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Calculation of Mass Concrete Temperature and Creep Stress under the Influence of Local Air Heat Transfer

Computer Modeling in Engineering & Sciences 2024年第9期140卷 2977-3000页

作者： Heng Zhang Chao Su Xiaohu Chen Zhizhong Song Weijie Zhan Academy of Science and Technology Changjiang Institute of Survey Planning Design and ResearchWuhan430010China College of water conservancy and Hydropower Engineering Hohai UniversityNanjing210098China Chief Engineer Office Wujiang Company of Goupitan Power Construction CooperationYuqing564408China

Temperature-induced cracking during the construction of mass concrete is a significant *** simulations of concrete temperature have primarily assumed that the concrete is placed in an open *** problem of heat transfer between the air and concrete has been simplified to the concrete’s heat dissipation ***,in the case of tubular concrete structures,where air inlet and outlet are relatively limited,the internal air temperature does not dissipate promptly to the external environment as it *** accurately simulate the temperature and creep stress in tubular concrete structures with enclosed air spaces during construction,we establish an air–concrete coupled heat transfer model according to the principles of conjugate heat transfer,and the accuracy of the model is verified through ***,we conduct a case study to analyze the impact of airflow within the ship lock corridor on concrete temperature and creep *** results demonstrate that enhancing airflow within the corridor can significantly reduce the maximum concrete *** with cases in which airflow within the corridor is neglected,the maximum concrete temperature and maximum tensile stress can be reduced by 12.5℃ and 0.7 MPa,respectively,under a wind speed of 4 m/*** results of the traditional calculation method are relatively close to those obtained at a wind speed of 1 m/***,the temperature reduction process in the traditional method is faster,and the method yields greater tensile stress values for the corridor location.

关键词： Conjugate heat transfer temperature field mass concrete creep stress

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Calculation of Mass Concrete Temperature Containing Cooling water Pipe Based on Substructure and Iteration Algorithm

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工程与科学中的计算机建模(英文) 2024年第1期138卷 813-826页

作者： Heng Zhang Chao Su Zhizhong Song Zhenzhong Shen Huiguang Lei Changjiang institute of survey PlanningDesign and ResearchWuhan430010China College ofwater conservancy and Hydropower Engineering Hohai UniversityNanjing210098China Chief Engineer Office Wujiang Company of Goupitan Power Construction CooperationYuqing564408China

Mathematical physics equations are often utilized to describe physical phenomena in various fields of science and *** such equation is the Fourier equation,which is a commonly used and effective method for evaluating the effectiveness of temperature control measures for mass *** important measure for temperature control in mass concrete is the use of cooling water ***,the mismatch of grids between large-scale concrete models and small-scale cooling pipe models can result in a significant waste of calculation time when using the finite element ***,the temperature of the water in the cooling pipe needs to be iteratively calculated during the thermal transfer *** substructure method can effectively solve this problem,and it has been validated by *** Abaqus/Python secondary development technology provides engineers with enough flexibility to combine the substructure method with an iteration algorithm,which enables the creation of a parametric modeling calculation for cooling water *** paper proposes such a method,which involves iterating the water pipe boundary and establishing the water pipe unit substructure to numerically simulate the concrete temperature field that contains a cooling water *** verify the feasibility and accuracy of the proposed method,two classic numerical examples were *** results showed that this method has good applicability in cooling pipe *** the value of the iteration parameterαis 0.4,the boundary temperature of the cooling water pipes can meet the accuracy requirements after 4∼5 iterations,effectively improving the computational ***,this approach provides a useful tool for engineers to analyze the temperature control measures accurately and efficiently for mass concrete,such as cooling water pipes,using Abaqus/Python secondary development.

关键词： Fourier equation cooling water pipe mass concrete iteration algorithm

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Research and Application of Recycled Concrete Technology in Prefabricated Buildings

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Research and Application of Materials Science 2024年第1期6卷 33-36页

作者： Shanshan DENG Gang SHI Chao SHANG Fuchuan ZHOU Masabo Gasper Masiko M.Kaziana Chongqing Telecommunication Polytechnic College Chongqing402247China Chongqing yuxi water conservancy and electric power survey and design institute CO. LTD.Chongqing402160China Chengde Thermal Power Engineering Installation Co. Ltd.Chengde067000China Chongqing Vocational institute of Engineering Chongqing402260China Undergraduate Architecture and Civil Engineering Dar es Salaam Institute of Technology{DIT}Dar es Salaam11103Tanzania

The utilization of waste concrete as a raw material for recycled concrete in the domain of prefabricated components is garnering greater *** paper delineates and examines the concept,categorization,methodologies of preparation,applicable sectors,and evaluative metrics of recycled concrete technology,highlighting its prospective ***,for the successful integration of recycled concrete technology into prefabricated component applications,it is imperative to systematically enhance its physical,mechanical,and attributes,as well as its environmental ***,to foster the continued advancement of recycled concrete technology,innovative initiatives,standardization,educational programs,demonstration projects,and collaborative efforts are crucial to promote broader adoption and realize improved outcomes within the realm of prefabricated *** conclusion,recycled concrete technology is poised to play a pivotal role in prefabricated construction,offering robust support for propelling the construction industry towards a sustainable future.

关键词： recycled concrete prefabricated buildings Environmental performance assessment

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Theory and Application of Loss of Life Risk Analysis for Dam Break

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Transactions of Tianjin University 2010年第5期16卷 383-387页

作者：孙月峰钟登华李明超李颖 School of Civil Engineering Tianjin University Tianjin Municipal water conservancy survey and design institute

The loss of life risk evaluation model for dam break is built in this *** using an improved Monte Carlo method,the overtopping probability induced by concurrent flood and wind is calculated,and the Latin Hypercube Sampling is used to generate random *** Graham method is used to calculate the loss of life resulting from dam *** Dongwushi reservoir located at Hebei Province taken as an example,the overtopping probability induced by concurrent flood and wind is calculated as 4.77×***...

关键词： overtopping probability loss of life risk risk assessment dam safety management

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A Siltation Simulation and Desiltation Measurement Study Downstream of the Suzhou Creek Sluice, China

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China Ocean Engineering 2013年第6期27卷 781-793页

作者：季永兴杨绯张汉云卢永金 College of water conservancy and Hydropower Engineering Hohai University Shanghai water Engineering design and Research institute

The Suzhou Creek Sluice is currently the largest underwater plain gate in the world, with a single span of 100 m. It is located in a tidal estuary at the junction of the Huangpu River and Suzhou Creek in Shanghai, China. In this study, physical and 2D vertical mathematical models were used to investigate and distinguish the mechanism of siltation downstream of an underwater plain gate from that of other gates types. According to quantitative data obtained by site investigation and the application of the physical hydrodynamic models, it was found that the characteristics of the tidal estuary as well as the fact that the sluice span is equal to the creek width are the major reasons contributing to siltation. A possible desiltation treatment system is proposed for the underwater plain gate. The system includes selection of a suitable location that allows the determination of a reasonable top elevation of the sluice floor, reserving sufficient space under the gate to accommodate siltation, setting up a mechanical desiltation system, and flushing silt along with overflow over the top of the gate. Furthermore, on-site hydraulic silt flushing experiments and a topography survey were conducted. These results showed that the measurement system is effective, and by maintaining this scheduled operation once a month, the downstream riverbed has been maintained in a good condition.

关键词： tidal estuary underwater plain gate siltation sluice Suzhou Creek

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FRACTIONAL-STEP FINITE ELEMENT METHOD FOR CALCULATION OF 3-D FREE SURFACE PROBLEM USING LEVEL SET METHOD

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Journal of Hydrodynamics 2006年第6期18卷 742-747页

作者： ZHAO Lan-hao LI Tong-chun WANG Ling HERREROS M. I. PASTOR M. College of water conservancy and Hydropower Engineering Hohai University Naniing 210098 China Anhui survey and design institute of water conservancy and Hydropower Hefei 230022 China CEDEX and E.T.S. de Caminos Madrid Spain

A two-step Taylor-Galerkin fractional-step finite element method, which is of second order accuracy in space and time, was proposed for the three-dimensional free surface problem. With this method, the intermediate velocity was explicitly obtained by neglecting pressure gradient term, and then the velocity was corrected by adding the effects of pressure once the pressure field had been obtained from the pressure Poisson equation. The level set approach was applied to track implicitly the free surface. In order to track the free surface, the transport equation of the level set function was solved at each time step and the level set function is reinitialized through iteration to maintain it as a distance function. The governing equations of the system were discretized by the two- step Taylor-Galerkin method, which is of high-order accuracy and easy to be used. The validity and reliability of this method in this article were proved by two numerical examples.

关键词： level set free surface two steps Taylor-Galerkin fractional step FEM

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Calibration and performance of two different constitutive models for rockfill materials

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water Science and Engineering 2016年第3期9卷 227-239页

作者： Lin-ke Li Zhan-jun Wang Si-hong Liu Erich Bauer institute of Applied Mechanics Graz University of Technology Changjiang institute of survey PlanningDesign and Research College of water conservancy and Hydropower Engineering Hohai University

In this paper, two different concepts for the constitutive modeling of the mechanical behavior of creep-sensitive rockfill materials are presented. Specifically, the performance of an extended generalized plasticity model proposed by Wang is compared with a simplified version of the hypoplastic constitutive model for weathered rockfill materials proposed by Bauer. Both models can reflect the influence of the mean stress on the incremental stiffness, the peak friction angle, and the dilatancy angle. The so-called solid hardness defined for a continuum description and originally introduced by Bauer is embedded in both models. Hydrochemical, thermal, and mechanical weathering are usually caused by environmental changes and are taken into account in a phenomenological description with an irreversible and time-dependent degradation of the solid hardness. A degradation of the solid hardness is usually accompanied by creep deformation of the stressed rockfill material. It is shown that appropriate modeling of creep deformation requires at least a unified description of the interaction between the time-dependent process of degradation of the solid hardness and the stress state. In this context, the solid hardness can be understood as a key parameter for describing the evolution of the state of weathering of the rockfill material. Particular attention is also paid to the necessary procedure for determining the constitutive constants of the two different constitutive models. Finally, the performance of the two different constitutive models is demonstrated by comparing the results obtained from numerical simulations with experimental data from the creep-sensitive rockfill material.

关键词： Rockfill material Creep Generalized plasticity Hypoplasticity Constitutive model

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water quality assessment for Ulansuhai Lake using fuzzy clustering and pattern recognition

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Chinese Journal of Oceanology and Limnology 2008年第3期26卷 339-344页

作者：任春涛李畅游贾克力张生李卫平曹有玲 Inner Mongolia Agricultural University Huhhot 010018 China Inner Mongolia Power Exploration & design institute Huhhot 010020 China Inner Mongolia survey & design institute of water conservancy & Hydropower Huhhot 010020 China

water quality assessment of lakes is important to determine functional zones of water *** the fuzziness during the partitioning process for lake water quality in an arid area,a multiplex model of fuzzy clustering with pattern recognition was developed by integrating transitive closure method,ISODATA algorithm in fuzzy clustering and fuzzy pattern *** model was applied to partition the Ulansuhai Lake,a typical shallow lake in arid climate zone in the west part of Inner Mongolia,China and grade the condition of water quality *** results showed that the partition well matched the real conditions of the lake,and the method has been proved accurate in the application.

关键词： transitive closure method ISODATA clustering algorithm fuzzy pattern recognition method partitioning of water quality

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Scour and silting evolution and its influencing factors in Inner Mongolian Reach of the Yellow River

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Journal of Geographical Sciences 2011年第6期21卷 1037-1046页

作者： QIN Yi ZHANG Xiaofang WANG Fenglong YAN Heng HAN Haijun Key Laboratory of North-West water Resources and Ecology Environment of Ministry of Education Xi＇an University of Technology Xi＇an 710048 China zhoushan water conservancy survey and design institute Zhoushan 316000 Zhejiang China Harbin water conservancy Plan and design institute Harbin 150076 China

Rivers with fluvial equilibrium are characterized by bed deformation adjustment. The erosion-deposition area in cross-section reflects this characteristic, which is a base of researching the river scour and deposition evolution by time series analysis. With an ero- sion-deposition area indicator method proposed in this paper, the time series of ero- sion-deposition area quantity at Bygl and Shhk stations were obtained with the series duration of 31 years from 1976 to 2006. After analysis of its trend and mutation, three different ten- dencies about the evolution were observed in general from the quasi-equilibrium phase through a rapid shrinkage to the final new quasi-equilibrium. It is also found that the trend of erosion-deposition area series will change once a big flood occurred in some of the tributaries and its ever greater influence is due to the decrease of deluge with the completion of up- stream reservoirs. Almost all the turning points were coincident with the time when hy- per-concentrated sediment flood occurred in some tributaries. With the time series of clear mutations since the late 1990s, the Inner Mongolian Reach has been in a new equilibrium phase. This can be concluded in two aspects. 1. The absence of big floods and sediment transportation from tributaries result in the river shrinkage, and to regain the channel flow-carrying capacity in Inner Mongolian Reach a large flood is needed both of high peak discharge and of lengthy interval to destroy the new equilibrium. 2. The proposed method of erosion-deposition area indicator is of great help to channel scour-deposition evolution analysis because it can demonstrate real time deformation of cross section in quantity.

关键词： Inner Mongolian Reach of the Yellow River erosion-deposition area indicator evolution equilibrium

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Two new approaches to dividing flood sub-seasons in flood season using the fractal theory

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Chinese Science Bulletin 2010年第1期55卷 105-110页

作者： FANG ChongHui GUO ShengLian DUAN YaHui DUONG Ductien State Key Laboratory of water Resources and Hydropower Engineering Wuhan University Wuhan 430072 China Hubei institute of water conservancy & Hydropower Engineering survey Exploration design Wuhan 430064 China Vietnam water Resources University Hanoi Vietnam

This paper is an attempt to analyze the hydrological phenomena’s non-linearity, randomicity, credibility and similarity. In the same season each year, the flood hydrograph is self-similar and exhibits fractal characteristics. It is an argument about using fractal theory. This paper presents two new approaches to dividing flood sub-seasons by using the fractal theory. Two approaches to calculating fractal dimensions are both the magnitude measurement in the temporal scale and the similarity measurement in the spacial scale. This paper chooses the sample series of the daily maximum discharge in the flood season from 1960 to 2002 at the Zhanghe Reservoir. Both results of the two new approaches to dividing flood sub-seasons by using fractal theory are the same. Both results of dividing flood-periods by using the fractal theory are uniform with the traditional approach. Compared with the traditional approach, fractal approaches have quantitative and objective characteristics and are convenient in calculation, and are widely used in practice.

关键词：分形理论洪水过程汛期自相似性传统方法相似性度量水文现象分形特征

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