检索结果-南通市图书馆

Three-dimensional hydro-mechanical coupling numerical simulation of shield-driven cross-river twin tunnels:A case study

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2024年第3期16卷 106-125页

作者： Chengwen Wang Xiaoli Liu Danqing Song Enzhi Wang Guohui Yan Ran Zhou department of Hydraulic Engineering State Key Laboratory of Hydroscience and EngineeringTsinghua UniversityBeijing 100084China YSD Rail Transit construction Company Limited Guangzhou 510630China

With the rapid development of urban underground space,the construction of shield-driven cross-river twin tunnels is increasing,and the complex hydro-mechanical coupling effects and twin-tunnel interactions bring huge construction risks to such projects,which have attracted more and more *** study aims to understand the excavation effects induced by shield driving of cross-river twin tunnels through numerical simulation.A refined three-dimensional numerical model based on the fully coupled hydro-mechanical theory is *** model considers the main components of the slurry pressure balance shield(SPBS)machine,including support force,jacking thrust,grouting pressure,shield-rock interaction and lining-grouting interaction,as well as the detailed construction *** purpose is to examine the excavation effects during construction,including rock deformation around tunnels,the change in pore pressure,and the response of the *** results show the influence range of twin-tunnel excavation on rock deformation and pore pressure,as well as the modes of lining *** addition,this study also systematically investigates the effects of water level fluctuation and burial depth on twin-tunnel *** results indicate that the increase of water level or burial depth will enhance the excavation effects and strengthen the twin-tunnel *** results provide useful insights for estimating the construction impact range and degree of twin tunnels,and serve as basic references for the design of cross-river twin tunnels.

关键词： Numerical modeling Twin tunnels Crossing river Hydro-mechanical coupling Lining response

Study on the tunnel shape and soil-lining interaction influencing the lining behavior under seismic loading

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2024年第4期23卷 845-862页

作者： Van Vi Pham Ngoc Anh Do Piotr Osinski Ngoc Thai Do Daniel Dias Sustainable development in Underground Engineering Research Team Hanoi University of Mining and GeologyHanoiVietnam department of Underground and Mining construction Faculty of Civil EngineeringHanoi University of Mining and GeologyHanoiVietnam department of Geotechnical Engineering Institute of Civil EngineeringWarsaw University of Life Sciences-SGGWWarszawaPoland Laboratory 3SR Grenoble Alpes UniversityGrenoble 38400France

The response of tunnels subjected to seismic loading is a complex mechanism and depends not only on the seismic nature but also on tunnel structure and surrounding soil *** individual behavior of circular,rectangular,and sub-rectangular tunnels subjected to seismic loadings has already been studied in the *** the present research,two case scenarios of circular,rectangular tunnels and four sub-rectangular shaped tunnels,with similar cross-section areas,were adopted to perform a comprehensive numerical *** purpose of the study was to determine the mechanical behavior of tunnels of different shapes,depending upon seismic *** were performed by considering the influence of soil-lining interaction,soil parameters,and lining thickness,as well as lining *** were performed for no-slip and full-slip *** results indicate that the tunnel shape design is of great importance when regarding the mechanical behavior of the surrounding *** concerns no-slip as well as full-slip soil-lining interaction,especially when the lining is subjected to seismic ***,it is shown that changes in incremental bending moments for circular,rectangular and sub-rectangular tunnels that depend upon the soil-lining interaction conditions differ significantly.

关键词： tunnel shape soil-lining interaction seismic loading internal forces numerical analysis

Preface:Heavy metal(loid)s at mining&metallurgical sites:Fate,risk and remediation

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2024年第4期31卷 1033-1035页

作者：薛生国李楚璇赵东叶吴川 School of Metallurgy and Environment Central South UniversityChangsha 410083China department of Civil Constructionand Environmental EngineeringSan Diego State UniversitySan DiegoCA 92182USA

The contamination of heavy metal(loid)s at mining&metallurgical sites has been a major environmental challenge worldwide[1].Typically,large amounts of metal(loid)s-bearing wastes are generated at these sites,such as smelting slag,combustion residues,mine tailings,wastewater,and exhaust gas[2].Due to their high mobility in the environment,the released heavy metal(loid)s can easily enter the soil and water environment,posing long-term and widespread threats to ecological and human health[3].

关键词： mining wastewater smelting

Effect of Lateritic Stone Aggregate and Coconut Husk Fiber on the Properties of Concrete

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Open Journal of Civil Engineering 2024年第2期14卷 240-257页

作者： Edmund Borbi Humphrey Danso Emmanuel Appiah-Kubi department of construction Technology and Management Education Akenten Appiah-Menka University of Skills Training and Entrepreneurial Development Kumasi Ghana department of Architecture and Civil Engineering Akenten Appiah-Menka University of Skills Training and Entrepreneurial Development Kumasi Ghana

Natural stone aggregate forms the bulk volume of concrete and has contributed to the increased cost of concrete production. This has led to the search for alternate aggregates such as lateritic stone for concrete production. This paper investigates the engineering properties of concrete produced with lateritic aggregate (LA) as the coarse aggregate replacement and coconut husk fibre (CHF) as reinforcement. Natural stone aggregate was replaced by LA at 0%, 10%, 20%, 30%, 40%, and 50%, with 0.25% constant CHF by weight. A mix proportion of 1:1.5:3 with a water-cement ratio of 0.6 was used for producing concrete. A total of 162 specimens (90 cubes and 72 beams) were prepared and tested at the 7, 14, 21, and 28 days of curing. The highest compressive strength was 43.36 N/mm2 (10% LA replacement) as compared to the control of 41.51 N/mm2. The 10% LA replacement obtained the highest flexural strength of 5.35 N/mm2 as compared with the 5.29 N/mm2 for the control. The water absorption of the concrete increased from 2.8% (control) to 3.57% (50% replacement LA). Scanning electron microscopy (SEM) revealed micro gaps between CHF and LA concrete. The study, therefore, concludes that the use of LA and CHF positively influenced the strength properties of concrete. 10% LA replacement of coarse aggregate and 0.25% CHF is recommended to practitioners for use.

关键词： Concrete Coarse Aggregate Compressive Strength Flexural Strength Natural Stone Aggregate SEM

Analysis of Calcined Red Mud Properties and Related Mortar Performances

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2024年第5期20卷 901-913页

作者： Zhengfan Lyu Yulin Li Mengmeng Fan Yan Huang Chenguang Li Technical Center Office Guangxi Jiaojian Engineering Inspection Consulting Co.Ltd.Nanning530001China Technical Center Office Guangxi Road Construction Engineering Group Co.Ltd.Nanning530001China Nanning Road construction Technology and Road construction Materials Engineering Technology Research Centre Guangxi Road Construction Engineering Group Co.Ltd.Nanning530001China

Red mud(RM)is a low-activity industrial solid waste,and its utilization as a resource is currently a hot *** this study,the micro characteristics of red mud at different calcination temperatures were analyzed using X-ray diffraction and scanning electron *** performance of calcined red mud was determined through mortar strength *** indicate that high-temperature calcination can change the mineral composition and microstructure of red mud,and increase the surface roughness and specific surface *** the optimal temperature of 700°C,the addition of calcined red mud still leads to a decrease in mortar strength,but its activity index and flexural coefficient increase by 16.2%and 11.9%with respect to uncalcined red mud,reaching values of 0.826 and 0.974,*** with the control group,the synergistic activation of calcined red mud with slag can increase the compressive and flexural strength of the mortar by 12.9%and 1.5%,reaching 8.7 and 62.4 MPa,***,the activity index and flexural coefficient of the calcined RM and GGBS(Ground Granulated Blast furnace Slag)mixtures also increase to 1.015 and 1.130,respectively.

关键词： Red mud slag thermal activation synergistic activation mortar test microscopic properties

MEMS Huygens Clock Based on Synchronized Micromechanical Resonators

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Engineering 2024年第5期36卷 124-131页

作者： Xueyong Wei Mingke Xu Qiqi Yang Liu Xu a Yonghong Qi Ziming Ren Juan Ren Ronghua Huan Zhuangde Jiang State Key Laboratory for Manufacturing System Engineering Xi’an Jiaotong UniversityXi’an 710049China School of construction Machinery Chang’an UniversityXi’an 710064China department of Mechanics Zhejiang UniversityHangzhou 310027China

With the continuous miniaturization of electronic devices,microelectromechanical system(MEMS)oscillators that can be combined with integrated circuits have attracted increasing *** study reports a MEMS Huygens clock based on the synchronization principle,comprising two synchronized MEMS oscillators and a frequency compensation *** MEMS Huygens clock improved shorttime stability,improving the Allan deviation by a factor of 3.73 from 19.3 to 5.17 ppb at 1 s.A frequency compensation system based on the MEMS oscillator’s temperature-frequency characteristics was developed to compensate for the frequency shift of the MEMS Huygens clock by controlling the resonator *** effectively improved the long-term stability of the oscillator,with the Allan deviation improving by 1.6343105 times to 30.9 ppt at 6000 *** power consumption for compensating both oscillators simultaneously is only 2.85 mW·℃^(-1).Our comprehensive solution scheme provides a novel and precise engineering solution for achieving high-precision MEMS oscillators and extends synchronization applications in MEMS.

关键词： Frequency stability Huygens clock MEMS Oscillator Synchronization

Environmental Impact Assessment of Onshore Wind Farms in the Region of Central Greece Using a Modified RIAM Method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental & Earth Sciences 2024年第1期6卷 71-82页

作者： Olga Korozi Dimitra G.Vagiona department of Spatial Planning and development Aristotle University of ThessalonikiThessaloniki 54124Greece

Wind energy is one of the most basic forms of renewable energy,which shows an increasing rate of development worldwide and also at the European ***,this rapid deployment of wind farms makes the need for an impact assessment of this type of projects on the natural and man-made environment *** present paper aims to identify and assess the environmental impacts of wind farm projects in the Region of Central Greece.A modified Rapid Impact Assessment Matrix(RIAM)method is used for this *** methodology includes the identification of the existing onshore wind farm projects in the study area,the appropriate modifications of the RIAM method to respond to the characteristics of the projects and the study area,the qualitative assessment of their potential impacts during construction and operational phases and the computation of the Environmental Performance Grade(EPG)of projects based on the pro-posed modified RIAM *** results reveal that although there are some slight negative impacts on the natural environment of the study area,the examined wind farms contribute positively both to the atmosphere and to the socio-economic environment of the *** study extends the potential for using RIAM as a tool in environmental impact assessment studies of renewable energy projects.

关键词： Environmental impact assessment Environmental components Region of central Greece Rapid impact assessment matrix(RIAM) Environmental performance grade(EPG)

Software and Mobile Apps as a Strategy for Productivity Improvement in the construction Industry

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Building construction and Planning Research 2024年第1期12卷 1-35页

作者： Stanley Owuotey Bonney Jonas Ekow Yankah Kofi Owusu Adjei Chris Kurbom Tieru department of Built Environment University of Environment and Sustainable Development Somanya Ghana department of construction Technology and Management Cape Coast Technical University Cape Coast Ghana department of Building Technology Kumasi Technical University Kumasi Ghana

The construction industry, known for its low productivity, is increasingly utilising software and mobile apps to enhance efficiency. However, more comprehensive research is needed to understand the effectiveness of these technology applications. The PRISMA principles utilised a scoping review methodology to ascertain pertinent studies and extract significant findings. From 2013 onwards, articles containing data on mobile applications or software designed to enhance productivity in the construction sector were obtained from multiple databases, including Emerald Insight, Science Direct, IEEE Xplore, and Google Scholar. After evaluating 2604 articles, 30 were determined to be pertinent to the study and were subsequently analysed for the review. The review identified five key themes: effectiveness, benefits, successful implementation examples, obstacles and limitations, and a comprehensive list of software and mobile apps. In addition, 71 software and mobile apps have shown potentially how these technologies can improve communication, collaboration, project management, real-time collaboration, document management, and on-the-go project information and estimating processes in the construction industry, increasing efficiency and productivity. The findings highlight the potential of these technologies such as Automation, Radio-Frequency Identification (RFID), Building Information Modeling (BIM), Augmented Reality (AR), Virtual Reality (VR), and Internet of Things (IoT) to improve efficiency and communication in the construction industry. Despite challenges such as cost, lack of awareness, resistance to change, compatibility concerns, human resources, technological and security concerns and licensing issues, the study identifies specific mobile applications and software with the potential to enhance efficiency significantly, improve productivity and streamline workflows. The broader societal impacts of construction software and mobile app development include increased effic

关键词： Software Mobile apps Productivity Technologies construction Industry

Linear and Non-Linear Dynamics of Inertial Waves in a Rotating Cylinder with Antiparallel Inclined Ends

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2024年第4期20卷 787-802页

作者： Mariya Shiryaeva Mariya Subbotina Stanislav Subbotin Laboratory of Vibrational Hydromechanics Perm State Humanitarian Pedagogical UniversityPerm614000Russia The department for construction Engineering and Material Science Perm National Research Polytechnic UniversityPerm614990Russia

This work is devoted to the experimental study of inertial wave regimes in a non-uniform rotating cylinder with antiparallel inclined *** this setting,the cross-section of the cylinder is divided into two regions where the fluid depth increases or decreases with *** different regimes are found:inertial wave attractor,global oscillations(the cavity’s resonant modes)and regime of symmetric reflection of wave *** linear wave regimes,a steady single vortex elongated along the rotation axis is *** location of the wave’s interaction with the sloping ends determines the vortex position and the vorticity *** non-linear regimes several pairs of the triadic resonance subharmonics are detected *** instability of triadic resonance is accompanied by the periodic generation of mean vortices drifting in the azimuthal ***,the appearance frequency of the vortices is consistent with the low-frequency subharmonic of the triadic *** experimental results shed light on the mechanisms of the inertial wave interaction with zonal flow and may be useful for the development of new methods of mixing.

关键词： Rotation inertial wave attractor triadic resonance zonal flow instability