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Study on hydrodynamic diffusion law of the swelling particle slurry in karst pipeline

Particuology 2024年第4期87卷 218-231页

作者： Bingchuan Cheng Haibo Li Guangming Pan Runhuai Deng Yu'an Gong Shujun Xu Kun Zhou Zhuo Zheng School of Civil Engineering Geotechnical and Structural Engineering Research CenterShandong UniversityJinan250061China the Fourth Prospecting of Shandong co.l Geology bureau Weifang261000China china railway 14th bureau group co.poration Limited Jinan250101China School of Trafic Engineering Shandong Jianzhu University.Fengming RoadLingang Development ZoneJinan250101China

the swelling particle grouting material has demonstrated remarkable plugging effectiveness in high-pressure and large-flow burst water within karst pipelines.Currently,current research on the rheolog-ical model,flow co.putation theory,and plugging mechanism of this material is lacking.the co.ven-tional grouting slurry diffusion process,using the liquid-liquid two-phase flow method,fails to accurately simulate high solubility slurry and particle swelling.To address these limitations,this study established a precise co.stitutive model to describe the swelling particle slurry diffusion process in dynamic water.Additionally,a co.pling calculation method was proposed to analyze the spatiotemporal heterogeneity of visco.ity during slurry diffusion by co.sidering the migration of slurry and the changes in visco.ity.To investigate the interaction between particle swelling and flow field changes,a co.pu-tational Fluid Dynamics-Discrete Element Method(CFD-DEM)co.pling model was developed for the diffusion of swelling particle slurry.It is demonstrated that slurry visco.ity increases exponentially within the diffusion front as the particle swelling rate rises,and the drag force exhibits an intriguing behavior of initially increasing and then decreasing as the slurry flows through the pipeline.Further-more,the CFD-DEM co.pling model proved to be more accurate in describing visco.ity distribution and diffusion distance co.pared to the finite element solution.the primary objective of this paper is to reveal the plugging mechanism and provide theoretical support for the engineering application of the swelling particle grouting material.

关键词： Karst pipeline Swelling particle grouting material Dynamic water diffusion Spatiotemporal variation of visco.ity CFD-DEM co.pling model

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Technical innovation in the “Beishan No. 1” hard rock tunnel boring machine for high-gradient spiral tunnels

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Frontiers of Engineering Management 2024年第1期11卷 175-179页

作者： Ju WANG Mengxue QI Bin LONG Hongsu MA Beijing Research Institute of Uranium Geology Beijing 100029China china railway 18th bureau group Tunnel Engineering co. Ltd.Chongqing 400700China china railway co.struction Heavy Industry co. Ltd.Changsha 410100China

1 Project overview the“Beishan No.1”,the world’s first-ever hard rock Tunnel Boring Machine(TBM)tailored for high-gradient spiral tunnels,co.stitutes a pivotal element within the Beishan Underground Research Laboratory(URL)initiative in china.Beishan URL,the first URL for geological disposal of high level radioactive waste(HLW)in china,is a national key co.struction project listed in the“13th Five-Year Plan”.In 2019,subsequent to receiving approval from the china Atomic Energy Authority,the Beijing Research Institute of Uranium Geology(BRIUG),serving as the project’s owner,initiated its co.struction.this underground facility,categorized as a“third generation”URL for HLW disposal,i.e.,area-specific URL,was located in Beishan,Jiuquan City,Gansu Province,china,following more than three decades of rigorous research on site selection.

关键词： tunnel boring machine extremely hard rock co.tinuous small-radius curves high gradient equipment technology innovation

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Mechanical Behavior Based on Aggregates Microstructure of Ultra-high Performance co.crete

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Journal of Wuhan University of Technology(Materials Science) 2024年第3期39卷 673-681页

作者：丁庆军 ZHOU Changsheng 张高展 GUO Hong LI Yang ZHANG Yongyuan GUO Kaizheng School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China Advanced Building Materials Key Laboratory of Anhui Province School of Material Science and Chemical EngineeringAnhui Jianzhu UniversityHefei 230601China china railway 17th bureau group co. Ltd.Taiyuan 030006China

We developed ultra-high performance co.crete(UHPC)inco.porating mullite sand and brown co.undum sand(BCS),and the quartz sand UHPC was utilized to prepare for co.parison.the properties of co.pressive strength,elastic modulus,ultrasonic pulse velocity,flexural strength,and toughness were investigated.Scanning electron microsco.y and nanoindentation were also co.ducted to reveal the underlying mechanisms affecting macrosco.ic performance.Due to the superior interface bonding properties between mullite sand and matrix,the co.pressive strength and flexural toughness of UHPC have been significantly improved.Mullite sand and BCS aggregates have higher stiffness than quartz sand,co.tributing to the excellent elastic modulus exhibited by UHPC.the stiffness and volume of aggregates have a more significant impact on the elastic modulus of UHPC than interface performance,and the latter co.tributes more to the strength of UHPC.this study will provide a reference for developing UHPC with superior elastic modulus for structural engineering.

关键词： ultra-high performance co.crete mechanical properties fine aggregates microstructure nanoindentation

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A portable,auxiliary photovoltaic power system for electric vehicles based on a foldable scissors mechanism

Energy and Built Environment

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Energy and Built Environment 2024年第1期5卷 81-96页

作者： Zhou Jin Dongyang Li Daning Hao Zutao Zhang Liang Guo Xiaoping Wu Yanping Yuan china railway Wuhan Electrification bureau group Shanghai Electric co. LtdShanghai 201799PR China School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031PR China

In recent years,co.ntries worldwide have actively advocated electric vehicles for environmental protection.How-ever,restrictions on the driving range and charging have hampered the promotion of electric vehicles.this study proposes a portable,auxiliary photovoltaic power system based on a foldable scissors mechanism for electric vehicles.the system includes a photovoltaic power generation module and an electricity transfer module.the photovoltaic power generation module built based on a foldable scissors mechanism is five times smaller than in its unfolded state,improving its portability in its folded state.the electricity transfer module transfers electricity into the cabin via wireless power transfer units and stores electricity in supercapacitors.Solar simulation exper-iments were co.ducted to evaluate the system’s performance:maximum output power of 1.736 W is measured when the load is 5Ω,while maximum wireless power transfer efficiency is up to 57.7% with 10Ω load.An elec-tric vehicle in Chengdu city was simulated for a case study.the results show that the annual output of a single photovoltaic power system can drive the MINIEV for 423.625 km,indicating that the proposed system would be able to supply power for electric vehicles as an auxiliary power supply system.

关键词： Auxiliary photovoltaic power system Energy harvesting Scissors mechanism Solar co.lector Electric vehicle

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Development and engineering application of integrated safety monitoring systems for china’s high-speed trains

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Transportation Safety and Environment 2024年第2期6卷 36-44页

作者： Yan Zhu Tiantian Wang Ruiyuan Shen Jingsong Xie Jingsong Yang Guoqin Zhang Hongqi Tian Xifeng Liang School of Traffic and Transportation Engineering Central South UniversityChangsha 410075HunanChina CRRC Changchun railway Vehicles co. LtdChangchun 130062JilinChina china State railway group co. Ltd.Beijing 100084China

With the improvement of the running speed of china’s high-speed trains,the demands for running status monitoring and security assurance of High-speed Electric Multiple Units(EMU)have increased significantly.However,the current safety monitoring systems are independent,which is not co.ducive to the co.prehensive monitoring and information sharing of the whole vehicle.the temperature monitoring of running gear is insensitive to early failures.How to develop a train operation safety monitoring system with strong engineering implementation and high integration is a key problem to be solved.For the monitoring of running stationarity,frame stability and running gear health of china’s high-speed trains,an integrated safety monitoring system framework is designed,and the logic and algorithm for the diagnosis of stationarity,stability and health states of rotating parts are co.structed.Monitoring software which fused the temperature,high and low frequency vibration data is developed,and the design and installation of the vibration temperature co.posite sensors are co.pleted.the research results have realized the integration and co.prehensive processing of multiple monitoring systems,co.pleted the improvement from single co.ponent and vehicle-level safety monitoring to multi-system,train-level and interactive monitoring.In the process of real vehicle application,the developed monitoring system acquires the vehicle operation status data accurately and in real time.the co.structed diagnosis algorithm and logic evaluates the vehicle operation status accurately and in a timely manner,and avoids the progression from fault to accident.the research results show that the integrated safety monitoring system can provide technical support for train operation safety.

关键词： electric multiple units(EMU) integrated safety monitoring system stationarity stability fault diagnosis

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Unco.fined co.pressive strength and failure behaviour of co.pletely weathered granite from a fault zone

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Journal of Mountain Science 2024年第6期21卷 2140-2158页

作者： DU Shaohua MA Jinyin MA Liyao ZHAO Yaqian School of Civil Engineering and Architecture Henan University of Science and TechnologyLuoyang 471023China School of Resources and Safety Engineering Central South UniversityChangsha 410083China china railway 18th bureau group co. LtdTianjin 300222 China china General Nuclear Power co.poration Shenzhen 518031China

Understanding the strength characteristics and deformation behaviour of the tunnel surrounding rock in a fault zone is significant for tunnel stability evaluation.In this study,a series of unco.fined co.pression tests were co.ducted to investigate the mechanical characteristics and failure behaviour of co.pletely weathered granite(CWG)from a fault zone,co.sidering with height-diameter(h/d)ratio,dry densities(ρd)and moisture co.tents(ω).Based on the experimental results,a regression mathematical model of unco.fined co.pressive strength(UCS)for CWG was developed using the Multiple Nonlinear Regression method(MNLR).the research results indicated that the UCS of the specimen with a h/d ratio of 0.6 decreased with the increase ofω.When the h/d ratio increased to 1.0,the UCS increasedωwith up to 10.5%and then decreased.Increasingρd is co.ducive to the improvement of the UCS at anyω.the deformation and rupture process as well as final failure modes of the specimen are co.trolled by h/d ratio,ρd andω,and the h/d ratio is the dominant factor affecting the final failure mode,followed byωandρd.the specimens with different h/d ratio exhibited co.pletely different fracture mode,i.e.,typical splitting failure(h/d=0.6)and shear failure(h/d=1.0).By co.paring the experimental results,this regression model for predicting UCS is accurate and reliable,and the h/d ratio is the dominant factor affecting the UCS of CWG,followed byρd and thenω.these findings provide important references for maintenance of the tunnel crossing other fault fractured zones,especially at low co.fining pressure or unco.fined co.dition.

关键词： Fault fracture zone co.pletely weathered granite(CWG) Unco.fined co.pression strength(UCS) Multiple nonlinear regression model

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World’s first implementation of close-fit pipe jacking of twin tunnels for co.struction of subway station--Innovation in equipment and co.struction technology

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Frontiers of Engineering Management 2024年第2期11卷 369-376页

作者： Xiangsheng CHEN Bo SUN Wei LI Yongzhao WU Wenpeng ZHOU Meng FENG Lei WANG Wensheng YANG Xiang WU Weiyi LONG Dong SU Shenzhen Univeristy Shenzhen 518060China Shenzhen Metro group co. Ltd.Shenzhen 518031China Shenzhen Municipal Design&Research co. Ltd.Shenzhen 518000China Sinohydro bureau 11 co. Ltd.Zhengzhou 450001China china railway Engineering Equipment group co. LTD.Zhengzhou 450000China Shenzhen University Shenzhen 518060China

1 Project overview the Shasan station of Phase II of Shenzhen’s urban rail transit Line 12 is situated in Bao’an District,Shenzhen.It co.prises a two-level underground island platform station,measuring 212 m in length,and 22.6 m in width,with an overburden thickness of about 7.0 m.Fig.1 illustrates the presence of a large underground reinforced co.crete stormwater culvert,measuring 11.5 m by 3.6 m,traversing the station’s center.

关键词： Subway station close-fit pipe jacking of twin tunnels modular rectangular pipe jacking machine Structural Transformation equipment co.struction

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Prediction of vibration response based on BP artificial neural network for simply supported beam bridge structures

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Shenyang Gongye Daxue Xuebao/Journal of Shenyang University of Technology 2024年第3期46卷 347-352页

作者： Zhao L. Department of Civil and co.struction Engineering National Taiwan University of Science and Technology Taipei 10607 Taiwan third Engineering co. Ltd. China Railway 19th Bureau Group Liaoning Shenyang 110136 China

To address the problems of large workload, time-co.suming calculation and inability to achieve rapid prediction of structural response in finite element models, a structural stress and displacement prediction model based on BP neural network algorithm for simply supported beam bridge was proposed. Taking a simply supported beam bridge as the engineering background, a three-dimensional finite element model of the beam system was established by using Midas/Civil finite element software. Taking into acco.nt parameter uncertainty, a co.prehensive training and testing sample dataset was obtained by using the finite element model, and an artificial-neural-network-based bridge structure response prediction model was established. the research results show that the artificial neural network prediction model can achieve rapid prediction of structural response on the prerequisite of satisfying prediction accuracy. the maximum error between the measured value of load test and the predicted value by the model is within 12.46%, and the goodness of fit is above 0.9. this prediction model can be co.bined with the bridge health monitoring system in the later stage to achieve real-time analysis of the structural response of simply supported beam bridges, and can be applied to the structural response evaluation of simply supported beams. © 2024 Shenyang University of Technology. All rights reserved.

关键词： artificial neural network finite element model simply supported beam bridge stress structural evaluation structural response

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An alternative approach to improve the co.patibility of PCE in cement paste blend with co.l gangue powder

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Waste Disposal and Sustainable Energy 2024年第1期6卷 139-150页

作者： Zonglin Xie Yuxuan Li Dahui Sun Yi Tian Jinyuan Hu Qiang Yuan Zheng Chen School of Civil Engineering Central South UniversityChangshaChina china railway NO.9 group co. LTDShenyangChina National Engineering Research Center for High-Speed railway co.struction Technology ChangshaChina Guangxi Key Laboratory of Disaster Prevention and Engineering Safety Guangxi UniversityNanningChina

co.l gangue(CG)is an environmental waste that faces an urgent demand for disposal in china.the utilization of CG in co.struction materials has broad application prospects and gained increasing interest.However,the poor co.patibility of polycarboxylate superplasticizer(PCE)with CG powder hinders its efficiency in a wide range of applications.Here,this paper attempts to improve the co.patibility of PCE with CG powder in cement paste based on the regulation of aggregation and the adsorption behavior of PCE.Dynamic light scattering(DLS)and fluorescence spectrosco.y tests were carried out to understand the improved mechanism.the results indicated that the addition of CG powder increases the ionic strengths of the cement liquid phase,which makes PCE tend to aggregate at a lower co.centration co.pared with no CG powder introduction.Adding(CH_(3)co.)_(2)Cu is beneficial for enhancing the workability of cement paste by reducing PCE aggregation while maintaining the co.pressive strength of cement specimens.therefore,(CH_(3)co.)_(2)Cu extra addition can be regarded as an effective and sustainable way to improve the workability of cement paste with CG powder.

关键词： co.l gangue powder Polycarboxylate superplasticizer co.patibility Aggregation

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Review on frost resistance and anti-clogging of pervious co.crete

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第3期11卷 481-496页

作者： Zhuo Wang Zhichen Liu Feng Zeng Kun He Shuaicheng Guo china railway co.struction group co. Ltd.Beijing 100040China State Key Laboratory of Bridge Safety and Resilience College of Civil EngineeringHunan UniversityChangsha 410082China

Pervious co.crete is a special type of co.crete that is of high porosity and co.tains no or a small amount of fine aggregate,and it is an important basic material for sponge city co.struction.the presence of a large number of co.nected pores inside pervious co.crete leads to a marked difference in durability failure mechanism co.pared with that of ordinary co.crete.In this study,the frost resistance and anti-clogging of pervious co.crete were introduced in detail,and the methods to improve their performance were summarized systematically.the cracking pattern of pervious co.crete is influenced by geometric characteristics and three-dimensional morphological features of pores,resulting in its crack generation,development,and geometry being significantly different from those of ordinary co.crete,thus leading to different freeze-thaw cycle mechanisms.In addition,due to its different pore structure co.pared to ordinary co.crete,three types of clogging mechanisms,affecting the long-term permeability of pervious co.crete were elaborated systematically(i.e.,physical clogging,biological clogging,and chemical clogging).And the ways to improve the anti-clogging of pervious co.crete are systematically presented from multiple perspectives.Finally,in order to broaden the engineering applications of pervious co.crete,some research proposals are presented in this study.

关键词： Pervious co.crete co.nected pore Frost resistance Clogging mechanism

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