Hydro-Mechanical Coupling Analyses of Cofferdam Stability of Taian Pumped Storage Power Station

2004 ◽  
Vol 261-263 ◽  
pp. 1545-1550
Author(s):  
Shu Cai Li ◽  
Shu Chen Li ◽  
Wei Shen Zhu ◽  
Wei Zhong Chen ◽  
Le Wen Zhang ◽  
...  
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Power Station ◽  
Local Effects ◽  
Mechanical Coupling ◽  
Excavation Process ◽  
Calculation Results ◽  
Pressure Grouting ◽  
Pumped Storage ◽  
The Stability

Three-dimensional hydro-mechanical coupling analyses have been conducted on the water-tight structure of the cofferdam for both intake and outlet of Taian pumped storage power station, located in Shandong Province of China. In addition, the effects of excavation on the cofferdam and foundation slopes were also studied by using the 3D FLAC. The calculation results show that the central core of high-pressure grouting has a prefect anti-seepage effect and therefore is able to strengthen the stability of the cofferdam and foundation slopes. The excavation process has only some local effects on the cofferdam and does not greatly affect the global stability of the cofferdam. Therefore, no failure takes place around slope toes. The results show that the width of platform left on the excavation side is reasonable.

scholarly journals Numerical Analyses on the Stability of a Deep Coalmine Roadway Passing through a Fault Zone: A Case Study of the Gugui Coalfield in China

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2114
Author(s):  
Yongshui Kang ◽  
Congcong Hou ◽  
Jingyi Liu ◽  
Zhi Geng ◽  
Jianben Chen ◽  
...  
Keyword(s):  
Fault Zone ◽  
Distinct Element ◽  
Three Dimensional ◽  
Tectonic Stress ◽  
Three Dimensional Model ◽  
Support Strategy ◽  
Failure Theory ◽  
Calculation Results ◽  
Pass Through ◽  
The Stability

Massive deformation often occurs when deep coalmine roadways pass through a fault zone due to the poor integrity of rock mass and high tectonic stress. To study deformation characteristics of the surrounding rock in the fault zone of a coalmine, a roadway passing through the FD1041 fault zone in China’s Gugui coalfield was investigated in this research. The geo-stress characteristics of this fault zone were analyzed based on the Mohr failure theory. Furthermore, a three-dimensional model for the experimental roadway in the FD1041 fault zone was built and calculated by a numerical program based on the distinct element method. Stability conditions of the roadway, using several types of support methods, were calculated and compared. Calculation results indicated that pre-grouting provides favorable conditions for the stability of a roadway in a fault zone. Finally, an optimized support strategy was proposed and implemented in the experimental roadway. Monitored results demonstrated that the optimized support strategy is appropriate for this fault zone.

Research on the Large Disturbance Characteristics of the Pumped Storage Motor with the Time-Stepping FEM Consequently

2015 ◽  
Vol 740 ◽  
pp. 339-342
Author(s):  
Sheng Huang ◽  
Jin Ping Kang
Keyword(s):  
Working Condition ◽  
Reactive Power ◽  
Reactive Power Compensation ◽  
The Other ◽  
Power Station ◽  
Time Stepping ◽  
Overall Efficiency ◽  
Pumped Storage ◽  
The Stability ◽  
Large Disturbance

In recent years, the proportion of pumped storage power station in the power grid is increasing, which has many special advantages. The pumped storage motor has two kinds of working condition of generator and motor, not only can the system regulate the reactive power, but also can modify the power factor of the grid resulting in the reduction of the investment on the reactive-power-compensation equipment. On the other hand, the above system is able to enhance both the stability and the overall efficiency. Pumped storage motor start-stop and working condition switch frequently. The test will be analysis and researched with the Time-stepping FEM Consequently, this paper analyses the large disturbance characteristics of the pumped storage motor.

Stability Analysis about the Impact of Soft Rock to the Underground Cavern Group

2013 ◽  
Vol 706-708 ◽  
pp. 560-564
Author(s):  
Yi Huan Zhu ◽  
Guo Jian Shao ◽  
Zhi Gao Dong
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Stability Analysis ◽  
Soft Rock ◽  
Element Model ◽  
Underground Excavation ◽  
Power Station ◽  
Excavation Process ◽  
The Stability ◽  
The Impact

Soft rock is frequently encountered in underground excavation process. It is difficult to excavate and support in soft rock mass which has low strength, large deformation and needs much time to be out of shape but little time to be self-stabilized. Based on a large underground power station, finite element model analysis was carried out to simulate the excavation process and the results of displacement, stress and plasticity area were compared between supported and unsupported conditions to evaluate the stability of the rock mass.

scholarly journals Effects of different processes of tunneling on displacements soil using 3D Finite Element Method

2021 ◽  
Vol 16 (2) ◽  
pp. 203-217
Author(s):  
Nawel Bousbia
Keyword(s):  
Three Dimensional ◽  
Urban Site ◽  
Tunnel Excavation ◽  
Excavation Process ◽  
Tunneling Method ◽  
The Stability ◽  
Full Face ◽  
Ground Stability ◽  
3D Finite Element Method ◽  
Underground Constructions

Abstract The excavation process of tunnels induces stresses and deformation in the surrounding soil. The method of excavation is one of the major problems related to the safety of the operators and the ground stability during the construction of underground works. So, it is necessary to choose an ideal method to minimize the displacements and stresses induced by tunneling. The main aim of this study is to simulate numerically the effect of different processes of tunneling on ground displacements, the settlements at surface soil and the internal efforts induced in the lining tunnel; in order to select the best process of excavation, which gives us a less effects on displacements generated by tunneling, thus, ensuring the stability and the solidity of the underground constructions. In addition, this study allows us to control and to predict the diverse movements generated by tunneling (displacements, settlements, efforts internes) exclusively for the shallow tunnel nearby to the underground constructions in the urban site. This modeling will be done by employing five different processes for tunnel excavation using the NATM (New Austrian Tunneling Method) method. The first process, the modeling of the excavation tunnel, is done almost in the same way as in reality; the partial face excavation, with seven slices, made by the excavation. The second process, by partial face excavation, is divided into eleven slices, next, we used the partial face excavation by nine slices, and then in thirteen slices. Finally, the dig is made by full-face excavation. The paper contributes to the prediction of the response of the soil environment to tunnel excavation using the NATM method and to minimize the diverse movements generated by tunneling. The appropriately chosen methodology confirms that displacements and subsidence are strongly influenced by the tunneling method. The three-dimensional Finite Elements Method using Plaxis3D program has been applied in the numerical simulation. The study resulted in the recommendation of a process that minimizes the effect of excavation on subsidence and ground displacement for a particular Setiha tunnel.

Optimization of Seepage Prevention of Ma Erdang Hydropower Station

2014 ◽  
Vol 1065-1069 ◽  
pp. 619-624
Author(s):  
Li Ting Qiu ◽  
Zhen Zhong Shen ◽  
Xiao Hu Tao
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Seepage Flow ◽  
Design Stage ◽  
Seepage Discharge ◽  
Element Analysis ◽  
Seepage Control ◽  
Calculation Results ◽  
Dam Site ◽  
The Stability

Base on the design of seepage control, the three-dimensional non-steady saturated - unsaturated seepage finite element analysis program CNPM3D is used to establish the three-dimentional finite element seepage model of junction area during operating period. The seepage field of dam site area is studied under the different anti-seepage curtain arrangement scheme. Specifically, the seepage gradient and the seepage discharge of the panel, major material zone, foundation curtains and two sides abutment curtains are analyzed to evaluate the stability of the major district of dam area, in order to provide suggestions for choosing the seepage control standard in the next deepen design stage.The calculation results show that the panel and the impervious curtain anti-seepage effect is remarkable.Impervious curtain can greatly reduce the total seepage flow of the dam and its foundation.However the curtain deepened to 1Lu has little effect on seepage discharge. It is showed that the seepage prevention standards of 3 lu should be proposed in the deepen design stage for both security and economic benefit. The achievement and experience of this seepage prevention design should be taken into consideration for other similar projects.

Rotordynamic Evaluation of Centrifugal Compressor Using Electromagnetic Exciter

2011 ◽  
Author(s):  
Naohiko Takahashi ◽  
Yohei Magara ◽  
Mitsuhiro Narita ◽  
Haruo Miura
Keyword(s):  
High Pressure ◽  
Frequency Response ◽  
Damping Ratio ◽  
Practical Method ◽  
Magnetic Bearing ◽  
Response Functions ◽  
Mathematical Operation ◽  
Frequency Response Functions ◽  
Calculation Results ◽  
The Stability

Since heavier gases exert larger effects on rotordynamic stability, stability evaluation is important in developing or designing high-pressure compressors. To evaluate the rotor stability during operation, an excitation test using a magnetic bearing is the most practical method. In stability analysis, labyrinth seals can produce significant cross-coupling forces, which particularly reduce the damping ratio of the first forward mode. Therefore, forward modes should be distinguished from backward modes in the excitation test. One method that excites only the forward modes, not the backward modes (and vice versa), is the use of a rotating excitation. In this method, the force is simultaneously applied to two axes to excite the rotor in circular orbits. Two trigonometric functions, i.e., cosine and sine functions, are used to generate this rotation force. Another method is the use of a unidirectional excitation and a mathematical operation to distinguish the forward whirl from the backward whirl. In this method, a directional frequency response function that separates the two modes in the frequency domain is obtained from four frequency response functions by using a complex number expression for the rotor motion. In this study, the latter method was employed to evaluate the rotor stability of a high-pressure compressor. To obtain the frequencies and damping ratios of the eigenvalues, the curve fitting based on system identification methods, such as the prediction error method, was introduced for the derived frequency response functions. Firstly, these methods were applied to a base evaluation under a low-pressure gas operation, in which the stability mainly depends on the bearing property. Using the obtained results, the bearing coefficients were estimated. Next, the same methods were applied to stability evaluations under high-pressure gas operations. The destabilizing forces were also estimated from the test results and compared with the calculation results.

Analysis of the Stability Conditions of Qing River Gushubao Landslide Mass

2011 ◽  
Vol 243-249 ◽  
pp. 5115-5121
Author(s):  
Zhang Shuo ◽  
Tan Wei ◽  
Li Feng
Keyword(s):  
Limit Equilibrium ◽  
Objective Assessment ◽  
Three Dimensional ◽  
Vertical Displacement ◽  
Stability Conditions ◽  
Nonlinear Fem ◽  
Management Measures ◽  
Landslide Mass ◽  
Calculation Results ◽  
The Stability

The stability conditions after the instability of sliding is a concern issue; it is the significant foundation to conduct objective assessment for selecting engineering management measures. According to the geological background and geological exploration data, some representative sections as well as their stability conditions were studied and analyzed based on limit equilibrium method for rigid block and three-dimensional nonlinear FEM in this paper. The impacts on the slop stability by different depths of the transient saturated zone caused by groundwater as well as rainfall infiltration were taken into consideration during the calculation analysis. It is indicated by the results that the impacts on the landslide mass displacement by rainfall have distinguish spatial properties; the impacts on vertical displacement is bigger than that of the horizontal direction; the obvious impacting zone is located in the little backer anterior border area of the landslide mass. The calculation results can provide important references for the control and reinforcement of the landslide mass as well as the prevention of landslide hazard during the later engineering construction activities.

scholarly journals Stability Analysis of High-Pile and high-pier Considering Initial Pier Deviation

2021 ◽  
Vol 261 ◽  
pp. 02050
Author(s):  
Mei-Liang Zhu ◽  
Li-Qing Zhang ◽  
Ye Ma ◽  
Shun-Kun Jiang
Keyword(s):  
Three Dimensional ◽  
Horizontal Displacement ◽  
Nonlinear Buckling ◽  
Buckling Loads ◽  
Dimensional Finite Element ◽  
Calculation Results ◽  
High Pier ◽  
The Stability ◽  
Three Dimensional Finite Element ◽  
Better Than

Based on the high-pile and high-pier bridge of Qianhuang Expressway, eigenvalue buckling analysis is carried out by establishing three-dimensional finite element models of three different bridge types and high-pier types, and the corresponding structural nonlinear buckling loads under different initial pier deviations are calculated. The calculation results show that the nonlinear buckling loads of three high-pier types are less than elastic buckling loads. The stability of column high-pile and high-pier of continuous bridge is better than that of simple supported bridge, and the stability of plate high-pier is better than that of other two high-piers. In addition, the corresponding buckling load decreases with the increase of the initial horizontal displacement, indicating that the pier top offset of the high-pile and high-pier bridge is not conducive to the stability of the structure.

Analysis of Surge Shaft Excavation Process Based on 3-Dimensional Finite Difference Method

2014 ◽  
Vol 620 ◽  
pp. 69-74
Author(s):  
Zhen Zhong Shen ◽  
Ning Wang ◽  
Nan Yao ◽  
Chao Xin Shao
Keyword(s):  
Finite Difference ◽  
Three Dimensional ◽  
Surrounding Rock ◽  
Hydroelectric Power Station ◽  
Hydroelectric Power ◽  
Analysis Method ◽  
3 Dimensional ◽  
Hydroelectric Project ◽  
Excavation Process ◽  
The Stability

As an important part of the structure of hydroelectric power station, surge shaft is embedded in the rock mass, whose body size and loading conditions are typically complex. Thus, it is necessary to evaluate safety of the design scheme in order to ensure construction safety. With upper background, three dimensional finite difference model of the surge shaft and surrounding rock of a hydroelectric project in Zambia were established based on three dimensional nonlinear finite difference analysis method. Calculation of the surge shaft stepped excavation with supporting at all levels of the construction process was done. The deformation and stress state of the surrounding rock of surge shaft and its variation law in excavation process was analyzed. Furthermore, the stability of surrounding rocks and rationality of the designed support measures were evaluated.

Dynamical Analysis on Underground Powerhouse of Yixing Pumped-Storage Power Station

2014 ◽  
Vol 580-583 ◽  
pp. 3021-3025
Author(s):  
Fang Han ◽  
Dong Wang Zhong ◽  
Ji Yun Mo ◽  
Gui Juan Chen
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Vibration Response ◽  
Dynamical Analysis ◽  
Power Station ◽  
Underground Powerhouse ◽  
Dimensional Finite Element ◽  
Pumped Storage ◽  
Three Dimensional Finite Element ◽  
House Structure

The vibration characteristics and vibration response under different load cases in the underground powerhouse structure of Yixing pumped-storage power station were studied by establishing three-dimensional finite element model. The harmonic and transient analysis methods were proposed to study the vibration response of the powerhouse structure under various generating unit dynamic loads and in transient process. The numerical results were evaluated according to the related rules and regulations. The result shows that the vibration response of the power house structure is in the limit of the rules and regulations and there was little chance of resonance.

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