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Recycling arsenic-containing bio-leaching residue after thermal treatment in cemented paste backfill:Structure modification,binder properties and environmental assessment

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2136-2147页

作者： Dengfeng Zhao Shiyu Zhang Yingliang Zhao Department of mining engineering Lyuliang UniversityLvliang 033000China school of civil and environmental engineering University of Science and Technology BeijingBeijing 100083China school of mining engineering Taiyuan University of TechnologyTaiyuan 030024China Department of civil and environmental engineering The Hong Kong Polytechnic UniversityHong Kong 00852China

The substantial arsenic(As)content present in arsenic-containing bio-leaching residue(ABR)presents noteworthy environ-mental challenges attributable to its inherent instability and susceptibility to *** its elevated calcium sulfate content,ABR exhibits considerable promise for industrial *** study delved into the feasibility of utilizing ABR as a source of sulfates for producing super sulfated cement(SSC),offering an innovative binder for cemented paste backfill(CPB).Thermal treatment at varying temperatures of 150,350,600,and 800℃ was employed to modify ABR’s *** investigation encompassed the examination of phase transformations and alterations in the chemical composition of As within ***,the hydration characteristics of SSC utilizing ABR,with or without thermal treatment,were studied,encompassing reaction kinetics,setting time,strength development,and *** findings revealed that thermal treatment changed the calcium sulfate structure in ABR,consequently impacting the resultant sample ***,calcination at 600℃ demonstrated optimal modification effects on both early and long-term strength *** enhanced performance can be attributed to the augmented formation of reaction products and a densified ***,the thermal treatment elicited modifications in the chemical As fractions within ABR,with limited impact on the As immobilization capacity of the prepared binders.

关键词： cemented paste backfill bio-leaching residue arsenic immobilization binder hydration calcination

A thermo-mechanical damage constitutive model for deep rock considering brittleness-ductility transition characteristics

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Journal of Central South university 2024年第7期31卷 2379-2392页

作者： FENG Chen-chen WANG Zhi-liang WANG Jian-guo LU Zhi-tang LI Song-yu school of civil and Hydraulic engineering Hefei University of TechnologyHefei 230009China school of Mechanics and civil engineering China University of Mining and TechnologyXuzhou 221116China school of Resources and environmental engineering Hefei University of TechnologyHefei 230009China

This paper developed a statistical damage constitutive model for deep rock by considering the effects of external load and thermal treatment temperature based on the distortion *** model parameters were determined through the extremum features of stress−strain ***,the model predictions were compared with experimental results of marble *** is found that when the treatment temperature rises,the coupling damage evolution curve shows an S-shape and the slope of ascending branch gradually decreases during the coupling damage evolution *** a constant temperature,confining pressure can suppress the expansion of *** the confining pressure increases the rock exhibits ductility characteristics,and the shape of coupling damage curve changes from an S-shape into a quasi-parabolic *** model can well characterize the influence of high temperature on the mechanical properties of deep rock and its brittleness-ductility transition characteristics under confining ***,it is suitable for sandstone and granite,especially in predicting the pre-peak stage and peak stress of stress−strain curve under the coupling action of confining pressure and high *** relevant results can provide a reference for further research on the constitutive relationship of rock-like materials and their engineering applications.

关键词： deep rock crack initiation threshold thermo-mechanical coupling statistical damage model distortion energy theory

Failure characterization of fully grouted rock bolts under triaxial testing

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Journal of Rock Mechanics and Geotechnical engineering 2024年第3期16卷 778-789页

作者： Hadi Nourizadeh Ali Mirzaghorbanali Mehdi Serati Elamin Mutaz Kevin McDougall Naj Aziz Centre for Future Materials(CFM) School of EngineeringUniversity of Southern QueenslandToowoombaQLD4350Australia school of engineering University of Southern QueenslandSpringfield CentralQLD4300Australia school of civil engineering University of QueenslandSt LuciaQLD4072Australia school of Surveying and Build Environment University of Southern QueenslandToowoombaQLD4350Australia school of civil Mining&Environmental EngineeringUniversity of WollongongWollongongNSW2500Australia

Confining stresses serve as a pivotal determinant in shaping the behavior of grouted rock ***,prior investigations have oversimplified the three-dimensional stress state,primarily assuming hydrostatic stress *** these conditions,it is assumed that the intermediate principal stress(σ_(2))equals the minimum principal stress(σ_(3)).This assumption overlooks the potential variations in magnitudes of in situ stress conditions along all three directions near an underground opening where a rock bolt is *** this study,a series of push tests was meticulously conducted under triaxial *** tests involved applying non-uniform confining stresses(σ_(2)≠σ_(3))to cubic specimens,aiming to unveil the previously overlooked influence of intermediate principal stresses on the strength properties of rock *** results show that as the confining stresses increase from zero to higher levels,the pre-failure behavior changes from linear to nonlinear forms,resulting in an increase in initial stiffness from 2.08 kN/mm to 32.51 kN/*** load-displacement curves further illuminate distinct post-failure behavior at elevated levels of confining stresses,characterized by enhanced ***,the peak load capacity ranged from 27.9 kN to 46.5 kN as confining stresses advanced from σ_(2)=σ_(3)=0 to σ_(2)=20 MPa and σ_(3)=10 ***,the outcomes highlight an influence of confining stress on the lateral deformation of *** levels of confinement prompt overall dilation in lateral deformation,while higher confinements maintain a state of ***,diverse failure modes have been identified,intricately tied to the arrangement of confining *** confinements tend to induce a splitting mode of failure,whereas higher loads bring about a shift towards a pure interfacial shear-off and shear-crushed failure mechanism.

关键词： Rock bolts Bolt-grout interface Bond strength Push test Triaxial tests

Predicting the International Roughness Index of JPCP and CRCP Rigid Pavement:A Random Forest(RF)Model Hybridized with Modified Beetle Antennae Search(MBAS)for Higher Accuracy

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Computer Modeling in engineering & Sciences 2024年第5期139卷 1557-1582页

作者： Zhou Ji Mengmeng Zhou Qiang Wang Jiandong Huang College of civil and environmental engineering Hunan University of Science and EngineeringYongzhou425006China school of Mines China University of Mining and TechnologyXuzhou221116China school of civil engineering Guangzhou UniversityGuangzhou510006China

To improve the prediction accuracy of the International Roughness Index(IRI)of Jointed PlainConcrete Pavements(JPCP)and Continuously Reinforced Concrete Pavements(CRCP),a machine learning approach is developed in this study for the modelling,combining an improved Beetle Antennae Search(MBAS)algorithm and Random Forest(RF)*** 10-fold cross-validation was applied to verify the reliability and accuracy of the model proposed in this *** importance scores of all input variables on the IRI of JPCP and CRCP were analysed as *** results by the comparative analysis showed the prediction accuracy of the IRI of the newly developed MBAS and RF hybrid machine learning model(RF-MBAS)in this study is higher,indicated by the RMSE and R values of 0.2732 and 0.9476 for the JPCP as well as the RMSE and R values of 0.1863 and 0.9182 for the *** accuracy of this obtained result far exceeds that of the IRI prediction model used in the traditional Mechanistic-Empirical Pavement Design Guide(MEPDG),indicating the great potential of this developed *** importance analysis showed that the IRI of JPCP and CRCP was proportional to the corresponding input variables in this study,including the total joint faulting cumulated per KM(TFAULT),percent subgrade material passing the 0.075-mm Sieve(P_(200))and pavement surface area with flexible and rigid patching(all Severities)(PATCH)which scored higher.

关键词： Cement pavement JPCP CRCP RF-MBAS IRI

Mechanical behavior of 2G NPR bolt anchored rock samples under static disturbance loading

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Journal of Mountain Science 2024年第7期21卷 2494-2516页

作者： WANG Jiong JIANG Jian WANG Siyu CHANG Yiwen LIU Peng HE Manchao CHENG Shuang State Key Laboratory for Tunnel engineering China University of Mining and Technology(Beijing)Beijing 100083China school of Mechanics and civil engineering China University of Mining and Technology(Beijing)Beijing 100083China

The deep mining of coal resources is accompanied by severe environmental challenges and various potential engineering *** implementation of NPR(negative Poisson's ratio)bolts are capable of controlling large deformations in the surrounding rock *** paper focuses on studying the mechanical properties of the NPR bolt under static disturbance *** deep nonlinear mechanical experimental system was used to study the mechanical behavior of rock samples with different anchored types(unanchored/PR anchored/2G NPR anchored)under static disturbance *** whole process of rock samples was taken by high-speed camera to obtain the real-time failure characteristics under static disturbance *** the same time,the acoustic emission signal was collected to obtain the key characteristic parameters of acoustic emission such as acoustic emission count,energy,and *** deformation at the failure of the samples was calculated and analyzed by digital speckle *** findings indicate that the failure mode of rock is influenced by different types of *** peak failure strength of 2G NPR bolt anchored rock samples exhibits an increase of 6.5%when compared to the unanchored rock *** cumulative count and cumulative energy of acoustic emission exhibit a decrease of 62.16%and 62.90%,*** maximum deformation of bearing capacity exhibits an increase of 59.27%,while the failure time demonstrates a delay of 42.86%.The peak failure strength of the 2G NPR bolt anchored ones under static disturbance load exhibits an increase of 5.94%when compared to the rock anchored by PR(Poisson's ratio)*** cumulative count and cumulative energy of acoustic emission exhibit a decrease of 47.16%and 43.86%,*** maximum deformation of the bearing capacity exhibits an increase of 50.43%,and the failure time demonstrates a delay of 32%.After anchoring by 2G NPR bolt,anchoring support effectively reduces the risk of damage caused by s

关键词： Anchored rock samples Static disturbance load Acoustic emission characteristics Digital speckle Negative Poisson's ratio

Failure process and monitoring data of an extra-large landslide at the Nanfen Open-pit Iron Mine

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Journal of Mountain Science 2024年第9期21卷 2918-2938页

作者： WANG Jingxiang YANG Xiaojie TAO Zhigang HE Manchao SHEN Fuxin State Key Laboratory for Tunnel engineering China University of Mining and Technology(Beijing)Beijing 100083China school of Mechanics and civil engineering China University of Mining and Technology(Beijing)Beijing 100083China

An extra-large landslide occurred on June 19,2021,on the footwall slope of the Nanfen Open-pit Iron Mine in Liaoning Province,China,with a volume of approximately 1.2×107 *** elucidate the causative factors,development process,and destructive mechanisms of this catastrophic landslide,comprehensive field tests,investigations,and laboratory experiments were ***,the heavily weathered rock mass of the slope was intersected by faults and joint fissures,facilitating rainwater ***,the landslide contained a substantial clay mineral with highly developed micro-cracks and micro-pores,exhibiting strong water-absorption *** moisture content increased,the rock mass underwent softening,resulting in reduced ***,continuous heavy rainfall infiltration amplified the slope's weight,diminishing the weak structural plane's strength,leading to fracture propagation,slip plane penetration,and extensive tensile-shear and uplift failure of the *** study highlights poor geological conditions as the decisive factor for this landslide,with continuous heavy rainfall as the triggering ***,adverse environmental factors persistently affect the landslide,and deformation and failure continue to ***,it is imperative to urgently implement integrated measures encompassing slope reinforcement,monitoring,and early-warning to real-time monitor the landslide's deformation and deep mechanical evolution trends.

关键词： Landslide development process Extra-large landslide Heavy rainfall Failure characteristics Instability mechanism Landslide monitoring and early-warning

Biomimetic 3D printing of composite structures with decreased cracking

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Nanotechnology and Precision engineering 2024年第3期7卷 24-34页

作者： Fan Du Kai Li Mingzhen Li Junyang Fang Long Sun Chao Wang Yexin Wang Maiqi Liu Jinbang Li Xiaoying Wang school of Mechanical engineering and Mechanics Ningbo UniversityNingbo 315211China school of Mechanical and Electrical engineering China University of Mining and TechnologyXuzhou 221116China Institute of Advanced Energy Storage Technology and Equipment Ningbo UniversityNingbo 315211China school of civil and environmental engineering and Geography Science Ningbo UniversityNingbo 315211China

The development of tissue engineering and regeneration research has created new platforms for bone ***,the prepara-tion of scaffolds with goodﬁber integrity is challenging,because scaffolds prepared by traditional printing methods are prone toﬁber cracking during solvent *** skin has an excellent natural heat-management system,which helps to maintain a constant body tem-perature through perspiration or blood-vessel *** this work,an electrohydrodynamic-jet 3D-printing method inspired by the thermal-management system of skin was *** this system,the evaporation of solvent in the printedﬁbers can be adjusted using the temperature-change rate of the substrate to prepare 3D structures with good structural *** investigate the solvent evaporation and the interlayer bonding of theﬁbers,ﬁnite-element analysis simulations of a three-layer microscale structure were carried *** results show that the solvent-evaporation path is from bottom to top,and the strain in the printed structure becomes smaller with a smaller temperature-change *** results veriﬁed the accuracy of these simulation results,and a variety of complex 3D structures with high aspect ratios were *** cracks were reduced to the nanoscale by adjusting the temperature-change rate from 2.5 to 0.5○C ***-mized process parameters were selected to prepare a tissue engineering scaffold with high *** was conﬁrmed that this printed scaffold had good biocompatibility and could be used for bone-tissue *** simple andﬂexible 3D-printing method can also help with the preparation of a wide range of micro-and nanostructured sensors and actuators.

关键词： 3D printing Electrohydrodynamic jet Biomimetic Structural integrity Composite scaffold

Predicting torsional capacity of reinforced concrete members by data-driven machine learning models

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Frontiers of Structural and civil engineering 2024年第3期18卷 444-460页

作者： Shenggang CHEN Congcong CHEN Shengyuan LI Junying GUO Quanquan GUO Chaolai LI school of Mechanics and civil engineering China University of Mining and TechnologyXuzhou 211116China Jiangsu Key Laboratory environmental Impact and Structural Safety in engineering China University of Mining and TechnologyXuzhou 211116China China Nuclear Power Design Co.Ltd. Shenzhen 518031China school of transportation and science engineering Beihang UniversityBeijing 100191China China Construction First Group Corporation Limited Beijing 100161China

Due to the complicated three-dimensional behaviors and testing limitations of reinforced concrete(RC)members in torsion,torsional mechanism exploration and torsional performance prediction have always been *** the present paper,several machine learning models were applied to predict the torsional capacity of RC *** results of a total of 287 torsional specimens were collected through an overall literature *** of extreme gradient boosting machine(XGBM),random forest regression,back propagation artificial neural network and support vector machine,were trained and tested by 10-fold cross-validation *** performances of proposed machine learning models were evaluated and compared,both with each other and with the calculated results of existing design codes,i.e.,GB 50010,ACI 318-19,and Eurocode *** results demonstrated that better predictive performance was achieved by machine learning models,whereas GB 50010 slightly overestimated the torsional capacity,and ACI 318-19 and Eurocode 2 underestimated it,especially in the case of ACI *** XGBM model gave the most favorable predictions with R^(2)=0.999,RMSE=1.386,MAE=0.86,andλ=***,strength of concrete was the most sensitive input parameters affecting the reliability of the predictive model,followed by transverse-to-longitudinal reinforcement ratio and total reinforcement ratio.

关键词： RC members torsional capacity machine learning models design codes

Experimental and theoretical insight into carbamazepine degradation by chlorine-based advanced oxidation processes:Efficiency,energy consumption,mechanism and DBPs formation

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Journal of environmental Sciences 2024年第5期139卷 72-83页

作者： Chunwei Liu Zuo Tong How Yue Ju Li Feng Xuefeng Ren Mohamed Gamal El-Din Key Laboratory ofCoal Processing and Efficient Utilization of Ministry of Education School of Chemical Engineering and TechnologyChina University of Mining and TechnologyJiangsu 221116China Department of civil and environmental engineering University of AlbertaEdmonton T6G 1H9AlbertaCanada school of Environment and Spatial Informatics China University of Mining and TechnologyJiangsu 221116China Key Laboratory of Agro-Forestry environmental Processes and Ecological Regulation ofHainan Province School of Ecology and EnvironmentHainan UniversityHainan 570228China

Chlorine has been widely used in different advanced oxidation processes(AOPs)for micropollutants *** this study,different chlorine-based AOPs,namely medium pressure(MP)UV/chlorine,low pressure(LP)UV/chlorine,and in-situ chlorination,were compared for carbamazepine(CBZ)removal efficiency,energy consumption,and disinfection by-products(DBPs)*** three processes could achieve nearly 100%CBZ removal,while the reaction time needed by in-situ chlorination was double the time required by UV/chlorine *** energy consumed per magnitude of CBZ removed(EE/O)of MP UV/chlorine was 13 times higher than that of LP UV/chlorine,and relative to that of in-situ chlorination ***,MP and LP UV/chlorine processes generated one to two orders of magnitude more hydroxyl radicals(^(·)OH)and reactive chlorine species(RCS)than in-situ ***,RCS were the dominant reactive species,contributing to 78.3%,75.6%,and 71.6% of CBZ removal in MP,LP UV/chlorine,and in-situ chlorination,*** to the Gibbs free energy barriers between CBZ and RCS/^(·)OH calculated based on density functional theory(DFT),RCS had more reaction routes with CBZ and showed lower energy barrier in the main CBZ degradation pathways like epoxidation and formation of *** applied to secondary wastewater effluent,UV/chlorine and in-situ chlorination produced overall DBPs ranging from 104.77 to 135.41μg/***,the production of chlorate during UV/chlorine processes was 15 times higher than that during in-situ chlorination.

关键词： UV/chlorine In-situ chlorination Energy efficiency Role of reactive species DFT calculation Disinfection by-products