scholarly journals Study on influence of dam foundation damage on seismic safety of gravity dam under combined action of main shock and aftershock

2019 ◽  
Vol 304 (4) ◽  
pp. 042063
Author(s):  
Liaojun Zhang ◽  
Yafei Zhai ◽  
Dongsheng Chen ◽  
Xiao Cui
Keyword(s):  
Main Shock ◽  
Gravity Dam ◽  
Dam Foundation ◽  
Seismic Safety ◽  
Combined Action

scholarly journals A Novel Method for Constructing Main-Aftershock Sequences and Its Application in the Global Damage Accumulation Effects Analysis of Gravity Dams

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Liaojun Zhang ◽  
Yafei Zhai ◽  
Binghui Cui ◽  
Yujie Tang ◽  
Zhonghui Bi
Keyword(s):  
Ground Motion ◽  
Damage Evolution ◽  
Main Shock ◽  
Gravity Dam ◽  
Shock Acceleration ◽  
Rock Foundation ◽  
Dam Foundation ◽  
Energy Characteristics ◽  
Aftershock Sequences ◽  
Dynamic Damage

The traditional linear elastic and Drucker–Prager (DP) models cannot truly reflect the strong nonlinear characteristics of the concrete and rock foundation of the dam under earthquake. Therefore, for comprehensive evaluation of the cumulative damage of the gravity dam structure caused by aftershock, the dynamic damage of the dam body concrete is analyzed by many scholars through the plastic damage mechanics method, but there is little research on rock material at the dam foundation with the method utilized; thus, the simulation of the whole dynamic damage evolution is worthy of investigation of the dam body and dam foundation. According to the randomness of ground motion, the transcendental probability (P) is introduced to express the statistical characteristics of aftershock intensity, and a new method for constructing main-aftershock sequences of ground motion is proposed in this paper. And then, the law of the damage evolution and energy characteristics of the concrete gravity dam under the combined action of the main shock and aftershock sequences is studied. The results are shown as follows: the smaller aftershocks do not cause further damage to the dam; as the aftershock intensity increases, the energy characteristics of the dam body and foundation have shown different changing rules; when the ratio of peak aftershock acceleration to peak main shock acceleration (∇PGA) approximately equals 0.68, the aftershock will cause larger secondary damage to the dam.

scholarly journals Probabilistic Seismic Analysis of the Deep Sliding Stability of a Concrete Gravity Dam-Foundation System

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Hui Liang ◽  
Shengshan Guo ◽  
Yifu Tian ◽  
Jin Tu ◽  
Deyu Li ◽  
...  
Keyword(s):  
Seismic Analysis ◽  
Safety Evaluation ◽  
Gravity Dam ◽  
Seismic Fragility ◽  
Concrete Gravity Dam ◽  
Dam Foundation ◽  
Seismic Safety ◽  
Sample Number ◽  
Seismic Safety Evaluation ◽  
Sliding Stability

There are various uncertainties in the design, construction, and operation of dams. These uncertainties have an important impact on the seismic response and seismic safety evaluation of concrete dams. In this research, a typical nonoverflow monolith of a concrete gravity dam is selected as a case study for the sliding stability analysis. Based on the analysis and demonstration of parameter sensitivity of friction coefficients and cohesion and their influence on the deep antisliding stability of the dam-foundation system, the probabilistic seismic analysis of a gravity dam-foundation system is carried out through Monte Carlo analysis with a large sample number. Damage levels are defined based on the sliding instability failure mode along with the corresponding threshold values of the damage index. Thus, seismic fragility analysis is investigated, and seismic fragility curves are obtained for the vulnerability assessment under earthquake hazards. The overall seismic stability of the gravity dam is evaluated, which provides the basis for the seismic safety evaluation in the probabilistic framework.

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 Application of Probabilistic Method to Stability Analysis of Gravity Dam Foundation over Multiple Sliding Planes

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Gang Wang ◽  
Zhenyue Ma
Keyword(s):  
Probabilistic Method ◽  
Complex Problem ◽  
Probabilistic Methods ◽  
Gravity Dam ◽  
Engineering Profession ◽  
Concrete Gravity Dam ◽  
Dam Foundation ◽  
Performance Function ◽  
Probability Calculation ◽  
Implicit Performance Function

The current challenge to the engineering profession is to carry out probabilistic methods in practice. The design point method in generalized random space (DPG method) associated with the method of divided difference can be utilized to deal with the complex problem of probability calculation of implicit performance function with nonnormal and correlated variables. For a practical concrete gravity dam, the suggested method is performed to calculate the instability probability of the dam foundation over multiple sliding places. The general conclusions drawn in the paper are identical to those in other research and the method is proved to be feasible, accurate, and efficient. As the same analysis principle, the method can also be used in other similar fields, such as in fields of slopes, earth-rock dams, levees, and embankments.

Study on Damage of Concrete Dam Subjected to Combined Action of Earthquake and Slide Surge

2014 ◽  
Vol 580-583 ◽  
pp. 2092-2095
Author(s):  
Jing Li ◽  
Qiang Xu ◽  
Jian Yun Chen ◽  
Guo Shuai Lu
Keyword(s):  
Damage Evolution ◽  
Safety Performance ◽  
Gravity Dam ◽  
Concrete Gravity Dam ◽  
Concrete Dam ◽  
Impact Action ◽  
Evolution Law ◽  
Combined Action ◽  
Action Models ◽  
Time Sequences

It is possible for hydraulic engineering located in high intensity earthquake area under the action of extreme disaster induced by earthquake and secondary slide surge. Several impact action models of slide surge were introduced and the damage evolution of concrete gravity dam subjected to combined action of different sequences of earthquake and secondary slide surge were studied based on nonlinear numerical analysis. The effects of different time sequences of combined earthquake and slide surge were compared and the safety performance analysis was performed. The results show that the combined form has great effects on the damage evolution law of concrete gravity dam.

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.

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.

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