Numerical Research on the Gravity Dam Deep Anti-Sliding with Engineering Mechanics Based on Damage Theory

2014 ◽  
Vol 910 ◽  
pp. 289-296
Author(s):  
Shuang Liu ◽  
Qing Wen Ren ◽  
Chen Lu Zhou
Keyword(s):  
Rock Mass ◽  
Numerical Model ◽  
Damage Mechanics ◽  
Failure Process ◽  
Gravity Dam ◽  
Instability Criterion ◽  
Gravity Dams ◽  
Dam Foundation ◽  
Sliding Stability ◽  
Foundation Rock

Currently, researches on the gravity dam deep and shallow anti-sliding stability mainly focus on the analysis method and instability criterion, while the studies on specifically test the breakage of gravity dams due to weakening foundation rock mass and structural planes under loading are rare. Based on damage mechanics theory, this paper established a numerical model that analyzed the damage failure process of dam foundation rock mass. Taking two typical gravity dam models as the study objects, the damage processes of the dam foundations were simulated dynamically. Additionally, a comparison with other two traditional methods further validated the correctness and feasibility of the numerical model. In sum, the study findings point out that the numerical model is not only applicable to the study of the breakage mechanism of dam foundation rock mass, but also can be used as a new method to analyze problems related to deep anti-sliding stability of gravity dams.

The Elastoplastic Finite Element Analysis for the Deep Anti-Sliding Stability of Gravity Dam by the Method of Overloading

2015 ◽  
Vol 1089 ◽  
pp. 270-276
Author(s):  
Jun Rui Pang ◽  
Wei Sun ◽  
Gang Wang ◽  
Long Su
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Safety Factor ◽  
Horizontal Displacement ◽  
Gravity Dam ◽  
Element Analysis ◽  
Dam Foundation ◽  
Finite Element Software ◽  
Sliding Stability ◽  
Foundation Rock

Combined with engineering requirements of the Qingyu reservoir, the ANSYS finite element software was used to establish an elastoplastic gravity dam calculation model which considered the mechanical properties of weak structural plane of rock in the dam foundation. An analysis based on not only the finite element iteration not converging,the plastic zones in dam foundation rock developing to through the foundation and the mutation in horizontal displacement of feature points, but also the discontinuous variation of the distribution of horizontal displacement of dam foundation rock, the dislocation between the above and below of weak layers and the leap of iterations were took as the criterions to get the deep anti-sliding stability safety factor of gravity dam by gradually increasing the load burdened on the upstream face of the dam. This thesis illustrated the principle of the elastoplastic finite element analysis for the deep stability of gravity dam by the method of overloading, demonstrated the feasibility of this method ,expanded the criterions to determine the safety factor and obtains the safety factor of this practical engineering under the elastoplastic overloading method.

Genetic Algorithm for Searching for Critical Slip Surface in Gravity Dams Based on Stress Fields

2013 ◽  
Vol 790 ◽  
pp. 146-149
Author(s):  
Jian Yun Chen ◽  
Shu Wang ◽  
Qiang Xu ◽  
Jing Li
Keyword(s):  
Genetic Algorithm ◽  
Slip Surface ◽  
Safety Evaluation ◽  
Fem Analysis ◽  
Stress Fields ◽  
Gravity Dam ◽  
Critical Slip Surface ◽  
Gravity Dams ◽  
Sliding Stability ◽  
Search Program

Currently, the safety evaluation of gravity dam concentrates on stress and anti-sliding stability of the dam. A lot of research shows that the upper area of the dam is one of the whole dams weakest areas during an earthquake and should be studied in details. In this study, the genetic algorithm and non-linear FEM analysis are combined, then a search program is written to search the critical slip surface in the dams upper area. Finally, the surface which has the least anti-sliding stability coefficient is obtained, the most dangerous slip surface and its anti-sliding coefficient as well as the corresponding time are acquired to evaluate the safety of the dam.

FAILURE PATTERNS OF SHEAR KEYS AND SEISMIC RESISTANCE OF A GRAVITY DAM WITH LONGITUDINAL JOINTS

2014 ◽  
Vol 08 (01) ◽  
pp. 1450004 ◽  
Author(s):  
LIAOJUN ZHANG ◽  
HANYUN ZHANG ◽  
SHAOWEI HU
Keyword(s):  
Time History ◽  
Gravity Dam ◽  
Seismic Resistance ◽  
Size Difference ◽  
Crack Model ◽  
Gravity Dams ◽  
Dam Foundation ◽  
Failure Patterns ◽  
Shear Keys ◽  
Longitudinal Joints

In order to thoroughly study the seismic resistance of gravity dams with longitudinal joints, a contact model based on constraint function method is used to simulate the shear keys within the joints and a concrete smeared crack model is selected to present the cracking characteristics of concrete materials. Because of the great size difference between the shear keys and the dam body, a glue mesh is proposed to implement multi-scale modeling. A dam-foundation-reservoir interaction system with longitudinal joints considering the various shear keys is developed and analyzed by nonlinear time-history method. On the basis of actual construction, arrangement and loading features of shear keys, a gravity dam is taken as a test case and a finite element model of the dam is established with triangular or trapezoidal shear keys. The working behaviors and failure patterns of various shear keys under earthquakes are explored. Moreover, the effects of various shear keys on the seismic resistance of the gravity dam are discussed. The results show that the seismic responses of shear keys are resulted in designed forms. The occlusion and dislocation of the shear keys within the longitudinal joints have an impact on seismic resistance of the gravity dams.

scholarly journals A Vibration-Isolating Blast Technique with Shock-Reflection Device for Dam Foundation Excavation in Complicated Geological Conditions

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Haoran Hu ◽  
Wenbo Lu ◽  
Peng Yan ◽  
Ming Chen ◽  
Qidong Gao
Keyword(s):  
Rock Mass ◽  
Field Experiments ◽  
Vertical Direction ◽  
Wave Impedance ◽  
Shock Reflection ◽  
Dam Foundation ◽  
Geological Conditions ◽  
Production Experiment ◽  
Bench Blasting ◽  
Foundation Rock

Under complicated geological conditions, the vibration in the dam foundation caused by blasting can lead to further deterioration of the foundation rock mass and adversely affect the safety of foundation. In order to effectively control the vibration in dam foundation rock mass, a new bench blasting technique with shock-reflection device is proposed. It introduces a shock-reflection device consisting of high wave impedance block and cushion material, which is placed at the bottom of vertical borehole. This shock-reflection device can effectively reflect the explosion shock wave from vertical direction to horizontal direction after detonation, which can make blasting energy concentrated on the rock mass above dam foundation, so the vibration in the foundation can be controlled. Field blasting experiment was carried out to contrast the blasting induced vibration in foundation rock by bench blasting with shock-reflection device and conventional bench blasting. The results indicate that the vibration in the foundation rock can be reduced by 30%~57%. In addition, the vibration at the bottom of the borehole is also demonstrated by numerical simulation, with results similar to the field experiments. The production experiment results show that the new blasting technique can replace the conventional excavation method of dam foundation in complicated geological conditions, and the new blasting technique has been successfully applied to the Baihetan dam foundation excavation.

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.

The Arch Dam Foundation Rock Mass Unloading and Relaxation Deformation Characteristics and their Monitoring Result Analysis

2011 ◽  
Vol 255-260 ◽  
pp. 3514-3523
Author(s):  
Shi Sheng Li ◽  
Ze Rong Dong ◽  
Qi Li ◽  
Hua Zhao ◽  
Hui Zhang
Keyword(s):  
Rock Mass ◽  
Scientific Basis ◽  
Arch Dam ◽  
Design Parameters ◽  
Dam Foundation ◽  
Whole Process ◽  
Deformation Test ◽  
Dam Stability ◽  
Result Analysis ◽  
Foundation Rock

After foundation excavation for a dam of a hydropower project, the rock mass would be unloaded and relaxed and its mechanical parameters would be lowered, thus influencing the dam stability. This paper makes an analysis of the deformation development law of the unloading rock mass of the dam foundation by analyzing the advance deformation of the dam foundation before excavation and the unloading rebound deformation of the dam foundation after excavation, and by analyzing the monitoring results of the compressive deformation after concreting of the dam and of the whole process deformation after impounding of the reservoir taking into account the results of both deformation test and acoustic test, which provides scientific basis for quality assessment of the arch dam foundation rock mass and for readjustment of the dam foundation rock mass mechanics design parameters, thus giving a reference to projects of the kind.

scholarly journals The Failure Mechanism of Concrete Gravity Dams considering Different Nonlinear Models under Strong Earthquakes

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Chunli Yan ◽  
Jin Tu ◽  
Deyu Li ◽  
Shengshan Guo ◽  
Hui Liang
Keyword(s):  
Nonlinear Models ◽  
Failure Process ◽  
Damage Model ◽  
Dynamic Contact ◽  
Gravity Dam ◽  
Concrete Gravity Dam ◽  
Seismic Capacity ◽  
Gravity Dams ◽  
Strong Earthquakes ◽  
Concrete Gravity Dams

The paper focuses on the failure process and mechanism of the concrete gravity dam considering different nonlinear models under strong earthquakes. By taking a typical monolith of a concrete gravity dam as a case study, a comparative analysis of the failure process and mechanism of the dam considering the plastic damage model and the dynamic contact model, respectively, is performed using the seismic overload method. Moreover, the ultimate seismic capacity of the dam is evaluated for both of the nonlinear models. It is found that the ultimate seismic capacity of the dam is slightly different, but the failure process has significant distinctions in each model. And, the damage model is recommended when the conditions permit.

Dynamic Analysis of Artificial Boundaries in Gravity Dam-Foundation Rock Interaction System

2014 ◽  
Vol 580-583 ◽  
pp. 1680-1686
Author(s):  
Wen Qiao ◽  
Guo Ming Liu
Keyword(s):  
Elastic Wave ◽  
Dynamic Analysis ◽  
Wave Velocity ◽  
Elastic Wave Velocity ◽  
Gravity Dam ◽  
Artificial Boundary ◽  
Dam Foundation ◽  
Artificial Boundaries ◽  
Input Load ◽  
Foundation Rock

ANSYS was used to focus on comparative analysis of several artificial boundary conditions that are widely used in engineering applications. The accuracy and stability of dynamic analysis results were then analyzed in details of a semi-infinite foundation with different artificial boundaries and different frequency input loads. Lastly, the seismic response of a gravity dam-foundation rock system was explored numerically. Experimental results revealed the simulation accuracy of artificial boundaries was closely related to the dynamic characteristics of input load and the elastic wave velocity. When the input load frequency was high, only the material with comparably higher elastic wave velocity could maintain the stability of the artificial boundary. Viscoelastic artificial boundary is practically simple and can better simulate the semi-infinite material elastic recovery ability and energy radiation outside the boundary.

scholarly journals Numerical Simulation of Shock Response and Dynamic Fracture of a Concrete Dam Subjected to Impact Load

2016 ◽  
Vol 20 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Lu Lu ◽  
Xin Li ◽  
Jing Zhou ◽  
Genda Chen ◽  
Dong Yun
Keyword(s):  
Dynamic Fracture ◽  
Impact Load ◽  
Failure Process ◽  
Gravity Dam ◽  
Strong Impact ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Shock Response ◽  
The Impact

<p>The shock response and dynamic fracture of concrete gravity dams under impact load are the key problems to evaluate the antiknock safety of the dam. This study aims at understanding the effects of impact shock on the elastic response and dynamic fracture of concrete gravity dams. Firstly, this paper uses acceleration records of a concrete gravity dam under impact to establish the correct way to determine the concrete gravity dam of the fundamental frequency and present cut sheets multi-degree-of-freedom dynamic modeling. Under strong impact loading, the constitutive relation of concrete gravity dam and the highest frequency of the impact are uncertain. So, the main advantage of this method is avoiding the use of elastic modulus in the calculation. The result indicates that the calculation method is a reliable computational method for concrete gravity dams subjected to impact. Subsequently, the failure process of dam models was numerically simulated based on ABAQUS commercial codes. Finally, this paper puts forward suggestions for future research based on the results of the analysis.</p>

Sign in / Sign up

Export Citation Format

Share Document