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Stochastic Analysis and Modeling of Velocity Observations in Turbulent Flows

Journal of Environmental & Earth Sciences 2024年第1期6卷 45-56页

作者： Evangelos Rozos Jorge Leandro demetris Koutsoyiannis Institute for Environmental Research&Sustainable development National Observatory of AthensAthens15236Greece Research Institute for Water and Environment University of SiegenSiegen57076Germany department of Water Resources and Environmental engineering School of civil engineering National Technical University of AthensAthens15780Greece

Highly turbulent water flows,often encountered near human constructions like bridge piers,spillways,and weirs,display intricate dynamics characterized by the formation of eddies and *** formations,varying in sizes and lifespans,significantly influence the distribution of fluid velocities within the ***,the rapid velocity fluctuations in highly turbulent flows lead to elevated shear and normal stress *** this reason,to meticulously study these dynamics,more often than not,physical modeling is employed for studying the impact of turbulent flows on the stability and longevity of nearby *** the effectiveness of physical modeling,various monitoring challenges arise,including flow disruption,the necessity for concurrent gauging at multiple locations,and the duration of *** these challenges,image velocimetry emerges as an ideal method in fluid mechanics,particularly for studying turbulent *** account for measurement duration,a probabilistic approach utilizing a probability density function(PdF)is suggested to mitigate uncertainty in estimated average and maximum ***,it becomes evident that deriving the PdF is not straightforward for all turbulence-induced *** response,this study proposes a novel approach by combining image velocimetry with a stochastic model to provide a generic yet accurate description of flow dynamics in such *** integration enables an approach based on the probability of failure,facilitating a more comprehensive analysis of turbulent *** an approach is essential for estimating both short-and long-term stresses on hydraulic constructions under assessment.

关键词： Smart modeling Turbulent flows data analysis Stochastic analysis Image velocimetry

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Investigation of micro-scale shear response of sand–rubber granule mixture in terms of particle shape and grain scale deformability effects

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Particuology 2024年第7期90卷 452-469页

作者： Abdulmuttalip Ari Suat Akbulut department of civil engineering Yildiz Technical UniversityIstanbul34220Turkey

In this study,the effects of particle shape of rigid sand and soft rubber materials on macro-scale shear response were reasoned based on micro-scale *** this purpose,first,the shape properties of three different sand and two different rubber samples were quantified using image processing techniques,and the contact model parameters were calibrated through physical *** direct shear test was simulated in a two-dimensional discrete element software with realistic particle *** soft nature of rubber particles was reflected using body-centered cubic packing with a linear-parallel bond contact *** a result,coordination number,distribution of contact forces(i.e.,strong contact,and fabric anisotropy),and contact sliding were derived by the numerical *** has been observed that the particle shape leads to distinctive micro-scale responses due to the variations in the stiffness of the contacts.

关键词： Particle shape Sand Rubber Shear response Micro-scale response discrete element method

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Microstructural analysis of marl stabilized with municipal solid waste and nano-MgO

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Journal of Rock Mechanics and Geotechnical engineering 2024年第8期16卷 3258-3269页

作者： Ali Ohadian Navid Khayat Mehdi Mokhberi department of civil engineering Ahvaz BranchIslamic Azad UniversityAhvazIran department of civil engineering Estahban BranchIslamic Azad UniversityEstahbanIran

Municipal solid waste(MSW)is accumulating over elapsed time across the world,and it is observed in many projects associated with weak soils,such as ***,effective solutions to the environmental problem are *** techniques for stabilizing marl generally use substances such as lime and cement,which could exacerbate *** this,some new stabilizers,***-MgO,are *** are large quantities of marls and MSW in Shiraz City,*** present study aims to evaluate the feasibility of using nano-MgO as a green low-carbon binder to remove MSW from the environment and make construction projects more *** drained shear tests were conducted to evaluate the mechanical behaviors of the nano-MgO treated marl specimens at high normal *** marl specimens containing MSW percentages of 15%,25%,35%,and 45%and nano-MgO percentages of 0.25%,0.5%,0.75%,and 1%,were *** is found that the marl containing 15%and 25%MSW and 0.5%nano-MgO at 28-d curing can perform cation exchange and form new cementitious *** soils with merely MSW show good performance due to the removal of the kaolinite and the formation of ***,the soil with 25%MSW and 0.5%nano-MgO shows the same strength enhancement as the specimen with the optimal nano-MgO(0.75%)through the formation of dolomite,with a 20.59%increase in strain energy(SE).

关键词： Marl Shear strength Microstructure Nano-MgO Municipal solid waste(MSW)

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Effect of recycled brick powder on the properties of selfcompacting fiber reinforced mortars produced with different cement types

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Frontiers of Structural and civil engineering 2024年第5期18卷 743-759页

作者： Serkan ETLI department of civil engineering Kahramanmaras Sutcu Imam UniversityKahramanmaraş46040Turkey

It is known that clay-based building materials such as bricks and tiles accumulate in landfills at the end of their useful *** an alternative,recycling clay-based building material can reduce the negative environmental *** brick powder(RBP)is obtained by grinding waste brick and tile collected from end-of-life *** the scope of the study,the use of self-compacting fiber reinforced mortars(SCFRMs)produced with RBP using CEM-I 42.5R and 52.5R class cements for two different cement classes was *** accordance with EFNARC,a water binding ratio of 0.42 was used to control the workability and strength of the *** the produced SCFRM,1%,2%,and 3%by weight binder Polypropylene(PP)fiber was added to the blends with 10%,20%,and 30%RBP substitutes.A total of 32 SCFRM mixes were produced and *** flexural and compressive strengths at 7,28,56,and 90 d were evaluated on the produced *** addition,porosity and water absorbency values were examined since these are significant for durability *** was observed that the use of RBP increases durability,and the use of fiber can have positive effects in terms of both durability and strength.

关键词： cement strength tile/brick dust self-compacting fiberized mortar

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Seismic performance evaluation of hybrid coupled shear wall system with shear and flexural fuse-type steel coupling beams

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Earthquake engineering and engineering Vibration 2024年第3期23卷 691-712页

作者： Zahra Ramezandoust Abbas Tajaddini Panam Zarfam department of civil engineering Science and Research branchIslamic Azad UniversityTehran 14778-93855Iran department of civil engineering Karaj BranchIslamic Azad UniversityKaraj 31485-313Iran

Replaceable flexural and shear fuse-type coupling beams are used in hybrid coupled shear wall(HCSW)systems,enabling concrete buildings to be promptly recovered after severe *** study aimed to analytically evaluate the seismic behavior of flexural and shear fuse beams situated in short-,medium-and high-rise RC buildings that have *** building groups hypothetically located in a high seismic hazard zone were studied.A series of 2d nonlinear time history analyses was accomplished in OpenSees,using the ground motion records scaled at the design basis earthquake *** was found that the effectiveness of fuses in HCSWs depends on various factors such as size and scale of the building,allowable rotation value,inter-story drift ratio,residual drift quantity,energy dissipation value of the fuses,*** results show that shear fuses better meet the requirements of rotations and *** contrast,flexural fuses dissipate more energy,but their sectional stiffness should increase to meet other *** was concluded that adoption of proper fuses depends on the overall scale of the building and on how associated factors are considered.

关键词： hybrid coupled shear wall steel fuse coupling beam shear and flexural fuse nonlinear dynamic analysis seismic performance

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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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High-resolution photogrammetry to measure physical aperture of two separated rock fracture surfaces

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Journal of Rock Mechanics and Geotechnical engineering 2024年第8期16卷 2922-2934页

作者： Masoud Torkan Mateusz Janiszewski Lauri Uotinen Alireza Baghbanan Mikael Rinne department of civil engineering Aalto UniversityEspooFinland department of Mining engineering Isfahan University of TechnologyIsfahanIran

Photogrammetry,reconstructing three-dimensional(3d)models from overlapping two-dimensional(2d)photos,finds application in rock mechanics and rock engineering to extract geometrical details of reconstructed objects,for example rock *** properties are important for determining the mechanical stability,permeability,strength,and shear behavior of the rock *** can be used to reconstruct detailed 3d models of two separated rock fracture surfaces to characterize fracture roughness and physical aperture,which controls the fluid flow,hydromechanical and shear behavior of the rock *** research aimed to determine the optimal number of scale bars required to produce high-precision 3d models of a fracture surface.A workflow has been developed to define the physical aperture of a fracture using *** blocks of Kuru granite(25 cm×25 cm×10 cm)with an artificially induced fracture,were *** scaling 3d models,321 markers were used as ground control points(GCPs)with predefined distances on each *** the samples were wellmatched in their original positions,the entire block was *** data of the GCPs were extracted from the 3d model of the *** half was surveyed separately and georeferenced by GCPs and merged into the same coordinate *** fracture surfaces were extracted from the 3d models and the vertical distance between the two surfaces was digitally calculated as physical *** assessment of the photogrammetric reconstruction showed a 20-30 mm digital control distance accuracy when compared to known distances defined between *** attain this accuracy,the study found that at least 200 scale bars were ***,photogrammetry was employed to measure changes in aperture under normal *** results obtained from this approach were found to be in good agreement with those obtained using linear variable displacement transducers(LVdTs),with differences ran

关键词： Photogrammetry Physical aperture Rock fracture Predefined distances Markers

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Seismic-induced surficial failure of cohesive slopes using three-dimensional limit analysis:A case study of the Wangjiayan landslide in Beichuan, China

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Earthquake engineering and engineering Vibration 2024年第3期23卷 537-545页

作者： Gao Yufeng Liu Yang Geng Weijuan Zhang Fei Key Laboratory of the Ministry of Education for Geomechanics and Embankment engineering College of Civil and Transportation EngineeringHohai UniversityNanjing 210098China department of civil engineering Faculty of Civil Engineering and MechanicsJiangsu UniversityZhenjiang 212013China

A seismic-induced landslide is a common geological catastrophe that occurs in *** Wangjiayan landslide,which was triggered by the Wenchuan earthquake,is a typical case in *** Wanjiayan landslide caused many casualties and resulted in enormous property *** study constructs a simple surficial failure model based on the upper bound approach of three-dimensional(3d)limit analysis to evaluate the slope stability of the Wangjiayan case,while a traditional two-dimensional(2d)analysis is also conducted as a reference for comparison with the results of the 3d analysis.A quasi-static calculation is used to study the effect of the earthquake in terms of horizontal ground acceleration,while a parametric study is conducted to evaluate the critical cohesion of *** than employing a 3d analysis,using the 2d analysis yields an underestimation regarding the safety *** the Wangjiayan landslide,the difference in the factors of safety between the 3d and 2d analyses can reach 20%.The sliding surface morphology as determined by the 3d method is similar to actual morphology,and the parameters of both are also compared to analyze the reliability of the proposed 3d method.

关键词： landslide Wenchuan earthquake surficial failure limit analysis stability quasi-static

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Biotransformation of 6:2 fluorotelomer sulfonate(6:2 FTS)in sulfur-rich media by Trametopsis cervina

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Frontiers of Environmental Science & engineering 2024年第9期18卷 17-26页

作者： Felix Grimberg Thomas M Holsen Sujan Fernando Siwen Wang department of civil and Environmental engineering Clarkson UniversityPotsdamNew York 13699USA

Biotransformation of 6:2 fluorotelomer sulfonate(6:2 FTS)by two species of white-rot fungi,Pleurotus ostreatus(***)and Trametopsis cervina(***),was investigated in a sulfurrich medium designed to stimulate production of lignin-degrading *** of 6:2 FTS was observed by *** over the study period of 30 d,but not by *** rates were comparable to those found in other studies investigating mixed culture degradation in nonsulfur limiting media,with approximately 50 mol%of applied 6:2 FTS removed after 30 *** transformation products were short-chain perfluorocarboxylic acids(PFCAs),including PFHxA(2.27 mol%),PFPeA(0.24 mol%),and PFBA(0.28 mol%).The main intermediate products include 5:2 sFTOH(16.3 mol%)and 5:3 FTCA(2.99 mol%),while 6:2 FTCA,6:2 FTuCA,and 5:2 ketone were also identified at low *** 60 mol%of detected products were assigned to the major pathway to 5:2 ketone,and 40 mol%were assigned to the minor pathway to 5:3 *** overall molar balance was found to decrease to 75 mol%by day 30,however,was closed to near 95 mol%with a theoretical estimation for the volatile intermediates in the headspace,5:2 ketone and 5:2 *** different capabilities of the two white-rot fungal species for 6:2 FTS biotransformation in sulfur-rich media suggest that the enzyme processes of *** to de-sulfonate 6:2 FTS may be unrelated to sulfur metabolism.

关键词： White-rot fungus 6:2 fluorotelomer sulfonate(6:2 FTS) Biotransformation Sulfur-rich medium Intermediate products

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A combined experimental and dEM investigation of grain interlocking in sheared granular assemblies

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Particuology 2024年第7期90卷 436-451页

作者： Rui Lu Qiang Luo Tengfei Wang david P.Connolly Tao Xie School of civil engineering Southwest Jiaotong UniversityChengdu 610031China Key Laboratory of High-Speed Railway engineering(Southwest Jiaotong university) Ministry of EducationChengdu 610031China School of civil engineering University of LeedsLeeds LS29JTUK department of civil engineering McMaster UniversityHamiltonONCanada

Compacted granular material,integral to geotechnical engineering,undergoes translation,rotation,and interlocking when subject to shear displacements or external *** present study focuses on the interlocking of heterogeneous granular materials,a complex behavior influenced by gradation,compaction,and varying particle geometry,and has consequently received limited attention in existing *** address this research gap,we conducted an analysis on the effect of grain interlocking on the shear resistance of granular assemblies,using a combination of laboratory testing and the discrete element method(dEM).Initially,large-scale direct shear tests were conducted on gravel−sand mixes with varying degrees of compaction and normal *** of the mixes also underwent subsequent shear reversal to explore the differences in grain interlocking between the two shearing processes on the shear *** analyzing the laboratory results,a mesoscopic scale investigation was performed by replicating the test using discrete element *** facilitate this,granular particle geometries were measured using 3d laser scanning based on the physical lab ***,based on these scans,discrete element R-block and ball models were utilized to construct both the coarse and fine particles within the *** vibro-compaction was employed to regulate the degree of *** results indicate that an increase in vertical pressure,coupled with a zero dilatancy angle,results in a rising stress ratio,indicative of grain *** interlocking exhibits a positive correlation with both the coarse content and the degree of compaction,and varies depending on the shear *** interlocking progresses,the shear band,induced by particle movement,expands and is associated with reduced particle rotation near the shear *** study further reveals a consistent positive correlation between interlocking and the principal orientation angle of strong normal c

关键词： Granular material Interlocking Shear resistance direct shear discrete element method Vibro-compaction

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