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Application of gray correlation analysis and artificial neural network in rock mass blasting

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Journal of Coal Science & engineering(China) 2005年第1期11卷 44-47页

作者：朱红兵吴亮 State Key Laboratory of water resource and Hydropower engineering Science Wuhan University

Studied forecasting and controlling the blasting fragmentation by using artifi- cial neural network for multi-ingredients. At the same time, according to the characteris- tic of multi-parameters input to network model, the gray correlation theory was employed to find out key factors, which can not only save time of computation and parameters in- put, but improve the stability of the model.

关键词： gray correlation analysis neural network rock mass blasting

Clear-water local scouring around three piers in a tandem arrangement

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Science China(Technological Sciences) 2016年第6期59卷 888-896页

作者： WANG Hao TANG HongWu XIAO JiangFeng WANG Yao JIANG Sheng State Key Laboratory of Hydrology-water resources and Hydraulic engineering Hohai University Nanjing 210098 China Huaihe River Commission of the Ministry of water resource Bengbu 233001 China

Experiments of local scouring around three piers were carried out under steady clear-water conditions. We investigated the role of pier spacing and flow rate in scour depth and progression. The scour-hole depth around the upstream pier was the same as that for single piers and independent of pier spacing. The scour behavior of the middle and downstream piers progressed through a synchronous scouring region, a transition region, and a radical deviation region as the fluid velocity increased. The critical velocity from the synchronous scouring region to the transition region for the middle and downstream piers was the same, which linearly increased with pier spacing. The degree of deviation in the radical deviation region for the middle and downstream piers was dependent on the pier spacing. The critical velocity from the transition region to the radical deviation region for the middle pier increased with the pier spacing. When the spacing was larger than 11 times the diameter of a pier, the scour depths of the three-pier configuration were the same as for the single piers, which indicates the limit of inter-pier fluid–structure interaction. Finally, the data from this study are used to derive adjustment factors to predict the local scour depth around three piers.

关键词： scouring piers critical velocity fluid-structure interaction

Experimental investigation on the stability of bride girder against tsunami forces

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Science China(Technological Sciences) 2014年第10期57卷 2028-2036页

作者： RAHMAN Sadia AKIB Shatirah SHIRAZI S M Department of Civil engineering Faculty of Engineering University of Malaya Institute of Environmental and water resources Management (IPASA) Faculty of EngineeringUniversiti Teknologi Malaysia

Bridges are the most useful part in the transportation *** disruption of the bridge structures may hamper the whole transportation *** the last recent tsunamis,numerous number of bridges were structurally damaged by the tsunami *** of proper provisions of tsunami forces in the design guidelines also contributes to the augmentations of the damage ***,proper evaluation of the tsunami forces on the bridge girder should be introduced in the design *** this study,laboratory experiments were carried out to reveal the damage mechanism of the bridge girder by assessing the exerted tsunami *** broken and unbroken waves were considered for the *** results showed that measured forces were larger for broken waves than those of unbroken *** force of the broken waves was 4.59 times as large as the hydrostatic ***,waves reached the peak value more rapidly for larger wave heights than those of smaller ***,a girder that is placed at a higher position is much vulnerable to tsunami hazard.

关键词： bridge force girder tsunami wave forms wave height

Critical velocities for local scour around twin piers in tandem

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Journal of Hydrodynamics 2018年第6期30卷 1165-1173页

作者： Quan-shuai Liu Hong-wu Tang Hao Wang Jian-feng Xiao State Key Laboratory of Hydrology-water resources and Hydraulic engineering Hohai University Nanjing 210098 China Huaihe River Commission of the Ministry of water resource Bengbu 233001 China

Experiments of the local scour around twin piers are carried out under steady clear-water conditions, including 95 tests to observe the influence of the pier spacing and the flow velocity on the local scour characteristics of the twin piers. It is shown that the start of the transition region is synchronous with the sediment transport from the upstream scour hole to the downstream one. The equations for the critical velocities are derived to quantify the velocity range of each of four different scour regions. Finally, a prediction formula of the downstream pier scour depth in the radical-deviation region is established.

关键词： Local scour clear-water scour twin piers critical velocity experiment

Investigation of the influence of intermediate principal stress on the dynamic responses of rocks subjected to true triaxial stress state

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International Journal of Mining Science and Technology 2021年第5期31卷 913-926页

作者： Wei You Feng Dai Yi Liu Hongbo Du Ruochen Jiang State Key Laboratory of Hydraulics and Mountain River engineering College of Water Resource and HydropowerSichuan UniversityChengdu 610065China

Precisely understanding the dynamic mechanical properties and failure modes of rocks subjected to true triaxial stress state(σ1>σ2>σ3,whereσ1,σ2,andσ3 are the major principal stress,intermediate principal stress,and minor principal stress,respectively)is essential to the safety of underground ***,in the laboratory,it is difficult to maintain the constant true triaxial stress state of rocks during the dynamic testing ***,a numerical servo triaxial Hopkinson bar(NSTHB)was developed to study the dynamic responses of rocks confronted with a true triaxial stress state,in which lateral stresses can maintain *** results indicate that the dynamic strength and elastic modulus of rocks increase with the rise of intermediate principal stressσ2,while the dynamic elastic modulus is independent of the dynamic strain *** acoustic emission distributions indicate that the intermediate principal stressσ2 dramatically affects dynamic failure modes of triaxial confined ***σ2 increases,the failure pattern switches from a single diagonal shear zone into two parallel shear zones with a small ***,a recent triaxial Hopkinson bar experimental system using three bar pairs is also numerically established,and the measuring discrepancies are identified between the two numerical bar *** proposed NSTHB system provides a controllable tool for studying the dynamic triaxial behavior of rocks.

关键词： Triaxial Hopkinson bar Intermediate principal stress Dynamic strength Failure modes Numerical simulation True triaxial stress

Chemical characteristics and source apportionment of atmospheric particles during heating period in Harbin, China

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Journal of Environmental Sciences 2014年第12期26卷 2475-2483页

作者： Likun Huang Guangzhi Wang School of Food engineering Harbin University of Commerce State Key Laboratory of Urban water resource and Environment Harbin Institute of Technology

Atmospheric particles（total suspended particles（TSPs）; particulate matter（PM） with particle size below 10 μm, PM10; particulate matter with particle size below 2.5 μm, PM2.5）were collected and analyzed during heating and non-heating periods in Harbin. The sources of PM10 and PM2.5were identified by the chemical mass balance（CMB） receptor *** indicated that PM2.5/TSP was the most prevalent and PM2.5was the main component of PM210, while the presence of PM10–100was relatively weak. SO-4and NO-3concentrations were more significant than other ions during the heating period. As compared with the non-heating period, Mn, Ni, Pb, S, Si, Ti, Zn, As, Ba, Cd, Cr, Fe and K were relatively higher during the heating period. In particular, Mn, Ni, S, Si, Ti, Zn and As in PM2.5were obviously higher during the heating period. Organic carbon（OC） in the heating period was 2–5 times higher than in the non-heating period. Elemental carbon（EC） did not change much. OC/EC ratios were 8–11 during the heating period, which was much higher than in other Chinese cities（OC/EC： 4–6）. Results from the CMB indicated that 11 pollution sources were identified, of which traffic, coal combustion, secondary sulfate, secondary nitrate, and secondary organic carbon made the greatest contribution. Before the heating period, dust and petrochemical industry made a larger contribution. In the heating period, coal combustion and secondary sulfate were higher. After the heating period, dust and petrochemical industry were higher. Some hazardous components in PM2.5were higher than in PM10, because PM2.5has a higher ability to absorb toxic substances. Thus PM2.5pollution is more significant regarding human health effects in the heating period.

关键词： Atmospheric particles Chemical characteristics Heating period Chemical mass balance

A comparative study of three different learning algorithms applied to ANFIS for predicting daily suspended sediment concentration

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International Journal of Sediment Research 2017年第3期32卷 340-350页

作者： Keivan Kaveh Minh Duc Bui Peter Rutschmann Department of hydraulic and water resource engineering/School of civil engineering Technische Universitt Mnchen (TUM)

The modeling and prediction of suspended sediment in a river are key elements in global water recourses and environment policy and management. In the present study, an Adaptive Neuro-Fuzzy Inference System model trained with the Levenberg-Marquardt learning algorithm is considered for time series modeling of suspended sediment concentration in a river. The model is trained and validated using daily river discharge and suspended sediment concentration data from the Schuylkill River in the United States. The results of the proposed method are evaluated and compared with similar networks trained with the common Hybrid and Back-Propagation algorithms, which are widely used in the literature for prediction of suspended sediment concentration. Obtained results demonstrate that models trained with the Hybrid and Levenberg-Marquardt algorithms are comparable in terms of prediction ***, the networks trained with the Levenberg-Marquardt algorithm perform better than those trained with the Hybrid approach.

关键词： Fuzzy Inference System Hybrid learning rule Levenberg-Marquardt algorithm Schuylkill river Suspended sediments

A refined representation method of the particle size distribution curve based on grading entropy

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Particuology 2024年第5期88卷 302-311页

作者： Xing Li Qun Chen Zhaozhao Liu Cheng Zhou Chen Wang Chen Chen State Key Laboratory of Hydraulics and Mountain River engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China

The particle size distribution(PSD)curve is an important expression of the basic properties of the *** characteristic parameters such as median particle size D_(50),effective particle size D_(10),and some combinations of characteristic parameters can only represent some points of the PSD curve,failing to represent all information of the PSD *** this paper,a fraction characteristic parameter F that could reflect the fraction size variation of the PSD curve was introduced based on grading *** a new presentation method of the A-B-F three parameters was proposed for a refined representation of the PSD *** was found that the newly constructed model not only better represents the differences in the width of PSD curves but also has a higher sensitivity than the A-B two-parameter model proposed by Lő*** PSD curves with similar distributions,the new presentation method has a higher degree of discrimination than that of the D_(50)-C_(u)-C_(c) three-parameter or the four-parameter combination G_(c) proposed by ***,the application of this new method in describing the spatial nonuniformity distribution of depositions and predicting the soil hydraulic conductivity was *** research results can provide a reference for the refined representation of PSD curves.

关键词： Grading entropy Particle size distribution curve Refined representation

Numerical simulation of gas-liquid two-phase flow impacting fixed structure by CLSVOF/IB method based on OpenFOAM

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Journal of Hydrodynamics 2021年第6期33卷 1176-1189页

作者： Wen-kang Meng Ching-hao Yu Jia Li Rui-dong An State Key Laboratory of Hydraulics and Mountain River engineering College of Water Resource and HydropowerSichuan UniversityChengdu 610065China

In this paper,a coupled level set and volume of fluid,immersed boundary(CLSVOF/IB)method is proposed and implemented into the interFoam solver of the OpenFOAM to simulate the gas-liquid two-phase flows,involving the gas-liquid and fluid-structure *** the volume of fluid(VOF)method,the multidimensional universal limiter with explicit solution(MULES)approach is used to restrain the volume *** approach for calculating the grid characteristic size for the level set(LS)initial function and the re-initialization equation is proposed in order to make it more applicable to non-uniform grids in the finite volume *** the proposed CLSVOF method,the continuous LS function is used to calculate the gas-liquid interface curvature so that the surface tension term can be calculated *** the immersed boundary(IB)method proposed in this paper,a virtual forcing term is introduced in the momentum equation to deal with the fluid-structure interface by defining a solid volume fraction,which is convenient for the three-dimensional numerical *** the present flow field solver,an improved scheme of the velocity predictor loop of the PIMPLE framework is also *** benchmark cases:the Zalesak’s notched disk and a circular bubble at equilibrium,are simulated first to examine the accuracy of the present CLSVOF ***,the effects of several gas-liquid two-phase flows on different fixed structures are *** simulation results are in good agreement with the published numerical and experimental results.

关键词： Volume of fluid(VOF)method level set(LS)method immersed boundary method gas-liquid interface fluid-structure interface