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Support design method for deep soft-rock tunnels in non-hydrostatic high in-situ stress field

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Journal of Central South University 2024年第7期31卷 2431-2445页

作者： ZHENG Ke-yue SHI Cheng-hua ZHAO Qian-jin LEI Ming-feng JIA Chao-jun PENG Zhu National Engineering Research Center of High-speed railway co.struction technology Changsha 410075China School of Civil Engineering Central South UniversityChangsha 410075China China railway Group co. Ltd.Beijing 100039China

Due to the long-term plate tectonic movements in southwestern China,the in-situ stress field in deep formations is *** passing through deep soft-rock mass under non-hydrostatic high in-situ stress field,tunnels will suffer serious asymmetric *** is no available support design method for tunnels under such a situation in existing studies to clarify the support time and support *** study first analyzed the mechanical behavior of tunnels in non-hydrostatic in-situ stress field and derived the theoretical equations of the ground squeezing curve(GSC)and ground loosening curve(GLC).Then,based on the co.vergence co.finement theory,the support design method of deep soft-rock tunnels under non-hydrostatic high in-situ stress field was established co.sidering both squeezing and loosening *** addition,this method can provide the clear support time and support stiffness of the seco.d layer of initial *** proposed design method was applied to the Wanhe tunnel of the China-Laos railway in *** data indicated that the optimal support scheme had a good effect on co.trolling the tunnel deformation in non-hydrostatic high in-situ stress *** applications showed that the seco.dary lining co.ld be co.structed properly.

关键词： non-hydrostatic stress field high in-situ stress deep soft-rock tunnel squeezing pressure loosening pressure support design method

A novel refined dynamic model of high-speed maglev train-bridge co.pled system for random vibration and running safety assessment

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Journal of Central South University 2024年第7期31卷 2532-2544页

作者： MAO Jian-feng LI Dao-hang YU Zhi-wu CAI Wen-feng GUO Wei ZHANG Guang-wen School of Civil Engineering Central South UniversityChangsha 410075China National Engineering Research Center of High-speed railway co.struction technology Changsha 410075China China railway Group Limited Beijing 100039China China railway Eryuan Engineering Group co. Ltd.Chengdu 610031China

Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great co.cern,especially need perfect refinement models in which all properties can be well characterized based on various stochastic excitations.A three-dimensional refined spatial random vibration analysis model of high-speed maglev train-bridge co.pled system is established in this paper,in which multi-source uncertainty excitation can be co.sidered simultaneously,and the probability density evolution method(PDEM)is adopted to reveal the system-specific uncertainty dynamic *** motion equation of the maglev vehicle model is co.posed of multi-rigid bodies with a total 210-degrees of freedom for each vehicle,and a refined electromagnetic force-air gap model is used to acco.nt for the interaction and co.pling effect between the moving train and track beam bridges,which are directly established by using finite element *** model is proven to be applicable by co.paring with Monte Carlo *** applying the proposed stochastic framework to the high maglev line,the random dynamic responses of maglev vehicles running on the bridges are studied for running safety and stability ***,the effects of track irregularity wavelength range under different amplitude and running speeds on the co.pled system are *** results show that the augmentation of train speed will move backward the sensitive wavelength interval,and track irregularity amplitude influences the response remarkably in the sensitive interval.

关键词： maglev train-bridge interaction electromagnetic force-air gap model stochastic dynamic analysis running safety assessment probability density evolution method

co.struction technology for deep tunnels crossing superhigh-temperature fault zones with high water surges

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Frontiers of Structural and Civil Engineering 2024年第8期18卷 1267-1280页

作者： Yong ZHAO Tingyu ZHU Li YU Ming LU Sichuan–Xizang railway co. Ltd.Linzhi 860000China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610036China

The harsh environment in tunnels with high geothermal temperatures and humidity can adversely impact machinery,personnel,and *** main causes of specific problems are the unknown mechanisms of local geothermal formation,inappropriate temperature co.trol measures,and insufficient systematic *** this study,three work sections relating to a high geothermal tunnel are:the tunnel face,middle-of-tunnel section,and outside-oftunnel section.A co.ling strategy is proposed to offer technical support in achieving co.prehensive co.ling,overall as well as for each of the ***,a co.prehensive geological survey explores the mechanism and exact location of the heat ***,grouting and centralized drainage measures are used to co.trol the heat release of hot *** ventilation,ice chillers and other applicable measures are used to co.trol the ambient ***,a monitoring and early warning system is established to prevent *** co.ling strategy has been applied in the field with good results.

关键词： high geothermal tunnels co.ling strategy co.prehensive co.ling measures safety and security

Vibration co.trol of the Rail Grinding Vehicle with Abrasive Belt Based on Structural Optimization and Lightweight Design

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 311-337页

作者： Wengang Fan Shuai Zhang Zhiwei Wu Yi Liu Jiangnan Yu School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control TechnologyMinistry of EducationBeijing 100044China China railway Materials Operation and Maintenance technology co. LtdBeijing 100036China

As a new grinding and maintenance technology,rail belt grinding shows significant advantages in many applications The dynamic characteristics of the rail belt grinding vehicle largely determines its grinding performance and service *** order to explore the vibration co.trol method of the rail grinding vehicle with abrasive belt,the vibration response changes in structural optimization and lightweight design are respectively analyzed through transient response and random vibration simulations in this ***,the transient response simulation analysis of the rail grinding vehicle with abrasive belt is carried out under operating co.ditions and non-operating ***,the vibration co.trol of the grinding vehicle is implemented by setting vibration isolation elements,optimizing the structure,and increasing ***,in order to further explore the dynamic characteristics of the rail grinding vehicle,the random vibration simulation analysis of the grinding vehicle is carried out under the co.dition of the horizontal irregularity of the American AAR6 ***,by replacing the Q235 steel frame material with 7075 aluminum alloy and LA43M magnesium alloy,both vibration co.trol and lightweight design can be achieved *** results of transient dynamic response analysis show that the acceleration of most positions in the two working co.ditions exceeds the standard value in GB/T 17426-1998 *** optimizing the structure of the grinding vehicle in three ways,the average vibration acceleration of the whole car is reduced by about 55.1%from 15.6 m/s^(2) to 7.0 m/s^(2).The results of random vibration analysis show that the grinding vehicle with Q235 steel frame does not meet the safety co.ditions of 3σ.By changing frame material,the maximum vibration stress of the vehicle can be reduced from 240.7 MPa to 160.0 MPa and the weight of the grinding vehicle is reduced by about 21.7%from 1500 kg to 1175 *** modal analysis results indic

关键词： Vibration co.trol Dynamic characteristics Structural optimization Lightweight design Modal analysis

An alternative approach to improve the co.patibility of PCE in cement paste blend with co.l gangue powder

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Waste Disposal and Sustainable Energy 2024年第1期6卷 139-150页

作者： Zonglin Xie Yuxuan Li Dahui Sun Yi Tian Jinyuan Hu Qiang Yuan Zheng Chen School of Civil Engineering Central South UniversityChangshaChina China railway NO.9 Group co. LTDShenyangChina National Engineering Research Center for High-Speed railway co.struction technology ChangshaChina Guangxi Key Laboratory of Disaster Prevention and Engineering Safety Guangxi UniversityNanningChina

co.l gangue(CG)is an environmental waste that faces an urgent demand for disposal in *** utilization of CG in co.struction materials has broad application prospects and gained increasing ***,the poor co.patibility of polycarboxylate superplasticizer(PCE)with CG powder hinders its efficiency in a wide range of ***,this paper attempts to improve the co.patibility of PCE with CG powder in cement paste based on the regulation of aggregation and the adsorption behavior of *** light scattering(DLS)and fluorescence spectrosco.y tests were carried out to understand the improved *** results indicated that the addition of CG powder increases the ionic strengths of the cement liquid phase,which makes PCE tend to aggregate at a lower co.centration co.pared with no CG powder ***(CH_(3)co.)_(2)Cu is beneficial for enhancing the workability of cement paste by reducing PCE aggregation while maintaining the co.pressive strength of cement ***,(CH_(3)co.)_(2)Cu extra addition can be regarded as an effective and sustainable way to improve the workability of cement paste with CG powder.

关键词： co.l gangue powder Polycarboxylate superplasticizer co.patibility Aggregation

Enhanced wear prediction of tunnel boring machine disc cutters for accurate remaining useful life estimation using a hybrid model

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 642-662页

作者： Xinghai ZHOU Yakun ZHANG Guofang GONG Huayong YANG Qiaosong CHEN Yuxi CHEN Zhixue SU The State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou 310027China Guangzhou Rail Transit co.struction Engineering co.sulting co. Ltd.Guangzhou 510000China China railway Engineering Equipment Group co. Ltd.Zhengzhou 450016China

In tunnel co.struction with tunnel boring machines(TBMs),accurate prediction of the remaining useful life(RUL)of disc cutters is critical for timely maintenance and replacement to avoid delays and co.t *** paper introduces a novel hybrid model,integrating fundamental and data-driven approaches,to enhance wear prediction of TBM disc cutters and enable accurate RUL *** fundamental model is improved by inco.porating co.posite wear mechanisms and load estimation techniques,showcasing superior prediction accuracy co.pared to single-mechanism ***,the hybrid model innovatively inco.porates a data-driven supplementary residual term into the improved fundamental model,leading to a high-performance wear prediction *** actual field data from a highway tunnel project in Shenzhen,the performance of the hybrid model is rigorously tested and co.pared with pure fundamental and data-driven *** hybrid model outperforms the other models,achieving the highest accuracy in predicting TBM disc cutter wear(mean absolute error(MAE)=0.53,root mean square error(RMSE)=0.64).Furthermore,this study thoroughly analyzes the hybrid model’s generalization capability,revealing significant impacts of geological co.ditions on prediction *** model’s generalization capability is also improved by expanding and updating the data *** RUL estimation results provided by the hybrid model are straightforward and effective,making it a valuable tool by which co.struction staff can monitor TBM disc cutters.

关键词： tunnel boring machine disc cutter wear prediction remaining useful life field data hybrid model

Efficient removal of tetracycline hydrochloride through novel Fe/BiOBr/Bi_(2)WO_(6) photocatalyst prepared by dual-strategy under visible-light irradiation

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Journal of Environmental Sciences 2024年第4期138卷 46-61页

作者： Guanlong Yu Kai Yang Yi Yang Yifu Li Qifang Sun Peiyuan Li Wenming Wang Fengming Song Tao Ling Xuejun Peng Zhi Yu Shiquan Sun School of Hydraulic and Environmental Engineering Changsha University of Science&TechnologyChangsha 410114China Key Laboratory of Dongting Lake Aquatic Eco.Environmental co.trol and Restoration of Hunan Province Changsha 410114China Hunan Pilot Yanghu Reclaimed Water co. Ltd.Changsha 410208China China railway Wuju Group the First Engineering co. Ltd.Changsha 410117China

It is important to investigate whether co.bining two modification strategies has a synergistic effect on the activity of *** this manuscript,Fe-doped BiOBr/Bi_(2)WO_(6) heterojunctions were synthesized by a one-pot solvothermal method,and excellent photocatalytic performance was obtained for the degradation of tetracycline hydrochloride(TCH)in water without the addition of *** experiments and characterization,the synergistic effect between Fe ion doping and the BiOBr/Bi_(2)WO_(6) heterojunction was *** Fe/BiOBr/Bi_(2)WO_(6) co.posite photocatalyst had a beneficial void structure,enhanced visible light response,and co.ld inhibit the reco.bination of photogenerated support well,which improved the photocatalytic *** presented experiments demonstrate that Fe/BiOBr/Bi_(2)WO_(6) removes 97% of TCH from aqueous solution,while pure BiOBr and Bi_(2)WO_(6) only remove 56% and 65% of TCH,***,the separation and transfer mechanisms of photoexcited carriers were determined in co.junction with the experimental *** study provides a new direction for the design of efficient photocatalysts through the use of a dual co.modification strategy.

关键词： BiOBr/Bi_(2)WO_(6) Fe-doping Dual strategy Tetracycline hydrochloride Photodegradation

Technical innovation in the “Beishan No. 1” hard rock tunnel boring machine for high-gradient spiral tunnels

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Frontiers of Engineering Management 2024年第1期11卷 175-179页

作者： Ju WANG Mengxue QI Bin LONG Hongsu MA Beijing Research Institute of Uranium Geology Beijing 100029China China railway 18th Bureau Group Tunnel Engineering co. Ltd.Chongqing 400700China China railway co.struction Heavy Industry co. Ltd.Changsha 410100China

1 Project overview The“Beishan No.1”,the world’s first-ever hard rock Tunnel Boring Machine(TBM)tailored for high-gradient spiral tunnels,co.stitutes a pivotal element within the Beishan Underground Research Laboratory(URL)initiative in *** URL,the first URL for geological disposal of high level radioactive waste(HLW)in China,is a national key co.struction project listed in the“13th Five-Year Plan”.In 2019,subsequent to receiving approval from the China Atomic Energy Authority,the Beijing Research Institute of Uranium Geology(BRIUG),serving as the project’s owner,initiated its *** underground facility,categorized as a“third generation”URL for HLW disposal,i.e.,area-specific URL,was located in Beishan,Jiuquan City,Gansu Province,China,following more than three decades of rigorous research on site selection.

关键词： tunnel boring machine extremely hard rock co.tinuous small-radius curves high gradient equipment technology innovation

Failure mechanism and infrared radiation characteristic of hard siltstone induced by stratification effect

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Journal of Mountain Science 2024年第3期21卷 1058-1074页

作者： CHENG Yun SONG Zhanping XU Zhiwei YANG Tengtian TIAN Xiaoxu School of Civil Engineering Yancheng Institute of TechnologyYancheng 224051China School of Civil Engineering Xi'an University of Architecture and TechnologyXi'an 710055China Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering Xi'an 710055China China railway co.struction Bridge Engineering Bureau Group co. Ltd.Tianjin 300300China

The deformation in sedimentary rock induced by train loads has potential threat to the safe operation of tunnels. This study investigated the influence of stratification structure on the infrared radiation and temporal damage mechanism of hard siltstone. The uniaxial co.pression tests, co.pled with aco.stic emission(AE) and infrared radiation temperature(IRT) were co.ducted on siltstones with different stratification effects. The results revealed that the stratigraphic structure significantly affects the stress-strain response and strength degradation characteristics. The mechanical parameters exhibit anisotropy characteristics, and the stratification effect exhibits a negative co.relation with the cracking stress and peak stress. The failure modes caused by the stratification effect show remarkable anisotropic features, including splitting failure(Ⅰ: 0°-22.50°, Ⅱ: 90°), co.posite failure(45°), and shearing failure(67.50°). The AE temporal sequences demonstrate a stepwise response characteristic to the loading stress level. The AE intensity indicates that the stress sensitivity of shearing failure and co.posite failure is generally greater than that of splitting failure. The IRT field has spatiotemporal migration and progressive dissimilation with stress loading and its dissimilation degree increases under higher stress levels. The stronger the stratification effect, the greater the dissimilation degree of the IRT field. The abnormal characteristic points of average infrared radiation temperature(AIRT) variance at local stress drop and peak stress can be used as early and late precursors to identify fracture instability. Theoretical analysis shows that the co.petitive relationship between co.paction strengthening and fracturing damage intensifies the dissimilation of the infrared thermal field for an increasing stress level. The present study provides a theoretical reference for disaster warnings in hard sedimentary rock mass.

关键词： Hard siltstone Failure mechanism Stratification effect Infrared radiation characteristic Temporal-damage mechanism Dissimilation