scholarly journals DDA in fluid-structure problems for the study of gravity dam failure

2010 ◽  
pp. 533-546
Author(s):  
Sami Kaidi ◽  
Abdellatif Ouahsine ◽  
Mohamed Rouainia ◽  
Hassan Smaoui
Keyword(s):  
Water Level ◽  
Coupled Model ◽  
Discontinuous Deformation Analysis ◽  
Gravity Dam ◽  
Dam Failure ◽  
Deformation Analysis ◽  
Deformable Solid ◽  
Fluid Structure ◽  
Discontinuous Medium ◽  
The Stability

In this paper, we present a 2D coupled fluid-structure interaction procedure to assess the stability of a cracked gravity dam against increasing water level. In this procedure the structure is assumed to be a discontinuous deformable solid containing pre-existing cracks. Thus, the Discontinuous Deformation Analysis DDA method is used to study the solid discontinuous medium, and the continuum finite element flow model to calculate the hydrostatic forces corresponding to the water level. The contact constraints between discrete blocks are imposed through an implicit augmented Lagrangian format. Numerical results show the potential of the proposed coupled model to quantify the direct influence of the nature and location of the internal cracks on the overall stability of common gravity dams.

STABILITY ANALYSES FOR ANCIENT MASONRY STRUCTURES USING DISCONTINUOUS DEFORMATION ANALYSIS AND NUMERICAL MANIFOLD METHOD

2011 ◽  
Vol 08 (02) ◽  
pp. 247-275 ◽  
Author(s):  
TAKESHI SASAKI ◽  
IKUO HAGIWARA ◽  
KASTUJI SASAKI ◽  
RYUNOSHIN YOSHINAKA ◽  
YUZO OHNISHI ◽  
...  
Keyword(s):  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Numerical Manifold Method ◽  
Masonry Structures ◽  
Stress Distributions ◽  
Isoparametric Element ◽  
Discontinuous Deformation ◽  
The Stability ◽  
Numerical Manifold ◽  
Physical Phenomena

In this paper, the stability including stress distribution of two ancient masonry structures, the pyramid of the Pharaoh Khufu, Egypt and the Pont of Gard, were analyzed using discontinuous deformation analysis (DDA) and numerical manifold method (NMM). For the simulation using NMM, the newly developed four-node isoparametric element was used. The stress distributions/concentration were calculated and compared between the two methods. The calculated results show qualitative agreement with observations. DDA and NMM are applicable to simulate the physical phenomena of masonry structures.

Stability Analysis of Surrounding Rock with Two Groups Parallel Joints Using DDARF Method

2014 ◽  
Vol 919-921 ◽  
pp. 735-739
Author(s):  
Hai Ping Ma ◽  
Li Ge Wang ◽  
Xue Wei Li
Keyword(s):  
Stability Analysis ◽  
Uniaxial Compression ◽  
Surrounding Rock ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Compression Tests ◽  
Underground Cavern ◽  
Excavation Process ◽  
Discontinuous Deformation ◽  
The Stability

In order to analyze the stability of surrounding rocks with two groups parallel joints under different angles, a new method, DDARF (discontinuous deformation analysis for rock failure) program was adopted to investigate three cases of uniaxial compression tests of two groups parallel joints sample with the angels 30, 45 and 60. The results show the sample with 30 is least prone to be destroyed and the sample with 60 are most likely to be destroyed. Then DDARF program was also applied to investigate the underground cavern excavation process of two groups parallel joints surrounding rocks with the angels 30, 45 and 60. The results show that the stability of underground cavern with joint angel of 60 is worst in the aspect of stability.

Stability Analysis of Dangerous Rocks on the Slope of a Hydropower Station

2013 ◽  
Vol 405-408 ◽  
pp. 621-629 ◽  
Author(s):  
Hai Feng Li ◽  
Guo Xing Zhang ◽  
Tao Huang ◽  
Qiu Jing Zhou
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Discontinuous Deformation Analysis ◽  
Hydropower Station ◽  
Deformation Analysis ◽  
Time Interval ◽  
Block Method ◽  
Fractured Rock Mass ◽  
Unstable Failure ◽  
The Stability

Dangerous rocks are among the most significant factors in analyzing the stability of high slopes, and are the main geological hazards on such slopes. These rocks are typical spatial blocks. The unstable failure of dangerous rocks poses evident spatial features. Consequently, their stability should be calculated by considering it as a three-dimensional (3-D) problem. In this research, the general block method of fractured rock mass and 3-D discontinuous deformation analysis (DDA) are used to study the stability of dangerous rocks on the slope of a hydropower station. The general block method of fractured rock mass is used to generate dangerous rocks and to assess the geometric mobility of blocks. The progressive unstable failure of dangerous rocks is also analyzed. Moreover, 3-D DDA is implemented to examine the stability of dangerous rocks, including the regularity of their unstable failure. The failure sequence of each batch of blocks estimated by general block theory is the same as that in the results of 3-D DDA. The decrease in the shear parameters of the structural plane shortens the time interval of failures, but increases the number and capacity of blocks.

DDA in fluid-structure problems for the study of gravity dam failure

2010 ◽  
Vol 19 (5-7) ◽  
pp. 533-546
Author(s):  
Sami Kaidi ◽  
Abdellatif Ouahsine ◽  
Mohamed Rouainia ◽  
Hassan Smaoui
Keyword(s):  
Gravity Dam ◽  
Dam Failure ◽  
Fluid Structure

scholarly journals Multibody Finite Element Method and Application in Hydraulic Structure Analysis

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Chao Su ◽  
Yebin Zhao ◽  
Yusong Jiang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Hydraulic Structure ◽  
Local Coordinate System ◽  
Contact Problems ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
The Stability ◽  
Dda Method ◽  
Element Method

Multibody finite element method is proposed for analysis of contact problems in hydraulic structure. This method is based on the block theory of discontinuous deformation analysis (DDA) method and combines advantages of finite element method (FEM) and the displacement compatibility equation in classical elastic mechanics. Each single block is analyzed using FEM in corresponding local coordinate system and all contacting blocks need to satisfy the displacement compatibility requirement between any two blocks in a blocky system. It is proved that this method is very efficient and practical to overcome the limitations in DDA method when tackling contact problems, such as the overlap problem and the equal strain assumption. In this paper, detailed theoretical basis and formulations are given. Two numerical examples are performed to verify the proposed method successfully. Furthermore, this method is adopted to study the stability issues of underground houses of a large hydropower station.

3D Numerical Simulation of Majiabian Concrete Gravity Dam

2011 ◽  
Vol 90-93 ◽  
pp. 2624-2632
Author(s):  
Lin Ke Li ◽  
Ai Jun Zhang ◽  
Jin Yu Liu ◽  
Chun Jiao Hou ◽  
Hao Dong Li
Keyword(s):  
Numerical Simulation ◽  
Sensitivity Analysis ◽  
Stability Analysis ◽  
Water Level ◽  
Deformation Modulus ◽  
Gravity Dam ◽  
Tension Stress ◽  
Concrete Gravity Dam ◽  
3D Numerical Simulation ◽  
The Stability

A new method that 3D numerical simulation combined with anti-cut stability analysis is employed to analyze the stability of Majiabian gravity dam, and the results of the analysis conform to the measured value. And this method can be used in analysis of congener gravity dam. When the results of 2D sliding stability analysis satisfy Code’s requirements, elastic material can be used in 3D numerical simulation. The results of water level sensitivity analysis and deformation modulus of its foundation sensitivity analysis indicates that this gravity dam is insensitive to water level; grouting method can be adopted to enhance its foundation. The results of abutment under tension stress analysis indicate that tension stress of abutment must be considered in high gravity dam design, and arch can be used for reducing the tension stress.

Stability of caisson-type breakwater subjected to strong hydrodynamic impacts using discontinuous deformation analysis method

2021 ◽  
pp. 095440622110426
Author(s):  
Dong Ding ◽  
Abdellatif Ouahsine
Keyword(s):  
Penalty Method ◽  
Numerical Study ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Rear Side ◽  
Analysis Method ◽  
Discontinuous Deformation ◽  
The Stability ◽  
Dimensionless Displacement ◽  
Dda Method

A numerical study using the Discontinuous Deformation Analysis (DDA) method is proposed to analyze the effect of the caisson sliding subjected to a hydrodynamic loading in the stability of the rear side of the caisson-type breakwater. The study takes into account the slope inclination of the breakwater as well as the contact between the armour units constituting the shoreward of the breakwater, where the contact stresses are imposed through a penalty method. A dimensionless displacement parameter, [Formula: see text], is defined to investigate the instability of armor units. The results of the simulation show that the shape of the armour units plays an important role in the stability of the breakwater, where the tetrapods and the acropods give better stability than the cubic shapes, with a clear superiority of the tetrapods. They also show that the reduction in the slope clearly contributes to the stability of caisson up to a slope of 1: 2, but below this ratio of 1: 2 this stability is no longer obvious. Furthermore, a new relation of the displacement of the armour units according to the slope is established.

Reinforcement with Rockbolts in Underground Powerhouse Excavation Using DDA Method

2011 ◽  
Vol 90-93 ◽  
pp. 2339-2342
Author(s):  
Song Yu ◽  
Wei Shen Zhu ◽  
Dun Fu Zhang
Keyword(s):  
Initial Stress ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Underground Powerhouse ◽  
Excavation Process ◽  
Splitting Failure ◽  
Discontinuous Deformation ◽  
Deformation Stress ◽  
The Stability ◽  
Dda Method

Discontinuous Deformation Analysis (DDA) method is used to analyze the stability, deformation and splitting failure of underground powerhouse excavation process with different lateral initial stress levels. Coefficient of lateral initial stress, reinforcement effect and joint structure pattern affecting on the surrounding rock are studied. The criterion for splitting failure in surrounding of underground is implemented to predict the depth of fracture area. It is shown that reinforcement with rockbolts will bring effects on rock surroundings in controlling deformation, stress distribution and stability.

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