scholarly journals Study on the Influence of Sponge Road Bioretention Facility on the Stability of Subgrade Slope

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3466
Author(s):  
Wensheng Tang ◽  
Haiyuan Ma ◽  
Xinyue Wang ◽  
Zhiyu Shao ◽  
Qiang He ◽  
...  
Keyword(s):  
Large Scale ◽  
Water Pressure ◽  
Three Dimensional ◽  
Road Construction ◽  
Element Model ◽  
Factors Affecting ◽  
Runoff Pollution Control ◽  
The Stability ◽  
Three Dimensional Finite Element ◽  
Geotechnical Tests

With the large-scale application of sponge city facilities, the bioretention facility in urban roads will be one of the key factors affecting the safety of construction facilities in areas with abundant rainfall. In this study, by establishing a three-dimensional finite element model for numerical analysis and combining it with geotechnical tests, the effects of bioretention facility on water pressure distribution, seepage path, and slope stability under rainwater seepage conditions are proposed. In addition, this study puts forward the relationship between the parameters of the bioretention facility and the stability of the slope in combination with the effect of runoff pollution control, which provides direction and basis for the planning, design, and construction of sponge cities in road construction.

Study on the critical loosening condition toward a new design guideline for bolted joints

2018 ◽  
Vol 233 (9) ◽  
pp. 3302-3316 ◽  
Author(s):  
Hao Gong ◽  
Jianhua Liu ◽  
Xiaoyu Ding
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Simulation Method ◽  
Bolted Joints ◽  
Design Guideline ◽  
Factors Affecting ◽  
Dimensional Finite Element ◽  
Frictional Coefficients ◽  
Three Dimensional Finite Element ◽  
Fit Tolerance

An understanding of conditions that trigger the loosening of bolted joints is essential to ensure joint reliability. In this study, a three-dimensional finite element model of a typical bolted joint is developed, and a new simulation method is proposed to quantitatively identify the critical transverse force for initiating loosening. This force is used to evaluate the anti-loosening capacity of bolted joints. Using the proposed simulation method, the effects of factors affecting critical loosening are systematically studied. It is found that the preload, frictional coefficients at the thread and the bearing surfaces, clamped length, and fit tolerance mainly affected loosening. When the preload and friction coefficients are increased, and the clamped length and fit tolerance are reduced, loosening is inhibited. Experiments are performed to demonstrate the reliability of the results. Finally, a suggestion is proposed to improve the design guideline VDI 2230 for bolted joints, which considers the requirement of avoiding loosening under vibrational loading.

Numerical Study of Welding Sequence on the Residual Stress Field in a Thick-Walled Tee Joint

2011 ◽  
Vol 219-220 ◽  
pp. 1211-1214
Author(s):  
Wei Jiang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Numerical Study ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Field ◽  
Factors Affecting ◽  
Welding Sequence ◽  
Welding Sequences ◽  
Three Dimensional Finite Element

Finite element simulation is an efficient method for studying factors affecting weld-induced residual stress distributions. In this paper, a validated three-dimensional finite element model consisting of sequentially coupled thermal and structural analyses was developed. Three possible symmetrical welding sequences, i.e. one-welder, two-welder and four-welder sequence, which were perceived to generate the least distortion in actual welding circumstances, were proposed and their influences on the residual stress fields in a thick-walled tee joint were investigated. Appropriate conclusions and recommendations regarding welding sequences are presented.

Three-Dimensional Seismic Analysis on Reactor Structure

2010 ◽  
Author(s):  
Naibin Jiang ◽  
Feng-gang Zang ◽  
Li-min Zhang ◽  
Chuan-yong Zhang
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Element Model ◽  
Earthquake Excitation ◽  
Finite Element Software ◽  
Reactor Structure ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The seismic analysis on reactor structure was performed with a new generation of finite element software. The amount of freedom degree of the model was more than twenty millions. The typical responses to operational basis earthquake excitation were given. They are larger than those with two-dimensional simplified finite element method, and the reasons of this phenomenon were analyzed. The feasibility of seismic analysis on large-scale three-dimensional finite element model under existing hardware condition was demonstrated, so some technological reserves for dynamic analysis on complicated equipments or systems in nuclear engineering are provided.

scholarly journals Three-Dimensional Response of the Supported-Deep Excavation System: Case Study of a Large Scale Underground Metro Station

Geosciences ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 76
Author(s):  
Ashraf Hefny ◽  
Mohamed Ezzat Al-Atroush ◽  
Mai Abualkhair ◽  
Mariam Juma Alnuaimi
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Two Dimensional ◽  
Deep Excavation ◽  
Metro Station ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The complexities and the economic computational infeasibility associated in some cases, with three-dimensional finite element models, has imposed a motive for many investigators to accept numerical modeling simplification solutions such as assuming two-dimensional (2D) plane strain conditions in simulation of several supported-deep excavation problems, especially for cases with a relatively high aspect ratio in plan dimensions. In this research, a two-dimensional finite element model was established to simulate the behavior of the supporting system of a large-scale deep excavation utilized in the construction of an underground metro station Rod El Farrag project (Egypt). The essential geotechnical engineering properties of soil layers were calculated using results of in-situ and laboratory tests and empirical correlations with SPT-N values. On the other hand, a three-dimensional finite element model was established with the same parameters adopted in the two-dimensional model. Sufficient sensitivity numerical analyses were performed to make the three-dimensional finite element model economically feasible. Results of the two-dimensional model were compared with those obtained from the field measurements and the three-dimensional numerical model. The comparison results showed that 3D high stiffening at the primary walls’ corners and also at the locations of cross walls has a significant effect on both the lateral wall deformations and the neighboring soil vertical settlement.

Investigation on Slider Structure Deformation and Crowning System of Large-Scale Press Brake

2011 ◽  
Vol 201-203 ◽  
pp. 1500-1503
Author(s):  
Heng Li ◽  
Quan Kun Liu ◽  
Ling Yun Qian ◽  
Yu Han
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Three Dimensional ◽  
Small Deformation ◽  
Element Model ◽  
Numerical Control ◽  
Large Size ◽  
The Press ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Improving the straightness accuracy of bending workpieces becomes an urgent problem for the development of bending equipment with large size and high precision. In order to obtain the characteristics of slider deformation, a three-dimensional finite element model was developed according to the mechanic characteristics of large-scale press brake and obtained the small deformation using FEM (finite element method). The numerical results are in good agreement with the experimentation. Then based on the simulation results we design a large-scale mechanical crowning system through which the press brake could be automatically compensated in the bend direction by means of a CNC (Computer Numerical Control)-powered motor and could also be compensated for local parts by adjusting the side screw nuts manually. The system has been successfully applied in production and its accuracy was increased 33% compared with the traditional ones. It is proved that the present investigation can provide a technical support and reliable system for the improvement of accuracy of the press brakes.

scholarly journals Three-dimensional modelling of the dynamics of Johnsons Glacier, Livingston Island, Antarctica

2004 ◽  
Vol 39 ◽  
pp. 1-8 ◽  
Author(s):  
Carlos Martín ◽  
Francisco Navarro ◽  
Jaime Otero ◽  
María L. Cuadrado ◽  
María I. Corcuera
Keyword(s):  
Water Pressure ◽  
Three Dimensional ◽  
Element Model ◽  
Glacier System ◽  
Ice Surface ◽  
Glacier Terminus ◽  
Livingston Island ◽  
Dimensional Finite Element ◽  
Order Of Magnitude ◽  
Three Dimensional Finite Element

AbstractA new three-dimensional finite-element model of the steady-state dynamics of temperate glaciers has been developed and applied to Johnsons Glacier, Livingston Island, Antarctica, with the aim of determining the velocity and stress fields for the present glacier configuration. It solves the full Stokes system of differential equations without recourse to simplifications such as those involved in the shallow-ice approximation. Rather high values of the stiffness parameter B (∼0.19–0.23MPaa1/3) are needed to match the observed ice surface velocities, although these results do not differ much from those found by other authors for temperate glaciers. Best-fit values of the coefficient k in the sliding law (*2.2–2.7 x 103m a–1MPa–2) are also of the same order of magnitude as those found by other authors. The results for velocities are satisfactory, though locally there exist significant discrepancies between computed and observed ice surface velocities, particularly for the vertical ones. This could be due to failures in the sliding law (in particular, the lack of information on water pressure), the use of an artificial down-edge boundary condition and the fact that bed deformation is not considered. For the whole glacier system, the driving stress is largely balanced by the basal drag (80% of the driving stress). Longitudinal stress gradients are only important in the divide areas and near the glacier terminus, while lateral drag is only important at both sides of the terminal zone.

Closure of a Nuclear Waste Repository Deeply Imbedded in a Stratified Salt Bed

1994 ◽  
Vol 116 (4) ◽  
pp. 567-573 ◽  
Author(s):  
Wei Xu ◽  
Joseph Genin
Keyword(s):  
Triaxial Compression ◽  
Three Dimensional ◽  
Element Model ◽  
Nuclear Waste Repository ◽  
Relaxation Functions ◽  
Dimensional Finite Element ◽  
Set Up ◽  
The Stability ◽  
Three Dimensional Finite Element

The Waste Isolation Pilot Plant (WIPP) is a repository vault, mined deep into a salt strata. It eventually closes in on itself, encapsulating its contents. At room temperature salt may be regarded as a linear, isotropic, viscoelastic material. In this study, using triaxial compression test results on salt, we determine the relaxation functions and set up the boundary value problem for the encapsulation mechanism of a salt vault. Closure of the repository as a function of time is determined using a three-dimensional finite element model. The Tresca failure criterion is used to predict the stability of the repository. Finally, the study is validated by comparing our results to in-situ measured data.

The Research on the Influence of the Forms of Foundation on the Behavior of Adjacent Excavation Based on Building Materials

2013 ◽  
Vol 788 ◽  
pp. 606-610
Author(s):  
Qing Xiang Ji ◽  
Xin Sheng Ge
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Building Materials ◽  
Three Dimensional ◽  
Element Model ◽  
Deep Excavation ◽  
Foundation Pit ◽  
Finite Element Software ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Foundation pit excavation could be affected to some extent by surrounding different kinds of building materials, building structure, foundation form and load distribution, especially in intensive buildings. In this paper, based on the large-scale finite element software ANSYS, a three-dimensional finite element model is established to analyze the consequences of these complex and uncertain factors faced with by deep excavation projects and the conclusions of the excavation affected by different foundations form of adjacent buildings are arrived at.

Buckling Analysis of Pile during Hammer Placement

2012 ◽  
Vol 256-259 ◽  
pp. 467-470
Author(s):  
Shao Zeng Guo ◽  
Run Liu
Keyword(s):  
Finite Element ◽  
Geometric Nonlinearity ◽  
Large Diameter ◽  
Three Dimensional ◽  
Element Model ◽  
Offshore Engineering ◽  
Dimensional Finite Element ◽  
The Stability ◽  
Three Dimensional Finite Element

Large diameter and thin thickness are the main characteristics of the steel pipe piles in offshore engineering. Before piling a pile, heavy hammer will be placed on the top of it, which may emerge a serious risk in pile buckling. A three dimensional finite element model of pile and soil was established for a case study. The modified Riks method which can automatically search a suitable increment factor of loads is adopted to assess the stability of the pile, and the geometric nonlinearity and pile-soil interaction were both considered. The practical example shows that the critical load considering pile-soil interaction is much smaller than that in a fixed constraint.

3D Numerical Simulation and Experimental Analysis of Spillway Tunnel

2015 ◽  
Vol 723 ◽  
pp. 171-175
Author(s):  
Hai Yan Huang ◽  
Ai Min Gong ◽  
Yong Qiu ◽  
Zen An Wangliang
Keyword(s):  
Numerical Simulation ◽  
Water Pressure ◽  
Three Dimensional ◽  
Element Model ◽  
Test Method ◽  
Jet Trajectory ◽  
Dimensional Finite Element ◽  
Velocity Changes ◽  
Spillway Tunnel ◽  
Three Dimensional Finite Element

A three-dimensional finite element model and an experimental model of a reservoir spillway tunnel are used to analyze the flow velocity changes. The basic numerical simulation theory and the experimental theory and method are firstly introduced. The water characteristic is obtained such as velocity, water surface curve, jet trajectory length, water pressure, etc. The water jet is Z shaped. The velocity, pressure and water flow of the whole spillway are gotten in Ansys software. The velocity measured in the test and the data computed with software are compared. The experimental results are agreement with the numerical results. The analysis and experimental progress and results show that the numerical model and the test method are feasible and well-suited for using in actual design problems.

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