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Sediment transport in pure acceleration-skewed oscillatory sheet flow

Journal of Hydrodynamics 2018年第6期30卷 1045-1054页

作者： Xin Chen Fu-jun Wang Gen-fa Chen Liu-chao Qiu College of Water Resources and Civil engineering China Agricultural University Beijing engineering research center of safety and Energy Saving technology for Water Supply Network System China Agricultural University China Institute of Water Resources and hydropower research

In the present study, an analytical concept model is built, using a two-phase model for the sediment transport in a pure acceleration-skewed oscillatory sheet flow. The analytical model is based on the asymmetric wave theory, the irregular boundary layer theory and the exponential concentration distribution theory, to be used for analyzing the phase lag and the boundary layer development related to the acceleration skewness. The two-phase model is applied for the calculations of the instantaneous erosion depth, the sediment flux, the boundary layer thickness and the sediment transport rate, as well as the differences between the positive acceleration stage and the negative acceleration stage caused by the acceleration skewness, as very important in the net current and sediment transport. The effects of the sediment diameter and the phase lag are explained by a comparison with the instantaneous type empirical formula, as is closely related to the acceleration skewness. With the analytical concept model and the two-phase model, the generation of the net sediment transport in the pure acceleration-skewed flows is clearly explained. The phase lag effect is important for the instantaneous sediment transport in the pure acceleration-skewed flow, whereas the boundary layer development difference between the positive acceleration stage and the negative acceleration stage plays a major role in the determination of the net sediment transport.

关键词： Acceleration skewness analytical concept model boundary layer thickness two-phase model sediment transport rate

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A new method of estimating the equivalent elastic modulus of RCCD

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Science China(Technological Sciences) 2007年第z1期50卷 136-143页

作者： GU ChongShi1,2?, WU Yuan1, SU HuaiZhi1,2 & TANG LiHui1 1 College of Water Conservancy and hydropower engineering, Hohai University, Nanjing 210098, China 2 National engineering research center of Water Resources Efficient Utilization and engineering safety, Nanjing 210098, China College of Water Conservancy and hydropower engineering Hohai University Nanjing 210098 China National engineering research center of Water Resources Efficient Utilization and engineering safety Nanjing 210098 China

Based on the composite material mechanic theory, the analysis method for the equivalent elastic moduli which are parallel and vertical to the construction interface of RCCD is studied in this paper. The differences between the equivalent elastic moduli which are vertical to the construction interface of RCCD gotten from different methods are discussed in detail. The variation range of the equivalent elastic modulus which is vertical to the construction interface of RCCD is studied based on the principle of minimum complementary energy and the principle of minimum potential energy. The effect of the related influential factors on the equivalent elastic modulus is analyzed. The estimation formula of the equivalent modulus which is vertical to the construction interface of RCCD is proposed. The feasibility of the approach proposed in this paper is analyzed through an example.

关键词： RCCD equivalent elastic modulus variation range estimation method

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Review on hidden trouble detection and health diagnosis of hydraulic concrete structures

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Science China(Technological Sciences) 2007年第z1期50卷 34-50页

作者： WU ZhongRu1,2?, LI Ji1, GU ChongShi1,2 & SU HuaiZhi1,2 1 College of Water Conservancy and hydropower engineering, Hohai University, Nanjing 210098, China 2 National engineering research center of Water Resources Efficient Utilization and engineering safety, Nanjing 210098, China College of Water Conservancy and hydropower engineering Hohai University Nanjing 210098 China National engineering research center of Water Resources Efficient Utilization and engineering safety Nanjing 210098 China

A large number of hydraulic concrete structures have hidden defects such as cracks, erosion, freeze and thaw, thermal fatigue, carbonization. These hidden defects seriously affect the strength, stability and durability of structures. These problems are studied mainly by single monitoring or diagnosis methods at present. The integration of multiple monitoring and diagnosis methods is not applied widely. Besides, the analysis theory on these problems is not developed very well. The systemic study on the aging mechanism of hydraulic concrete structures, time- variation model and health diagnosis is still not enough. The support for engineering practice is limited. Aimed at these major scientific and technological problems and combined with specific projects, study on detection of hidden defects and health diagnosis of hydraulic concrete structure has been carried out. This study includes the following content: field non-destructive examination of hidden defects of hydraulic concrete structures, seepage detection, the construction of in-situ sensing system, the combination of field detection and in-situ monitoring, the mechanism of crack, freeze and thaw, erosion and carbonization of hydraulic concrete structure, mechanism of combination aging; time-variation model of hydraulic concrete structure, theories and methods for health diagnosis of hydraulic concrete structures.

关键词： hydraulic concrete structure hidden trouble detection health diagnosis

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Evaluation model for service life of dam based on time-varying risk probability

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Science China(Technological Sciences) 2009年第7期52卷 1966-1973页

作者： SU HuaiZhi WEN ZhiPing HU Jiang WU ZhongRu College of Water Conservancy and hydropower engineering of Hohai University Nanjing 210098China National engineering research center of Water Resources Efficient Utilization and engineering safety Nanjing 210098China College of Computer engineering Nanjing Institute of TechnologyNanjing 211167China

For many dam projects in China, the 50-year designed life time is coming to an end. It is urgent to study the theory and method to evaluate the dam service life. In this paper, firstly, the probability theory of fuzzy event and time-varying effect theory are used to analyze the time-variety of various risk factors in the process of dam operations. A method is proposed to quantify the above time-variety and a model to describe the fuzzy time-varying risk probability for the dam structure is also built. Secondly, the information entropy theory is used to analyze the uncertain degree relationship between the characteristic value of membership function and fuzzy risk probability, and a mathematical method is presented to calculate the time-varying risk probability accordingly. Thirdly, the relation mode between time-varying risk probability and service life is discussed. Based on this relation mode and the acceptable risk probability of dams in China, a method is put forward to evaluate and forecast the dam service life. Finally, the proposed theory and method are used to analyze one concrete dam. The dynamic variability and mutation feature of the dam risk probability are analyzed. The remaining service life of this dam is forecasted. The obtained results can provide technology support for the project management department to make treatment measures of engineering and reasonably arrange reinforce cost. The principles in this paper have wide applicability and can be used in risk analysis for slope instability and other fields.

关键词： dam service life evaluation time-varying risk probability fuzzy probability theory information entropy theory

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Modeling and Optimization of Stand-Alone Hybrid Power System : a Case Study for a Household in Urumqi,China

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Journal of Donghua University(English Edition) 2015年第5期32卷 792-799页

作者：李冲郑源朱大胜宋晨光 School of Mechanical engineering Nanjing Institute of Technology National engineering research center of Water Resources Efficient Utilization and engineering safety College of Energy and Electrical engineering Hohai University College of Water Conservancy and hydropower engineering Hohai University

In order to alleviate environmental pollution of Urumqi,China,a stand-alone hybrid wind / PV / battery power system was studied for this region. An accurate structure and model of the standalone hybrid wind / PV / battery power system for a household in that region was presented in this study. On the basis of wind speed,solar radiation,ambient temperature,and load data,the optimal design of the hybrid system is determined using a genetic algorithm( GA). As a result,the optimal hybrid system for a household consists of one wind turbine,21. 407 6 m^2 of PV arrays,and 20. 958 kW ·h of battery bank capacity. The system has a loss of power supply probability( LPSP) of 0. 019 9 and the minimum total annualized cost is $ 35 333.

关键词： wind/PV/battery power system genetic algorithm(GA) Urumqi

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Game model of safety monitoring for arch dam deformation

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Science China(Technological Sciences) 2008年第S2期51卷 76-81页

作者： SU HuaiZhi1,2,WU ZhongRu1,2,GU YanChang1,2,HU Jiang1 & WEN ZhiPing3 1 College of Water Conservancy and hydropower engineering,Hohai University,Nanjing 210098,China 2 National engineering research center of Water Resources Efficient Utilization and engineering safety,Nanjing 210098,China 3 Department of Computer engineering,Nanjing Institute of technology,Nanjing 210013,China College of Water Conservancy and hydropower engineering Hohai University Nanjing 210098 China National engineering research center of Water Resources Efficient Utilization and engineering safety Nanjing 210098 China Department of Computer engineering Nanjing Institute of Technology Nanjing 210013 China

Arch dam deformation is comprehensively affected by water pressure,temperature,dam's structural behavior and material properties as well as other *** them the water pressure and temperature are external factors(source factors) that cause dam deformation,and dam's structural behavior and material properties are the internal factors of deformation(resistance factors).The dam deformation is the result of the mutual game playing between source factors and resistance ***,resistance factors of structure and materials that reflect resistance character of arch dam structure are introduced into the traditional model,where structure factor is embodied by the flexibility coefficient of dam body and the maximum dam height,and material property is embodied by the elastic modulus of *** the basis of analyzing the correlation between dam deformation and resistance factors,the game model of safety monitoring for arch dam deformation is put forward.

关键词： arch dam deformation monitoring model flexibility coefficient game theory

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Assessment model of dam operation risk based on monitoring data

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Science China(Technological Sciences) 2007年第z1期50卷 144-152页

作者： WU ZhongRu1,2?, SU HuaiZhi1,2 & GUO HaiQing1 1 College of Water Conservancy and hydropower engineering, Hohai University, Nanjing 210098, China 2 National engineering research center of Water Resources Efficient Utilization and engineering safety, Nanjing 210098, China 1. College of Water Conservancy and hydropower engineering Hohai University Nanjing 210098 China 2. National engineering research center of Water Resources Efficient Utilization and engineering safety Nanjing 210098 China

Although the dams produce remarkable social and economic benefits, the threat made by unsafe dams to the life and property of people who live in the lower river area is un-negligible. Based on the monitoring data which reflect the safety condition of dams, the risk degree concept is proposed and the analysis system and model for evaluating risk degree (rate) are established in this paper by combining the reliability theory and field monitoring data. The analysis method for risk degree is presented based on Bayesian approach. A five-grade risk degree system for dam operation risk and corresponding risk degree is put forward according to the safety condition of dams. The operation risks of four cascade dams on some river are analyzed by the model and approach presented here and the result is adopted by the owner.

关键词： dam monitoring data operation risk degree analysis model

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Slope analysis based on local strength reduction method and variable-modulus elasto-plastic model

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Journal of Central South University 2014年第5期21卷 2041-2050页

作者：杨光华钟志辉傅旭东张玉成温勇张明飞 School of Civil and Architectural engineering Wuhan University Guangdong research Institute of Water Resources and hydropower Geotechnical engineering technology center of Guangdong Province School of Civil engineering and Transportation South China University of Technology

Employing an ideal elasto-plastic model,the typically used strength reduction method reduced the strength of all soil elements of a ***,this method was called the global strength reduction method(GSRM).However,the deformation field obtained by GSRM could not reflect the real deformation of a slope when the slope became *** most slopes,failure occurs once the strength of some regional soil is sufficiently weakened; thus,the local strength reduction method(LSRM)was proposed to analyze slope *** contrast with GSRM,LSRM only reduces the strength of local soil,while the strength of other soil remains ***,deformation by LSRM is more reasonable than that by *** addition,the accuracy of the slope's deformation depends on the constitutive model to a large degree,and the variable-modulus elasto-plastic model was thus *** constitutive model was an improvement of the Duncan–Chang model,which modified soil's deformation modulus according to stress level,and it thus better reflected the plastic feature of *** importantly,the parameters of the variable-modulus elasto-plastic model could be determined through in-situ tests,and parameters determination by plate loading test and pressuremeter test were ***,it is easy to put this model into ***,LSRM and the variable-modulus elasto-plastic model were used to analyze Egongdai ancient *** factor,deformation field,and optimal reinforcement measures for Egongdai ancient landslide were obtained based on the proposed method.

关键词： slope stability local strength reduction method variable-modulus elasto-plastic model in-situ test

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Mechanical effects of excavation rebound of arch dam bedrock and better concreting time of dam body

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Science China(Technological Sciences) 2009年第2期52卷 513-517页

作者： WU ZhongRu GU YanChang SU HuaiZhi GUO HaiQing College of Water Conservancy and hydropower engineering Hohai UniversityNanjing 210098China National engineering research center of Water Resources Efficient Utilization and engineering safety Nanjing 210098China Hydraulic research Institute Nanjing 210029China

In this study, a nonlinear model is presented for analysis of damage-cracking behavior in arch dams during strong earthquakes using different seismic input mechanisms. The nonlinear system includes a plastic-damage model for cyclic loading of concrete considering strain softening and a contact boundary model of contraction joint opening. Two different earthquake input mechanisms are used for comparison, including massless foundation input model and viscous-spring boundary model considering radiation damping due to infinite canyon. The results demonstrate that effects of seismic input mechanism and radiation damping on nonlinear response and damage-cracking of the dam are significant. Compared with the results of using massless foundation input model, the damage-cracking region and contraction joint opening are substantially reduced when using viscous-spring boundary model to take into account radiation damping. However, if the damping ratio of the dam is artificially increased to about 10%–15% for massless foundation input model, the joint opening and damage-cracking of the dam are comparable to the results obtained from the viscous-spring boundary model.

关键词： rebound deformation mechanical effects deformation modulus better concreting time

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Evaluation of toppling rock slopes using a composite cloud model with DEMATEL–CRITIC method

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Water Science and engineering 2023年第3期16卷 280-288页

作者： Huan-ling Wang Xu-fei Zhao Hong-jie Chen Kui Yi Wei-chau Xie Wei-ya Xu research Institute of Geotechnical engineering Hohai UniversityNanjing 210098China huaneng Lancang River hydropower Ltd. Technology R&D CenterKunming 650214China Department of Civil and Environmental engineering University of WaterlooWaterlooOntario N2L 3G1Canada

safety evaluation of toppling rock slopes developing in reservoir areas is crucial. To reduce the uncertainty of safety evaluation, this study developed a composite cloud model, which improved the combination weights of the decision-making trial and evaluation laboratory (DEMATEL) and criteria importance through intercriteria correlation (CRITIC) methods. A safety evaluation system was developed according to in situ monitoring data. The backward cloud generator was used to calculate the numerical characteristics of a cloud model of quantitative indices, and different virtual clouds were used to synthesize some clouds into a generalized one. The synthesized numerical characteristics were calculated to comprehensively evaluate the safety of toppling rock slopes. A case study of a toppling rock slope near the Huangdeng hydropower Station in China was conducted using monitoring data collected since operation of the hydropower project began. The results indicated that the toppling rock slope was moderately safe with a low safety margin. The composite cloud model considers the fuzziness and randomness of safety evaluation and enables interchange between qualitative and quantitative knowledge. This study provides a new theoretical method for evaluating the safety of toppling rock slopes. It can aid in the predication, control, and even prevention of disasters.

关键词： Toppling rock slope safety evaluation Composite cloud model DEMATEL CRITIC Huangdeng hydropower Project

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