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Location monitoring approach of underground pipelines using time-sequential images

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Underground Space 2024年第2期15卷 59-75页

作者： Haoruo Xu Lei He Yuyang Chu Junchen He Huaiguang Xiao Chengmeng Shao School of civil {1. Southeast UniversityNanjing 210096JiangsuChina The 3rd branch China Railway 16th Bureau Group Co.LTDHuzhou 313000ZhejiangChina

The location monitoring of underground pipelines is of utmost significance as it helps the effective management and maintenance of the pipelines,and facilitates the planning of nearby projects,preventing damage to the ***,currently there is a serious lack of data on the locations of underground *** paper proposes an image-based approach for monitoring the locations of underground pipelines by combing deep learning and visual-based *** proposed approach can build the monitoring model for underground pipelines and characterize their locations through their centroid *** advantages are:(1.simplicity:it only requires time-sequential images of the inner walls of underground pipelines;(2)clarity:the location model and the location curve of underground pipelines can be provided quickly;(3)robustness:it can cope with some existing problems in underground pipelines,such as light variations and small viewing angles.A lightweight approach for monitoring the locations of underground pipelines is *** proposed approach’s effectiveness has been validated through laboratory simulation experiments,demonstrating accuracy at the millimeter level.

关键词： Underground pipelines Location monitoring Time-sequential images Visual-based reconstruction Deep learning

Toward equitable,transparent,and collaborative human mobility computing for smart cities

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The Innovation 2024年第5期5卷 15-16页

作者： Yong Chen Xiqun(Michael)Chen Ziyou Gao Institute of Intelligent Transportation Systems College of Civil Engineering and ArchitectureZhejiang UniversityHangzhou 310058China School of Systems Science Beijing Jiaotong UniversityBeijing 100044China

Cities constitute vast and intricate systems in which diverse entities(e.g.,people,vehicles,and roads)interact collaboratively and *** and understanding the core elements of people in complex urban mobility systems provides a crucial means for smart city *** the era of global digitization,the exponential surge in geolocation data linked to human travel has profoundly transformed our understanding of human travel *** science enables us to comprehensively capture human mobility characteristics1.at the individual and population levels;these characteristics include regularity,diversity,and *** by data science,human mobility computing research has shaped a closed-loop scientific ecosystem involving data training models,model serving applications,and application feedback data(Figure 1..

关键词： computing smart travel

Prediction of the Pore-Pressure Built-Up and Temperature of Fire-Loaded Concrete with Pix2Pix

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Computers, Materials & Continua 2024年第5期79卷 2907-2922页

作者： Xueya Wang Yiming Zhang Qi Liu Huanran Wang Mechanics and Materials Science Research Center Ningbo UniversityNingbo315211China Jinyun Institute Zhejiang Sci-Tech UniversityLishui321400China School of civil {1. and Architecture Zhejiang Sci-Tech UniversityHangzhou310018China School of Computer Science Nanjing University of Information Science and TechnologyNanjing210044China

Concrete subjected to fire loads is susceptible to explosive spalling, which can lead to the exposure of reinforcingsteel bars to the fire, substantially jeopardizing the structural safety and stability. The spalling of fire-loaded concreteis closely related to the evolution of pore pressure and temperature. Conventional analytical methods involve theresolution of complex, strongly coupled multifield equations, necessitating significant computational efforts. Torapidly and accurately obtain the distributions of pore-pressure and temperature, the Pix2Pix model is adoptedin this work, which is celebrated for its capabilities in image generation. The open-source dataset used hereinfeatures RGB images we generated using a sophisticated coupled model, while the grayscale images encapsulate the1. principal variables influencing spalling. After conducting a series of tests with different layers configurations,activation functions and loss functions, the Pix2Pix model suitable for assessing the spalling risk of fire-loadedconcrete has been meticulously designed and trained. The applicability and reliability of the Pix2Pix model inconcrete parameter prediction are verified by comparing its outcomes with those derived fromthe strong couplingTHC model. Notably, for the practical engineering applications, our findings indicate that utilizing monochromeimages as the initial target for analysis yields more dependable results. This work not only offers valuable insightsfor {1. engineers specializing in concrete structures but also establishes a robust methodological approach forresearchers seeking to create similar predictive models.

关键词： Fire loaded concrete spalling risk pore pressure generative adversarial network(GAN) Pix2Pix

Experimental study on performance of spring damping support structure system for large deformation tunnel in soft rock

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Underground Space 2024年第2期15卷 221-243页

作者： Jinfeng Xu Xiongyao Xie Zhou Shi Wuqiang Cai Dinglun Xu Chen Xu department of Geotechnical {1. College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground engineering Ministry of EducationTongji UniversityShanghai 200092China Zhaotong City Zhaolu Expressway Investment and Development Co. ZhaotongYunnan Province 657000China Institute of Rock Mechanics Ningbo UniversityNingboZhejiang 315211China

According to the convergence confinement theory,it is an effective measure to control the large deformation of high ground stress in fractured soft rock tunnels by using yielding *** yielding support can be classified as either radial or circumferential yielding *** yielding support is achieved by transforming radial displacement into circumferential tangential closure without compromising the support capacity of the primary lining support *** on this,and inspired by the design principle of dampers,a yielding support structure system with spring damping elements as its core was developed,based on the connection characteristics of steel arches in highway tunnel,which can provide increasing support resistance in the yielding deformation *** the mechanical properties of spring damping elements were obtained through indoor axial pressure and flexural *** addition,according to these results with numerical calculations,the yielding support structure system with embedded spring damping elements can reduce the internal force of the support structure by approximately 1.%and increase the area of the plastic zone of the surrounding rock by 1..23%,which can fully utilize the self-bearing capacity of surrounding rock and verify the effectiveness of circumferential yielding ***,the spring damping support structure system was designed with reference to the construction process of the tunnel excavated by drilling and blasting method,and the transformation of the spring damping element to spring damping support structure was *** on field test results,surrounding ground pressure for the yielding support optimization scheme was reduced by 40%and more evenly distributed,resulting in the successful application and a reduction in the construction cost of large deformation tunnels in soft rock.

关键词： Soft rock Highway tunnel Convergence confinement method Circumferential yielding support with spring damping element Numerical calculations Field test

An extended micromechanical-based plastic damage model for understanding water effects on quasi-brittle rocks

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International Journal of Mining Science and Technology 2024年第3期34卷 289-304页

作者： Qiaojuan Yu Shigui Du Qizhi Zhu Zhanyou Luo Sili Liu Lunyang Zhao Institute of Rock Mechanics Ningbo UniversityNingbo 315211China Ningbo Key Laboratory of Energy Geostructure Ningbo UniversityNingbo 315211China College of civil and Transportation {1. Hohai UniversityNanjing 210098China College of civil {1. Jiangsu Open UniversityNanjing 210036China South China Institution of Geotechnical engineering School of Civil Engineering and TransportationSouth China University of TechnologyGuangzhou 510641China

Water effects on the mechanical properties of rocks have been extensively investigated through experiments and numerical ***,few studies have established a comprehensive link between the microscopic mechanisms of water-related micro-crack and the constitutive behaviors of *** this work,we shall propose an extended micromechanical-based plastic damage model for understanding weakening effect induced by the presence of water between micro-crack’s surfaces on quasi-brittle rocks,based on the Mori-Tanaka homogenization and irreversible thermodynamics *** the physical mechanism,water strengthens micro-crack propagation,which induces damage evolution during the pre-and post-stage,and weakens the elastic effective properties of rock *** proposing a special calibration procedure for the determination of model parameters based on the laboratory compression tests,the proposed micromechanical-based model is verified by comparing the model predictions to the experimental *** model effectively captures the mechanical behaviors of quasibrittle rocks subjected to the weakening effects of water.

关键词： Water Micro-crack Damage Micro-mechanics Constitutive model Cohesive force

Stability behavior of the Lanxi ancient flood control levee after reinforcement with upside-down hanging wells and grouting curtain

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Journal of Mountain Science 2024年第1期21卷 84-99页

作者： QIN Zipeng TIAN Yan GAO Siyuan ZHOU Jianfen HE Xiaohui HE Weizhong GAO Jingquan School of Water Conservancy and Environment engineering Zhejiang University of Water Resources and Electric PowerHangzhou 310018China department of {1. engineering Imperial College LondonLondonSW71BFEngland Lanxi Water Affairs Bureau Lanxi 321102China zhejiang Water Conservancy {1. Consulting Co. LtdHangzhou 310051China

The stability of the ancient flood control levees is mainly influenced by water level fluctuations, groundwater concentration and rainfalls. This paper takes the Lanxi ancient levee as a research object to study the evolution laws of its seepage, displacement and stability before and after reinforcement with the upside-down hanging wells and grouting curtain through numerical simulation methods combined with experiments and observations. The study results indicate that the filled soil is less affected by water level fluctuations and groundwater concentration after reinforcement. A high groundwater level is detrimental to the levee's long-term stability, and the drainage issues need to be fully considered. The deformation of the reinforced levee is effectively controlled since the fill deformation is mainly borne by the upside-down hanging wells. The safety factors of the levee before reinforcement vary significantly with the water level. The minimum value of the safety factors is 0.886 during the water level decreasing period, indicating a very high risk of the instability. While it reached 1.478 after reinforcement, the stability of the ancient levee is improved by a large margin.

关键词： Stability analysis Multiple factors Antiseepage reinforcement Upside-down hanging well Grouting curtain Ancient levee

Analytical solution for tunnelling-induced response of an overlying pipeline considering gap formation

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Underground Space 2024年第2期15卷 298-311页

作者： Cungang Lin Junjie Zheng Yiwen Ye Farrokh Nadim Zhongqiang Liu Chenyang Zhao Yu Chen Zhi Ding Guangdong Research Center for Underground Space Exploitation Technology School of Civil EngineeringSun Yat-sen UniversityGuangzhou 510275China Guangdong Key Laboratory of Marine civil {1. School of Civil EngineeringSun Yat-sen UniversityGuangzhou 510275China State Key Laboratory for Tunnel engineering Ministry of EducationGuangzhou 510275China Southern Marine Science and engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China School of civil {1. Wuhan UniversityWuhan 430072China Guangdong Road and Bridge Construction Development Co. Ltd.Guangzhou 510660China Norwegian Geotechnical Institute Oslo 0806Norway Key Laboratory of Safe Construction and Intelligent Maintenance for Urban Shield Tunnels of zhejiang Province Hangzhou 310015China

Soil-pipeline separation due to tunnelling has been certainly substantiated in previous model ***,this phenomenon has seldom been considered in current analytical *** study formulates a tensionless Winkler solution that could make allowance for gap formation in soil-pipeline interaction *** solution is validated by comparisons with existing experimental measurements and two recognized analytical ***,its advantage over an existing Winkler solution is *** parametric studies reveal that the effects of gap formation on the response of a pipeline rely largely on the tunnel volume loss and the pipeline’s bending stiffness and burial *** general,a pipeline’s bending moments and subgrade reaction forces are more susceptible than its deflections to the gap formation.

关键词： Soil-pipeline interaction Tunnelling Tensionless Winkler model Ground settlement Analytical solution Gap formation

Numerical Study of Flow Features Around Submerged Circular and Square Piles at Flat and Scoured Beds Using OpenFOAM

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Journal of Ocean university of China 2024年第4期23卷 897-914页

作者： WANG Chaolin WU Guoxiang WANG Dianhe DU Shengtao ZHANG Zhiyong JIN Heng ZHU David Z. LIANG Bingchen Donghai Academy School of Civil&Environmental Engineering and Geography ScienceNingbo UniversityNingbo 315211China Key Laboratory of Estuary and Coast of zhejiang Province and Zhejiang Institute of Hydraulics and EstuaryHangzhou 310020China Shandong Provincial Key Laboratory of Ocean engineering and College of EngineeringOcean University of ChinaQingdao 266100China Shandong Water Conservancy Vocational College Rizhao 276826China School of Mechanical and Energy engineering Ningbotech UniversityNingbo 315211China

Elucidating the flow features around piles in local scouring processes is crucial for studies of local scouring mechanisms and scour depth *** study details the flow turbulence characteristics of two submerged piles that are determined by solving the Navier-Stokes equations with the improved delayed detached eddy simulation *** model is verified by comparing experimental and numerical results for hydrodynamic parameters with the literature for both square-crossing piles(SCPs)and circular-crossing piles(CCPs).Original topographies of flat and scoured beds(i.e.,the initial and equilibrium scouring stages)are based on experimental results obtained by the authors in the present *** and CCP flow features in the scouring process are *** results indicate that during the scouring process,the time-averaged drag coefficient and root mean square(rms)of the lift coefficient increase linearly in the CCP test,while the rms of the lift coefficient in the SCP test decreases ***,the minimum pressure coefficient is always located in the upstream corners in the SCP case but moves from 72.5°to 79.5°when the scour hole is completely developed in the CCP *** flow behind the pile,which is generated by separated boundary layers above the top face of the pile,can reach the sand bed and turn the separated shear layers into patches of small vortices in the near-wake ***,the high shear stress zones are mainly at the scour edges under scoured-bed conditions.

关键词： flat bed scoured bed local scour OpenFOAM bed shear stress

考虑Steigmann-Ogden界面的复合材料远场解析解

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Acta Mechanica Sinica 2024年第1期40卷 35-43页

作者：高梦园贺哲龙 Ougbe Anseme Ahehehinnou 王冠楠 department of {1. engineering Zhejiang UniversityHangzhou 310058China Center for Balance Architecture Zhejiang UniversityHangzhou 310007China College of Mechanical and Vehicle engineering Hunan UniversityChangsha 410082China

本文给出了含有纳米纤维或孔隙的二维异质材料在远场载荷作用下的Steigmann-Ogden弹性面的解析解.该求解与最近文献中复函数法的数值结果进行了验证,并提供了具体位移和应力场的闭式表达式.数值研究了表面弹性参数、表面残余应力、纤维... 详细信息

本文给出了含有纳米纤维或孔隙的二维异质材料在远场载荷作用下的Steigmann-Ogden弹性面的解析解.该求解与最近文献中复函数法的数值结果进行了验证,并提供了具体位移和应力场的闭式表达式.数值研究了表面弹性参数、表面残余应力、纤维/孔径和远场载荷对局部应力分布的影响.结果表明,表面弹性参数会扰乱纤维域内的内应力,而表面弯曲刚度参数会显著影响应力集中,这与经典Eshelby问题中的均匀应力分布不同.分析表达式揭示了一些有趣的现象,例如,纤维复合材料在静水载荷作用下的应力/位移场仅与表面Lamé参数有关,剪切载荷作用下分析表达式中的非常数系数保持为单轴拉伸载荷作用下的两倍,这些都是本文首次报道的.所建立的解决方案对于准确捕捉具有显著表面效应的纳米复合材料的力学响应至关重要.

关键词：纳米复合材料异质材料表面效应纤维复合材料弹性参数载荷作用剪切载荷弯曲刚度