The mechanism of coal fatigue failure and its numerical analysis under pulsating water pressure

2014 ◽  
pp. 897-901
Author(s):  
Hongqing Zhu ◽  
Minbo Zhang ◽  
Jian Shen ◽  
Bolong Lei ◽  
Guowei Jia
Keyword(s):  
Numerical Analysis ◽  
Fatigue Failure ◽  
Water Pressure

scholarly journals Analysis of Pore Water Pressure and Piping of Hydraulic Well

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 502
Author(s):  
Jinman Kim ◽  
Heuisoo Han ◽  
Yoonhwa Jin
Keyword(s):  
Numerical Analysis ◽  
Water Level ◽  
Pore Water ◽  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Hydraulic Gradient ◽  
Water Levels ◽  
Seepage Velocity ◽  
Seepage Analysis

This paper shows the results of a field appliance study of the hydraulic well method to prevent embankment piping, which is proposed by the Japanese Matsuyama River National Highway Office. The large-scale embankment experiment and seepage analysis were conducted to examine the hydraulic well. The experimental procedure is focused on the pore water pressure. The water levels of the hydraulic well were compared with pore water pressure data, which were used to look over the seepage variations. Two different types of large-scale experiments were conducted according to the installation points of hydraulic wells. The seepage velocity results by the experiment were almost similar to those of the analyses. Further, the pore water pressure oriented from the water level variations in the hydraulic well showed similar patterns between the experiment and numerical analysis; however, deeper from the surface, the larger pore water pressure of the numerical analysis was calculated compared to the experimental values. In addition, the piping effect according to the water level and location of the hydraulic well was quantitatively examined for an embankment having a piping guide part. As a result of applying the hydraulic well to the point where piping occurred, the hydraulic well with a 1.0 m water level reduced the seepage velocity by up to 86%. This is because the difference in the water level between the riverside and the protected side is reduced, and it resulted in reducing the seepage pressure. As a result of the theoretical and numerical hydraulic gradient analysis according to the change in the water level of the hydraulic well, the hydraulic gradient decreased linearly according to the water level of the hydraulic well. From the results according to the location of the hydraulic well, installation of it at the point where piping occurred was found to be the most effective. A hydraulic well is a good device for preventing the piping of an embankment if it is installed at the piping point and the proper water level of the hydraulic well is applied.

Numerical Analysis on Fatigue Failure of Sleeve in Oil-Film Bearing

2006 ◽  
pp. 323-326
Author(s):  
Jian Mei Wang ◽  
Qing Xue Huang ◽  
Chun Jiang Zhao ◽  
Li Feng Ma
Keyword(s):  
Numerical Analysis ◽  
Fatigue Failure ◽  
Oil Film

scholarly journals Elastic-Plastic Numerical Analysis of Tunnel Stability Based on the Closest Point Projection Method Considering the Effect of Water Pressure

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Zhan-ping Song ◽  
Ten-tian Yang ◽  
An-nan Jiang
Keyword(s):  
Rock Mass ◽  
Numerical Analysis ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Surrounding Rock ◽  
Tunnel Stability ◽  
Elastic Plastic ◽  
Closest Point Projection ◽  
Point Projection

To study the tunnel stability at various static water pressures and determine the mechanical properties and deformation behavior of surrounding rock, a modified effective stress formula was introduced into a numerical integration algorithm of elastic-plastic constitutive equation, that is, closest point projection method (CPPM). Taking the effects of water pressure and seepage into account, a CPPM-based formula was derived and a CPPM algorithm based on Drucker-Prager yield criterion considering the effect of pore water pressure was provided. On this basis, a CPPM-based elastic-plastic numerical analysis program considering pore water pressure was developed, which can be applied in the engineering of tunnels and other underground structures. The algorithm can accurately take the effects of groundwater on stability of surrounding rock mass into account and it can show the more pronounced effect of pore water pressure on stress, deformation, and the plastic zone in a tunnel. The stability of water flooding in Fusong tunnel was systematically analyzed using the developed program. The analysis results showed that the existence of groundwater seepage under tunnel construction will give rise to stress redistribution in the surrounding rock mass. Pore water pressure has a significant effect on the surrounding rock mass.

FEA of the Influence of Assembly Parameters on the Fatigue Life of Metal-Composite Bolted Joints

2012 ◽  
Vol 713 ◽  
pp. 73-78 ◽  
Author(s):  
I. Álvarez ◽  
F.J. Doblas ◽  
C. Vallellano ◽  
A. Portal ◽  
P.J. Arroyo
Keyword(s):  
Fatigue Life ◽  
Numerical Analysis ◽  
Fatigue Failure ◽  
Fatigue Resistance ◽  
Composite Laminate ◽  
Bolted Joints ◽  
Metal Composite ◽  
Critical Areas ◽  
Hybrid Joints ◽  
Al 2024

This paper presents a numerical analysis of the influence on the fatigue life of hybrid metal/CFRP bolted joints of some deviations in certain assembly parameters. Two types of hybrid joints typically used in aircraft are analyzed, the Ti-6Al-4V/CFRP and the Al-2024-T3/CFRP, riveted with blind bolts. The parameters analyzed are: the thickness of sealant between metal sheet and composite laminate, the angle of countersunk and the adjustment or chamfer at the countersunk-drill zone. The analysis highlights critical areas for fatigue failure and the relative influence of these parameters on the fatigue resistance of the joint.

Numerical Analysis on the Excess Pore Water Pressure of Pipe-Pile with Hole during the Static-Sinking Pile

2015 ◽  
Vol 744-746 ◽  
pp. 540-546
Author(s):  
Ke Lin Chen ◽  
Jin Bo Lei ◽  
Zhi Liu
Keyword(s):  
Numerical Analysis ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Effective Radius ◽  
Excess Pore Water Pressure ◽  
Pipe Pile ◽  
Time Space ◽  
Theory Research ◽  
Excess Pore

The time-space change rules of the environmental effects of the analysis of excess pore water pressure dissipation have also been studied during the static sinking-pile of the pipe-pile with hole. The results show: The excess pore water pressure will be dissipated with the time extending during the static sinking-pile of the 3 kinds of pipe-pole with hole. On the condition of the same effective radius, the depth of the observation dot is bigger, the excess pore water pressure will be bigger. On the contrast to the pipe-pole without hole, to some extent, the pipe-pole with hole can reduce the maximum of excess pore water pressure, and expedite the excess pore water pressure dissipation. This results can be provided the credible base for the theory research on the pipe-pole with hole and its application.

The Numerical Analysis and Field Measurements of the Shield Tunnel Passing through the Pipeline Groups

2012 ◽  
Vol 226-228 ◽  
pp. 1488-1494
Author(s):  
Guan Shui Liu ◽  
Lian Wei Sun ◽  
Bo Wang ◽  
Shi Ming Wu ◽  
Cheng Po Hong ◽  
...  
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Numerical Model ◽  
Water Pressure ◽  
Large Diameter ◽  
Field Measurements ◽  
Numerical Results ◽  
Shield Tunnel ◽  
Sewer Pipes

In this work, research was carried out based on the shield tunnel of metro line 1 in Hangzhou. The construction of this tunnel beneath the sewage pipelines, which have large diameter with water pressure. The project studied in this treatise is relatively rare in China in terms of sewer pipes, the number of sewers, spacing between shield and sewers and the crossing times. A numerical model was established to analyze the construction of metro across the sewage pipelines with water pressure, taking the interactions between tunnel, pipelines and soil into account. The stress of pipelines, settlement of pipelines and ground during the crossing process were calculated. The finite element results were compared with measured results to verify the reliability of numerical results. Some meaningful results were achieved.

Numerical analysis and monitoring of Pappadai dam

2005 ◽  
Vol 42 (6) ◽  
pp. 1631-1643 ◽  
Author(s):  
Piernicola Lollino ◽  
Federica Cotecchia ◽  
Lidija Zdravkovic ◽  
David M Potts
Keyword(s):  
Numerical Analysis ◽  
Soil Structure ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Constitutive Models ◽  
Foundation Soil ◽  
Reservoir Impoundment ◽  
Stiff Clay ◽  
Pressure Changes ◽  
Deformation Patterns

This paper presents a case history for the construction of the Pappadai dam in Italy. The dam is constructed from rockfill, with an upstream bituminous membrane, and is built on stiff clay foundations. The instrumentation of the dam and of the foundation soil provides detailed insight into the deformation patterns and pore-water pressure changes during dam construction and for the subsequent 7 years. Two-dimensional plane-strain finite element analyses, using fairly simple constitutive models for soil and rockfill behaviour, were performed to reproduce the soil–structure interaction so that the effects of reservoir impoundment, which has yet to be carried out, could be investigated. The paper shows that a careful choice of parameters and an understanding of the mechanical behaviour of the in situ soils can result in satisfactory predictions of the overall soil–structure interaction.Key words: rockfill, stiff clay, dam, field data, numerical analysis.

scholarly journals An Investigation on performance of the cut off wall and numerical analysis of seepage and pore water pressure of Eyvashan earth dam

2021 ◽  
Author(s):  
Behrang Beiranvand ◽  
Mehdi Komasi
Keyword(s):  
Numerical Analysis ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Earth Dam ◽  
Coefficient Of Determination ◽  
Correct Operation ◽  
Seepage Rate ◽  
Reservoir Conditions ◽  
Good Agreement

AbstractOne of the most important issues in earth dams is the control rate of seepage from the foundation and dam bodies. Due to the site of the dams, to increase the creep length and reduce the seepage, there are several methods for sealing the reservoir of dams that construction of the cut-off wall under the clay core of the dams is one of the most effective methods. In this study, the seepage rate and pore water pressure of the Eyvashan earth dam, comparison of instrument results with the results of numerical analysis and, finally, the performance of the cut-off wall are investigated. According to the results of instrumental and numerical analysis, the maximum seepage rate in full reservoir conditions is equal to 831,604 m3/year. To fit the data of instrumentation and numerical analysis, multivariate regression was used and the coefficient of determination was used which R2 = 0.9892 and R2 = 0.9834, respectively, were obtained for seepage and pore water pressure. Very good agreement between the results of the observed data and the predicted data indicates the proper behavior of the dam in terms of pore water pressure. Also, due to the results of numerical simulation and instrumentation, the pore water pressure in the downstream part of the cut-off wall is suddenly dropped, which indicates the correct operation of the cut-off wall.

Determining Range of Saturated Ground around Leakage Pipeline Using Unsteady Seepage Numerical Analysis

2012 ◽  
Vol 204-208 ◽  
pp. 609-613
Author(s):  
Xing Gao Li ◽  
Chao Jie Duan
Keyword(s):  
Numerical Analysis ◽  
Hydraulic Conductivity ◽  
Water Content ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Injection Well ◽  
Exponential Relationship ◽  
Seepage Analysis ◽  
Conductivity Function

It is of great significance to estimate the range of saturated ground around leakage pipelines when tunneling near the pipelines. The range of saturated ground can be determined from the distributions of the water content and pore-water pressure in ground around the leakage pipelines. The leakage pipeline being modeled as an injection well, a series of unsteady seepage numerical analysis is performed to understand the effects of the internal water pressure of pipelines on the range of saturated ground surrounding the pipelines, and computation results show the exponential relationship between them. In the unsteady seepage analysis, the hydraulic conductivity function and the volumetric water content function must be determined beforehand to get reasonable results of the range of saturated ground.

scholarly journals Numerical analysis of earthquake response of an ultra-high earth-rockfill dam

2013 ◽  
Vol 1 (3) ◽  
pp. 2319-2351 ◽  
Author(s):  
W. X. Dong ◽  
W. J. Xu ◽  
Y. Z. Yu ◽  
H. Lv
Keyword(s):  
Numerical Analysis ◽  
Stress Field ◽  
Seismic Analysis ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Dynamic Responses ◽  
Economic Damage ◽  
Earth Dams ◽  
Nonlinear Method ◽  
Rockfill Dam

Abstract. Failure of high earth dams under earthquake may cause disastrous economic damage and loss of lives. It is necessary to conduct seismic safety assessment, and numerical analysis is an effective way. Solid-fluid interaction has a significant influence on the dynamic responses of geotechnical materials, which should be considered in the seismic analysis of earth dams. The initial stress field needed for dynamic computation is often obtained from postulation, without considering the effects of early construction and reservoir impounding. In this study, coupled static analyses are conducted to simulate the construction and impounding of an ultra-high earth rockfill dam in China. Then based on the initial static stress field, dynamic response of the dam is studied with fully coupled nonlinear method. Results show that excess pore water pressure accumulates gradually with earthquake and the maximum value occurs at the bottom of core. Acceleration amplification reaches the maximum at the crest as a result of whiplash effect. Horizontal and vertical permanent displacements both reach the maximum values at the dam crest.

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