scholarly journals Dynamic Stability Discrimination Method for Concrete Dam under Complex Geological Conditions

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Liaojun Zhang ◽  
Tianxiao Ma ◽  
Hanyun Zhang ◽  
Dongsheng Chen
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Dynamic Instability ◽  
Limit Equilibrium ◽  
Element Model ◽  
Safety Factors ◽  
Stability Calculation ◽  
Dam Foundation ◽  
Geological Conditions ◽  
Dam Foundations

The instability of dams will bring immeasurable personal and property losses to the downstream, so it has always been a trendy topic worthy of investigation. Currently, the rigid body limit equilibrium method is the most commonly used method for the dynamic stability analysis of dams. However, under the action of earthquakes, the instability of the integral dam-foundation system threatens the safety of the dams and is of great concern. In this paper, a stability analysis method that can reflect the complex geological structural forms of dam foundations is proposed in this paper. The advantages are that this method deals with the difficulty in assuming sliding surfaces and the lack of quantitative criteria for the dynamic instability analysis of dams with complex geological structural forms of dam foundations. In addition, through the method, the sliding channels that may appear in the dam foundations can be automatically searched under random earthquake action, and the safety factors of the dynamic instability of dams be quantitatively obtained. Taking a high RCC gravity dam under construction in China as an example, the proposed method is applied to the three-dimensional finite element model of the dam-foundation system of this dam, and then the dynamic stability calculation is carried out. Through this method, the formation process of the dam foundation’s plastic zone and the failure of sliding channels with different strength reduction coefficients are studied on and analyzed detailedly, and the quantitative acquisition of the safety factors is realized. The results show that the method is reasonable and feasible, and helps provide a new idea and method for the dynamic stability analysis of dams.

Dynamic Stability of Timoshenko Beams by Finite Element Method

1976 ◽  
Vol 98 (4) ◽  
pp. 1145-1149 ◽  
Author(s):  
J. Thomas ◽  
B. A. H. Abbas
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stability Analysis ◽  
Shear Deformation ◽  
Dynamic Stability ◽  
Timoshenko Beam ◽  
Dynamic Instability ◽  
Rotary Inertia ◽  
Timoshenko Beams ◽  
Buckling Loads

A Finite Element model is developed for the stability analysis of Timoshenko beam subjected to periodic axial loads. The effect of the shear deformation on the static buckling loads is studied by finite element method. The results obtained show excellent agreement with those obtained by other analytical methods for the first three buckling loads. The effect of shear deformation and for the first time the effect of rotary inertia on the regions of dynamic instability are investigated. The elastic stiffness, geometric stiffness, and inertia matrices are developed and presented in this paper for a Timoshenko beam. The matrix equation for the dynamic stability analysis is derived and solved for hinged-hinged and cantilevered Timoshenko beams and the results are presented. Values of critical loads for beams with various shear parameters are presented in a graphical form. First four regions of dynamic instability for different values of rotary inertia parameters are presented. As the rotary inertia parameter increases the regions of instability get closer to each other and the width of the regions increases thus making the beam more sensitive to periodic forces.

Deep Anti-Sliding Stability of Wudu RCC Gravity Dam

2012 ◽  
Vol 446-449 ◽  
pp. 2776-2782 ◽  
Author(s):  
Fan Feng ◽  
Guo Xin Zhang
Keyword(s):  
Finite Element ◽  
Limit Equilibrium ◽  
Test Method ◽  
Gravity Dam ◽  
Nonlinear Finite Element Method ◽  
Fissure Zone ◽  
Dam Foundation ◽  
Geological Conditions ◽  
Joint Element ◽  
Sliding Stability

The deep anti-sliding stability of dam foundation has been an important issue in the study of dam field. Rigid body limit equilibrium method and nonlinear finite element method have been adopted on the analysis of sliding stability. In the current paper, the joint element is used to simulate faults, interlayer shear zone and slight inclined fissure zone in complicated geological conditions of Wudu dam. Stress integral method, overload method and strength reduction method are utilized for analysis on deep anti-sliding of Wudu RCC gravity dam, moreover, after being compared with the results by Sarma method, finite element direct force method and geomechanical model test method etc., the consistent conclusion is obtained.

scholarly journals Failure Process and Stability Analysis of Rock Blocks in a Large Underground Excavation Based on a Numerical Method

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Shijie Chen ◽  
Ming Xiao ◽  
Juntao Chen
Keyword(s):  
Stability Analysis ◽  
Numerical Analysis ◽  
Numerical Method ◽  
Failure Process ◽  
Surrounding Rock ◽  
Underground Excavation ◽  
Analysis Method ◽  
Safety Factors ◽  
Geological Conditions ◽  
The Stability

A numerical analysis method for block failure is proposed that is based on continuum mechanics. First, a mesh model that includes marked blocks was established based on the grid-based block identification method. Then, expressions of the contact force under various contact states were derived based on the explicit contact force algorithm, and a contact simulation method between blocks and the surrounding rock was proposed. The safety factors of the blocks were calculated based on the strength reduction method. This numerical analysis method can simulate both the continuous deformation of the surrounding rock and the discontinuous failure processes of the blocks. A simple example of a sliding block was used to evaluate the accuracy and rationality of the numerical method. Finally, combined with a deep underground excavation project under complex geological conditions, the stability of the blocks and rock were analyzed. The results indicate that the key blocks are damaged after excavation, the potentially dangerous blocks loosen and undergo large deformations, and the cracks between the blocks and the rock gradually increase as the excavation proceeds. The safety factors of the blocks change during the excavation. The numerical results demonstrate the influence of the surrounding rock on the failure process and on the stability of the blocks, and an effective analysis method is provided for the stability analysis of blocks under complex geological conditions.

Dynamic Instability of Laminated-Composite and Sandwich Plates Using a New Inverse Trigonometric Zigzag Theory

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Rosalin Sahoo ◽  
B. N. Singh
Keyword(s):  
Stability Analysis ◽  
Boundary Conditions ◽  
Dynamic Stability ◽  
Dynamic Instability ◽  
Excitation Frequency ◽  
Laminated Composite ◽  
Sandwich Plates ◽  
Load Amplitude ◽  
Instability Regions ◽  
Zigzag Theory

A structure with periodic dynamic load may lead to dynamic instability due to parametric resonance. In the present work, the dynamic stability analysis of laminated composite and sandwich plate due to in-plane periodic loads is studied based on recently developed inverse trigonometric zigzag theory (ITZZT). Transverse shear stress continuity at layer interfaces along with traction-free boundary conditions on the plate surfaces is satisfied by the model obviating the need of shear correction factor. An efficient C0 continuous, eight noded isoparametric element with seven field variable is employed for the dynamic stability analysis of laminated composite and sandwich plates. The boundaries of instability regions are determined using Bolotin's approach and the first instability zone is presented either in the nondimensional load amplitude–excitation frequency plane or load amplitude–load frequency plane. The influences of various parameters such as degrees of orthotropy, span-thickness ratios, boundary conditions, static load factors, and thickness ratios on the dynamic instability regions (DIRs) are studied by solving a number of problems. The evaluated results are validated with the available results in the literature based on different deformation theories. The efficiency of the present model is ascertained by the improved accuracy of predicted results at the cost of less computational involvement.

Correlation of Risk Analysis Method Results with Numerical and Limit Equilibrium Methods in Overall Slope Stability Analysis of Southern Wall of Chadormalu Iron Open Pit Mine-Iran / Korelacja wyników analizy ryzyka z wynikami obliczeń numerycznych oraz wynikami uzyskanymi w oparciu o metodę równowagi granicznej zastosowanych do badania stabilności wyrobiska pochyłego na południowej ścianie odkrywkowej kopalni rud żelaza w chadormalu w Iranie

2013 ◽  
Vol 58 (2) ◽  
pp. 505-519
Author(s):  
Kaveh Ahangari ◽  
Arman Gholinezhad Paji ◽  
Alireza Siami Behdani
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Limit Equilibrium ◽  
Slope Stability Analysis ◽  
Probabilistic Methods ◽  
Open Pit ◽  
Risk Matrix ◽  
Safety Factors ◽  
Limit Equilibrium Methods ◽  
Southern Wall

Slope stability analysis is one of the most important factors in designing open pit mines. Therefore an optimal slope design that supports both aspects of economy and safety is very significant. There are many different methods in slope stability analysis including empirical, limit equilibrium, block theory, numerical, and probabilistic methods. In this study, to analyze the overall slope stability of southern wall of Chadormalu iron open pit mine three numerical, limit equilibrium and probabilistic methods have been used. Software and methods that is used for analytical investigation in this study are FLAC software for numerical analysis, SLIDE software and circuit failure chart for limit equilibrium analysis and qualitative fault tree and semi-quantitative risk matrix for probabilistic analysis. The results of all above mentioned methods, was a circular failure occurrence in Metasomatite rock zone between 1405 to 1525 m levels. The main factors of failure occurrence in this range were heavily jointing and existing of faults. Safety factors resulted from numerical method; Circular chart method and SLIDE software are 1.16, 1.25 and 1.27 respectively. Regarding instability and safety factors in Metasomatite rock zone, in order to stabilize the given zone, some considerations such as bench angle and height reduction should be planned. In results of risk matrix method this zone was mentioned too as a high risk zone that numerical and limit equilibrium methods confirmed this.

Integral Anti-Slide Stability Analysis of RCC Gravity Dam

2013 ◽  
Vol 275-277 ◽  
pp. 1480-1483
Author(s):  
Li Zhang ◽  
Dan Pang ◽  
Jian Liu
Keyword(s):  
Stability Analysis ◽  
Safety Factor ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Gravity Dam ◽  
Safety Factors ◽  
Standard Requirement ◽  
Load Combination ◽  
Dam Stability ◽  
The Stability

The main purpose of the gravity dam stability analysis is to examine the stability safety in all possible load combination cases. Combined with the engineering example, the method of modeling , loading and analysis for the gravity dam by ansys is introduced in this paper, then the limit equilibrium method and the strength reserve method are adopt to calculate the safety factor under two conditions. The results indicate that the two safety factors which are calculated under two conditions can all satisfy the standard requirement; it is reasonable to analyze the gravity dam stability through two methods.

Dynamic Stability and Reinforcement Effect Analyses of Dagangshan High Arch Dam Abutment

2012 ◽  
Vol 594-597 ◽  
pp. 1922-1931
Author(s):  
Qiong Yang ◽  
Jian Hai Zhang ◽  
Jing Dong Shao ◽  
Man Lin Li
Keyword(s):  
Dynamic Stability ◽  
Seismic Intensity ◽  
Arch Dam ◽  
Maximum Height ◽  
Reinforcement Effect ◽  
Safety Factors ◽  
High Arch Dam ◽  
Spring Element ◽  
Geological Conditions ◽  
Left And Right

The maximum height of Dagangshan arch dam is 210m. Its geological conditions are complex. The basic seismic intensity of the dam is VIII. The crest value of earthquake acceleration that 100 years beyond the probability of 2% is 0.5575g. Using the rigid body-spring element method, this paper simulated Dagangshan arch dam’s abutment dynamic stability under earthquake action. Searching the governing sliding bodies and evaluating the reinforcement effect. The results show that under the action of earthquake, the left and right bank’s key slide blocks are L1 and R2 respectively. Before reinforcement, their minimum instantaneous dynamic safety factors dropped from 5.053 and 3.076 of static values to 1.045 and 0.922 respectively. After the pre-stressed anchor cable reinforcement on the left and right abutment, the minimum instantaneous dynamic safety factors of blocks L1, R2 are raised up to 1.091 and 1.145 respectively, meeting the requirements of designing value, the reinforcement measures are very effective.

Dynamic Stability Analysis of K8 Single-Layer Latticed Shell Structures Suffered from Earthquakes

2011 ◽  
Vol 94-96 ◽  
pp. 52-56
Author(s):  
Wen Feng Du ◽  
Fu Dong Yu ◽  
Zhi Yong Zhou
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Dynamic Instability ◽  
Single Layer ◽  
Dynamic Responses ◽  
Shell Structures ◽  
Seismic Load ◽  
The Finite Element Method ◽  
The Third ◽  
Peak Value

Aiming at the dynamic stability of the K8 single-layer latticed shell structures, it was carried out the dynamic stability analysis based on the finite element method(FEM) in this paper. The dynamic responses of the structure are calculated using the FEM and the B-R rule is applied to determine the dynamic instability critical loads. Results show that the dynamic instability is prone to take place in the K8 single-layer latticed shell structures under the severe seismic load and the dynamic instability critical seismic wave peak value is about 0.7g. The location of instability starts from the intersection between the third circular members and the radial members, then it spreads abroad until the structure collapses.

Rockmass Stability Analysis of YunYang’s Arch Dam Left Shoulder

2012 ◽  
Vol 518-523 ◽  
pp. 4405-4408
Author(s):  
Shu Lin Dai ◽  
Yong Liang Lv
Keyword(s):  
Stability Analysis ◽  
Limit Equilibrium ◽  
Arch Dam ◽  
Left Shoulder ◽  
Left Bank ◽  
Geological Condition ◽  
Engineering Geological Condition ◽  
Multiple Faults ◽  
Economic Significance ◽  
Geological Conditions

Arch dam abutment stability analysis of arch dam design, construction, is the primary problem of operation. From home, outside the related data that appear most, arch dam accident due to abutment instability caused by. On the engineering geological condition is suitable, the arch dam is safe and reliable, economic and reasonable and the broad masses of the people welcomed the dam type. But it must be based on abutment stability based on. Therefore in the arch dam design, there is a need for dam abutment rock mass are detailed and thorough exploration and stability analysis of. This paper adopts the rigid body limit equilibrium method based on arch dam on the left bank of the slide stability analysis and dam abutment stability analysis of arch dam plane, gives the dam safety stability evaluation. A cover of hyperbolic arch dam, the dam height is 163.00m, is a type of buildings. The engineering geological conditions in the dam area is more complex, the existence of multiple faults, joints, fissures, karst cave is developed. Study of a dam on the left abutment stability, reliability and stability of project evaluation is a very important technical and economic significance.

LATERAL DYNAMIC STABILITY ANALYSIS OF A CANTILEVER LAMINATED COMPOSITE BEAM WITH AN ELASTIC SUPPORT

2007 ◽  
Vol 07 (03) ◽  
pp. 377-402 ◽  
Author(s):  
CELALETTIN KARAAGAC ◽  
HASAN ÖZTÜRK ◽  
MUSTAFA SABUNCU
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Composite Beam ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Element Model ◽  
Elastic Support ◽  
Euler Beam ◽  
Laminated Composite Beam ◽  
The Finite Element Model

In this paper, static and dynamic stabilities of a cantilever laminated composite beam, having a linear translation spring as elastic support whose position is changeable from the free end to midspan of the beam, subjected to periodic vertical end loading, are examined. The beam is assumed to be an Euler beam and the finite element model used can accommodate symmetric and antisymmetric lay-ups. Solutions referred to as combination resonance are investigated for the dynamic stability analysis. The effects of length-to-thickness ratio, the variation of cross-section in one direction, orientation angle, static and dynamic load parameters, stiffness and position of the elastic support on stability are examined.

Sign in / Sign up

Export Citation Format

Share Document