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Numerical Analysis of cold-Formed Thin-Walled Steel Short columns with Pitting corrosion during Bridge construction

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Structural Durability & Health Monitoring 2024年第2期18卷 181-196页

作者： Hongzhang Wang Jing Guo Shanjun Yang Chaoheng Cheng Jing Chen Zhihao Chen cccc second Harbor engineering Third engineering co. Ltd.Zhenjiang212000China Suqian highway Development Center Suqian223800China School of Mechanics and Civil engineering China University of Mining and TechnologyXuzhou221116China

Pitting corrosion is harmful during bridge construction,which will lead to uneven roughness of steel surfaces and reduce the thickness of ***,the effect of pitting corrosion on the mechanical properties of cold-formed thin-walled steel stub columns is studied,and the empirical formulas are established through regression fitting to predict the ultimate load of web and flange under pitting *** detail,the failure modes and load-displacement curves of specimens with different locations,area ratios,and depths are obtained through a large number of non-linear finite element *** for the specimens with pitting corrosion on the web,all the specimens are subject to local buckling failure,and the failure mode will not change with pitting corrosion,but the failure location will change with pitting corrosion location;the size,location,and area ratio of pitting corrosion have little influence on the ultimate load of cold-formed thin-walled steel short columns,but the loss rate of pitting corrosion section area has a greater impact on the ultimate bearing *** for the specimen with flange pitting corrosion,the location and area ratio of pitting corrosion have less influence on the ultimate load of cold-formed thin-walled steel short columns,and the section area loss rate has greater influence on the ultimate bearing capacity;the impact of web pitting corrosion on the ultimate load is greater than that of flange pitting corrosion under the same condition of pitting corrosion section *** prediction formulas of limit load which are suitable for pitting corrosion of web and flange are established,which can provide a reference for performance evaluation of corroded cold-formed thin-walled steel.

关键词： Pitting corrosion cold-formed thin-walled steel ultimate load prediction formula short columns

Stability analysis of loose accumulation slopes under rainfall:case study of a high‑speed railway in Southwest China

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Railway engineering Science 2024年第1期32卷 95-106页

作者： Xin Wang Qian Su Zongyu Zhang Feihu Huang Chenfang He School of Civil engineering Southwest Jiaotong UniversityChengdu 610031China Key Laboratory of High‑Speed Railway engineering Ministry of Education School of Civil EngineeringSouthwest Jiaotong UniversityChengdu 610031China cccc second highway consultants co. Ltd.Wuhan 430056China

The high and steep slopes along a high-speed railway in the mountainous area of Southwest China are mostly composed of loose accumulations of debris with large internal pores and poor stability,which can easily induce adverse geological disasters under rainfall *** ensure the smooth construction of the high-speed railway and the subsequent safe operation,it is necessary to master the stability evolution process of the loose accumulation slope under *** article simulates rainfall using the finite element analysis software’s hydromechanical coupling *** slope stability under various rainfall situations is calculated and analysed based on the strength reduction *** validate the simulation results,a field monitoring system is established to study the deformation characteristics of the slope under *** results show that rainfall duration is the key factor affecting slope *** a constant amount of rainfall,the stability of the slope decreases with increasing duration of ***,when the amount and duration of rainfall are constant,continuous rainfall has a greater impact on slope stability than intermittent *** setting of the field retaining structures has a significant role in improving slope *** field monitoring data show that the slope is in the initial deformation stage and has good stability,which verifies the rationality of the numerical simulation *** research results can provide some references for understanding the influence of rainfall on the stability of loose accumulation slopes along high-speed railways and establishing a monitoring system.

关键词： High-speed railway Loose accumulation slope Slope stability analysis Rainfall effect Strength reduction

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Predicting Rock Burst in Underground engineering Leveraging a Novel Metaheuristic-Based LightGBM Model

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computer Modeling in engineering & Sciences 2024年第7期140卷 229-253页

作者： Kai Wang Biao He Pijush Samui Jian Zhou No.Three engineering co. Ltd.CCCC First Highway Engineering CompanyBeijing101102China Department of Civil engineering Faculty of EngineeringUniversiti MalayaKuala Lumpur50603Malaysia Department of Civil engineering National Institute of Technology PatnaBihar800005India School of Resources and Safety engineering Central South UniversityChangsha410083China

Rock bursts represent a formidable challenge in underground engineering,posing substantial risks to both infrastructure and human *** sudden and violent failures of rock masses are characterized by the rapid release of accumulated stress within the rock,leading to severe seismic events and structural ***,the development of reliable prediction models for rock bursts is paramount to mitigating these *** study aims to propose a tree-based model—a Light Gradient Boosting Machine(LightGBM)—to predict the intensity of rock bursts in underground engineering.322 actual rock burst cases are collected to constitute an exhaustive rock burst dataset,which serves to train the *** population-basedmetaheuristic algorithms are used to optimize the hyperparameters of the LightGBM ***,the sensitivity analysis is used to identify the predominant factors that may incur the occurrence of rock *** results show that the population-based metaheuristic algorithms have a good ability to search out the optimal hyperparameters of the LightGBM *** developed LightGBM model yields promising performance in predicting the intensity of rock bursts,with which accuracy on training and testing sets are 0.972 and 0.944,*** sensitivity analysis discloses that the risk of occurring rock burst is significantly sensitive to three factors:uniaxial compressive strength(σc),stress concentration factor(SCF),and elastic strain energy index(Wet).Moreover,this study clarifies the particular impact of these three factors on the intensity of rock bursts through the partial dependence plot.

关键词： Rock burst prediction LightGBM coati optimization algorithm pelican optimization algorithm partial dependence plot

Centrifuge modeling of a large-scale surcharge on adjacent foundation

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Journal of Rock Mechanics and Geotechnical engineering 2024年第8期16卷 3181-3191页

作者： Jinzhang Zhang Zhenwei Ye Dongming Zhang Hongwei Huang Shijie Han Tong Zou Le Zhang Key Laboratory of Geotechnical and Underground engineering of Ministry of Education and Department of Geotechnical engineering Tongji UniversityShanghai200092China cccc Third Harbor consultants co LtdShanghai200032China Qingdao conson Jiaozhou Bay second Subsea Tunnel co. LtdQingdao266000China

This study investigates the ground and structural response of adjacent raft foundations induced by largescale surcharge by ore in soft soil areas through a 130g centrifuge modeling test with an innovative layered loading *** prototype of the test is a coastal iron ore yard with a natural foundation of deep soft ***,it is necessary to adopt some measures to reduce the influence of the large-scale surcharge on the adjacent raft foundation,such as installing stone columns for foundation *** an acceleration of 130 g,the model conducts similar simulations of iron ore,stone columns,and raft foundation *** tested soil mass has dimensions of 900 mm×700 mm×300 mm(lengthwidthdepth),which is remodeled from the soil extracted from the drilling *** test conditions are consistent with the actual engineering conditions and the effects of four-level loading conditions on the composite foundation of stone columns,unreinforced zone,and raft foundations are *** automatic layer-by-layer loading device was innovatively developed to simulate the loading process of actual engineering more *** composite foundation of stone columns had a large settlement after the loading,forming an obvious settlement trough and causing the surface of the unreinforced zone to *** 12 m surcharge loading causes a horizontal displacement of 13.19 cm and a vertical settlement of 1.37 m in the raft *** stone columns located on both sides of the unreinforced zone suffered significant shear damage at the sand-mud *** to the reinforcement effect of stone columns,the sand layer below the top of the stone columns moves ***,the horizontal earth pressure in the raft foundation zone increases *** stone columns will form new drainage channels and accelerate the dissipation of excess pore pressure.

关键词： Centrifuge modeling Stone column composite foundation Ground movement Raft foundation

Shear mechanical properties and frictional sliding responses of rough joint surfaces under dynamic normal displacement conditions

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Journal of Central South University 2024年第7期31卷 2393-2410页

作者： ZHU Qiang YIN Qian TAO Zhi-gang HE Man-chao ZHENG Bo-wen JING Hong-wen REN Shu-lin ZHANG Qiang MENG Bo BAI Dong-feng WU Sai-sai WU Jiang-yu State Key Laboratory of Intelligent construction and Healthy Operation and Maintenance of Deep Underground engineering Xuzhou 221116China State Key Laboratory for Geomechanics&Deep Underground engineering China University of Mining and Technology(Beijing)Beijing 100083China Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China cccc First highway Survey and Design Research Institute co. Ltd.Xi’an 710075China

A comprehensive understanding of the dynamic frictional characteristics in rock joints under high normal load and strong confinement is essential for ensuring the safety of deep engineering construction and mitigating geological *** study conducted shear experiments on rough rock joints under displacement-controlled dynamic normal loads,investigating the shear behaviors of joints across varying initial normal loads,normal loading frequencies,and normal loading *** results showed that the peak/valley shear force values increased with initial normal loads and normal loading frequencies but showed an initial increase followed by a decrease with normal loading *** normal loading can either increase or decrease shear strength,while this study demonstrates that higher frequencies lead to enhanced *** initial normal loading and normal loading frequency result in a gradual decrease in joint roughness coefficient(JRC)values of joint surfaces after *** correlations existed between frictional energy dissipation and peak shear forces,while post-shear joint surface roughness exhibited a negative correlation with peak shear forces through linear regression *** study contributes to a better understanding of the sliding responses and shear mechanical characteristics of rock joints under dynamic disturbances.

关键词： dynamic normal displacement shear strength variations phase lag phenomenon stick-slip

Mechanical behaviors of warm and ice-rich frozen soil stabilized with sulphoaluminate cement

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Journal of Mountain Science 2024年第1期21卷 335-345页

作者： WANG Honglei ZHANG Hu ZHANG Jianming ZHANG Qi YIN Zhenhua State Key Laboratory of Frozen Soil engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China School of Civil engineering and Transportation Northeast Forestry UniversityHarbin 150040China National Key Laboratory of Green and Long-Life Road engineering in Extreme Environment CCCC First Highway Consultants Co.LtdXi'an 710065China Railway engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China

The warm and ice-rich frozen soil is characterized by high unfrozen water content, low shear strength and large compressibility, which is unreliable to meet the stability requirements of engineering infrastructures and foundations in permafrost regions. In this study, a novel approach for stabilizing the warm and ice-rich frozen soil with sulphoaluminate cement was proposed based on chemical stabilization. The mechanical behaviors of the stabilized soil, such as strength and stress-strain relationship, were investigated through a series of triaxial compression tests conducted at -1.0℃, and the mechanism of strength variations of the stabilized soil was also explained based on scanning electron microscope test. The investigations indicated that the strength of stabilized soil to resist failure has been improved, and the linear Mohr-coulomb criteria can accurately reflect the shear strength of stabilized soil under various applied confining pressure. The increase in both curing age and cement mixing ratio were favorable to the growth of cohesion and internal friction angle. More importantly, the strength improvement mechanism of the stabilized soil is attributed to the formation of structural skeleton and the generation of cementitious hydration products within itself. Therefore, the investigations conducted in this study provide valuable references for chemical stabilization of warm and ice-rich frozen ground, thereby providing a basis for in-situ ground improvement for reinforcing warm and ice-rich permafrost foundations by soil-cement column installation.

关键词： Permafrost regions Frozen soil Mechanical behavior Chemical stabilization Ground improvement Ground modification

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Performance Characterization of CR/PU Asphalt for Potential Application in Assembled Fast-Repairing engineering

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Fluid Dynamics & Materials Processing 2024年第5期20卷 1063-1074页

作者： Hong Pang Ao Lu Ming Xiong Chen Chen Xian Cao Xiong Xu Jing Wang Hubei Regional Management Headquarters CCCC Asset Management Co.Ltd.Beijing101399China School of Civil engineering and Architecture Wuhan Institute of TechnologyWuhan430073China Hubei Provincial engineering Research Center for Green Civil engineering Materials and Structures Wuhan Institute of TechnologyWuhan430073China

conventional repairing methods for asphalt pavement have some inconveniences,such as insufficient strength,and are typically *** address these issues,this study proposes a new technological method to design and prepare a high-performance assembled asphalt concrete block for fast repair of the potholes.A series of composite modified asphalt binders with 10%crumb rubber(CR)and different dosages(0%,1%,3%,5%)of polyurethane(PU)are examined to determine the optimized ***,the corresponding asphalt mixtures are prepared for further comparison and assessment of engineering properties,such as moistureinduced damage,high-temperature deformation,and low-temperature cracking *** test results show that PU can significantly improve the high-temperature performance and hardness of(crumb rubber modified asphalt)CRMA binder;3%PU contributes allowing the resistance of CRMA mixture to moisture-induced damage at higher levels,particularly under water whole immersion;as 3%PU is added,the high-temperature rutting deformation resistance of the CRMA mixture increases significantly,and the low-temperature anti-cracking properties are also improved ***,the innovatively designed high-quality assembled fast-repairing asphalt concrete block is recommended as an appropriate option for highway maintenance.

关键词： composite modified asphalt crumb rubber polyurethane assembled fast-repairing asphalt concrete maintenance engineering

Mechanical responses of underground carriageway structures due to construction of metro tunnels beneath the existing structure:A case study

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Deep Underground Science and engineering 2024年第2期3卷 231-246页

作者： Xin Han Fei Ye Xingbo Han Chao Ren Jing Song Ruliang Zhao School of highway Chang'an UniversityXi'anChina Shandong Province Transportation Planning and Design Institute JinanChina China Water Resources Beifang Investigation Design and Research Co.Ltd.TianjinChina

To understand the mechanical response pattern of the existing structure and ground due to the construction of metro tunnels underneath,the finite difference method is adopted to study the torsional deformation and stress variation of the existing structure and the effect of underground carriageway structures on the surface *** curves of the maximum differential subsidence,torsion angle,and distortion of the cross-section of the existing structure show two peaks in succession during traversing of two metro tunnels beneath *** torsion angle of the existing structure changes when the two tunnels traverse beneath it in opposite *** first traversing of the shield tunnel mainly induces the magnitude variation in torsional deformation of the existing structure,but the second traversing of the subsurface tunnel may cause a dynamic change in the magnitude and form of torsional deformation in the existing *** shielding effect can reduce the surface subsidence caused by metro tunnel excavation to a certain extent,and the development trend of subsidence becomes slower as the excavation continues.

关键词： metro tunnel numerical simulation structural deformation surface subsidence underground carriageway structure

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Multi-objective and multi-scheme research on water and sediment regulation potential of reservoirs in the upper Yellow River

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International Journal of Sediment Research 2023年第2期38卷 203-215页

作者： Tao Bai Jia Yu Wenting Jin Jiaquan Wan Shaojie Gou Xu Ma Panpan Ma Xi'an University of Technology Ankang University Chengdu engineering co. Ltd. cccc First highway consultants co. Ltd.

The problems of the deteriorating relation between water and sediment, and the escalating conflict between water supply and demand in the upper Yellow River(YR), need to be addressed. Reservoirs of Longyangxia, Liujiaxia, and Heishanxia(Long-Liu-Hei) in the upper YR are taken as the research object, and a multi-objective, water-sediment optimal operation model for cascade reservoirs Long-Liu-Hei has been developed. This operation model considers the comprehensive requirements of water supply, power generation, flood control, and especially, water and sediment regulation. The improved Non-dominated Sorting Genetic Algorithms(NSGA-II) method is used to demonstrate the water and sediment regulation potential of three scenario schemes under long-term conditions, and the adjustable water allocation of four schemes under typical year conditions are calculated. It is recommended to use the mode of generating hydropower depending on the available water amount as the best operating mode under the conditions of a long time series and for typical years. This recommended operation mode has verified the rationality and accuracy of the reservoir operations *** the same time, compared with the calculation results for water and sediment regulation after the construction of the Heishanxia, the current research indicates:(1) Under the recommended model, the potential for water and sediment regulation under the long-term series and typical years is once every four years.(2) Inter-basin water transfer greatly improves the cascade power generation. When the adjustable water volume is converted into the controlled volume for water and sediment regulation,the intensity frequency of water and sediment regulation of cascade reservoirs are improved.(3) With the intensification of the contradiction between the supply of and demand for water resources in the upper YR in the future, the amount of transferable water exhibits a decreasing trend, and the regulation of water and sediment in th

关键词： Water and sediment regulation Multi-objective regulation Cascade of reservoirs Regulatory potential