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Tensile strength and failure behavior of rock-mortar interfaces: Direct and indirect measurements

Journal of Rock Mechanics and Geotechnical engineering 2024年第1期16卷 41-55页

作者： Ghasem Shams Patrice Rivard Omid Moradian civil engineering and Building engineering department Universitéde SherbrookeSherbrookeQuébecCanada department of earth Sciences Swiss Federal Institute of Technology(ETH)ZurichSwitzerland department of civil and Environmental engineering Colorado School of MinesGoldenCOUSA

The tensile strength at the rock-concrete interface is one of the crucial factors controlling the failure mechanisms of structures,such as concrete gravity *** the critical importance of the failure mechanism and tensile strength of rock-concrete interfaces,understanding of these factors remains very *** study investigated the tensile strength and fracturing processes at rock-mortar interfaces subjected to direct and indirect tensile *** image correlation(DIC)and acoustic emission(AE)techniques were used to monitor the failure mechanisms of specimens subjected to direct tension and indirect loading(Brazilian tests).The results indicated that the direct tensile strength of the rock-mortar specimens was lower than their indirect tensile strength,with a direct/indirect tensile strength ratio of 65%.DIC strain field data and moment tensor inversions(MTI)of AE events indicated that a significant number of shear microcracks occurred in the specimens subjected to the Brazilian *** presence of these shear microcracks,which require more energy to break,resulted in a higher tensile strength during the Brazilian *** contrast,microcracks were predominantly tensile in specimens subjected to direct tension,leading to a lower tensile *** monitoring of the cracking processes in the rock-mortar interfaces revealed that they show AE precursors before failure under the Brazilian test,whereas they show a minimal number of AE events before failure under direct *** to different microcracking mechanisms,specimens tested under Brazilian tests showed lower roughness with flatter fracture surfaces than those tested under direct tension with jagged and rough fracture *** results of this study shed light on better understanding the micromechanics of damage in the rock-concrete interfaces for a safer design of engineering structures.

关键词： Rock-mortar Rock-concrete Moment tensor inversion(MTI) Acoustic emission(AE) Digital image correlation(DIC) Tensile strength Direct tensile test Brazilian test

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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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A stable implicit nodal integration-based particle finite element method(N-PFEM)for modelling saturated soil dynamics

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Journal of Rock Mechanics and Geotechnical engineering 2024年第6期16卷 2172-2183页

作者： Liang Wang Xue Zhang Jingjing Meng Qinghua Lei department of earth Sciences ETH ZürichZürich8092Switzerland department of civil engineering and Industrial Design University of LiverpoolLiverpoolL693BXUK department of civil Environmental and Natural Resources EngineeringLuleåUniversity of TechnologyLuleå97187Sweden department of earth Sciences Uppsala UniversityUppsala75105Sweden

In this study,we present a novel nodal integration-based particle finite element method(N-PFEM)designed for the dynamic analysis of saturated *** approach incorporates the nodal integration technique into a generalised Hellinger-Reissner(HR)variational principle,creating an implicit PFEM *** mitigate the volumetric locking issue in low-order elements,we employ a node-based strain smoothing *** discretising field variables at the centre of smoothing cells,we achieve nodal integration over cells,eliminating the need for sophisticated mapping operations after re-meshing in the *** express the discretised governing equations as a min-max optimisation problem,which is further reformulated as a standard second-order cone programming(SOCP)***,pore water pressure,and displacements are simultaneously determined using the advanced primal-dual interior point ***,our numerical model offers improved accuracy for stresses and pore water pressure compared to the displacement-based PFEM *** experiments demonstrate that the N-PFEM efficiently captures both transient and long-term hydro-mechanical behaviour of saturated soils with high accuracy,obviating the need for stabilisation or regularisation techniques commonly employed in other nodal integration-based PFEM *** work holds significant implications for the development of robust and accurate numerical tools for studying saturated soil dynamics.

关键词： Particle finite element method Nodal integration Dynamic saturated media Second-order cone programming(SOCP)

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A performance-based hybrid deep learning model for predicting TBM advance rate using Attention-ResNet-LSTM

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Journal of Rock Mechanics and Geotechnical engineering 2024年第1期16卷 65-80页

作者： Sihao Yu Zixin Zhang Shuaifeng Wang Xin Huang Qinghua Lei department of Geotechnical engineering College of Civil EngineeringTongji UniversityShanghaiChina Key Laboratory of Geotechnical and Underground engineering Ministry of EducationTongji UniversityShanghaiChina department of earth Sciences ETH ZürichZürichSwitzerland department of earth Sciences Uppsala UniversityUppsalaSweden

The technology of tunnel boring machine(TBM)has been widely applied for underground construction worldwide;however,how to ensure the TBM tunneling process safe and efficient remains a major *** rate is a key parameter of TBM operation and reflects the TBM-ground interaction,for which a reliable prediction helps optimize the TBM ***,we develop a hybrid neural network model,called Attention-ResNet-LSTM,for accurate prediction of the TBM advance rate.A database including geological properties and TBM operational parameters from the Yangtze River Natural Gas Pipeline Project is used to train and test this deep learning *** evolutionary polynomial regression method is adopted to aid the selection of input *** results of numerical exper-iments show that our Attention-ResNet-LSTM model outperforms other commonly-used intelligent models with a lower root mean square error and a lower mean absolute percentage ***,parametric analyses are conducted to explore the effects of the sequence length of historical data and the model architecture on the prediction accuracy.A correlation analysis between the input and output parameters is also implemented to provide guidance for adjusting relevant TBM operational *** performance of our hybrid intelligent model is demonstrated in a case study of TBM tunneling through a complex ground with variable ***,data collected from the Baimang River Tunnel Project in Shenzhen of China are used to further test the generalization of our *** results indicate that,compared to the conventional ResNet-LSTM model,our model has a better predictive capability for scenarios with unknown datasets due to its self-adaptive characteristic.

关键词： Tunnel boring machine(TBM) Advance rate Deep learning Attention-ResNet-LSTM Evolutionary polynomial regression

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Loading capacity and emulsification phenomena of HREE extraction by dialkylphosphinic acids with different β,γ,δ-substituents

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Journal of Rare earths 2024年第1期42卷 191-199,I0007页

作者： Junlian Wang Guodong Xu Wen Xu Jianguo Cui Yufu Chen Ziyong Chang School of civil and resource engineering University of Science and Technology BeijingBeijing100083China Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mines Beijing100083China State Key Laboratory of Baiyunobo Rare earth resource Researches and Comprehensive Utilization Baotou Research Institute of Rare EarthsBaotou014030China

The relationship between dialkylphosphinic acid structure and their loading capacity for HREEs and emulsification phenomena has rarely been *** this paper,we took Lu extraction as an example to study the effect of β,γ,δ-substituents of dialkylphosphinic acids on their loading capacity and anti-emulsification performance for *** discuss conveniently,the dialkylphosphinic acids were classified into two groups:β-substituent group(P208,INET-1,P218,USTB-1 and P227)and γ,δ-substituent group(P218,P2132 and Cyanex 272).For β-substituent group extractants,their loading capacities are in the order P208(299.7 mg/L)≈INET-1(299.5 mg/L)>P218(270.8 mg/L)>>USTB-1(163.1 mg/L)>P227(151.4 mg/L),while their anti-emulsification/gelation performances are just in the opposite order P227>USTB-1>P218>P208≈INET-1 under the studied *** γ,δ-substituent group extractants,their loading capacities are in the order P218(270.8 mg/L)>P2132(192.3 mg/L)>Cyanex272(131.7 mg/L),while the anti-emulsification performance of P218 is better than those of P2132 and Cyanex *** loading capacity data given in the parentheses are obtained through repeatedly extracting Lu from ~4×10^(-4)mol/L of Lu aqueous feed solution with initial pH of 2.40 by 0.01 mol/L extractant at phase ratio A/O of 1:1.

关键词： Heavy rare earth element Dialkylphosphinic acid Extraction Loading capacity Emulsification

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Fire resistance evaluation through synthetic fire tests and generative adversarial networks

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Frontiers of Structural and civil engineering 2024年第4期18卷 587-614页

作者： AybikeÖzyükselÇiftçioğlua M.Z.Naser department of civil engineering Manisa Celal Bayar University45140Türkiye School of civil&Environmental engineering and earth Sciences(SCEEES) Clemson UniversityClemsonSC 29631USA Artificial Intelligence Research Institute for Science and engineering(AIRISE) Clemson UniversityClemsonSC 29631USA

This paper introduces a machine learning approach to address the challenge of limited data resulting from costly and time-consuming fire experiments by enlarging small fire test data sets and predicting the fire resistance of reinforced concrete *** approach begins by creating deep learning models,namely generative adversarial networks and variational autoencoders,to learn the spatial distribution of real fire *** then use these models to generate synthetic tabular samples that closely resemble realistic fire resistance values for reinforced concrete *** generated data are employed to train state-of-the-art machine learning techniques,including Extreme Gradient Boost,Light Gradient Boosting Machine,Categorical Boosting Algorithm,Support Vector Regression,Random Forest,Decision Tree,Multiple Linear Regression,Polynomial Regression,Support Vector Machine,Kernel Support Vector Machine,Naive Bayes,and K-Nearest Neighbors,which can predict the fire resistance of the columns through regression and *** learning analyses achieved highly accurate predictions of fire resistance values,outperforming traditional models that relied solely on limited experimental *** study highlights the potential for using machine learning and deep learning analyses to revolutionize the field of structural engineering by improving the accuracy and efficiency of fire resistance evaluations while reducing the reliance on costly and time-consuming experiments.

关键词： deep learning fire resistance generative adversarial networks machine learning

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Magnetic Co-doped 1D/2D structuredγ-Fe_(2)O_(3)/MoS_(2) effectively activated peroxymonosulfate for efficient abatement of bisphenol A via both radical and non-radical pathways

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Frontiers of Environmental Science & engineering 2024年第3期18卷 143-159页

作者： Junge Xu Dong Wang Die Hu Ziwei Zhang Junhong Chen Yingmu Wang Yifeng Zhang College of civil engineering Fuzhou UniversityFuzhou 350116China China Nuclear Power engineering Co. Ltd.Shenzhen 518120China department of Environmental&resource engineering Technical University of DenmarkLyngby DK-2800Denmark

Iron-based catalysts have been widely used to treat refractory organic pollutants in *** this paper,magnetic Co-γ-Fe_(2)O_(3)was synthesized by a facile tartaric acid-assisted hydrothermal method,and Co-γ-Fe_(2)O_(3)/MoS_(2) nanocomposite catalyst was obtained via in situ growth of MoS_(2) nanosheets on Co-γ-Fe_(2)O_(3)*** nanocomposite catalysts were used to decompose bisphenol A(BPA)by activating peroxymonosulfate(PMS).It was shown that only 0.15 g/L catalyst and 0.5 mmol/L PMS degraded 10 mg/L of BPA(99.3%within 10 min)in the pH range of 3–*** was activated due to redox cycling among the pairs Co(III)/Co(II),Fe(III)/Fe(II),and Mo(VI)/Mo(IV).Quenching experiments and electron paramagnetic resonance spectroscopy demonstrated that both radical and non-radical pathways were involved in BPA degradation,in which active radical sulfate radical and non-radical singlet oxygen were the main reactive oxygen *** intermediates were identified by liquid chromatography-coupled mass spectrometry,and three possible BPA degradation pathways were *** toxicity of several degradation intermediates was lower,and Co-γ-Fe_(2)O_(3)/MoS_(2) exhibited excellent reusability and could be magnetically recovered.

关键词： Magnetic Co-γ-Fe_(2)O_(3) /MoS_(2) Hydrothermal method Bisphenol A Degradation pathways Toxicity analysis

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Sliding behaviors of the trapezoidal roof rock block under a lateral dynamic disturbance

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Journal of Rock Mechanics and Geotechnical engineering 2024年第3期16卷 741-760页

作者： Feng Dai Wancheng Zhu Min Ren Shunchuan Wu Leilei Niu Faculty of Land resources engineering Kunming University of Science and TechnologyKunming650093China Center for Rock Instability and Seismicity Research Department of Mining EngineeringSchool of Resource and Civil EngineeringNortheastern UniversityShenyang110819China

The surrounding rock of underground space is always affected by external dynamic disturbance from the side position,such as blasting vibration from a stope at the same level or seismic waves from adjacent strata.A series of laboratory tests,numerical simulations and theoretical analyses were carried out in this study to disclose the sliding mechanism of roof rock blocks under lateral ***,the experiments on trapezoidal key block under various clamping loads and disturbance were conducted,followed by numerical simulations using the fast Lagrangian analysis of continua(FLAC3D).Then,based on the conventional wave propagation model and the classical shear-slip constitutive model,a theoretical model was proposed to capture the relative displacement between blocks and the sliding displacement of the key *** results indicate that the sliding displacement of the key block increased linearly with the disturbance energy and decreased exponentially with the clamping load when the key block was disturbed to slide(without instability).Meanwhile,when the key block was disturbed to fall,two types of instability process may appear as immediate type or delayed *** addition,the propagation of stress waves in the block system exhibited obvious low-velocity and lowfrequency characteristics,resulting in the friction reduction effect appearing at the contact interface,which is the essential reason for the sliding of rock *** results can be applied to practical underground engineering and provide valuable guidance for the early detection and prevention of rockfalling disasters.

关键词： Lateral dynamic disturbance Trapezoidal rock block system Low-velocity and low-frequency wave Friction reduction effect Instability mode

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Electroactivity of the magnetotactic bacteria Magnetospirillum magneticum AMB-1 and Magnetospirillum gryphiswaldense MSR-1

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Frontiers of Environmental Science & engineering 2024年第4期18卷 103-110页

作者： Mathias Fessler Qingxian Su Marlene Mark Jensen Yifeng Zhang department of Environmental and resource engineering Technical University of DenmarkCopenhagenDK-2800Denmark

Magnetotactic bacteria reside in sediments and stratified water *** are named after their ability to synthesize internal magnetic particles that allow them to align and swim along the earth’s magnetic field ***,we show that two magnetotactic species,Magnetospirillum magneticum strain AMB-1 and Magnetospirillum gryphiswaldense strain MSR-1,are *** *** and *** were able to generate current in microbial fuel cells with maximum power densities of 27 and 11μW/m^(2),*** the presence of the electron shuttle resazurin both species were able to reduce the crystalline iron oxide hematite(Fe_(2)O_(3)).In addition,*** could reduce poorly crystalline iron oxide(FeOOH).Our study adds *** and *** to the growing list of known electroactive bacteria,and implies that electroactivity might be common for bacteria within the Magnetospirillum genus.

关键词： Magnetotactic bacteria Magnetospirillum magneticum Magnetospirillum gryphiswaldense Extracellular electron transfer Microbial fuel cells

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Envisioning Water-Resilient Cities Through the Lens of Blue-Green-Grey Solutions

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engineering 2024年第5期36卷 1-2页

作者： Nan-Qi Ren Glen Daigger School of civil and Environmental engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China State Key Laboratory of Urban Water resource and Environment Harbin Institute of TechnologyHarbin 150090China department of civil and Environmental engineering University of MichiganAnn ArborMI 48109USA

Cities are dynamic systems,and the urban water systems within them can be evolved to provide water services to both humans and the environment while also enhancing the broader urban *** is done by embracing innovation and technological advancement while focusing on increased service to the human population and the local and broader *** the contemporary era,characterized by the rise of low-carbon and intelligent technologies,the swift pace of socioeconomic expansion highlights the critical need to address issues of urban water security and environmental *** escalating resource and environmental constraints,adopting holistic blue-green-grey strategies becomes imperative for the sustainable governance of urban water *** integrated approach is needed to navigate the intricate challenges of urban water dynamics while fostering enhanced ecological performance and resilience.

关键词： services urban advancement

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