ◽  
The Stability

The stability of a decelerating boundary-layer flow is investigated experimentally and numerically. Experimentally, a flat plate having a Blasius boundary layer is decelerated in an 18 m towing tank. The boundary layer becomes unstable to two-dimensional waves, which break down into three-dimensional patterns, hairpin vortices, and finally turbulent bursts when the vortices lift off the wall. The unsteady boundary-layer equations are solved numerically to generate instantaneous velocity profiles for a range of boundary and initial conditions. A quasi-steady approximation is invoked and the stability of local velocity profiles is determined by solving the Orr–Sommerfeld equation using Chebyshev matrix methods. Comparisons are made between the numerical predictions and the experimentally observed instabilities.

A 3D slope stability analysis method assuming parallel lines of intersection and differential straining of block contacts

2002 ◽  
Vol 39 (4) ◽  
pp. 799-811 ◽  
Author(s):  
Muhsiung Chang
Keyword(s):  
Slope Stability ◽  
Factor Of Safety ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Three Dimensional ◽  
Shear Stresses ◽  
Block System ◽  
Stability Of Slopes ◽  
Sliding Mechanism ◽  
The Stability

A three-dimensional (3D) method of analysis of the stability of slopes was developed based on the sliding mechanism observed in the 1988 failure of the Kettleman Hills landfill slope (Kettleman City, California) and the associated model studies. By adopting a limit equilibrium concept, the method assumes the sliding mass as a block system in which the contacts between blocks are inclined. The lines of intersection of the block contacts are assumed to be parallel, which enables the sliding kinematics. In consideration of the differential straining between blocks, the shear stresses on the slip surface and the block contacts are evaluated based on the degree of shear strength mobilization on these contacts. The overall factor of safety is calculated based on the force equilibrium of the individual blocks and the entire block system as well. Based on comparisons with a series of hypothetical 3D and 2D problems with known solutions, the method was generally found to be accurate in predicting the stability of slopes involving a translational type of sliding failure. For rotational sliding failures in clays, however, the method appears to slightly overestimate the calculated factor of safety; up to as much as 10% in a typical problem examined in this study.Key words: slope stability, 3D method, limit equilibrium, block kinematics, strain incompatibility.

Three-Dimensional Modeling of Rate-Dependent Deformation in Shape Memory Alloys at High Temperatures

2009 ◽  
Author(s):  
Darren Hartl ◽  
George Chatzigeorgiou ◽  
Dimitris Lagoudas
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
High Temperatures ◽  
Evolution Equations ◽  
Strong Dependence ◽  
Three Dimensional ◽  
Rate Dependency ◽  
Three Dimensional Modeling ◽  
Rate Dependent ◽  
User Material Subroutine

Active structures composed of Shape Memory Alloys (SMAs) and High Temperature SMAs (HTSMAs) continue to be developed for applications that benefit from solid-state actuation. The need to account for the response of these materials under non-conventional loading paths that include elevated temperature conditions has become important. Conventional SMAs are exposed to such temperatures during processing, including final shape-setting. HTSMAs, by virtue of their title, are exposed to such high temperatures during transformation. This work addresses new developments in the constitutive modeling and numerical analysis pertaining to irrecoverable inelasticity in SMAs at high temperatures, where this behavior becomes rate-dependent. The description of such behavior requires the development of a theoretical framework able to capture the coupling between the rate-independent transformation and the rate-dependent creep. The proposed phase transformation-viscoplastic model is based on continuum thermodynamics; here the elastic relations, the inelastic evolution equations, and the transformation criteria are summarized. The evolution equation for the viscoplastic strain is non-homogeneous in time, and thus rate-dependency results. The viscoplastic parameters are generally assumed to exhibit a strong dependence on temperature. The rate-independent and rate-dependent constitutive equations that comprise the full 3-D model are numerically integrated using a scheme that accounts for both transformation and viscoplastic deformation in a coupled manner. The implementation allows for 3-D analysis of SMA bodies using an FEA framework that includes Abaqus and an associated user material subroutine. Example analyses are discussed, including shape-setting in a conventional SMA and experimentally validated structural analysis of an HTSMA specimen.

Evaluation of Pile Application for Slopes on Bedrock Stability

2015 ◽  
Vol 744-746 ◽  
pp. 479-484
Author(s):  
Mudthir Bakri ◽  
Yuan You Xia ◽  
Chun Shu Chen ◽  
Hua Bin Wang
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Numerical Study ◽  
Soil Layer ◽  
Three Dimensional ◽  
Single Pile ◽  
Stability Of Slopes ◽  
Maximum Value ◽  
The Stability ◽  
Sliding Soil

This paper presents a numerical study that performs the stability of slopes on bedrock reinforced with single pile row at different locations. The slope is formed of top sliding soil layer that underlies over rock. The numerical analysis has been implemented by employing the three dimensional analysis using FLAC3D. The results indicate that as the pile location is moved towards the slope crest the displacement increases.In the single row of pile application, the factor of safety reached its maximum value when the pile located at the top middle of the slope. Considering the failure mode the results has conclude three failure modes; above, in front, and through the pile according to the location of the pile. Failure mode is also affected by socketed length of pile in bedrock layer. It is believed that the findings of this study contribute to the engineers performing slope stability analysis in practice.

A Liquid Metal Flow Between Two Coaxial Cylinders System

2019 ◽  
Vol 11 (1) ◽  
pp. 79-86
Author(s):  
Abdelkrim Merah ◽  
Ridha Kelaiaia ◽  
Faiza Mokhtari
Keyword(s):  
Couette Flow ◽  
Metal Flow ◽  
Three Dimensional ◽  
Liquid Sodium ◽  
Taylor Vortex ◽  
Turbulent Regime ◽  
Coaxial Cylinders ◽  
Concentric Cylinders ◽  
Ideal Tool ◽  
The Stability

Abstract The Taylor-Couette flow between two rotating coaxial cylinders remains an ideal tool for understanding the mechanism of the transition from laminar to turbulent regime in rotating flow for the scientific community. We present for different Taylor numbers a set of three-dimensional numerical investigations of the stability and transition from Couette flow to Taylor vortex regime of a viscous incompressible fluid (liquid sodium) between two concentric cylinders with the inner one rotating and the outer one at rest. We seek the onset of the first instability and we compare the obtained results for different velocity rates. We calculate the corresponding Taylor number in order to show its effect on flow patterns and pressure field.

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