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Sha S.,Tsinghua University | Sha S.,China Institute of Water Resources and Hydropower Research | Lei Z.,China Institute of Water Resources and Hydropower Research | Zhang X.,Powerchina Beijing Engineering Corporation Ltd
Proceedings - 2016 International Conference on Smart City and Systems Engineering, ICSCSE 2016 | Year: 2016

The roller compacted concrete gravity dam is poured by thin layers and there are many horizontal layer surfaces and joint surfaces in the dam. The shear strength of these surfaces is obviously lower than that of the RCC concrete. These horizontal layer surfaces and joint surface are the key positions affecting the strength, stability and seepage of the dam. The height of the most RCC gravity dams is about 100m. The height is relatively low and the horizontal thrust is relatively small. So anti-sliding stability issue along the layer surfaces has not attracted enough attention. But for the dams 200m high, this problem is very prominent. In this study, using an isotropic damage model, based on the effective stress principle of porous media, taking the stress-seepage-damage coupling effect into account, the failure mechanism of Huangdeng RCC gravity dam is discussed. The results show that the failure mechanism of RCC gravity dam is the shear slipping along the layer surfaces and the foundation surface. © 2016 IEEE.


Chen Y.,China University of Petroleum - Beijing | Zhang H.,China University of Petroleum - Beijing | Zhang J.,PowerChina Beijing Engineering Corporation Ltd | Liu X.,China University of Petroleum - Beijing | And 2 more authors.
Engineering Failure Analysis | Year: 2015

Corrosion defects may compromise the safety of oil and gas pipelines. This paper investigates the failure behavior and failure pressure of X80 pipelines with longitudinally and circumferentially aligned interacting corrosion defects based on nonlinear finite element method, X80 pipeline with single corrosion defect is studied as well. On the basis of proposed failure pressure regression equations for X80 pipeline with single corrosion defect, this paper develops an assessment procedure for predicting failure pressure of pipeline with interacting corrosion defects. Through comparing predicted failure pressures using proposed solutions and assessment methods as well as experimental results available in previous literature, the accuracy of proposed solutions is demonstrated consequently. © 2014 Elsevier Ltd.


Qin N.,Power China Beijing Engineering Corporation Ltd | Cheng X.-P.,Power China Beijing Engineering Corporation Ltd | Jiang F.,Power China Beijing Engineering Corporation Ltd
Advanced Engineering and Technology II - Proceedings of the 2nd Annual Congress on Advanced Engineering and Technology, CAET 2015 | Year: 2015

This paper presents a composite element model for jointed rock masses supported by shotcrete lining and bolt. In this model, general finite element mesh can be generated without considering the existence of joint, bolt and shotcrete lining, and then composite element information can be formed according to the relevant information. Also it should be taken into consideration the behavior of every components and the localized nonlinear deformation and interactive relationship of bolt and shotcrete lining on joint. This composite element model includes the advantages of equivalent simulation and discrete simulation to be of good application prospect. © 2015 Taylor & Francis Group, London.


Wan Y.,CAS Wuhan Institute of Rock and Soil Mechanics | Xue Q.,CAS Wuhan Institute of Rock and Soil Mechanics | Wu Y.,PowerChina Beijing Engineering Corporation Ltd | Zhao L.-Y.,CAS Wuhan Institute of Rock and Soil Mechanics
Yantu Lixue/Rock and Soil Mechanics | Year: 2015

To investigate the problems such as the failure of compacted clay liners as the anti-seepage structure in the landfills cover system under the action of drying-wetting cycles, experiments under the simulated climatic environment of landfills have been conducted to determine the mechanical properties of compacted clay and its microstructure characteristics during the drying-wetting cycles and hence to reveals the intrinsic nature of the damage of compacted clay from the micro level. The experimental results show that as the number of drying-wetting cycle increases, all the secant moduli of low-, medium- and high-compacted clays increase at initial stage, while they decrease significantly at later stage, and the magnitude of secant modulus variation increases with the increase of initial compactness. Meanwhile, the shear strengths of above-mentioned three compacted clays decrease, and the magnitude of variation decreases with the increase of initial compactness or confining pressure. After three drying-wetting cycles, the total pore volume of compacted clay shows irreversible shrinkage, resulting in the increase of initial tangent modulus and shear strength. The shrinkage ratio decreases with the increase of compactness, and the shrinkage ratios of low- and high-compacted clays are 20.5% and 11.5%, respectively. The large pore volumes of low- and high-compacted clays increase 25.7% and 53.9% and the microcrack volumes increase 3.1% and 41.7%, respectively, resulting in a decrease in the shear strength and tangent modulus at later stage. The effect of drying-wetting cycles on the mechanical property of compacted clay with different compactness is controlled by two factors, i.e. the decrease of total pore volume and the increase of big-pore and microcracks. ©, 2015, Science Press. All right reserved.


Chen Y.,China University of Petroleum - Beijing | Zhang J.,Powerchina Beijing Engineering Corporation Ltd | Zhang H.,China University of Petroleum - Beijing
JVC/Journal of Vibration and Control | Year: 2016

Although flapwise bending vibration of rotating tapered beams has been extensively studied since the 1970s, most of these studies were based on approximations with varying degrees of accuracy and complexity. The flapwise bending vibration of rotating tapered beams is re-examined in this paper using the technique of variational iteration, which is relatively new and capable of providing accurate results for eigenvalue problems with good convergence. Natural frequencies and mode shapes of rotating beams are extracted for various rotational speeds and taper ratios, and solutions are compared with results published in the literature where available. © The Author(s) 2014.


Chen Y.,China University of Petroleum - Beijing | Zhang H.,China University of Petroleum - Beijing | Zhang J.,PowerChina Beijing Engineering Corporation Ltd | Li X.,Dalian University of Technology | Zhou J.,Dalian University of Technology
Materials and Design | Year: 2015

Corrosion will compromise safety operation of oil and gas pipelines, accurate determination of failure pressure finds importance in residual strength assessment and corrosion allowance design of onshore and offshore pipelines. This paper investigates failure pressure of high strength pipeline with single and multiple corrosions using nonlinear finite element analysis. On the basis of developed regression equations for failure pressure prediction of high strength pipeline with single corrosion, the paper proposes an assessment procedure for predicting failure pressure of high strength pipeline with multiple corrosions. Furthermore, failure pressures predicted by proposed solutions are compared with experimental results and various assessment methods available in literature, where accuracy and versatility are demonstrated. © 2014 Elsevier Ltd.


Sun P.,POWERCHINA Beijing Engineering Corporation Ltd | Jiang Z.-Q.,Huazhong University of Science and Technology | Wang T.-T.,POWERCHINA Beijing Engineering Corporation Ltd | Zhang Y.-K.,North China Electrical Power University
Water Resources Management | Year: 2016

In order to improve the premature convergence problem of traditional shuffled frog leaping algorithm (SFLA), this paper proposed a normal cloud mutation shuffled frog leaping algorithm (NCM-SFLA) by mixing the cloud model algorithm (NCM) with SFLA algorithm, NCM is used to overcome the shortage of SFLA which is easy to fall into local optimal solution. The proposed NCM-SFLA has a good parallel characteristic, and the parallel computing can be implemented easily in multi core environment. In case study, this paper takes the Li Xianjiang cascade reservoirs in China as an instance to solve the cascade reservoirs operation optimization problem by the proposed NCM-SFLA. The results show that, compared with the Multi- dimensional Dynamic Programming (MDP), NCM-SFLA has the better global search ability and faster convergence speed, and the corresponding parallel computing can effectively shorten the run-time of NCM-SFLA. Therefore, the feasibility and rationality of the proposed NCM-SFLA and its parallel computing are effectively proved by the case study results. © 2015, Springer Science+Business Media Dordrecht.


Li Z.-F.,China Earthquake Administration | Xiao H.-B.,PowerChina Beijing Engineering Corporation Ltd | Zhou B.-G.,China Earthquake Administration
Dizhen Dizhi | Year: 2015

Based on the data of 28 strike-slip fault steps and the surface rupture traces at home and abroad, the paper analyzes the relations between the step type, size and earthquake rupture by using the mathematical statistical method, and obtains the barriers yardsticks that stop rupture propagation of earthquakes with different magnitude intervals by using the method of statistical analysis. The results show that the limiting dimensions of strike-slip fault step are different for different magnitude intervals. The limiting dimension of step width is about 3km for magnitude between 6.5 to 6.9, 4km for magnitude between 7.0 to 7.5, 6km for magnitude between 7.5 to 8.0, and about 8km for magnitude between 8.0 to 8.5. The result implies that releasing steps should be easier to rupture through than restraining steps. The limiting dimension of step width determined in this paper is basis for rupture segmentation and is of practical importance to seismic hazard analysis. ©, 2015, State Seismology Administration. All right reserved.


Yan M.,Chengdu University of Technology | Zheng X.,Chengdu University of Technology | Zheng X.,Guangxi University | Zhu L.,Chengdu University of Technology | Chen Y.,PowerChina Beijing Engineering Corporation Ltd
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2016

The study area is located at the right bank of a proposed hydropower station on River Nu of Yunnan. The slope is mainly composed of migmatitic granite and mixed gneiss and the phenomenon of deformation and fracture controlled by low-angle and tilt-valley faults is very distinct. Although the macroscopic combination mode shows sliding-fracturing, but these faults were not cut and exposed at the slope toe and were buried inside the toe or below a certain depth of the valley. It is difficult to understand the cause of this phenomenon according to the views of traditional engineering geology and rock mechanics. Based on the field geological survey and the analysis of geological and mechanical conditions, the above phenomenon of deformation and fracture was found to be caused by the weathering and softening of rock in the valley bottom(slope toe and valley below) during the neoid geological period, which was a time-dependent deformation and fracture phenomenon. The result was verified by the numerical simulation. For the evolution of rock slopes, the softening effect of valley bottom (slope toe) is a kind of geological function with universal significance. © 2016, Science Press. All right reserved.


Chen Y.,China University of Petroleum - Beijing | Zhang J.,PowerChina Beijing Engineering Corporation Ltd | Zhang H.,China University of Petroleum - Beijing | Li X.,Dalian University of Technology | Zhou J.,Dalian University of Technology
Ocean Engineering | Year: 2015

Marine risers are important components operating in offshore oil and gas industry. The vortex-induced vibration design of marine risers requires accurate knowledge of natural frequencies and mode shapes. Free vibration of marine risers are re-examined in this paper by means of variational iteration method, which is relatively new technique capable of dealing with eigenvalue problems rather efficiently. Solutions from the variational iteration method are compared to approximate solutions previously proposed in literatures via a numerical example. Furthermore, validation of the technique is demonstrated by comparing experimentally measured natural frequencies of model marine riser with the predicted ones. © 2014 Elsevier Ltd. All rights reserved.

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