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

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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

Experimental and numerical investigation of the impacts of rotor tip-rake on excitation forces of pump-jet propulsors

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Journal of Hydrodynamics 2024年第1期36卷 142-157页

作者： Xue-qin Ji Xiao-song Zhang Chen-jun Yang Xiao-qian Dong State Key Laboratory of Ocean engineering Marine Numerical Experiment CentreSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China CSSC shanghai Marine Energy Saving technology co. Ltd.Shanghai200011China China Ship Scientific Research Center shanghai Branch Shanghai200011China

The tip-clearance flow in a pump-jet propulsor exerts great impacts on the fluctuating pressures and resultant unsteady forces,which are important sources of structural vibrations and radiated noise *** blade geometry close to the tip is an important factor determining the vortex strength in the tip-clearance *** the open-water condition,the effects of raking the rotor tips on the duct-surface fluctuating pressures and the resultant unsteady forces acting on different components of the propulsor are investigated via physical model experiments and the numerical solution of Reynolds-averaged Navier-Stokes(RANS)equations coupled with the SST k-ωturbulence *** measured and simulated results of hydrodynamic pressures are consistent to each other,and the simulated flows help better understand why the fluctuating pressures change with the tip *** strong fluctuations of duct-surface pressures are caused by intensive tip separation *** duct-surface pressure fluctuations are effectively reduced by using the rake distribution near the tip towards blade back side and,for the combination of the five-bladed rotor and the seven-bladed stator,the resultant unsteady horizontal(and vertical)forces acting on the duct and stator are also reduced;while increasing rake leads to negative effect on pressure fluctuations and unsteady horizontal(and vertical)forces acting on all the components of the propulsor.

关键词： Pump-jet tip-clearance tip-rake fluctuating pressures excitation forces

Experimental Study on Vortex-Induced Vibration of Rough Risers with coupling Interference Effect Under Side-by-Side Arrangement

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China Ocean engineering 2024年第1期38卷 18-28页

作者： HU Ze-bo LIU Zhen LI Peng GUO Hai-yan WANG Shu-bing REN Xiao-hui HOU Hao WANG Ye-shuo college of civil engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Qingdao Key Laboratory of Marine civil engineering Materials and Structures Qingdao 266590China college of engineering Ocean University of ChinaQingdao 266100China CHEC Dredging co. LtdShanghai 200136China

A vortex-induced vibration(VIV)experiment of rough risers with coupling interference effect under a side-by-side arrangement was carried out in a wave-current combined *** roughness of the riser was characterized by arranging different specifications of surface attachments on the surface of the *** risers with three different roughnesses were arranged side by side with smooth risers to explore the VIV response of the riser under the combined action of roughness and interference effect,and to reveal the coupling mechanism between roughness and interference *** experimental results show that,compared with that of a smooth riser,the VIV of a rough riser under the coupling interference effect has a wider"lock-in"region,and the displacement decreases more significantly at a high reduced velocity,which is more likely to excite higher-order modes and frequency *** addition,the displacement response and frequency response of the smooth riser are not significantly affected by wake interference from the rough riser,which is caused by the decrease of the wake region due to the delay of the boundary layer separation point of the rough riser.

关键词： marine riser vortex-induced vibration side-by-side arrangement roughness interference effect

Calcium Carbonate and Ettringite Induced Efflorescence in CAC-Anhydrite Binary Systems

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Journal of Wuhan University of technology(Materials Science) 2024年第5期39卷 1129-1137页

作者： SUN Zixuan CHEN Yuting XU Linglin LIU Siyu YU Long PAN Feng WANG Chaoqiang WU Kai YANG Zhenghong Key Laboratory of Advanced civil engineering Materials of Ministry of Education School of Materials Science and EngineeringTongji UniversityShanghai 201804China shanghai construction No.5(Group)co. Ltd.Shanghai 200063China School of Material Science and engineering Chongqing Jiaotong UniversityChongqing 400074China

We focused on the efflorescence induced microstructural evolution of ettringite-rich systems prepared with calcium aluminate cement(CAC)and *** effects of anhydrite on the visible efflorescence,and the corresponding capillary absorption of CAC-anhydrite mortars were *** composition and microstructure of efflorescence-causing substances were investigated by optical microscope,in-situ Raman spectroscopy,scanning electron microscope,energy dispersive spectrometer,thermogravimetric analysis,and differential scanning calorimetry,at *** indicate that,besides the calcium carbonate,ettringite is another main component of efflorescence-causing *** with the neat CAC mortars,the addition of anhydrite has a significant effect on the degree of efflorescence by acting on the composition of hydration products and pore *** addition,methods are proposed for the prevention of efflorescence of CAC-anhydrite binary system.

关键词： calcium aluminate cement anhydrite efflorescence ettringite phase assemblage pore structure

Surrounding rock classification from onsite images with deep transfer learning based on EfficientNet

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Frontiers of Structural and civil engineering 2024年第9期18卷 1311-1320页

作者： Xiaoying ZHUANG Wenjie FAN Hongwei GUO Xuefeng CHEN Qimin WANG Department of Geotechnical engineering College of Civil EngineeringTongji UniversityShanghai 200092China Chair of computational Science and Simulation technology Institute of PhotonicsLeibniz University HannoverHannover 30167Germany Key Laboratory of Geotechnical and Underground engineering of Ministry of Education Tongji UniversityShanghai 200092China Guizhou Xingyi Huancheng Expressway co. Ltd.Xingyi 562400China

This paper proposes an accurate,efficient and explainable method for the classification of the surrounding rock based on a convolutional neural network(CNN).The state-of-the-art robust CNN model(EfficientNet)is applied to tunnel wall image *** filtering,data augmentation and other data pre-processing techniques are used to improve the data quality and *** with transfer learning,the generality,accuracy and efficiency of the deep learning(DL)model are further improved,and finally we achieve 89.96%*** with other state-of-the-art CNN architectures,such as ResNet and Inception-ResNet-V2(IRV2),the presented deep transfer learning model is more stable,accurate and *** reveal the rock classification mechanism of the proposed model,Gradient-weight Class Activation Map(Grad-CAM)visualizations are integrated into the model to enable its explainability and *** developed deep transfer learning model has been applied to support the tunneling of the Xingyi City Bypass in the high mountain area of Guizhou,China,with great results.

关键词： surrounding rock classification convolutional neural network EfficientNet Gradient-weight Class Activation Map

Exploring the combination of biochar‐amended soil and automated irrigation technology for water regulation and preservation in green infrastructure

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Deep Underground Science and engineering 2024年第1期3卷 39-52页

作者： Honghu Zhu Yuanxu Huang Haihong Song Jian Chen Songlei Han Tanwee Mazumder Ankit Garg School of Earth Sciences and engineering Nanjing UniversityNanjingChina Department of civil and Smart engineering construction Guangdong Engineering Center for Structure Safety and Health MonitoringShantou UniversityShantouChina shanghai Municipal engineering Design co. LtdShanghaiChina Indian Institute of technology Madras ChennaiIndia

Biochar is a carbon sink material with the potential to improve water retention in various ***,for the long‐term maintenance of green infrastructure,there is an additional need to regulate the water contents in the covers to maintain vegetation growth in semiarid *** this study,biochar‐amended soil was combined with subsurface drip irrigation,and the water preservation characteristics of this treatment were investigated through a series of one‐dimensional soil column *** ascertain the best treatment method specific to semiarid climatic conditions,the test soil was amended with 0%,1%,3%,and 5%*** irrigation devices equipped with soil moisture sensors were used to control the subsurface water content with the aim of enhancing vegetation *** soil column test lasted 150 h,during which the volumetric water contents and soil suction data were *** experimental results reveal that the soil specimen amended with 3%biochar is the most water‐saving regardless of the time *** with a higher biochar content(e.g.,5%)consumes a more significant amount of water due to the enhancement of the water‐holding *** on the experimental results,it can be concluded that the appropriate ratio can be determined within 1%–3%,which can reduce not only the amount of irrigated/used water but also the time *** technology can be explored for water content regulation in green infrastructure and the development of barriers for protecting the environment around deep underground waste containment.

关键词： biochar drip irrigation underground water preservation water regulation

Simulation of wave scattering over a floating platform in the ocean with a coupled CFD-IBM model

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Theoretical & Applied Mechanics Letters 2024年第3期14卷 157-161页

作者： Pengxuan Luo Jingxin Zhang Yongyong Cao Shaohong Song School of Naval Architecture Ocean&Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China MOE Key Laboratory of Hydrodynamics Shanghai Jiao Tong UniversityShanghai 200240China shanghai city Tou waterway construction co. LTDShanghai 200092China

A numerical study of linear wave scattering over a floating platform has been simulated by an efficient numericalmodel in this *** non-hydrostatic model is used to simulate the free surface and the uneven *** thesolid body modelling,the immersed boundary method(IBM)is implemented by introducing a virtual boundaryforce into the momentum equations to emulate the boundary *** implementation enhances theability of the model to simulate interactions between waves and floating structures.A numerical case involvingwave interactions with a floating platform is studied to validate the numerical *** simulating the wavepropagation,the numerical model captures the variation of the wave scattering very well,which verifies theperformance of the numerical model and the robust strategy of the IBM.

关键词： Non-hydrostatic model Immersed boundary method Wave structure interaction Floating platform

Experimental Investigation on Vertical Hydraulic Transport of Ores in Deepsea Mining

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China Ocean engineering 2024年第1期38卷 42-53页

作者： LIU Lei LIU Jian-cheng LI Xin XU Li-xin ZHANG Xiu-zhan State Key Laboratory of Ocean engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Sanya Yazhou Bay Institution of Deep-sea Sci-Tech Shanghai Jiao Tong UniversitySanya 572000China China Merchants Marine And Offshore Research Institute co. Ltd.Shenzhen 518067China China Merchants Deepsea Research Institute(Sanya)co. Ltd.Sanya 572000China School of Naval Architecture and Ocean engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on *** hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for industrial *** the present study,an indoor model test of the vertical hydraulic transport of particles was conducted.A noncontact optical method has been proposed to measure the local characteristics of the particles inside a vertical pipe,including the local concentration and particle *** hydraulic gradient of ore transport was evaluated with various particle size distributions,particle densities,feeding concentrations and mixture flow *** transport,the local concentration is larger than the feeding concentration,whereas the particle velocity is less than the mixture *** qualitative effects of the local concentration and local fluid velocity on the particle velocity and slip velocity were *** local fluid velocity contributes significantly to particle velocity and slip velocity,whereas the effect of the local concentration is marginal.A higher feeding concentration and mixture flow velocity result in an increased hydraulic *** effect of the particle size gradation is slight,whereas the particle density plays a crucial role in the transport.

关键词： deepsea mining vertical hydraulic transport experiment flow characteristics

A Simplified Method for the Stress Analysis of Underground Transfer Structures Crossing Multiple Subway Tunnels

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computer Modeling in engineering & Sciences 2024年第6期139卷 2893-2915页

作者： Shen Yan Dajiang Geng Ning Dai Mingjian Long Zhicheng Bai college of civil engineering Tongji UniversityShanghai200092China China construction 4th engineering Bureau 6th corp. Ltd.Shanghai201199China Department of civil and Architecture engineering Hubei Polytechnic UniversityHuangshi435003China

According to the design specifications,the construction of extended piles involves traversing the tunnel’s upper region and extending to the underlying rock *** address this challenge,a subterranean transfer structure spanning multiple subway tunnels was *** on the function of piles in the transfer structure as springs with axial and bending stiffness,and taking into account the force balance and deformation coordination conditions of beams and plates within the transfer structure,we established a simplified mechanical model that incorporates soil stratification by combining it with the Winkler elastic foundation beam *** resolved established simplifiedmechanicalmodel employed finite difference technology and the Newton-Simpsonmethod,elucidating the mechanical mechanism of the transfer *** research findings suggest that the load carried by the upper structural columns can be transferred to the pile foundation beneath the beams through the transfer structure,subsequently reaching the deep soil layer and ensuring minimal impact on adjacent *** established simplified analysis method can be used for stress analysis of the transfer structure,concurrently considering soil stratification,pile foundation behavior,and plate *** pile length,pile section size,and beam section size within the transfer structure should account for the characteristics of the upper load,ensuring an even distribution of the beam bending moment.

关键词： Crossing tunnels transfer structure force mechanism simplify analysis layered soil mass