检索结果-南通市图书馆

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

在线全文

学校读者我要写书评

暂无评论

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 Construction 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 compression tests, coupled with acoustic emission(AE) and infrared radiation temperature(IRT) were conducted 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 correlation 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°), composite 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 composite 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 competitive relationship between compaction 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

Effect of Shrinkage Reducing Agent and Steel Fiber on the Fluidity and Cracking Performance of Ultra-High Performance Concrete

在线全文

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2024年第9期20卷 1941-1956页

作者： Yong Wan Li Li Jiaxin Zou Hucheng Xiao Mengdi Zhu Ying Su Jin Yang Wuhan Metro bridge and Tunnel Management Co. Ltd.Wuhan430068China School of Civil engineering Architecture and EnvironmentHubei University of TechnologyWuhan430068China

Due to the low water-cement ratio of ultra-high-performance concrete(UHPC),fluidity and shrinkage cracking are key aspects determining the performance and durability of this type of *** this study,the effects of different types of cementitious materials,chemical shrinkage-reducing agents(SRA)and steel fiber(SF)were *** with M2-UHPC and M3-UHPC,M1-UHPC was found to have better fluidity and shrinkage cracking ***,different SRA incorporation methods,dosage and different SF types and aspect ratios were *** incorporation of SRA and SF led to a decrease in the fluidity of *** internal content of 1%(NSRA-1%),SRA external content of 1%(WSRA-1%),STS-0.22 and STE-0.7 decreased the fluidity of UHPC by 3.3%,8.3%,9.2%and 25%,***,SRA and SF improved the UHPC shrinkage cracking ***-1%and STE-0.7 reduced the shrinkage value of UHPC by 40%and 60%,respectively,and increased the crack resistance by 338%and 175%,*** addition,the addition of SF was observed to make the microstructure of UHPC more compact,and the compressive strength and flexural strength of 28 d were increased by 26.9%and 19.9%,respectively.

关键词： Ultra-high performance concrete chemical shrinkage reducing agent steel fiber shrinkage cracking repair and reinforcement

Exploring the feasibility of prestressed anchor cables as an alternative to temporary support in the excavation of super-large-span tunnel

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Railway engineering Science 2024年第3期32卷 344-360页

作者： Shunhua Zhou Yuyin Jin Zhiyao Tian Chunhua Zou Heming Zhao Zengrun Miao Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety Tongji UniversityShanghai 201804China Key Laboratory of Road and Traffic engineering of the Ministry of Education Tongji UniversityShanghai 201804China China Railway Construction Corporation Limited Beijing 100855China The 2nd engineering Co. Ltd.of China Railway Construction Bridge Engineering Bureau GroupShenzhen 518083China China Railway Construction bridge engineering Bureau Group Co. LtdTianjin 300300China

Excavating super-large-span tunnels in soft rock masses presents significant *** ensure safety,the sequential excavation method is commonly *** utilizes internal temporary supports to spatially partition the tunnel face and divide the excavation into multiple ***,these internal supports generally impose spatial constraints,limiting the use of large-scale excavation equipment and reducing construction *** address this constraint,this study adopts the“Shed-frame”principle to explore the feasibility of an innovative support system,which aims to replace internal supports with prestressed anchor cables and thus provide a more spacious working space with fewer internal *** evaluate its effectiveness,a field case involving the excavation of a 24-m span tunnel in soft rock is presented,and an analysis of extensive field data is conducted to study the deformation characteristics of the surrounding rock and the mechanical behavior of the support *** results revealed that prestressed anchor cables integrated the initial support with the shed,creating an effective“shed-frame”system,which successively maintained tunnel deformation and frame stress levels within safe regulatory ***,the prestressed anchor cables bolstered the surrounding rock effectively and reduced the excavation-induced disturbance zone *** summary,the proposed support system balances construction efficiency and *** field experiences may offer valuable insights into the popularization and further development of prestressed anchor cable support systems.

关键词： Super-large-span tunnel Construction safety Sequential excavation method Shed-frame principle Prestressed anchor cables

Multi-Scale Feature Fusion Model for bridge Appearance Defect Detection

在线全文

学校读者我要写书评

暂无评论

Big Data Mining and Analytics 2024年第1期7卷 1-11页

作者： Rong Pang Yan Yang Aiguo Huang Yan Liu Peng Zhang Guangwu Tang School of Computing and Artificial Intelligence Southwest Jiaotong UniversityChengdu 611756China China Merchants Chongqing Road engineering Inspection Center Co. Ltd.Chongqing 400067China State Key Laboratory of bridge engineering Structural Dynamics Chongqing 400067China

Although the Faster Region-based Convolutional Neural Network(Faster R-CNN)model has obvious advantages in defect recognition,it still cannot overcome challenging problems,such as time-consuming,small targets,irregular shapes,and strong noise interference in bridge defect *** deal with these issues,this paper proposes a novel Multi-scale Feature Fusion(MFF)model for bridge appearance disease ***,the Faster R-CNN model adopts Region Of Interest(ROl)pooling,which omits the edge information of the target area,resulting in some missed detections and inaccuracies in both detecting and localizing bridge ***,this paper proposes an MFF based on regional feature Aggregation(MFF-A),which reduces the missed detection rate of bridge defect detection and improves the positioning accuracy of the target ***,the Faster R-CNN model is insensitive to small targets,irregular shapes,and strong noises in bridge defect detection,which results in a long training time and low recognition ***,a novel Lightweight MFF(namely MFF-L)model for bridge appearance defect detection using a lightweight network EfficientNetV2 and a feature pyramid network is proposed,which fuses multi-scale features to shorten the training speed and improve recognition ***,the effectiveness of the proposed method is evaluated on the bridge disease dataset and public computational fluid dynamic dataset.

关键词： defect detection Multi-scale Feature Fusion(MFF) Region Of Interest(ROl)alignment lightweight network

Experimental Study on engineering Behavior of Solidified Soil for Scour Repair and Protection

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Ocean engineering 2024年第4期38卷 625-635页

作者： WU Xiao-ni LI Ru-yu SHU Jian TANG Chao CHEN Jin-jian WANG Hui-li JIANG Hai-li WANG Xiao State Key Laboratory of Ocean engineering Department of Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Shanghai Road and bridge Group Co. Ltd.Shanghai 200433China Shanghai engineering Research Center of Urban Infrastructure Renewal Shanghai 200032China Jiangsu Kunze Technology Co. Ltd.Nanjing 210000China

A new scour countermeasure using solidified slurry for offshore foundation has been proposed *** solidified slurry is pumped to seabed area around foundation for scour protection or pumped into the developed scour holes for scour repair as the fluidized material solidifies *** the pumping operation and solidification,the engineering behaviors of solidified slurry require to be considered synthetically for the reliable application in scour repair and protection of ocean engineering such as the pumpability related flow value,flow diffusion behavior related rheological property,anti-scour performance related retention rate in solidification and bearing capacity related strength property after *** this study,a series of laboratory tests are conducted to investigate the effects of mix proportion(initial water content and binder content)on the flow value,rheological properties,density,retention rate of solidified slurry and unconfined compressive strength(UCS).The results reveal that the flow value increases with the water content and decreases with the binder *** the solidified slurry exhibits Bingham plastic behavior when the shear rate is larger than 5 s^(-1).The Bingham model has been employed to fit the rheology test results,and empirical formulas for obtaining the density,yield stress and viscosity are established,providing scientific support for the numerical assessment of flow and diffusion of solidified *** rate of solidified slurry decreases with the water flow velocity and flow value,which means the pumpability of solidified slurry is contrary to anti-scour *** unconfined compressive strength after solidification reduces as the water content increases and binder content decreases.A design and application procedure of solidified soil for scour repair and protection is also proposed for engineering reference.

关键词： scour repair and protection solidified soil pumpability strength flow properties anti-scour performance

Optimal design for rubber concrete layered periodic foundations based on the analytical approximations of band gaps and mapping relations

在线全文

学校读者我要写书评

暂无评论

Earthquake engineering and engineering Vibration 2024年第3期23卷 593-608页

作者： Wu Qiaoyun Xu Zhifeng Xu Peishan Zeng Wenxuan Chen Xuyong School of Civil engineering and Architecture Wuhan Institute of TechnologyWuhan 430073China State Key Laboratory for Health and Safety of bridge Structures Wuhan 430034China Wuhan Urban Construction Group Co. Ltd.Wuhan 430022China

The seismic performance of rubber concrete-layered periodic foundations are significantly influenced by their design,in which the band gaps play a paramount *** at providing better designs for these foundations,this study first proposes and validates the analytical formulas to approximate the bounds of the first few band *** addition,the mapping relations linking the frequencies of different band gaps are ***,an optimal design method for these foundations is developed,which is validated through an engineering *** is demonstrated that ensuring the superstructure’s resonance zones are completely covered by the corresponding periodic foundation’s band gaps can achieve satisfactory vibration attenuation effects,which is a good strategy for the design of rubber concrete layered periodic foundations.

关键词： periodic foundation band gap vibration attenuation seismic isolation optimal design

Utilization of recycled solid waste as ecological reclamation materials based on plant growth experiments and soil quality analysis

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第3期21卷 820-834页

作者： QIN Xiaochun NI Anchen YANG Dongxiao XING Wenhu LIU Shiliang College of Civil engineering Beijing Jiaotong UniversityBeijing 100044China Shanxi Road&bridge Construction Group Co. LtdShanxi 030006China School of Environment Beijing Normal UniversityBeijing 111875China

During the highway construction,a large number of spoil areas will be generated while a large amount of waste slag and soil could not be rationally ***,the vegetation recovery is slow in the spoil areas due to the soil *** at recycling the solid waste,the sieved engineering waste slag with local red clay and corn straw biochar was supplied to solve the problem of insufficient nutrients in engineering waste slag and *** addition,planting experiments of alfalfa(Medicago sativa L.)and Amorpha fruticosa *** with physical and chemical experiments were carried out to prove the feasibility of the novel improved substrate for the reclamation of spoil *** results show that the substrate's improvement effect is mainly affected by the soil to slag ratio and the biochar *** improvement effect of soil matrix in highway spoil area decreases with the increase of the waste slag content,especially when the soil-slag ratio is less than 3,and the promotion of plants is *** the contrary,the improvement effect is proportional to the biochar content(3%-8%).But it is noted that the Cu and Pb in the soil will exceed the clean limit corresponding to the Nemero soil pollution index level when the biochar content is 8%.Therefore,it is recommended that the soil-slag ratio should be≥3,and the biochar content should reach 3%-5%.This research provides experimental basis and technical support for utilizing solid waste resources in the reclamation of highway spoil areas.

关键词： Highway Spoil area Waste slag Modified soil Ecological reclamation

Heterogeneous bimetallic oxides/phosphides nanorod with upshifted d band center for efficient overall water splitting

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第9期35卷 414-420页

作者： Ji Chen Yifan Zhao Shuwen Zhao Hua Zhang Youyu Long Lingfeng Yang Min Xi Zitao Ni Yao Zhou Anran Chen School of Materials and Energy Yunnan UniversityKunming 650091China School of engineering The University of EdinburghSouth BridgeEdinburgh EH89YLUnited Kingdom Electron Microscopy Center Yunnan UniversityKunming 650091China School of Internet of Things engineering Jiangnan UniversityWuxi 214122China

Electrocatalytic water splitting is the most directly available route to generate renewable and sustainable ***,we report the design of a composite material in which arrays of square pillar-like NiMoO4nanorods coated with N,P-doped carbon layers are uniformly contained in numerous nested nanoparticle *** catalysts have superior catalytic activity,requiring only 59 mV and 187 mV for HER and OER to attain a current density of 10 mA/cm^(2),*** assembled two-electrode electrolytic cell required a voltage of 1.48 V to reach 10 mA/cm^(2),along with excellent long-term *** calculations reveal that electrons aggregate and redistribute at the heterogeneous interface,with the d-band centers of the Ni and Fe atoms being positively shifted compared to the Fermi level,effectively optimizing the adsorption of intermediates and reducing the Gibbs free energy,thus accelerating the catalytic ***,an integrated solar-driven water-splitting system demonstrated a high and stable solar-to-hydrogen efficiency of 18.20%.This work provides new possibilities for developing non-precious metal-based bifunctional electrocatalysts for large-scale water splitting applications.

关键词： Hydrogen evolution reaction Bimetallic oxides Bimetallic phosphides Overall water splitting Solar-to-hydrogen efficiency

Comparative Analysis of ARIMA and LSTM Model-Based Anomaly Detection for Unannotated Structural Health Monitoring Data in an Immersed Tunnel

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in engineering & Sciences 2024年第5期139卷 1797-1827页

作者： Qing Ai Hao Tian Hui Wang Qing Lang Xingchun Huang Xinghong Jiang Qiang Jing School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Key Laboratory of Road and bridge Detection and Maintenance Technology of Zhejiang Province Hangzhou311305China Zhejiang Scientific Research Institute of Transport Hangzhou310023China State Key Laboratory of Coal Mine Dynamics and Control Chongqing UniversityChongqing400044China Hong Kong-Zhuhai-Macao bridge Authority Zhuhai519060China

Structural Health Monitoring(SHM)systems have become a crucial tool for the operational management of long *** immersed tunnels exposed to both traffic loads and the effects of the marine environment,efficiently identifying abnormal conditions from the extensive unannotated SHM data presents a significant *** study proposed amodel-based approach for anomaly detection and conducted validation and comparative analysis of two distinct temporal predictive models using SHM data from a real immersed ***,a dynamic predictive model-based anomaly detectionmethod is proposed,which utilizes a rolling time window for modeling to achieve dynamic *** the assumption of temporal data similarity,an interval prediction value deviation was employed to determine the abnormality of the ***,dynamic predictive models were constructed based on the Autoregressive Integrated Moving Average(ARIMA)and Long Short-Term Memory(LSTM)*** hyperparameters of these models were optimized and selected using monitoring data from the immersed tunnel,yielding viable static and dynamic predictive ***,the models were applied within the same segment of SHM data,to validate the effectiveness of the anomaly detection approach based on dynamic predictive modeling.A detailed comparative analysis discusses the discrepancies in temporal anomaly detection between the ARIMA-and LSTM-based *** results demonstrated that the dynamic predictive modelbased anomaly detection approach was effective for dealing with unannotated SHM *** a comparison between ARIMA and LSTM,it was found that ARIMA demonstrated higher modeling efficiency,rendering it suitable for short-term *** contrast,the LSTM model exhibited greater capacity to capture long-term performance trends and enhanced early warning capabilities,thereby resulting in superior overall performance.

关键词： Anomaly detection dynamic predictive model structural health monitoring immersed tunnel LSTM ARIMA