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3D suitability evaluation of urban underground space using a variable weight method and considering ground restrictions

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Underground Space 2024年第6期19卷 208-226页

作者： Jian Pu Yu Huang Yandong Bi Zhen Guo Fei Deng Xingyue Li Chong Xu Department of Geotechnical engineering College of Civil EngineeringTongji UniversityShanghai 200092China The state {1. laboratory on disaster reduction in civil engineering Tongji UniversityShanghai 200092China Foshan Bureau of Geological Survey of Guangdong Province Foshan 52800China National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China

The evaluation of urban underground space(UUS)suitability involves multiple *** weight to these indicators is crucial for accurate *** paper presents a method for spatially variable weight assignment of indicators using the order relation analysis method(G1.method),the entropy weight method,an improved grey relational analysis(GRA)and a set of spatial weight adjustment ***,the subjective and objective weights of indicators for engineering geological and hydrogeological conditions were determined by the G1.method and entropy weight method,respectively,and their combined weights were then obtained using the principle of minimum discriminatory *** study highlighted the impact of surface restrictions,such as buildings,on UUS,and the degree of the influence of these buildings gradually decreased with the increase in depth of the rock and soil mass in UUS,which resulted in changes in weights of indicators with *** address this issue,a coefficient was defined as the standardized value of the ratio of additional stress applied by restrictions to the self-weight stress of soil at the same depth to modify the combined weights so that all weights of indicators could vary in ***,an improved GRA was used to determine the suitability level of each evaluation cell using the maximum correlation *** method was applied to the 3D suitability evaluation of UUS in Sanlong Bay,Foshan City,Guangdong Province,China,including 1. evaluation *** study comprehensively considered the influence of multiple factors,thereby providing reference for evaluating the suitability of UUS in big cities.

关键词： 3D suitability evaluation Urban underground space Ground restriction Variable weight method Improved grey relational analysis

Seismic responses of an intensively constructed metro station-passageway-shaft structure system

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Frontiers of Structural and civil {1. 2024年第5期18卷 760-775页

作者： Ruohan LI Yong YUAN Hong CHEN Xinxing LI Emilio BILOTTA Department of Geotechnical engineering Tongji UniversityShanghai 200092China Department of civil Architectural and Environmental EngineeringUniversity of Naples Federico IINaples 80125Italy state {1. laboratory of disaster reduction in civil engineering Tongji UniversityShanghai 200092China Shanghai Tunnel engineering&Rail Transit Design and Research Institute Shanghai 200235China

Intensive construction methods offer benefits for metro station development,yet they present challenges for seismic design due to the spatially asymmetric configuration of passageway-shaft *** this study,a detailed numerical model of a station-passageway-shaft structure system built using intensive construction methods was developed and the deformation and damage modes under seismic loadings were *** results indicate that inconsistent deformation between the shaft and the station generates interaction through the connecting passageway,leading to damage near the opening of the station structure and both ends of the connecting passageway Damage is more severe under longitudinal *** with the opening plan that spans four segments,the opening plan that spans five segments exacerbates the overall degree of damage to the structure *** transverse excitation,the presence of interior structures intensifies the damage to the station and connecting passageway,while with such internal structure in place the impact is relatively minor under longitudinal *** with steel segments near the station opening can appreciably attenuate the *** contrast,introducing flexible joints at both ends of the connecting passageway intensifies the ***,reinforcement using steel segments emerges as an optimal seismic mitigation strategy.

关键词： earthquake intensive construction metro station numerical simulation

Thickness regression for backfill grouting of shield tunnels based on GPR data and CatBoost&BO-TPE:A full-scale model test study

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Underground Space 2024年第4期17卷 100-119页

作者： Kang Li Xiongyao Xie Biao Zhou Changfu Huang Wei Lin Yihan Zhou Cheng Wang Department of Geotechnical engineering College of Civil EngineeringTongji UniversityShanghai 200092China state {1. laboratory of disaster reduction in civil engineering Tongji UniversityShanghai 200092China key {1. of Geotechnical and Underground of Ministry of Education Tongji UniversityShanghai 200092China China Railway 1.th Bureau Group Co.Ltd. Shanghai 200070China state Grid Shanghai Municipal Electric Power Company Shanghai 200122China

Ground penetrating radar(GPR)is a vital non-destructive testing(NDT)technology that can be employed for detecting the backfill grouting of shield *** achieve intelligent analysis of GPR data and overcome the subjectivity of traditional data processing methods,the CatBoost&BO-TPE model was constructed for regressing the grouting thickness based on GPR waveforms.A full-scale model test and corresponding numerical simulations were carried out to collect GPR data at 400 and 900 MHz,with known backfill grouting *** model test helps address the limitation of not knowing the grout body condition in actual field *** data were then used to create machine learning *** method of feature selection was proposed based on the analysis of feature importance and the electromagnetic(EM)propagation law in *** research shows that:(1.the CatBoost&BO-TPE model exhibited outstanding performance in both experimental and numerical data,achieving R^(2)values of 0.9760,0.8971.0.8808,and 0.5437 for numerical data and test data at 400 and 900 *** outperformed extreme gradient boosting(XGBoost)and random forest(RF)in terms of performance in the backfill grouting thickness regression;(2)compared with the full-waveform GPR data,the feature selection method proposed in this paper can promote the performance of the *** selected features within the 5–30 ns of the A-scan can yield the best performance for the model;(3)compared to GPR data at 900 MHz,GPR data at 400 MHz exhibited better performance in the CatBoost&BO-TPE *** indicates that the results of the machine learning model can provide feedback for the selection of GPR parameters;(4)the application results of the trained CatBoost&BO-TPE model in engineering are in line with the patterns observed through traditional processing methods,yet they demonstrate a more quantitative and objective nature compared to the traditional method.

关键词： Shield tunnel Backfill grouting GPR Model test gprMax Machine learning CatBoost&BO-TPE Thickness regression

Enhanced properties of stone coal-based composite phase change materials for thermal energy storage

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 206-215页

作者： Baoshan Xie Huan Ma Chuanchang Li Jian Chen key {1. of Renewable Energy Electric-Technology of Hunan Province School of Energy and Power EngineeringChangsha University of Science and TechnologyChangsha 410114China state {1. laboratory of disaster Prevention and reduction for Power Grid Changsha University of Science and TechnologyChangsha 410114China

Phase change materials (PCMs) can be incorporated with low-cost minerals to synthesize composites for thermal energy storage in building *** coal (SC) after vanadium extraction treatment shows potential for secondary utilization in composite *** prepared SC-based composite PCMs with SC as a matrix,stearic acid (SA) as a PCM,and expanded graphite (EG) as an *** combined roasting and acid leaching treatment of raw SC was conducted to understand the effect of vanadium extraction on promoting loading *** showed that the combined treatment of roasting at 900℃ and leaching increased the SC loading of the composite by 6.2%by improving the specific surface *** loading capacity and thermal conductivity of the composite obviously increased by 1.7%and 48.1.%,respectively,due to the contribution of 3wt% *** data were supported by the high load of 66.69%and thermal conductivity of 0.59 W·m^(-1.·K-1.f the designed *** obtained composite exhibited a phase change temperature of 52.1.℃,melting latent heat of 1.1.5 J·g^(-1.,and good chemical *** SC-based composite has prospects in building applications exploiting the secondary utilization of minerals.

关键词： thermal energy storage phase change material stone coal vanadium extraction secondary utilization

Negative Poisson’s ratio cable compensation support for 32 m super-large-span highway tunnel:A case study

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Underground Space 2024年第1期14卷 156-175页

作者： Aipeng Guo Manchao He Songyuan Liu Zhifeng Du Zengwang Lyu Zhigang Tao state {1. laboratory for Geomechanics and Deep Underground engineering Beijing 100083China School of Mechanics and civil {1. China University of Mining and Technology(Beijing)Beijing 100083China Department of civil and Mineral {1. University of TorontoToronto M5S 1A4Canada state {1. laboratory for Geomechanics and Deep Underground engineering Sanmenxia Research CenterHenan 472099China

Although super-large-span tunnels ensure convenient transportation,they face many support *** lack of normative construction guidance and the limited number of reference engineering cases pose a significant challenge to the stability control of superlarge-span *** on the geological conditions of a super-large-span tunnel(span=32.1. m)at the bifurcation section of the Shenzhen interchange,this study determined support parameters via theoretical calculation,numerical simulation,and engineering *** support effects of negative Poisson’s ratio(NPR)anchor cables and ordinary anchor cables on super-long-span tunnels were simulated and ***,based on FLAC3D simulations,the surrounding rock stress field of NPR anchor cables was analyzed under different prestressing conditions,and the mechanism of a long-short combination,high-prestress compensation NPR anchor cable support was *** the basis of numerical simulations,to our knowledge,the three-dimensional(3D)geomechanical model test of the NPR anchor cable and ordinary anchor cable support for super-large-span tunnel excavation is conducted for the first time,revealing the stress evolution law of super-large-span tunnels,deformation and failure characteristics of the surrounding rock,and the changing trend of the anchor cable’s axial force,and verifies that NPR anchor cables with high preloads are suitable for super-large-span tunnel support and have advantages over ordinary anchor *** study can provide a reliable theoretical reference for the support design and stability control of the surrounding rock of similar shallow-buried super-large-span tunnels.

关键词： Super-large-span tunnel Negative Poisson’s ratio(NPR)anchor cable Excavation compensation method Numerical simulation Geomechanical model test

New method to identify optimal discontinuity set number of rock tunnel excavation face orientation based on Fisher mixed evaluation

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Underground Space 2024年第4期17卷 300-319页

作者： Keshen Zhang Wei Wu Min Zhang Yongsheng Liu Yong Huang Baolin Chen College of civil {1. Tongji UniversityShanghai 200092China key {1. of Geotechnical and Underground engineering of Ministry of Education Tongji UniversityShanghai 200092China state {1. laboratory of disaster reduction in civil engineering Tongji UniversityShanghai 200092China Shudao Investment Group Co.Ltd Chengdu 610095China China Railway Tunnel Group Co.Ltd Guangzhou 511466China China Railway First Survey and Design Institute Group Co.Ltd Xi’an 710043China Zhejiang Institute of Communications Co.Ltd Hangzhou 310012China

Discontinuity is critical for strength,deformability,and permeability of rock *** information is one of the essential discontinuity characteristics and is usually accessed by orientation *** methods of identifying optimal discontinuity set numbers are usually achieved by clustering validity indexes,which mainly relies on the aggregation and dispersion of clusters and leads to the inaccuracy and instability of *** paper proposes a new method of Fisher mixed evaluation(FME)to identify optimal group numbers of rock mass discontinuity *** FME,orientation distribution is regarded as the superposition of Fisher mixed *** grouping results are identified by considering the fitting accuracy of Fisher mixed distributions,the probability monopoly and central location significance of independent Fisher centers.A Halley-Expectation-Maximization(EM)algorithm is derived to achieve an automatic fitting of Fisher mixed *** real rock discontinuity models combined with three orientation clustering algorithms are adopted for discontinuity *** clustering validity indexes are used to automatically identify optimal group numbers for *** results show that FME is more accurate and robust than the other clustering validity indexes in optimal discontinuity group number identification for different rock models and orientation clustering algorithms.

关键词： Rock mass discontinuity Orientation grouping Fisher mixed distribution 3D point cloud Stereo photogrammetry

Impact of ozonation on disinfection byproducts formation from phenylalanine during chlorination

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Journal of Environmental Sciences 2024年第10期144卷 199-211页

作者： Sinong Huang Hongwei Liu Kunming Wei Liang Zhang Xiaoyan Ma Qingsong Li Xueyan Li Andrea M.Dietrich College of civil {1. Zhejiang Key Laboratory of Civil Engineering Structures&Disaster Prevention and Mitigation TechnologyZhejiang University of TechnologyHangzhou 310023China Water Resources and Environmental Institute Xiamen University of TechnologyXiamen 361005China School of Environmental Science and engineering Suzhou University of Science and TechnologySuzhou 215009China civil and Environmental {1. Virginia Polytechnic Institute and State UniversityBlackburgVA 24061USA

As a strong oxidizing agent,ozone is used in some water treatment facilities for disinfection,taste and odor control,and removal of organic ***(Phe)was used as the target amino acid to comprehensively investigate variability of disinfection byproducts(DBPs)formation during chlorine disinfection and residual chlorine conditions subsequent to *** results showed that subsequent to ozonation,the typical regulated and unregulated DBPs formation potential(DBPsFP),including trichloromethane(TCM),dichloroacetonitrile(DCAN),chloral hydrate(CH),dichloroacetic acid(DCAA),trichloroacetic acid(TCAA),and trichloroacetamide(TCAcAm)increased substantially,by 2.4,3.3,5.6,1.2,2.5,and 6.0 times,respectively,compared with only *** also significantly increased the DBPs yield under a 2 day simulated residual chlorine condition that mimicked the water distribution *** formations followed pseudo first order *** formation rates of DBPs in the first 6 hr were higher for TCM(0.21. hr^(−1.),DCAN(0.244 hr^(−1.),CH(0.1.5 hr^(−1.),TCAcAm(0.234 hr^(−1.),DCAA(0.375 hr^(−1.)and TCAA(0.1.0 hr^(−1.)than *** peak DBPsFP of TCM,DCAN,CH,TCAcAm,DCAA,and TCAA were obtained when that ozonation time was set at 5–1. *** times>30 min increased the mineralization of Phe and decreased the formation of DBPs upon *** bromine ion(Br^(−1.)concentration increased production of bromine-DBPs and decreased chlorine-DBPs formation by 59.3%–92.2%.Higher ozone dosages and slight alkaline favored to reduce DBP formation and *** ozonation conditions should be optimized for all application purposes including DBPs reduction.

关键词： Ozone Amino acids Chlorination Disinfection by-products

Heterointerface engineering-Induced Oxygen Defects for the Manganese Dissolution Inhibition in Aqueous Zinc Ion Batteries

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Energy & Environmental Materials 2024年第3期7卷 112-122页

作者： Wentao Qu Yong Cai Baohui Chen Ming Zhang Hunan Provincial key {1. of Low-Dimensional Structural Physics&Devices School of Physics and ElectronicsHunan UniversityChangsha 410082China engineering Research Center of Advanced Semiconductor Technology and Application of Ministry of Education&{1. laboratory for Micro-/Nano-Optoelectronic Devices of Ministry of Education College of Semiconductors(College of Integrated Circuits)Hunan UniversityChangsha 410082China Changsha Semiconductor Technology and Application Innovation Research Institute College of Semiconductors(College of Integrated Circuits)Hunan UniversityChangsha 410082China state {1. laboratory of disaster Prevention&reduction for Power Grid Transmission and Distribution Equipment(Hunan Electric Power Corporation disaster Prevention and reduction Center) Changsha 410007China

Manganese-based material is a prospective cathode material for aqueous zinc ion batteries(ZIBs)by virtue of its high theoretical capacity,high operating voltage,and low ***,the manganese dissolution during the electrochemical reaction causes its electrochemical cycling stability to be *** this work,heterointerface engineering-induced oxygen defects are introduced into heterostructure MnO_(2)(δa-MnO_(2))by in situ electrochemical activation to inhibit manganese dissolution for aqueous zinc ion ***,the heterointerface between the disordered amorphous and the crystalline MnO_(2)ofδa-MnO_(2)is decisive for the formation of oxygen *** the experimental results indicate that the manganese dissolution ofδa-MnO_(2)is considerably inhibited during the charge/discharge *** analysis indicates that the oxygen defect regulates the electronic and band structure and the Mn-O bonding {1. of the electrode material,thereby promoting electron transport kinetics as well as inhibiting Mn ***,the capacity ofδa-MnO_(2)does not degrade after 1.0 cycles at a current density of 0.5 Ag^(-1.and also 91.capacity retention after 500cycles at 1.Ag^(-1..This study provides a promising insight into the development of high-performance manganese-based cathode materials through a facile and low-cost strategy.

关键词： electrochemical activation heterointerface manganese dissolution inhibition oxygen defects zinc ion batteries

Anisotropic shearing mechanism of Kangding slate:Experimental investigation and numerical analysis

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Journal of Rock Mechanics and Geotechnical engineering 2024年第5期16卷 1487-1504页

作者： Ping Liu Quansheng Liu Penghai Deng Yucong Pan Yiming Lei Chenglei Du Xianqi Xie The key {1. of Geotechnical and Structural engineering Safety of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China state {1. laboratory of Water Resources and Hydropower engineering Science Wuhan UniversityWuhan430072China

The shear mechanical behavior is regarded as an essential factor affecting the stability of the surrounding rocks in underground *** shear strength and failure mechanisms of layered rock are significantly affected by the foliation *** shear tests were conducted on cubic slate samples with foliation angles of 0°,30°,45°,60°,and 90°.The effect of foliation angles on failure patterns,acoustic emission(AE)characteristics,and shear strength parameters was *** on AE characteristics,the slate failure process could be divided into four stages:quiet period,step-like increasing period,dramatic increasing period,and remission period.A new empirical expression of cohesion for layered rock was proposed,which was compared with linear and sinusoidal cohesion expressions based on the results made by this paper and previous *** comparative analysis demonstrated that the new expression has better prediction ability than other *** proposed empirical equation was used for direct shear simulations with the combined finite-discrete element method(FDEM),and it was found to align well with the experimental *** both computational efficiency and accuracy,it was recommended to use a shear rate of 0.01.m/s for FDEM to carry out direct shear *** balance the relationship between the number of elements and the simulation results in the direct shear simulations,the recommended element size is 1.mm.

关键词： Anisotropy Empirical expression of cohesion foliation angles Combined finite-discrete element method(FDEM) Shear rate Element size