Abstract:After years of development,China’s inland waterway transportation has achieved significant progress,playing an irreplaceable role in regional comprehensive transportation system and economic and social development of the area along the shipping route.We systematically review the development process of China’s inland waterway network since the founding of the People’s Republic of China,analyze the stage characteristics of the volume and composition of inland waterway development,and summarize the crucial supporting role of inland waterway transportation in regional economic and social development.Through comparative analysis with developed countries and regions,we analyze the existing challenges in the development of China’s waterway network deeply.On the basis of the characteristics of different cargo types,such as low-value bulk goods,medium-value bulk goods,and high-value precision goods,we propose a series of development strategies from two dimensions:improving operation efficiency and extending layouts of the inland waterway,put forward enhancing the punctuality and efficiency of lockage,addressing local bottlenecks in high-grade inland waterways,strengthening the integration of water conservancy network,inland waterway network and hydropower network,and promoting efficient connections between high-grade inland waterways and seaports.Focusing on the construction technology of high-dam navigation structures with significant market demand in central and western regions,we systematically identify critical technical bottlenecks that urgently need breakthroughs,such as water conveyance system technology,hydraulic structure of ship lock, gate and valve design,and intermediate channel and navigation tunnel technology.

Abstract:The maneuverability of a new 10,000-ton class river-sea direct vessel designed for the Three Gorges new navigation channel is investigated in this paper,with the objective of enhancing a ship motion simulation platform that incorporates the hydrodynamic characteristics of inland waterways.Numerical simulation methods are combined with circulating water channel resistance tests to analyze the hydrodynamic derivatives for ship roll and yaw under varying water depths and motion frequencies.By the maneuvering modeling group model,a 3-degree-of-freedom maneuvering motion simulation platform is developed for the 10,000-ton class river-sea direct vessel.The verification of platform’s reliability is carried out against publicly available large-scale ship model maneuverability test data.The results demonstrate that the vessel’s turning ability,course-keeping,and stopping characteristics all comply with the JT/T 258-2021 Criteria of Maneuverability for Transport Ship in Yangtze River,and the platform’s reliability is validated.The results provide a theoretical foundation for the safe operation of 10,000-ton class vessels in inland waters and offer technical support for the development of inland ship maneuvering simulators.

Abstract:To address the limitations of traditional harmonic analysis methods in identifying major tidal constituents from short-term current data,a comparative study is conducted using the tidal admittance method and the ratio-of-amplitudes method.Field observations from a typical cross-section in the lower Huangpu River during neap,medium,and spring tides are used.By fitting the normalized amplitude and phase lag of major constituents as functions of frequency,a smooth tidal admittance model is constructed and its predictive performance is evaluated.The results indicate that the admittance method,without relying on long-term data or empirical amplitude ratios,can effectively applied to the harmonic analysis and velocity prediction of short-term tidal currents.Compared with the ratio-of-amplitudes method,it reduces the root-mean-square error of current prediction by an average of 8.9%.Quadratic fitting further reveals a continuous relationship between frequency,the normalized amplitude and delay angle of diurnal and semidiurnal constituents,confirming the smoothness of the admittance function and its applicability in harmonic analysis.This method enhances short-term tidal forecasting and supports hydrological and engineering decision-making.

Abstract:The armor layer of a breakwater dissipates wave energy through friction and percolation,thereby reducing wave overtopping.Most existing overtopping calculation methods employ a constant roughness coefficient related to armor block type,which fails to account for the influence of different structural parameters of the armor layer.To evaluate the rationality of using constant roughness coefficients as input in machine learning models for wave overtopping prediction,this study utilizes the overtopping database from the EU CLASH project.Data for single-slope breakwaters (including simple slopes,slopes with crown walls,slopes with berms,and composite slopes) encompassing overtopping,wave,and structural parameters are selected to develop a neural network model for fitting armor layer roughness coefficients.By comparing the model performance across different structural types,the applicability of the recommended roughness coefficients in the database for neural network-based overtopping prediction is assessed.The results reveal significant variations in model accuracy depending on the breakwater slope structure,indicating substantial limitations and uncertainties in the current practice of using constant roughness coefficients.To further enhance the precision of neural network models for overtopping prediction,input parameters should incorporate armor block characteristics that directly influence hydrodynamic performance.

Abstract:In plain rivers,sediment transport is dominated by suspended load.When vegetation is present in the flow,significant changes occur in the flow field,which in turn affect the settling velocity and spatial distribution of suspended particles.In this study,a three-dimensional hydro-sediment numerical model incorporating the effects of rigid vegetation is developed based on the OpenFOAM solver driftFluxFoam.The model is validated through flume experiments involving flow around cylinders and partition plates.Four vegetation submergence ratios （h/H=0.4,0.6,0.8,1.0） are considered to simulate flow structures and suspended sediment distribution around vegetation under different submergence conditions.The results show that as vegetation submergence increases,the influence of submerged vegetation on flow velocity is confined to the vegetation layer.The vertical velocity decays significantly at 5D downstream of the vegetation,with a maximum increase in instantaneous velocity of approximately 55%.Bed shear stress increases within 5D upstream of the vegetation,the critical emergent vegetation shear stress is about 70% higher than that of submerged vegetation.A peak in shear stress forms along the centerline at 5D downstream,with low-stress zones appearing at 2D on either side of the centerline,and the wake region shows limited influence.The variation range of suspended sediment concentration gradually narrows,and the annular low-concentration zone at the vegetation base decreases.Submerged vegetation has a limited impact on near-bed longitudinal suspended sediment concentration differences,while critical emergent vegetation shows the opposite trend.The normalized time-averaged suspended sediment concentration at 50D downstream (CE/CA) is approximately 1.46.

Abstract:To address the issue of traditional buoys drifting significantly and losing navigational accuracy in strong currents in rivers and coastal areas,a study is conducted on reducing buoy offset by utilizing the combined effects of hydrodynamic lift generated by an underwater lifting body float and tension forces from a taut anchor chain.A numerical simulation method is employed to analyze the lift and drag characteristics of four NACA airfoil types:NACA 0012,NACA 0015,NACA 2412,and NACA 2415.Based on the analysis results,the NACA 2412 is selected as the baseline airfoil for constructing the underwater lifting body.A three-dimensional underwater lifting body is constructed by modifying this airfoil,and its lift and drag characteristics are subsequently analyzed to obtain a viable design for an underwater lifting body float.Numerical simulations and physical model experiments are applied to analyze the variation of buoy offset with flow velocity for a buoy model equipped with an underwater lifting body float,as well as for a series of buoy models using cylindrical float of the same volume.The results show that under equivalent flow velocity conditions above 2.5 m/s,the buoy equipped with an underwater lifting body buoy exhibited a 25% reduction in offset and a 58% decrease in maximum mooring cable tension compared with the cylindrical float buoy.Additionally,attitude stability is improved.The underwater lifting body buoy can meet the requirements of low offset and high navigation accuracy in strong current environments.However,the overall design must avoid negative angle of attack conditions for underwater lifting body.

Abstract:Aiming at the practical problems of intermodal transport network planning in the hinterland of inland ports under the “dual-carbon” strategy,a mathematical model of intermodal transport hub location in the hinterland of inland river ports is proposed and a solution method is designed.The mathematical model is constructed with the objective of minimizing the enterprise transportation cost (including cargo transportation cost,transit cost and carbon emission cost) and hub operation cost (including fixed operation cost and renovation/expansion cost) during the planning period,and the solution method is designed based on the idea of “preliminary selection-preferred selection-optimization”.The method firstly determines the list of alternative hubs based on the results of gravity method;secondly,based on the indicators of site size,development space and service capacity,the AHP-TOPSIS method is used to select the hubs corresponding to the number of hubs at each stage and the number of hubs from the alternative hubs,and obtains the set of preferred hubs;lastly,the multimodal hub location mathematical model is used to obtain the final hub siting scheme.Taking a port group along an inland river as an example,the hub location under different decision preferences is determined.The results show that the proposed model and algorithm are convenient and reliable,and provide a systematic methodological tool for multimodal hub planning in the hinterland of inland waterways,which can help reduce logistics costs and promote the transformation of low-carbon logistics.

Abstract:To address the medium to long-term deformation issues of underground diaphragm wall sheet pile wharf，we focus on the 100,000-ton-class curtain-type underground diaphragm wall sheet pile wharf project at Jingtang port area of Tangshan Port.Using prototype observation method,we investigate the medium to long-term deformation characteristics of the curtain-type underground diaphragm wall sheet pile structure during both the construction period and operational period,and obtain the structural deformation and anchor point displacement of the front diaphragm wall,curtain piles,and anchorage wall at different excavation stages and during operation period.The results demonstrate that the rate of change in horizontal displacement of the structure is greatest during the construction period of the curtain-type underground diaphragm wall sheet pile wharf structure dredged deep to near the design elevation.The cumulative horizontal displacement accounts for 80%-93%.The cumulative displacement of the anchor points accounts for 85%-91%.The dredging depth at the front of the wharf is highly sensitive to horizontal displacement,especially when it approaches the design value.The deformation stabilization time of the curtain-type underground diaphragm wall sheet pile wharf structure is approximately 7 years in the relied project.

Abstract:nder the context of rapid development in intelligent water transport,the safety status monitoring of the entire life-cycle of high-pile wharves has become a core issue in ensuring the reliability of port infrastructure.However,abnormal monitoring data caused by complex environmental conditions severely constrain accurate assessment and prediction of the status of high-pile wharves.To address the frequent occurrence of high-frequency noise and transient distortion in monitoring data from high-pile wharves,as well as the incompatibility of conventional denoising methods with non-stationary signal characteristics,a time-frequency joint denoising method integrating mean filtering and wavelet decomposition is proposed.A multi-indicator evaluation model prioritizing correlation coefficient and signal-to-noise ratio is established.Through comparative method analysis and feature parameter optimization,the optimal parameter combination is selected and validated from two dimensions:data quality improvement and prediction accuracy enhancement.Research shows that the time-frequency joint denoising method based on mean filtering wavelet decomposition effectively balances signal detail preservation and trend smoothing requirements while suppressing random noise and improving signal-to-noise ratio.The correlation between the denoised data and the original signal is significantly better than that of a single filtering method.The research results provide a solution that balances efficiency and accuracy for the processing and prediction of monitoring data for high-pile wharves.

Abstract:When the wave overtopping exceeds the critical value,the secondary waves generated behind the breakwater will pose a safety threat to the rear facilities (such as pile-supported wharves).To ensure the structural safety of pile-supported wharves under overtopping conditions,it is necessary to reassess the wave-induced forces acting on the wharf structure.In response to the problem of the current research gap concerning the calculation of uplift forces caused by secondary waves on panels of pile-supported wharves,the wave-induced uplift forces under overtopping conditions are investigated in this paper.A physical wave model test is established to examine the wave distribution within the harbor and the corresponding wave loads on the wharf,focusing on the combined effects of secondary waves generated by wave overtopping and diffracted waves entering the harbor around the breakwater head.The test results are compared with the calculation results by empirical formulas from design code.The fundamental reasons for the overestimation and limited applicability of the code formulas is identified by analyzing the characteristics of wave trains after overtopping.The results show that the measured maximum total uplift force on the wharf panel caused by secondary waves is approximately 50% of the value predicted by the empirical formulas,indicating significant safety redundancy.It is recommended that when calculating the maximum total uplift forces of secondary waves after overtopping,a breaking wave reduction coefficient of 0.5-0.7 should be introduced on the basis of the code formulas.

Abstract:As the coastal liquid chemical port areas and petrochemical industrial bases develop rapidly,the requirements for safety and environmental risk prevention in port zones are increasing.To make full use of existing infrastructure and ensure emergency oil spill response in the port area,taking the bucket-type structure foundation of the east breakwater in Xuwei port area of Lianyungang Port as an example,the spatial characteristics and load-bearing capacity of the buckets are analyzed.Partial functional modifications are made to the existing bucket-type structure,transforming it into an emergency pool within the port area.This forms a zonal emergency pool system within the port,which is used to collect and store oil and various wastewater that may leak along the public utility corridor in emergencies.This helps reduce pollution and ecological damage to the marine environment,and meets the accident wastewater interception capacity requirements stipulated in the environmental assessment.Compared with building new emergency pools,this approach can save 78.5% of construction investment,shorten the construction period by 66.7%,and save 100% of sea area usage.Considering factors such as construction investment,construction period,safety and environmental protection,maintenance costs,and rapid response,this solution is feasible.It explores an operational management model for port infrastructure that serves both routine and emergency needs,providing an innovative solution for similar coastal industrial port areas to address safety and environmental risk emergency prevention and control.

Abstract:With the large-scale construction of wharves,increasing demands are being placed on the bearing capacity of steel sheet pile wharves.The conventional steel sheet pile structure is subjected to high stress and high cost under deep water conditions,while the curtain-type steel sheet pile structure can effectively share the active soil pressure of the rear soil,optimize the stress conditions of the front sheet pile and anchoring system,and has the advantages of reasonable load distribution,small deformation,and economic efficiency.However,the current research on the stress characteristics and influencing factors of the curtain type steel sheet pile structure is not deep enough and needs further research.Based on a steel sheet pile wharf project,this paper uses model analysis software to establish a model and analyze the factors that affect the stress characteristics of curtain type steel sheet piles.The results show that the economic performance of the curtain-type steel sheet pile structure is improved by approximately 17.9% relative to the conventional steel sheet pile structure.When the distance between curtain piles is 2.8 m and the pile diameter is at least 0.8 m,the curtain effect can be fully utilized,leading to a pronounced soil arching effect.However,if the distance between the curtain pile and the front sheet pile exceeds 7 times the diameter of the curtain pile,the curtain effect diminishes considerably.In practical engineering applications,it is essential to comprehensively consider the loading and unloading processes in conjunction with the requirements of the upper structure.This study is intended to offer valuable references and guidance for the design and application of deep-water curtain-type steel sheet pile wharves.

Abstract:Complex navigation hub is a complex navigation facility composed of multiple locks,ship lifts,navigation tunnels and intermediate channels and other navigation buildings,the intermediate channel,as a key water connecting different navigation facilities,undertakes the function of ship collection,channelization and temporary berthing,the capacity configuration of its intermediate channel rendezvous section is of great significance for enhancing the overall passing ability of the hub.In response to the problem of mismatch between the capacity configuration of the middle channel rendezvous section and the through capacity of the complex navigation hub,taking the Goupipan navigation hub of Wujiang River as the research object,a simulation model of the complex navigation hub is constructed using Arena simulation platform.Through simulation experiments and data analysis,the influence of the capacity of the middle channel rendezvous section on the through capacity of the hub and the waiting time of ships is explored under different daily opening time of the hub.The results show that by reasonably adjusting the capacity of the middle channel rendezvous section based on the opening operation time of the hub,the throughput capacity of the hub can be improved and the waiting time of upstream and downstream ships at the hub can be reduced.After optimization,Goupitan navigation hub can increase its freight throughput by up to 13.9% and reduce the average waiting time of upstream and downstream ships at the hub by 13.6%.The research results can provide theoretical and technical support for the design and operation of the middle channel rendezvous section capacity of complex navigation hubs.

Abstract:In view of the problems of low efficiency,narrow coverage,insufficient data integration,and strong subjectivity in evaluation in traditional health monitoring methods (manual inspection,single technology) for bank protection projects in inland waterways,a multi-dimensional health status monitoring and evaluation index system for bank protection is built on the basis of “water-land-air-space” multi-source sensing and DERU-AHP quantitative model.Shore-based video,UAV laser point cloud,unmanned ship sonar,distributed optical fiber sensing,Beidou navigation and other technologies are innovatively integrated,and an air-space-shore-water-underwater integrated collaborative monitoring network is built to achieve all-round perception of surface,internal and underwater diseases of revetment structures.The analytic hierarchy process (AHP) is used to determine the index weights,and the damage-extent-reflection-urgency (DERU) model is introduced into the field of bank protection health assessment to establish four-dimensional quantitative grading evaluation criteria.The system is verified by the application in a gravity-type bank protection project in the middle of the Yangtze River.The results show that the system accurately identifies hidden crack propagation and internal stress anomalies missed by manual inspection,and the comprehensive evaluation score (62.5 points,Class III) is more in line with actual maintenance needs than the traditional method (Class II,80-90 points).Quantitative analysis shows that the evaluation error is reduced by 25.4%,and the risk assessment efficiency is improved by 40%.The results can provide accurate and efficient technical support for the intelligent operation and maintenance of revetment projects,and are of great significance for improving the full life cycle management level of waterway infrastructure.

Abstract:The navigable flow conditions in the estuary reach where the Yuxi River converges into the Yangtze River are complex due to the dual influence of upstream sluice operation and the water-sediment dynamics of the Yangtze River.A depth-averaged 2D hydrodynamic model is employed to analyze navigable flow parameters conditions such as water depth,flow velocity,and direction in the Yuxi River estuary.The influence of hub operation schemes on flow diversion ratio at the original meander reach is investigated by Pearson correlation coefficient analytical method.The results show that based on the current channel scale requirements,the designed navigation channel can basically meet the maintenance water depth requirement of 4.0 m,but there is a problem of insufficient water depth in local areas of the channel.The overall flow state of the engineering river section is directly controlled by the water level of the main stream of the Yangtze River and the operation and discharge status of the Yuxi Ship Lock.When the uplift effect of the main stream of the Yangtze River is weak and the discharge flow of Yuxi Ship Lock is small,the overall hydrodynamic conditions of the river section are relatively weak.There is a strong positive correlation between the original bend section and the total discharge of the hub,as well as the flow rate of the control gate,while there is a negative correlation with the filling and discharge volume from the ship lock.The research results can provide references for the safety of ships in the Yuxi estuary and offer theoretical support for the subsequent maintenance of the waterway.

Abstract:To address the low efficiency of fish passage caused by poor flow conditions,this study proposes a new kind of fishway design,named as the L-shaped baffle fishway.The water flow conditions inside the fishway are investigated by numerical simulation.The results show that the flow is stable and maintained in the center of L-shaped baffle fishway.There are similar and stable recirculation zones on both sides of the main stream,with the lowest velocity occurring in the center of recirculation zone.The main flow width of 0.45 m,which is comparable to the vertical slots of the L-shaped baffle fishway,and the hydraulic properties of the individual water layers are essentially the same.The maximum mean flow velocity of the fishway decreases with the decrease of bottom slope.When the bottom slope decreases from 1/70 to 1/90,the maximum flow velocity of the fishway decreases from 1.06 m/s to 0.91 m/s,which is a decrease of 16.5%.When the bottom slope is lower than 1/80,the turbulent kinetic energy in the main flow region keeps at 0.05 m2/s2，the turbulent kinetic energy in the pool is less than 0.05 m2/s2，and the low turbulent kinetic energy area is more than 70%.This study can provide quantifiable design parameters for the fishway project.In combination with the requirements of design specifications,when the bottom slope of the fishway is 1/80 or less,it can meet the upstream requirements of fish.

Abstract:With the rapid development of China’s inland waterway transportation,the increasing number of large-scale ship lock projects with ultra-high heads has made energy dissipater performance a core concern in their design and operation.This study focuses on a four-section outflow cover-plate energy dissipation ship lock characterized by a single-stage head of 40.25 m and chamber dimensions of 265 m × 34 m (length × width).A three-dimensional turbulent flow mathematical model is established,employing the RNG k-ε turbulence model and volume of fluid (VOF) method to simulate hydraulic characteristics during lock filling process.The investigation analyzes three-dimensional flow fields in the chamber,flow distribution through top branch orifices,and energy dissipation mechanisms of cover plates.The results demonstrate that water enters the chamber through top branch orifices as high-velocity jets.During initial filling stages,jet velocities decrease along the flow direction from the longitudinal corridor inlet.When flow rates exceed 100 m3/s,jet velocities progressively increase along the path,with increasingly uneven velocity distribution among top orifices,and the maximum velocity ratio between initial and terminal outflow orifices reaches 1.75.The cover plates effectively reduce jet velocities through obstruction and energy dissipation,with primary energy dissipation concentrated in confined spaces formed between top orifices and cover plates.These findings reveal the regulatory mechanism of cover plate structures on jet flow control and energy dissipation,providing technical references for water conveyance system design in similar ultra-high head and large-scale ship locks.

Abstract:To address the constraints of limited space and the complex construction and operational environment at Huai’an East Ship Lock,the study on its layout is conducted using mathematical and physical modeling.The research comprehensively considered multiple factors,including traffic capacity,the impact on flood and embankment stability of the general channel for irrigation and the Huaihe River estuary waterway,as well as navigation flow conditions.The results show that the upstream separation levee should adopt a uniform porous structure with 67% porosity,while the downstream separation levee requires a gradual transition porous structure with 8%-25% porosity.Moreover,after the width of the upstream entrance area is increased to 112.5 m,the navigation water flow conditions meet the requirements.The main and auxiliary navigation walls adopt an empty box structure and a plastic concrete diaphragm wall anti-seepage structure,which can effectively reduce the occupation of flood discharge area.After dredging 103,000 and 360,000 m3 of flood discharge compensation measures in the upstream and downstream respectively,the impact of ship lock construction on the flood discharge of the main channel and the sea channel can be basically eliminated.The research results can provide reference and guidance for the layout and safe operation of similar ship locks.

Abstract:During the operation of ship locks,the triangular gates may experience abnormal vibrations during the water discharge process due to stress concentration,wear,and hidden faults in the supporting components.These vibrations pose a serious threat to the operational safety and structural durability of the gates.However,the stress characteristics of the triangular gates and their supporting components during the water discharge process are not fully understood.This study focuses on the triangular gates of a certain ship lock in our country,establishing a three-dimensional finite element numerical model based on the geometric dimensions of its prototype structure.Using numerical simulation methods,the study analyzes the load response characteristics of the triangular gates and their supporting components under different water level differences during the water discharge process.It reveals the stress distribution patterns between the gate leaf and the supporting components and clarifies the key sensitive areas and their stress response relationships.The results indicate that typical stress-sensitive areas exist in lock gates and supporting components.By measuring the characteristic response parameters from these stress-sensitive areas,the correlation between the leaf and the top pivot,as well as between the leaf and the bottom pivot,has been quantified.This allows for the preliminary dynamic assessment of the operational status of concealed supporting components (such as the bottom pivot) through real-time monitoring of response parameters (e.g.,stress,strain,vibration acceleration,etc.) in the stress-sensitive areas of the gate leaf and top pivot.The findings provide a theoretical basis for real-time monitoring of the operational status of triangular gates in navigation locks,contributing to the advancement of intelligent operation and maintenance in lock engineering.

Abstract:In addressing the uncertainties regarding the laws of riverbed erosion-deposition,flow division ratio,and river channel volume changes before and after the implementation of the west waterway of Tongzhou Sand Shoal regulation project within the comprehensive regulation of the Chengtong Reach in the lower Yangtze River,and the need to ensure the safe operation of the 12.5 m deepwater navigation channel,we integrate riverbed evolution analysis and project impact assessment methodologies to systematically study the impacts of the west waterway regulation project (from 2011 to 2016) on the channel flow distribution pattern,erosion-deposition distribution,and volume variation relying on measured hydrological and topographic data from 2010 to 2023.The results reveal that the regulation project has effectively curbed the atrophy trend of the west waterway,stabilized the head of Tongzhou Sand Shoal,transformed the middle reach from a wide-shallow morphology into a single deep channel,and increased the flow division ratio to a stable range of 10%-12%.However,current siltation in the inlet and lower reaches restricts inflow conditions,leading to a slow overall silting trend in the west waterway.This trend currently exerts no significant adverse effects on the operation of the 12.5 m deepwater channel.The research outcomes provide field-measured data support for navigation channel maintenance in Chengtong Reach and effectiveness evaluation of similar river engineering regulation projects.It is recommended to enhance monitoring of sediment deposition in the inlet section and optimize the dredging scheme to maintain channel flow capacity in future practices.

Abstract:Since September 2018,the persistent operation of the Xinglong Hub below the dead water level has significantly altered the navigation conditions of the new estuary reach,resulting in frequent occurrences of navigation obstruction phenomena.To address the problem,we employ comprehensive data analysis and comparative research methodologies to analyze the variations in flow-sediment characteristics under abnormal hub operations on the basis of hydrological data of Huangzhuang and Shayang stations in Hanjiang River,along with measured topographic data of the new estuary reach.We further elucidate the underlying mechanisms by which these changes contribute to navigation obstruction risks.The results demonstrate that prolonged low-water-level operation of the Xinglong Hub has led to insufficient channel depth near the new estuary sluice.Furthermore,constrained by both channel morphology and upstream flow-sediment conditions,accumulated sediment cannot be effectively transported downstream,resulting in frequent navigation obstructions during dry seasons.Through the implementation of river channel regulation and targeted dredging projects,the beach-trough pattern can be effectively improved,navigation safety during the dry season can be ensured,and the collaborative improvement of waterway governance and ecological stability can be achieved.

Abstract:Based on the dredging project of south Jiangsu section of the Beijing-Hangzhou Grand Canal,combined with short-term and long-term on-site monitoring,the restoration effects of water quality,sediment and aquatic biodiversity in the river after backhoe dredging are investigated.The results show that the backhoe dredging operation increases the turbidity of the water body by 6.3%,and the turbidity at some points return to the pre-dredging level within 2 hours after the operation.The concentrations of ammonia nitrogen and total nitrogen slightly increase after the operation,but none of them exceed the relevant standard limits.The concentrations of total phosphorus,pH value and dissolved oxygen remaine basically unchanged during the operation.Dredging helps remove nutrients such as nitrogen and phosphorus from the sediment,and the reduction effects of 60.2% and 29.6% are maintained half a year after the operation.Although dredging leads to a decrease in the density and biomass of planktonic and benthic organisms,the biomass and biodiversity of planktonic and benthic organisms have been restored half a year after the operation,and the biomass of planktonic organisms even exceeds the pre-dredging level.The research results can provide a reference for the environmental protection design of canal dredging projects.

Abstract:When ships pass through the ship lock,there may be damage to the ship lock facilities such as mooring columns and miter gates due to behaviors such as overspeed and line crossing,as well as adverse effects such as obstruction by hydraulic structures and unstable vessel traffic services(VTS) signals in the ship lock chamber.The safety supervision in the ship lock chamber mainly relies on manual work,and there are certain deficiencies in the intelligence,timeliness,and accuracy of ship safety supervision,which increase the safety risks of ships in the ship lock chamber.We aim to solve the above problems by studying the monitoring of the passing ship overspeed and line crossing on the basis of ship recognition models and radar speed measurement principles.Through theoretical derivation,we propose a layout plan and calculation approach for ship overspeed and line crossing monitoring devices,and put forward an intelligent monitoring design for overspeed and line crossing in ship lock chambers,which has been successfully applied in the Gezhouba ship lock.The results indicate that intelligent monitoring can effectively monitor potential risks such as overspeed and line crossing of the passing ships,with a warning accuracy rate of over 99.5%,effectively reducing ship lock safety risks.

Abstract:Gravity dock slope excavation is characterized by extensive excavation areas and prolonged construction periods.Traditional terminal displacement warning methods are difficult to achieve differentiated stability assessments across various stages of the long excavation period.As a static mechanical evaluation model,the limit equilibrium analysis method requires precise physical and mechanical property indices of the slope.However,when environmental or construction factors significantly influence the dock slope during excavation,the model becomes further distorted,exhibiting notable limitations.Based on this,this study establishes a multi-level dynamic early warning system for dock slopes.The system employs automated monitoring devices to conduct remote,automatic,and real-time monitoring of dock slopes,followed by similarity analysis of time-series data to identify abnormal environmental and construction factors during excavation.On this basis,the system invokes the PLAXIS interface for stability evaluation at each excavation stage,enabling multi-level dynamic warnings for gravity dock slopes.During the excavation of a dock slope in Zhoushan,the multi-level dynamic warning system accurately identified abnormal environmental factors,dynamically adjusted initial geotechnical physical-mechanical parameters,achieving advanced prediction of slope displacement and excavation stability at all levels,guiding construction personnel to protect in a timely manner,avoiding economic losses and casualties.This system provides new evaluation methods and advanced prediction directions for dock slope disaster prediction.

Abstract:A study on real-time monitoring method based on digital twin and video fusion is carried on to address key technical challenges in real-time monitoring of surface flow pattern in channels,such as difficulty in fusing multi-source information,insufficient accuracy in correcting geometric distortions in videos,and inaccurate dynamic mapping of 3D scenes.By developing panoramic real-time video surveillance coupling technology,the compatibility problem of heterogeneous device data is solved,and the video stream access delay is reduced to less than 0.5 s.By developing an intelligent fusion algorithm for surface flow monitoring videos,the pixel level matching error between monitoring images and 3D scenes is achieved with less than 0.1 pixels.On-site testing of the surface flow state intelligent perception system is carried out in the Three Gorges channel of the Yangtze River,achieving an automatic recognition accuracy of 95.3% for typical flow states such as rapids and backflow,and controlling the flow velocity measurement error within ±0.05 m/s.The results indicate that the proposed intelligent fusion algorithm and system architecture significantly improve the real-time and accuracy of channel flow monitoring,providing reliable technical support for navigation safety management under complex hydrological conditions.

Abstract:There are very few studies on breccia geology at present.On the basis of the results of axial compression static load tests of two steel pipe piles in Yantian Port,we apply finite element method and hyperbolic fitting method to study the bearing capacity of large-diameter steel pipe piles in breccia geology.The results show that the load-settlement (Q-s) curves are basically linearly elastic when the loads of SZ1 and SZ2 test piles are less than 12 687.5 and 5 862.5 kN respectively.By the finite element method,the compressive ultimate bearing capacity obtained by the SZ1 and SZ2 test piles according to the code has a surplus of 61% and 71% respectively compared with the design requirements,and the compressive ultimate bearing capacity obtained according to the project technical specification has a surplus of 122% and 90% respectively compared with the design requirements.The elastic modulus,friction angle,dilation angle,and cohesion yield stress of fully weathered breccia,strong weathered breccia,and middle weathered breccia which obtained by using the finite element method and test results can better reflect the geotechnical properties of this project,and can be used to supplement geographic exploration data and optimize pile length.

Abstract:To address the lack of accurate evaluation methods for the mechanical properties of remolded soils with varying structural levels,this study adopts a combined cement-salt particle modification technique to prepare artificially structured specimens.Samples with different cement contents (0%,2%,3%,4%,and 5%) are subjected to consolidated undrained triaxial tests to systematically investigate their stress-strain characteristics and shear strength evolution laws at different structural levels.The results show that with the increase of cement content,the peak strength and initial stiffness of the soil are significantly improved.The stress-strain curves transition from strain-hardening to strain-softening,indicating a shift from plastic to brittle behavior as structure increases.Peak strength increases linearly with confining pressure,while the initial modulus increases with the power function of the confining pressure and is linearly related to cement content.Based on the above experimental results,a comprehensive stress-strain mathematical model is constructed by integrating the Duncan-Chang model with the exponential softening stage.The model has high fitting accuracy (R2＞0.99) and can accurately describe the mechanical properties of soil under various conditions.For practical applications,a cement content of 3%-4% is recommended to balance strength enhancement and brittleness control.This work provides theoretical support for the constitutive modeling and foundation improvement of structured marine soft soil.

Abstract:The foundation soil in a certain channel of the Yangtze River Estuary is generally deep soft clay,which is prone to strength weakening under wave cyclic loadings,affecting the safety and stability of hydraulic structures.Static triaxial tests and dynamic triaxial tests under cyclic loading are conducted for three typical sections of soft clay in the channel of the Yangtze River Estuary.The strength and deformation weakening characteristics of the foundation soil under actual wave loadings are studied.The experimental results show that wave cyclic loadings have a significant impact on the strength and deformation characteristics of the undisturbed foundation soil in the channel of the Yangtze River Estuary.There is a clear weakening phenomenon in the strength and deformation parameters,The maximum deviatoric stress of the foundation soil in the undrained shear test decreases by 9% to 20%,the dynamic elastic modulus decreases by 5% to 14%,and the undrained shear line modulus Eu，1% decreases by up to 36%.The influence of foundation soil weakening needs to be considered during the operation of hydraulic structures.Through comparison,it is found that the consolidation process of foundation soil can significantly improve strength,reduce deformation,and reduce the impact of cyclic loading on strength weakening,thereby enhancing the bearing capacity of hydraulic structures' foundations.The research results can provide reference and basis for the design,construction,and resilience improvement of hydraulic structures in the channel of the Yangtze River Estuary.

Abstract:The smear effect induced by plastic drainage board installation significantly impacts soft ground improvement,yet the influence of pile boot type on the smear zone remains unclear.In this study,transparent soil and particle image velocimetry (PIV) techniques are used to establish a “sand-over-clay” layered foundation model.Visualization tests are conducted with five pile boot types (circular/irregular/triangular cross-section stick,plate-type,and duckbill-less circular) under varying insertion depths.The research show that：1） The smear zone comprises a strong smear zone and a weak smear zone.Within the strong smear zone (0d-4d,d represents diametre of the sleeve),the lateral soil displacement attenuation rate reaches 75%/d.In contrast,the weak smear zone exhibits an attenuation rate of ＜5%/d.2) For dredged slurry and coastal silt,the strong smear zone consistently extends to 4d regardless of pile boot type.However,the weak smear zone ranges from 7d to 10d depending on boot geometry,with irregular stick boots reaching 10d and circular boots limited to 7d.3) When insertion depth increases from 10d to 14d,the weak smear zone expands from 6d to 9.5d,while the relative displacement u/d (u represents soil horizontal displacement) within the strong smear zone increase 0.04.The research provides quantitative criteria for selecting pile boots and assessing smear effects in engineering practice.

Abstract:As global climate issues intensify,society is paying more attention to low-carbon development.Carbon accounting is crucial for achieving carbon peaking and neutrality,with carbon emission calculation being a key part.Land reclamation projects,known for their large scale and large engineering volume,have significant carbon emissions.As one of its core structures,the steel cylinder is of great significance for carbon emission measurement.This study uses the carbon emission factor method to calculate and analyze carbon emissions during the construction stage of a steel cylinder island-wall structure in a certain project.It also compares these emissions with those of slope-type and bucket-foundation breakwaters.The results show that carbon emissions during the construction phase of steel cylinders mainly come from materials,accounting for 94%,and steel is the main source of carbon emissions.Indirect emissions from material use are higher than direct emissions.Transport ships and crane ships rank among the top two in terms of carbon emissions in ship machinery equipment.The carbon emissions per meter of the main material for the steel cylinder breakwater structure are 77 t,which is higher than the 69 t of slope-type breakwaters but lower than the 103.5 t of bucket-foundation breakwaters.This study provides a scientific basis for the formulation of engineering carbon reduction strategies and helps promote the development of land reclamation projects towards low-carbon direction.