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Modifying effects and mechanisms of superfine stainless wires on microstructures and mechanical properties of ultra-high performance seawater sea-sand concrete

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Science China Technological Sciences 2024年第10期67卷 3205-3220页

作者： YU Feng DONG SuFen ASHOUR Ashraf DING SiQi HAN BaoGuo School of infrastructure Engineering Dalian University of Technology Faculty of Engineering & Informatics University of Bradford department of Civil and Environmental Engineering The Hong Kong Polytechnic University

Ultra-high-performance seawater sea-sand concrete（UHPSSC） presents a prospective solution to address the natural resource shortage in marine infrastructure construction. To eliminate the corrosion risk of steel fibers and broaden the applicability of UHPSSC, this study investigates the mechanical properties and free chloride ion content as well as microstructures of UHPSSC reinforced with superfine stainless wires（SSWs） under natural curing. The results indicate that 1.5% SSWs can remarkably improve the flexural strength and toughness of UHPSSC by 127% and 1724%, respectively, and mitigate the long-term strength degradation of UHPSSC. The strong interfacial bond between SSW and UHPSSC improves the compactness of UHPSSC, thus reducing the growth space for Ca（OH）2crystals and swelling hydration products generated by sulfate and magnesium ions. This can be supported by the observed reduction in the Ca/Si ratio of C–S–H gels, CH crystal orientation index, and ***, through mechanisms such as pull-out, rupture, overlapping network, and internal anchor interface, SSWs effectively prevent microcrack growth and propagation, transforming single long-connected microcracks into multiple-emission microcracks centered on SSW. Additionally, the free chloride ion content of the composites at 28 and 180 d meets the ACI 318-19 standard requirements for concrete exposed to seawater. This compliance is attributed to the chloride immobilization facilitated by Friedel's salt and C–S–H gels within the interfaces around SSWs and sea-sand. Consequently, SSWs-reinforced UHPSSC exhibits considerable potential for applications in sustainable marine infrastructures, demanding long-term mechanical properties and high durability.

关键词： ultra-high performance seawater sea-sand concrete superfine stainless wire mechanical properties chloride ion content microstructure

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A CFD study on the hydrodynamic response of a small-scale ice floe induced by a passing ship

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Journal of Hydrodynamics 2024年第2期36卷 290-299页

作者： Zongyu Jiang Spyros Hirdaris Sasan Tavakoli Mikko Suominen Pentti Kujala Marine and Arctic Technology Department of Mechanical EngineeringAalto UniversityEspooFinland Global Ship Systems Centre ABS Hellenic SM LLC.AthensGreece department of infrastructure Engineering The University of MelbourneMelbourneAustralia

A Reynolds averaged Navier-Stokes(RANS)computational fluid dynamics(CFD)model is built to investigate the hydrodynamic response of a circular ice floe under the influence of a passing ship in calm *** ship,mirroring the KRISO Container Ship’s hull design,progresses near an ice floe whose diameter is 30%of the ship’s length and its thickness is 3 *** ship advances at a constant speed,which is handled by using the overset mesh *** study focuses on the ice floe’s motions and the hydrodynamic forces induced by three speeds and three transverse distances of the passing *** reveal that ship-generated wakes notably influence the ice floe’s motions,with a greater influence on sway than ***,the ship’s speed and proximity distinctly affect the ice floe’s motions.

关键词： Hydrodynamics ship-ice interactions ice floe Reynolds averaged Navier-Stokes(RANS)computational fluid dynamics(CFD)

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Detection of internal crack growth in polyethylene pipe using guided wave ultrasonic testing

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 319-329页

作者： Jay Kumar Shah Hao Wang Said El-Hawwat Centre of Advanced infrastructure and Transportation RutgersThe State University of New JerseyNJ 08854USA department of Civil and Environmental Engineering RutgersThe State University of New JerseyNJ 08854USA

Despite the success of guided wave ultrasonic inspection for internal defect detection in steel pipes,its application on polyethylene(PE)pipe remains relatively *** growth of internal cracks in PE pipe severely affects its pressure-holding capacity,hence the early detection of internal cracks is crucial for effective pipeline maintenance *** study extends the scope of guided wave-based ultrasonic testing to detect the growth of internal cracks in a natural gas distribution PE *** experiments and a finite element model were planned to study the wave-crack interaction at different stages of axially oriented internal crack growth with a piezoceramic transducer-based setup arranged in a pitch-catch *** dispersion analysis supplemented with preliminary experiments was performed to isolate the optimal inspection frequency,leading to the selection of the T(0,1)mode at 50-kHz for the investigation.A transmission index based on the energy of the T(0,1)mode was developed to trace the extent of simulated crack *** findings revealed an inverse linear correlation between the transmission index and the crack depth for crack growth beyond 20%crack depth.

关键词： polyethylene pipes internal cracks guided wave ultrasonic testing torsional modes finite element modeling

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Determination of riding comfort on cycleways using a smartphone application

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第4期11卷 747-760页

作者： Anna Niska Leif Sjögren Peter Andrén Christian Weber Tineke de Jong Aslak Fyhri department of infrastructure Maintenance Swedish National Road and Transport Research Institute(VTI)Linköping SE-58195Sweden department of Safety and Behavior Institute of Transport EconomicsGaustadalleen 210349 OsloNorway

Well maintained cycleways will encourage more people to cycle,as the condition of cycleways is important for the safety,accessibility and riding comfort of *** that,only a few models used to describe the quality of service for cyclists take the surface condition into *** measuring methods are needed to enable reliable and effective assessment of surface conditions,and measurable performance criteria related to the needs of cyclists should be *** purpose of this study has been to test the reliability and validity of using accelerometers in smartphones to assess the riding comfort on cycleways.A smartphone application converting three-dimensional accelerometer measurements into a single indicator for cycleways has been used to assess road surfaces in two field studies,in Sweden and Norway,*** studies assessed test sections of varying *** relate the measurements to subjective riding comfort assessments by cyclists,recruited cyclists collected quantitative data using the app,whilst also rating their perceived riding comfort by completing a *** were also related to standard road surface condition indicators,generated from a road surface tester equipped with 19 laser sensors:international roughness index(IRI),mega-and *** results show that it is possible to describe the unevenness of a cycleway using the technology present in smartphones.A software application can be used to collect and analyse data from the acceleration sensors in the phone,which can then be used to describe the riding comfort of *** is mainly the unevenness in the 50-1000 mm sizerange that create the greatest discomfort for cyclists,and intermittent vibrations are perceived as more uncomfortable than more evenly distributed ***,IRI is not a relevant measurement for describing the riding comfort of cyclists.

关键词： Cyclist Comfort Assessment Road surface measurement Smartphone application

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Managing underground legal boundaries in 3D-extending the CityGML standard

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Underground Space 2024年第1期14卷 239-262页

作者： Bahram Saeidian Abbas Rajabifard Behnam Atazadeh Mohsen Kalantari The Centre for Spatial Data infrastructures and Land Administration Department of Infrastructure EngineeringThe University of MelbourneParkvilleVIC 3010Australia School of Civil and Environmental Engineering University of New South WalesSydneyNSW 2052Australia

Legal boundaries are used for delineating the spatial extent of ownership property’s *** underground environments,these boundaries are defined by referencing physical objects,surveying measurements,or ***,there is a gap in connecting and managing these boundaries and underground legal spaces,due to a lack of data model.A 3D data model supporting underground land administration(ULA)should define and model these boundaries and the relationships between them and underground ownership *** 3D data models can be enriched to model underground legal *** research aims to propose a new taxonomy of underground legal boundaries and model them by extending CityGML,which is a widely used 3D data model in the geospatial science *** developed,implemented,and tested the model for different types of underground legal *** implemented prototype showcased the potential benefits of CityGML for managing underground legal boundaries in *** proposed 3D underground model can be used to address current challenges associated with communicating and managing legal boundaries in underground *** this data model was specifically developed for Victoria,Australia,the proposed model and approach can be used and replicated in other jurisdictions by adjusting the data requirements for underground legal boundaries.

关键词： Underground Legal boundaries Land administration 3D data model City model

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Parametric study on contact sensors for MASW measurement-based interfacial debonding detection for SCCS

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 331-344页

作者： Chen Hongbing Pang Xin Gan Shiyu Li Yuanyuan Gokarna Chalise Nie Xin Research Institute of Urbanization and Urban Safety School of Civil and Resource EngineeringUniversity of Science and Technology BeijingBeijing 100083China department of Civil Engineering Tsinghua UniversityBeijing 100084China Faculty of infrastructure Engineering Dalian University of TechnologyDalian 116081China

Steel-concrete composite structures(SCCS)have been widely used as primary load-bearing components in large-scale civil *** the basis of the co-working ability of steel plate and concrete,the bonding status plays an essential role in guaranteeing the structural performance of ***,efficient non-destructive testing(NDT)on interfacial debondings in SCCS has become a prominent research ***-channel analysis of surface waves(MASW)has been validated as an effective NDT technique for interfacial debonding detection for ***,the feasibility of MASW must be validated using experimental *** study establishes a high-frequency data synchronous acquisition system with 32 channels to perform comparative verification experiments in ***,the current sensing approaches for high-frequency vibration and stress waves are ***,three types of contact sensors,namely,piezoelectric lead-zirconate-titanate(PZT)patches,accelerometers,and ultrasonic transducers,are selected for MASW ***,the selection and optimization of the force hammer head are *** experiments are carried out for the optimal selection of ultrasonic transducers,PZT patches,and accelerometers for MASW *** addition,the influence of different pasting methods on the output signal of the sensor array is *** results indicate that optimized PZT patches,acceleration sensors,and ultrasonic transducers can provide efficient data acquisition for MASW-based non-destructive *** research findings in this study lay a solid foundation for analyzing the recognition accuracy of contact MASW measurement using different sensor arrays.

关键词： steel-concrete composite structures(SCCS) interface debonding detection multi-channel analysis of surface waves(MASW) sensor selection comparative experimental study

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Rapid profiling rock mass quality underneath tunnel face for Sichuan-Xizang Railway

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Underground Space 2024年第6期19卷 138-152页

作者： Siyuan Wu Min Qiu Zhao Yang Fuquan Ji Zhongqi Quentin Yue department of Civil Engineering The University of Hong KongHong Kong 999077China CCCC Second Harbor Engineering Company Ltd. Wuhan 430000China Research and Development Center of Transport Industry of Intelligent Manufacturing Technologies of Transport infrastructure Wuhan 430000China

The Sichuan-Xizang Railway is a global challenge,surpassing other known railway projects in terms of geological and topographical *** paper presents an approach for rapidly profiling rock mass quality underneath tunnel face for the ongoing construction of the Sichuan-Xizang *** adopts the time-series method and carries out the quantitative analysis of the rock mass quality using the depth-series measurement-while-drilling(MWD)data associated with drilling of blastholes.A tunnel face with 15 blastholes is examined for *** results include identification of the boundary of homogeneous geomaterial by plotting the blasthole depth against the net drilling time,as well as quantification of rock mass quality through the recalculation of the new specific *** new specific energy profile is compared and highly consistent with laboratory test,manual logging and tunnel seismic prediction *** consistency can enhance the blasthole pattern design and facilitate the dynamic determination of charge placement and *** paper highlights the importance of digital monitoring during blasthole drilling for rapidly profiling rock mass quality underneath and ahead of tunnel *** upgrades the MWD technique for rapid profiling rock mass quality in drilling and blasting tunnels.

关键词： Measurement-while-drilling Drilling and blasting Rock mass quality New specific energy Constant penetration rate Sichuan-Xizang railway Tunnelling

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Prediction of maximum upward displacement of shield tunnel linings during construction using particle swarm optimization-random forest algorithm

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第1期25卷 1-17页

作者： Xiaowei YE Xiaolong ZHANG Yanbo CHEN Yujun WEI Yang DING MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Zhejiang UniversityHangzhou310058China department of Civil Engineering Zhejiang UniversityHangzhou310058China Zhejiang Engineering Research Center of Intelligent Urban infrastructure Hangzhou City UniversityHangzhou310015China

During construction,the shield linings of tunnels often face the problem of local or overall upward movement after leaving the shield tail in soft soil areas or during some large diameter shield *** floating will increase the initial stress on the segments and bolts which is harmful to the service performance of the *** this study we used a random forest(RF)algorithm combined particle swarm optimization(PSO)and 5-fold cross-validation(5-fold CV)to predict the maximum upward displacement of tunnel linings induced by shield tunnel *** mechanism and factors causing upward movement of the tunnel lining are comprehensively *** input variables were selected according to results from analysis of influencing *** prediction performance of two models,PSO-RF and RF(default)were *** Gini value was obtained to represent the relative importance of the influencing factors to the upward displacement of *** PSO-RF model successfully predicted the maximum upward displacement of the tunnel linings with a low error(mean absolute error(MAE)=4.04 mm,root mean square error(RMSE)=5.67 mm)and high correlation(R^(2)=0.915).The thrust and depth of the tunnel were the most important factors in the prediction model influencing the upward displacement of the tunnel linings.

关键词： Random forest(RF) Particle swarm optimization(PSO) Upward displacement of lining Machine learning prediction Shieldtunneling construction

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Microstructures and mechanical properties of laser-directed energy deposited CrCoNi medium-entropy alloy

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Rare Metals 2024年第7期43卷 3286-3300页

作者： Wen-Jie Zhao Chang-Yu Liu Peng-Cheng Che Zhi-Liang Ning Hong-Bo Fan Jian-Fei Sun Yong-Jiang Huang Alfonso H.W.Ngan National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China Space Environment Simulation Research infrastructure Harbin Institute of TechnologyHarbin 150001China department of Mechanical Engineering The University of Hong KongHong Kong 999077China

The distinctive intrinsic heat treatment(IHT)originating from cyclic reheating in the laser-directed energy deposition(LDED) has attracted growing attention in recent *** this investigation,simulations and experimental characterizations were performed to examine the impact of IHT on the micros true ture and mechanical properties of LDED-fabricated CrCoNi medium-entropy alloy(MEA).The results show that the intensity of the IHT is proportional to the utilized laser energy density(LED).As the LED increased,significant dynamic recrystallization and grain refinement occurred within the alloy due to the enhanced intensity of ***,the high LED leads to severe hot cracking within the as-built MEA,resulting in inferior *** decreasing LED,the hot cracking was effectively ***,low LED weakened the intensity of IHT and consequently inhibited kinetic conditions of dynamic recrystallization,resulting in a heterogeneous grain structure characterized by multi-scale-sized *** structure provides significant hetero-deformation-induced hardening during plastic deformation,enabling the alloy to have a sustainable work-hardening *** expect that this work will have implications in taking full advantage of the unique IHT of the LDED process to fabricate ME As with excellent metallurgical quality and mechanical performance.

关键词： Intrinsic heat treatment Laser-directed energy deposition CrCoNi MEA Dynamic recrystallization Heterogeneous grain structure

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Characterization and Propagation of Historical and Projected Droughts in the Umatilla River Basin, Oregon, USA

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Advances in Atmospheric Sciences 2024年第2期41卷 247-262,I0020-I0028页

作者： Sudip GAUTAM Alok SAMANTARAY Meghna BABBAR-SEBENS Meenu RAMADAS School of Civil and Construction Engineering Oregon State UniversityCorvallisOR 97331USA School of infrastructure Indian Institute of TechnologyBhubaneswarOdisha 752050India

Climate change is expected to have long-term impacts on drought and wildfire risks in Oregon as summers continue to become warmer and drier. This paper investigates the projected changes in drought characteristics and drought propagation in the Umatilla River Basin in northeastern Oregon for mid-century(2030–2059) and late-century(2070–2099) climate scenarios. Drought characteristics for projected climates were determined using downscaled CMIP5 climate datasets from ten climate models and Soil and Water Assessment Tool to simulate effects on hydrologic processes. Short-term(three months) drought characteristics(frequency, duration, and severity) were analyzed using four drought indices, including the Standardized Precipitation Index(SPI-3), Standardized Precipitation-Evapotranspiration Index(SPEI-3), Standardized Streamflow Index(SSI-3), and the Standardized Soil Moisture Index(SSMI-3). Results indicate that short-term meteorological droughts are projected to become more prevalent, with up to a 20% increase in the frequency of SPI-3drought events. Short-term hydrological droughts are projected to become more frequent(average increase of 11% in frequency of SSI-3 drought events), more severe, and longer in duration(average increase of 8% for short-term droughts).Similarly, short-term agricultural droughts are projected to become more frequent(average increase of 28% in frequency of SSMI-3 drought events) but slightly shorter in duration(average decrease of 4%) in the future. Historically, drought propagation time from meteorological to hydrological drought is shorter than from meteorological to agricultural drought in most sub-basins. For the projected climate scenarios, the decrease in drought propagation time will likely stress the timing and capacity of water supply in the basin for irrigation and other uses.

关键词： Umatilla drought SPI SPEI SSI SSMI

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