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Liu Y.,Tsinghua University | He Z.,Tsinghua University | Yang Q.,Tsinghua University | Deng J.,Tsinghua University | Xue L.,Chengdu Engineering Corporation Ltd
International Journal of Geomechanics | Year: 2017

A high arch dam project causes an intense disturbance to its geological environment, with high in situ stress in the critical instability state, and the creep and damage of abutment rock mass resulting from the process of nonequilibrium evolution have a serious impact on the long-term safety of an arch dam. In this study, the long-term stability of an arch dam was evaluated with time-dependent deformation reinforcement theory (TDRT), in which plastic complementary energy (PCE) was used to judge the steady state or viscoplastic flow of the structure, the overstresses beyond the yield criterion were the driving force for nonequilibrium evolution of rock structures, and the unbalanced forces were the required reinforcement forces. Based on a viscoplastic model and asymptotic stability analysis, the principle of minimum plastic complementary energy was proved for perfect and hardening yielding, in which viscoplastic structures deform to the limit steady state at which the PCE is minimized under time-invariant loading and boundary conditions. Thus, the PCE is a reasonable and quantitative criterion for stability evolution, and unbalanced forces can be used to determine the reinforcement because they have a completely mathematical basis. The expression of PCE and unbalanced forces for the finite-element method (FEM) were programmed, the theory was implemented in a parallel FEM code, and the long-term safety of Jinping Arch Dam in China was evaluated. © 2016 American Society of Civil Engineers.

Zheng X.-Y.,Chengdu Engineering Corporation Ltd | Shen J.,University of Electronic Science and Technology of China
Civil Engineering and Urban Planning IV - Proceedings of the 4th International Conference on Civil Engineering and Urban Planning, CEUP 2015 | Year: 2016

Diversion tunnel is often characterized by long tunnel line, extremely complicated geologic conditions and construction techniques, great embedded depth, inspection and maintenance difficulties. Consequently, the problems of construction management and engineering construction schedule control could occur, especially diversion tunnel groups. In this paper, a new ontology-based model for diversion tunnel is proposed, and design and development of the context management system for mobile computing, which is an intelligent context-aware system, is described. Moreover, knowledge sharing and knowledge reuse are also provided by using the ontology model. The context management system makes use of rulebased reasoning that provides derivation of a high-level context from a low-level context. The test results validate the feasibility of the context management system. The achievements of this paper could provide references for the management of diversion tunnel or similar rock engineering. Technical support and scientific basis are also provided for its process control, safety warning, later inspection and maintenance. © 2016 Taylor & Francis Group, London.

Sun L.M.,North China University of Water Conservancy and Electric Power | Liu X.,Chengdu Engineering Corporation | Zhang Z.R.,China Railway Siyuan Survey and Design Group Co.
Applied Mechanics and Materials | Year: 2013

According to the tested physical and mechanical soil parameters of the Coastal Railway in West Guangdong along the broad coastal plain region, the correlation relations between compression modulus, compression coefficient and void ratio, moisture content, density, standard penetration number are analyzed by the linear regression method. The results show that the compression modulus increases with the increase of water content and void ratio, with correlation coefficients being 0.6985 and 0.8147, respectively; the compression modulus decreases with the increase of density and standard penetration number, with correlation coefficients being 0.7827 and 0.4934, respectively; the compression coefficient decreases with the increase of water content and void ratio, with correlation coefficients being 0.9131 and 0.9412, respectively; the compression coefficient decreases with the increase of density and standard penetration number, with correlation coefficients being 0.8187 and 0.4985, respectively. The parameters which are hardly obtained from the test directly can be easily evaluated by using these formulas. © (2013) Trans Tech Publications, Switzerland.

Lin C.,Tsinghua University | Yang Q.,Tsinghua University | Wang H.-B.,Chengdu Engineering Corporation Ltd | Li R.-H.,Chengdu Engineering Corporation Ltd
Yantu Lixue/Rock and Soil Mechanics | Year: 2016

Mengdigou Hydropower Station is the fifth cascade hydropower station in Yalong River's middle reaches. Due to the maximum dam height of 200 m and complex geological conditions, it is of significant importance for engineering safety to ensure the dam's good workability and global stability after impounding. Based on deformation reinforcement theory (DRT), a 3D finite element model of Mengdigou is built to analyze the behavior of the dam's displacements, plastic zones extension and global stability under both normal and overloading conditions. The results show that the displacements and overloading capacity meet the stability requirement. The introduction of fillet significantly reduces the plastic complementary energy of both the dam and base, which is beneficial to the global stability. Two ways of replacement treatment for f4 fault are investigated. It turns out to be more favorable using shallow replacement together with grid replacement for the dam's global stability. © 2016, Science Press. All right reserved.

Xiao Y.,Hohai University | Zhou S.,Hohai University | Lou X.,Chengdu Engineering Corporation Ltd
ICCREM 2015 - Environment and the Sustainable Building - Proceedings of the 2015 International Conference on Construction and Real Estate Management | Year: 2015

Currently the organizational project management capacity in EPC project has become more and more concerned. The focus of the project management capacity is about a dynamic process that improves the organization and coordination, and enhances the scientific and standardized degree in project management. Evaluation of project management is the foundation for improving the project management capabilities for organization. The project management maturity model (PMMM) is proposed in this context to evaluation project management maturity of the hydropower EPC contractor. By the PMMM and combining with the specific characteristics and the current study situation hydropower project management at home and abroad, here we built a maturity framework and the evaluation system for hydropower EPC contractor on project management. And propose the evaluation method based on gray comprehensive evaluation. The empirical analysis of the EPC contract practices in SOPLADORA hydropower project shows that it is feasible and effective to analyze the maturity of the management. © 2015 ASCE.

PubMed | China Earthquake Administration, Chengdu Engineering Corporation, University of Potsdam and California Institute of Technology
Type: Comment | Journal: Science (New York, N.Y.) | Year: 2015

In their Comment, Zeitler et al. do not challenge our results or interpretation. Our study does not disprove coupling between tectonic uplift and erosion but suggests that this coupling cannot be the sole explanation of rapid uplift in the Himalayan syntaxes.

PubMed | China Earthquake Administration, Chengdu Engineering Corporation, University of Potsdam and California Institute of Technology
Type: Journal Article | Journal: Science (New York, N.Y.) | Year: 2014

The Himalayan mountains are dissected by some of the deepest and most impressive gorges on Earth. Constraining the interplay between river incision and rock uplift is important for understanding tectonic deformation in this region. We report here the discovery of a deeply incised canyon of the Yarlung Tsangpo River, at the eastern end of the Himalaya, which is now buried under more than 500 meters of sediments. By reconstructing the former valley bottom and dating sediments at the base of the valley fill, we show that steepening of the Tsangpo Gorge started at about 2 million to 2.5 million years ago as a consequence of an increase in rock uplift rates. The high erosion rates within the gorge are therefore a direct consequence of rapid rock uplift.

Li C.,Chengdu Engineering Corporation Ltd | Azzam R.,RWTH Aachen | Fernandez-Steeger T.M.,TU Berlin
Sensors (Switzerland) | Year: 2016

The fast development of wireless sensor networks and MEMS make it possible to set up today real-time wireless geotechnical monitoring. To handle interferences and noises from the output data, Kalman filter can be selected as a method to achieve a more realistic estimate of the observations. In this paper, a one-day wireless measurement using accelerometers and inclinometers was deployed on top of a tunnel section under construction in order to monitor ground subsidence. The normal vectors of the sensors were firstly obtained with the help of rotation matrices, and then be projected to the plane of longitudinal section, by which the dip angles over time would be obtained via a trigonometric function. Finally, a centralized Kalman filter was applied to estimate the tilt angles of the sensor nodes based on the data from the embedded accelerometer and the inclinometer. Comparing the results from two sensor nodes deployed away and on the track respectively, the passing of the tunnel boring machine can be identified from unusual performances. Using this method, the ground settlement due to excavation can be measured and a real-time monitoring of ground subsidence can be realized. © 2016 by the authors; licensee MDPI, Basel, Switzerland.

Guo Q.,University of Sichuan | Pei L.,University of Sichuan | Zhou Z.,Chengdu Engineering Corporation Ltd | Chen J.,University of Sichuan | Yao F.,Dadu River Hydropower Development Co.
Computers and Geotechnics | Year: 2016

High core rockfill dams exhibit complex deformation mechanisms because of complicated geological conditions, many material partitions and severe weather conditions. When realistic parameters cannot be obtained through laboratory tests or engineering analogies because of effects of size or time, back analysis is necessary to predict deformation characteristics. This paper proposes a method of deformation back analysis based on the response surface method and genetic optimization theory. The parameters of the creep and Duncan-Chang models for the Pubugou gravelly soil core rockfill dam are sequentially calculated. Back analysis performed using this method efficiently yields more precise results than those obtained from laboratory-determined parameters. © 2016 Elsevier Ltd.

Chang L.-Y.,Chengdu Engineering Corporation Ltd | Chen Q.,University of Sichuan | Ye F.-M.,Chengdu Engineering Corporation Ltd
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2016

Contact erosion easily occurs at the interface between two soil layers subjected to a groundwater flow. Particles of the fine soils are eroded by the flow and transported through the pores of the coarse layer, which may lead to failure of a hydraulic structure. To investigate the meso-mechanism of contact erosion, different layers consisting of uniform particles subjected to a flow parallel to the interface are simulated using the particle flow code. The results show that when the ratio of the effective diameter of the fine layer to the effective pore diameter of the coarse layer is larger than 0.50|, the contact erosion does not occur. When the contact erosion happens between layers, the fine particles at the interface will move and be transported by the flows. With the increase in the loss quantity of the fine particles, the coarse particles will sink and the flow velocity will increase. © 2016, Editorial Office of Chinese Journal of Geotechnical Engineering. All right reserved.

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