Abstract:To further refine the classification criteria for muddy-silty coasts,we conduct the sedimentation-consolidation experiments on sediments with clay contents ranging from 10% to 30% on the basis of the projects of the 300,000-ton channel of Lianyungang Port.By integrating historical data with field observations,we systematically refine the methodological principle and methodologies for determining critical thresholds of three critical parameters in coastal classification criteria including specifically median grain size,clay content,and plasticity index,and optimize and improve the classification criteria for silt-sandy coasts.The results show that the coasts with median diameter less than or equal to 0.03 mm,clay content greater than or equal to 25%,and plasticity index greater than 17 are defined as the muddy coasts.The coasts with median diameter between 0.03 mm(not included) and 0.06 mm,clay content between 15% and 25%(not included),and plasticity index between 10(not included) and 17 are defined as transitional between muddy and silty coasts.The coasts with median diameter between 0.06 mm(not included) and 0.10 mm,clay content less than 15% and plasticity index less than or equal to 10 are defined as the silty coasts.The coasts with median diameter greater than 0.10 mm and clay content nearly 0% are defined as the sandy coast.

Abstract:In response to the serious sedimentation in dredging projects of rivers,lakes,and reservoirs in China,as well as the high construction cost and low environmental protection performance of traditional cutter suction dredgers,the development of the “Junlan” large depth fully electric drive assembled cutter suction dredger is carried out.The overall layout,main dimensions,power configuration,connection devices,and intelligent control system of the ship are studied.Diesel and shore electric dual power drive are used,and the construction cost of pure shore electric drive is reduced by 66.7%,while reducing carbon emissions.The cutter,underwater pump,and cabin pump are driven by variable frequency motors,which intelligently control the speed of the mud pump and cutter to increase suction concentration and reduce construction costs.Equipped with independently developed high-efficiency mud pump and cutter system,the conveying efficiency is increased by more than 10%.The cutter is adopted a thin slice design,and the excavation efficiency is increased by more than 15%.The “Junlan” is successfully achieved the design and construction of a fully electric drive assembled cutter suction dredger with a depth of 25 m,and achieves significant effect in construction cost control,environmental protection performance,excavation efficiency,and suction efficiency.

Abstract:Aiming at the problem of sedimentation in excavated basin,sediment model tests are conducted to investigate the siltation patterns of excavated basins under different water and sediment conditions.The results indicate that in the year of heavy water and sand,such as 1963,the sedimentation in the harbor basin reached 74,200 m3,with the average silting thickness was about 0.4-0.5 m.Sediment mainly accumulated near the entrance of the harbor basin and within the original main river channel,reaching up to 1.3 m in the local area.However,the sedimentation thickness within the harbor basin was only 0.1-0.2 m.After 13 years of operation,sedimentation occurred in the whole section of the river,with the average silting thickness was about 1.0 m and up to 2.0 m in some areas.The main areas of sediment accumulation remained unchanged.Specifically,an area of approximately 60 m at the entrance of the harbor basin experienced significant elevation after sedimentation,potentially causing navigation obstacles during periods of low water levels and small flow rates.As the years of operation increases,the sediment in the harbor basin accumulates cumulatively and depth of the harbor basin is gradually decreasing.In the mountainous river,it is feasible to construct excavated basins utilizing backwater eddies,and sediment accumulation can be controlled.

Abstract:To address the issue of local seabed scouring induced by pile-supported permeable breakwaters in engineering applications,we investigate the effects of baffle opening modes and porosity on the flow field structure and sediment scouring characteristics in front of the breakwater,using an inclined baffle structure as the research object.On the basis of a FLOW-3D numerical model,we design three flow intensities and five baffle configurations,and reveal the mechanisms of different structural parameters affecting local scour through simulation analysis of the surrounding flow velocity field,vorticity field,and seabed morphological evolution.The results show that under the same flow velocity,a lower baffle porosity leads to stronger vortex structures behind the baffle and in the front of piles,resulting in significantly increased scour depth and range,and a downstream shift in sediment deposition position.Under the same porosity,a smaller opening size of lower part of the baffle causes greater disturbance to the near-bed flow,thereby intensifying scouring.The baffle configuration has a significant impact on seabed scour.It is necessary to comprehensively consider the coordinated performance of both wave dissipation and scour resistance in the structural design of such breakwaters.

Abstract:The development trend of large-scale container ships poses challenges to the berthing capacity of port terminals,and some existing container terminals need to deepen their harbors to meet the berthing requirements of large container ships.To explore the influence of the dredging depth of the harbor basin on the structural stress of the high-pile wharf,the changes of the mechanical properties of the overall structure after the excavation of the waters in front of the wharf are studied based on the ABAQUS finite element software.By setting different excavation depth conditions in the front waters,the overall deformation of the wharf and the force changes of the pile foundation structure under different load conditions are analyzed.The results show that with the increase of dredging depth:1) The horizontal displacement of the front cushion cap structure reaches a maximum of 2.55 cm,which is larger than that of the rear cushion cap structure,the two parts are gradually brought closer together,the reserved gap is reduced,and there is a possibility of collision between the two cushion caps.2) The displacement of the upper part of the front cushion cap structure is 8 times that of the bottom,and the front cushion cap structure as a whole shows a tendency to dump to the land.3) The dredging depth aggravates the unevenness of the load bearing on each pile from the superstructure,and some piles may be locally damaged due to excessive compression.4) The maximum bending moment of the pile foundation is located near the soil section,and the area with the largest difference in the maximum bending moment of the pile foundation under the condition of each dredging depth is in the middle area of the wharf structure,and the pile in this area may be damaged due to excessive bending.

Abstract:To address the limitations of traditional accounting methods in fully reflecting the spatial distribution and dynamic evolution of port carbon emissions,this study conducts a carbon emission footprint analysis based on spatiotemporal data field theory.Taking a large port in northern China as the research object,a theoretical framework of spatiotemporal data fields is introduced to construct a port carbon emission potential field model.By integrating emission data from different port areas across spatial and temporal dimensions,and applying methods such as potential value superposition and spatiotemporal distance transformation,spatiotemporal mapping,trend forecasting,and emission reduction evaluation can be achieved.The results show that port carbon emissions exhibit significant spatial heterogeneity and temporal persistence.Specifically,the production area accounts for 40%-45% of emissions,with an annual growth rate of 2.64%.emissions in the dock area are closely related to berthing density and decreased by 10%-15% after the widespread adoption of shore power systems.Through the comparison of model prediction and actual data,it is verified that under differentiated emission reduction measures,the annual growth rate of port emissions dropped from 4.28% to 2.15%,with an annual reduction potential of 447 t.The model can provide theoretical support for dynamic monitoring and predictive analysis of carbon emissions in complex systems,and can contributes to the low-carbon transformation of the port industry and the construction of green and smart ports.

Abstract:To address the issue of data anomalies in the structure health monitoring system of a dock due to sensor failures,which subsequently affects the accuracy of structural safety assessment,a fault data identification and correction method is proposed based on an improved box plot method.By integrating the improved box plot method with scatter plot analysis technique,a statistical feature recognition model is constructed that includes four types of data:no fault,spike fault,drift fault,and bias fault,achieving precise classification of fault types.In the experimental verification phase,the method exhibits a 91.07% fault recognition accuracy rate among 56 sets of actual measurement data segments.For different fault types,the research designs differentiated correction strategies:using Lagrange interpolation for spike faults,applying moving window mean fitting to correct drift and bias faults.Finally,by comparing the autocorrelation of data before and after correction,the effectiveness of data correction is verified.The research results provide reliable data quality assurance method for the dock structure health monitoring system and have significant practical significance for improving the level of safety monitoring of major infrastructure.

Abstract:As a crucial component of modern transportation infrastructure,port engineering requires emergency repair and rapid construction during peacetime or wartime due to potential damage.Seawater sea-sand concrete(SSC),which made from seawater and sea-sand,demonstrates significant application value and development potential in emergency port engineering rehabilitation due to its local material availability,early strength development,and rapid setting characteristics.On the basis of the current research status on SSC both domestically and internationally,we summarize the mechanisms by which seawater and sea-sand influence concrete properties,and analyze the key properties of SSC to focus on in emergency repair and rapid construction for port engineering,including compressive strength,setting rate,and workability.The results show that,natural seawater and sea-sand can effectively shorten construction periods and reduce costs for port emergency repair and rapid construction,with SSC preparation requiring no desalination treatment.It is necessary to control the replacement rate of sea-sand within 50%,or to reduce the content of impurities such as shells and coral sand in sea-sand through pretreatment.Incorporating appropriate supplementary cementitious materials and nanomaterials can regulate the initial/final setting time of SSC and enhance its adaptability for emergency repair and rapid construction.Compared with SSC,fiber reinforced SSC and ultra-high performance SSC exhibit excellent superior mechanical properties and durability,presenting broad application prospects in the emergency repair and rapid construction for port engineering.

Abstract:Yangkou Port Yangguang Island is an important LNG receiving port in China,this paper analyzes the long-term dynamic changes of the tidal flat evolution,the erosion and deposition situation in the LNG terminal area,and the impact on the foundation piles of the terminal by comparing underwater topographic data from different periods.The results show that with the gradual completion of the artificial island and terminal supporting facilities,the Dahonggengzi sandbar on the northeast side of the artificial island has been moving westward year by year.The northern waterway continues to maintain a westward and northward extension trend.The head of the central waterway has slowed its westward extension,but shows a trend of continuous southward compression and widening.The LNG terminal area exhibits different patterns of erosion and deposition at different stages.In the early stage,it was mainly a micro-sedimentation state.After 2010,due to the impact of terminal construction,significant scour occurred around the A1 and B1 docks.By 2018,the terminal area gradually transitioned to a deposition state,and the sediment on the northern slope of the artificial island significantly increased.For the proposed A2 terminal project,a protection approach combining preliminary protection and post-construction protection with reserved scouring depth will be adopted to reduce the scouring rate of the pile foundation and prolong the service life of the pile foundation.

Abstract:In view of the mooring stability of liquefied natural gas(LNG) bunkering vessels during alongside bukering of cargo ships at non-dedicated terminals under extreme conditions,the ship-to-ship (STS) mooring system for a 30,000 m3?LNG bunkering vessel and a 14,000 TEU LNG dual-fuel container ship at a container terminal is focused on.A shore-side STS mooring solution is proposed.A coupled shore-side STS mooring model is established by numerical analysis software to simulate vessel displacements,mooring line tensions,and fender forces under combined environmental loads (wind,waves,and current).The omnidirectional ultimate environmental load-bearing capacity (critical wind speed/current speed) is forecasted.Furthermore,the impact of mooring line pre-tension on mooring performance is systematically quantified through extended analyses involving various ship type combinations.The results demonstrate that under standard container terminal environmental conditions,this solution meets regulatory requirements for mooring stability during LNG bunkering operations.When the pre-tension is optimized to approximately 13% of the minimum breaking load of the mooring lines,the peak line tension is minimized,and vessel motion displacements can be reduced to below 35% of those observed in scenarios without pre-tension.

Abstract:Regarding the potential threats to the stability of riverbeds of existing hydraulic structures caused by changes in the regional topography and sediment conditions in the Fujiangsha Waterway of the Yangtze River due to the deepwater channel project,especially local scouring risks from historical pile foundations.This study focuses on the residual pile groups at Tian Gang Wharf.A two-dimensional hydro-sediment model for the Ligang-Tianshenggang river reach is developed to predict the trend of riverbed erosion and deposition.The research results show that:1)In normal sediment-water years,sedimentation dominates in the shoal area near the wharf and within 200 m upstream and downstream,the upstream side experiences erosion,the downstream shoal area shows slight sedimentation,and a strip-shaped sedimentation zone appears about 300 m offshore.2)In high-flow years,scouring in the nearshore shoal area is more extensive than in normal hydro-sediment years,but sedimentation still primarily occurs within 100 m of the wharf front.The modeling technique involved in this study can provide references for numerical simulations of residual pile groups at similar wharves,and the research results can provide scientific support for pile groups treatment plan in renovation and expansion projects of similar wharves.

Abstract:This paper takes a new container terminal project in Senegal as an example to explore the layout scheme of spur breakwater under swell conditions and its impact on waves at the front of the terminal.Through wave mathematical model experiments,the effects of different spur breakwater lengths on the waves at the terminal front are compared and analyzed,and the downtime under each scheme is calculated.The results show that the length of the spur breakwater has a significant impact on the shielding effect of waves in the harbor,and longer breakwater support can effectively reduce downtime.Specifically,the downtime for Scheme 1 (with a spur breakwater length of 323 m) is 0.7%,for Scheme 2 (with a spur breakwater length of 120 m) is 2.23%,and for Scheme 3 (without a spur breakwater but with adjusted channel bottom elevation) is 1.47%.The study also found that when other conditions（such as raising the dock front berthing water area,harbor basin,and outer channel）are adjusted,even if the breakwater support is cancelled,it may still achieve a good shielding effect.This research provides a reference for the design of breakwaters in similar port projects and offers insights for the construction and optimization of breakwater schemes under long-period wave conditions in the future.

Abstract:Aiming at the safety problem of ship mooring stability in the intermediate channel with a combination arrangement of 1,000-ton class ship locks and ship lifts,a planar two-dimensional turbulence mathematical model is used to study the influence of channel width,initial water depth and ship lock discharge time and other parameters on the ship mooring stability.The formula for calculating the average flow rate of maximum discharge that a ship can withstand is proposed.The results show that:1) The maximum flow velocity and maximum gradient in the berthing section showed the process of first increasing and then decreasing with the water discharge from the ship lock,and the shorter the discharge time,the earlier the peak of the maximum flow velocity appeared;the smaller the initial water depth,the later the maximum gradient peak appeared.2) As the width of the intermediate channel,initial water depth,and ship lock discharge time increase,when two of these parameters remain constant,the longitudinal mooring force of the ship decreases in a negative power function relationship with the third parameter.3) Under the same section coefficient of channel,the longitudinal mooring force increases linearly with the increase of the average discharge flow rate of the ship lock.The maximum average discharge flow rate that a ship can withstand is increased linearly related to the section coefficient.The research results can provide a theoretical basis for the formulation of safety standards for ship mooring in intermediate channels under the combined arrangement of ship locks and ship lifts.

Abstract:To address the significant challenges in plane layout under complex constraints for the Wuxi junction second-line ship lock,we summarize general layout principles of ship lock.Meanwhile,we fully consider influencing factors such as navigable flow conditions,geological compatibility,constructability,structural stability,flood control impacts,management area configuration,single-transit efficiency,land acquisition requirements,excavation volumes,and project costs.Adopting the method of combining quantitative and qualitative analysis,we select a reasonable general layout scheme through comprehensive comparative analysis.Based on this scheme,we conduct normal fixed-bed physical model tests and ship model tests to investigate the navigable flow conditions in the upstream approach channel of the second-line ship lock and their impacts on vessel navigation,using indicators such as maximum longitudinal/transverse flow velocities,maximum rudder angles,and minimum sailing speeds.We optimize the layout and structural type of the bulkhead through this experimental analysis.The results show that the scheme with the ship lock main structure located downstream of the anti-seepage cutoff wall is superior,as we find it reduces flood control pressures while ensuring construction convenience,better economic performance,and better structural stability.For the upstream bulkhead,we recommend the combination scheme of 100 m pile row (1.5 m center spacing) and 100 m pile inserted separation wall,which effectively addresses cofferdam challenges in the reservoir area during first-line ship lock navigation,and reduces project costs.The proposed layout scheme and methodology offer a valuable reference for the general arrangement of ship locks in similarly constrained reservoir areas,particularly those subject to multifaceted environmental and operational limitations.

Abstract:The Chaohu Ship Lock Hub is located at the entrance from Chaohu River to the Yuxi River,and is a key control project for the Heyu line channel and Chaohu River flood control.Its upstream is adjacent to the Chaohu ecological scenic area.Due to the constraints of ecological and flood prevention factors,construction conditions are restricted.The current technical condition of the first-line ship lock is poor and cannot operate normally.The throughput capacity of ship lock cannot meet the demand for transportation volume.Based on the width of the old lock chamber and the analysis of the proportion of ships passing through the lock chamber with different widths,it is proposed that the ships passing through the lock chamber should choose the ship lock with better adaptability to the size of the lock chamber according to the width of the ship,and try to improve the utilization rate of the lock chamber as much as possible.After the renovation of the first-line ship lock,the minimum water depth of the threshold is 4.5 m.Through the analysis of the critical speed of the ships passing through the lock,it is found that under normal entry and exit speed conditions,the maximum draft of the designed ship when fully loaded can be increased from the allowable value of 2.80 m to 2.92 m.The proportion of 2,000-ton class ships that meet the requirements for passing through the lock can be increased from 64.68% to 83.10%.When the speed is reduced to 0.6 m/s,it can basically meet the requirements for all designed 2,000-ton class ships to pass through the lock.At the same time,from the perspective of transportation economy,the rationality of the maximum draft value of the designed ship is demonstrated by analyzing the matching between the threshold water depth of the ship lock and the downstream channel design water depth through the design of the ship type.

Abstract:The complex vortex structure causes navigation-obstructing obstruction in the fluctuating backwater area of the Three Gorges.However,the dynamic evolution mechanism of the vortex structure is unclear,making it difficult to effectively guide ship navigation.To address this issue,a high-precision unmanned aerial vehicle (UAV) image acquisition system is built to carry out the observation of the vortex structure in the Hujiatan Reach.An image processing technology for surface vortex structure identification and tracking is proposed,and the spatiotemporal evolution characteristics of the vortex structure in the variable return water area are quantitatively analyzed.The core area of the vortex is identified through gray-scale conversion,binarization segmentation and morphological detection methods,and its geometric characteristics are quantified by the equivalent circle method.Combined with the inter-frame displacement method,the dynamic evolution parameters between frames of the vortex structure are extracted.The results show that the vortex structure exhibits a distinct three-stage evolution characteristic during its motion process.There is a significant positive correlation between the radius of the vortex structure and its movement velocity,and this correlation shows stage dependence:in the expansion stage,the correlation is weak due to the influence of external factors;in the contraction stage,the correlation is strong,dominated by internal hydrodynamicmechanisms.Furthermore,the growth rate jump point during the rapid expansion period of the vortex structure's movement and migration process can be regarded as a key node for the pre-adjustment of the ship's course,providing theoretical support for the subsequent discovery of the influence of the vortex structure in the fluctuating backwater area of the Three Gorges on ship movement.

Abstract:Reasonable anti-collision reinforcement of the gate structure can effectively reduce collision risks and ensure the safe operation of the ship lock.To study its collision avoidance effect,taking the triangular gate of a ship lock as the research object,using the finite element software ANSYS,three kinds of models are built:before reinforcement,after reinforcement (straight-line anti-collision plate) and after reinforcement (broken-line anti-collision plate).Considering the open and closed status,forward and reverse water levels and different impact point positions,17 working conditions are constructed.The stress and deformation of the main components and the support reaction at the pivot seat and hoist rod under different working conditions are compared and analyzed.The results show that,when the ship impact force is not considered,the maximum stress of each component of the gate after reinforcement is reduced under the forward water level,but the maximum stress of the panel and main beam increases by about 30% under the reverse water level.Under the impact force of the ship,when the ship hits the column and the middle straight arm,the maximum stress of the gate component with the straight-line anti-collision plate is 30%-40% lower than that of the broken-line anti-collision plate,and the maximum deformation is reduced by about 50%.The anti-collision performance of the straight-line anti-collision plate is better.

Abstract:The determination of slope gradient for waterway dredging is related to the stability of channel dredging slope and the normal operation of the waterway,as well as the dredging engineering quantity and engineering investment,especially for shallow and deeply excavated waterway.At present,the table lookup method is still used to determine the dredging slope gradient in the specification.The value range of waterway slope gradient is given according to different rock and soil types,and it is pointed out that slope gradient of open waterway under strong wave action needs to be slowed down,but there is no specific method to consider the wave dynamic loads.Based on phase II project of 300,000-ton class waterway in Lianyungang Port,this paper introduces the design wave standard and uses the empirical formula to determine the wave dynamic load acting on the dredging slope of waterway.The vibration triaxial test is used to simulate the wave dynamic load on the dredging slope soil,obtain the soil strength index after the wave load,calculate the soil mechanical stability safety factor of the waterway slope,and form a method for determining the waterway dredging slope quantitatively considering the influence of wave dynamic load.On the basis of the general provisions of the specification,it provides useful supplements for reasonably determining the slope gradient of waterway dredging slopes.

Abstract:To the problem of normalized congestion of ships passing through locks with limited capacity in areas with busy water transportation in plain river networks,this paper is based on Yuxi double-line ship lock project to carry out a model study on the operating conditions for navigable open-gate mode.A two-dimensional hydrodynamic numerical model is used to research the influence law of key influencing factors,such as the difference in water level,the operation mode of ship locks,and the operation mode of the regulation lock on the water flow conditions for navigable open-gate mode.The test results show that the control node for water flow conditions during open-gate operation is located at the upper gate head.The reasonable operating water level difference for the navigable open-gate mode of the Yuxi Hub double-line ship lock should not exceed 20 cm.The formation time of the open-gate operational conditions is related to the operation mode of the ship lock.The larger the scale of the ship lock and the more lines it has,the shorter the creation time,which generally takes about 30 min.Under the premise of a certain water level difference,the combined operation mode of using multi-line locks and control gates can effectively improve the water flow conditions during open-gate operation and reduce the water flow velocity in the lock by more than 50%.The research results can be used as a reference for similar ship lock projects that plan to use the method of navigable open-gate mode to improve throughput capacity.

Abstract:In response to the problem of the influence of construction wide joints on the internal force of the integral lock chamber bottom plate,the bending moment calculation analysis and research of the bottom plate are carried out under different wide joint positions,different filling heights before sealing,and different foundation conditions.Using the finite element method,taking maintenance conditions as an example,the situation with wide joints is compared with no wide joint.The results show that when the distance between the wide joint and the side wall L is 3-17 m,the negative bending moment at the mid span decreases by 26%-39%.When the filling height before sealing is 3-9 m,the negative bending moment at the mid span decreases by 18% to 40%.For soil or composite foundations,when the elastic modulus is taken as 20-100 MPa,the negative bending moment at the mid span decreases by 29%-33%.For pile foundations,when the elastic modulus of the soil is set to 20-40 MPa,the negative bending moment at the mid span decreases by 41% to 45%.For rock foundations,the negative bending moment at the mid span remains unchanged.Under soil foundation,composite foundation,or pile foundation conditions,the wide joints should be symmetrically arranged at L ranging from 0.1-0.2 times the width of the lock chamber,where the bending moment and stress are minimized.Under rock foundation conditions,construction joints can be used instead of construction wide joints.

Abstract:Regarding the changes in the navigation conditions of the Xiongcheng (Xiongjiazhou-Chenglingji) river section of middle reaches of the Yangtze River over the next decade following the implementation of the waterway regulation project,this study adopts the research method of movable-bed model experiments to establish a physical model of the Xiongcheng river section.By reproducing the natural water and sediment conditions of the river section from February 2022 to March 2023,the rationality of the model design,sediment selection,and various scales is verified.Model tests are conducted in typical and series years to analyze changes in riverbed scour and deposition,as well as the evolution of shoal-channel patterns in the Xiongcheng river section after the implementation of the waterway regulation project.The results show that after implementation of the remediation plan,the riverbed of the river section has been eroded,the pattern of the beach and channel has not changed much,and the navigation conditions have significantly improved,which can achieve the remediation goals.Local erosion pits have appeared at the head of the stone throwing prism in the straight transition section on the west side of Baxingzhou,and there has been a certain degree of siltation in some areas of the Qigongling bend section at the end of each year,with the largest at the end of 4 years,which requires maintenance and dredging to ensure smooth flow.It is recommended to strengthen the observation of the Qigongling and Qixingzhou bends after the implementation of the project.If there are adverse changes or navigation problems,timely maintenance measures should be taken to ensure smooth navigation.

Abstract:The Minjiang River is the largest river in Fujian Province,playing a pivotal role in regional economic development,flood control safety,shipping transportation,and ecological environment.Since 1998,under the dual influence of human activities and natural factors,the riverbed of the South Port has been comprehensively deepened,water levels have dropped,water flow has become unobstructed,and the diversion volume has increased sharply.While the estuary of the North Port has been silted up,with overall slight siltation,the water flow is in a state of blocked upstream and hindered downstream,and the diversion volume has decreased sharply.The pattern change of the diversion ratio between the North and South Ports,as well as the drastic changes in riverbed deepening and flow pattern,have posed severe threats to the shipping safety of ships in the North and South Ports,bridge safety,flood control,drinking water quality in Fuzhou,ecological environment,and urban landscape.This paper comprehensively uses historical data and measured data in recent years to fully analyze the laws of river regime changes and existing problems in the North and South Ports,and proposes targeted governance schemes such as dredging the large shallow ridges at the estuary of the North Port and dredging the main channel of the North Port with a length of about 5 km,and adjusting the single-hole two-way navigation of the Xia'nan bridge group in the South Port to a double-hole one-way navigation scheme.At the same time,a mathematical model is applied to preliminarily predict that the diversion volume of the North Port will be increased from the current 20% to 28%,and a ship model is used to verify the shipping safety of the new route scheme in the bridge group area of the South Port,providing reference for the comprehensive development and governance of the North and South Ports in the lower reaches of the Minjiang River.

Abstract:As the endpoint of the Hangzhou section of the second channel of the Beijing-Hangzhou Grand Canal,the Babao ship lock is a thousand ton level ship lock built simultaneously on both tracks in strong tidal bore river sections in China,which plays an important role in both navigation and tide blocking.The water flow conditions in the Qiantang River tidal bore section where the ship lock is located are complex,and the tidal bore load has a significant impact on the operation of the gate.Therefore,it is crucial to choose a reasonable gate type of ship lock.A comprehensive and systematic comparative study is conducted on various common gate types (such as herringbone gate,flat steel gate,triangular gate,etc) from multiple dimensions,including navigation smoothness,tide blocking reliability,and structural stability,on the basis of the actual operating conditions of Babao ship lock.The results show that the combination design of herringbone gates and flat steel gates has outstanding advantages in navigation smoothness and tide blocking reliability,and can better adapt to the navigation and tide blocking needs of the Babao ship lock in strong tidal environments,providing technical guarantees for the safe operation of the Babao ship lock.

Abstract:The large span truss gate structure is complex.Design calculation cannot be absolutely solved by graphic design method.Based on the working conditions and structural requirements of the gate,a structural form of panel and solid web thin frame and truss beam system combination structure is proposed.Both forward and reverse directions adopt simply supported wheels.To facilitate the installation and disassembly,the simply supported wheels are installed on the wing edges of the side columns.In response to the high risk of overturning of the locking beam and the difficulty of locking in place detection,the locking device adopts a rotating push-pull locking beam with an electric push rod operation.The article analyses gate structure layout,main beam,supporting structure,gate lock device,then arrangement of the large span truss gate structure is generally completed.The static analysis of the truss gate is conducted using the finite element method to identify the weak points of the structure and propose improvement measures.The strength and displacement of the improved gate structure can satisfy design specification in the operating mode of water retaining and gate lifting.The research results can provide references for the design of large-span truss gates.

Abstract:To address the issue of cross currents intruding into the main navigation channel at the Feifengjiao waterway downstream of the Datengxia ship lock under low discharge conditions (700-2,000 m3/s),which poses risks to vessel navigation safety,this study investigates the hydrodynamic causes of cross currents and develops targeted remediation methods.By integrating geological surveys,numerical model simulations,and engineering quantity calculation using cross-sectional area method,an optimized phased remediation scheme is proposed through multi-scheme comparative analysis,tailored to local topographic and hydrological characteristics.The results indicate that the cross currents primarily originate from three factors:significant narrowing of the dam's discharge channel (21 m contour width reduced by approximately 50%),elevated riverbed morphology,and flow concentration under low discharges.Short-term measures,including optimized channel alignment design,excision of the S-shaped shoal bend,and expansion of the flow cross-section,effectively reduced cross-current intensity (lateral velocity decreased by 18.5%-29.2%) and water surface gradient (70%-84% reduction),substantially improving navigability.The long-term scheme reserves expansion capacity to triple the current width of the channel throat,balancing cost efficiency with adaptive flexibility while allowing dynamic adjustments for future hydrological uncertainties.The findings demonstrate that the phased remediation strategy successfully alleviates critical bottleneck constraints,validates the efficacy of the “short-term mitigation + long-term resolution” framework,and offers actionable insights for managing similar navigation challenges downstream of hydraulic hubs in mountainous river systems.

Abstract:The layout of the water conveyance system is the core and soul of ship lock design.It is necessary to conduct a comprehensive comparative study of similar water conveyance systems to select a more reasonable layout,ensuring efficient and safe passage of vessels and reducing congestion.This paper comprehensively considers factors such as water conveyance efficiency of ship lock,berthing stability conditions,throughput capacity,plan layout,construction difficulty,project investment,structural durability,and the impact on working gate vibrations.By employing technical methods such as three-dimensional mathematical model analysis and physical model testing,it separately investigates the fully dispersed water conveyance system with side branch holes in the long corridor of the lock wall and the combined water conveyance system within similar water conveyance systems.The research results indicate that both systems meet the expected design goals and requirements in terms of various indicators and berthing stability conditions.The combined water conveyance system has a slightly longer water conveyance time,and it is recommended to adopt the fully dispersed water conveyance system with side branch holes in the long corridor of the lock wall.This water conveyance system can further enhance the water conveyance efficiency of ship lock,improve throughput capacity,and ensure the safe and efficient operation of the ship lock.

Abstract:Shenzhen-Zhongshan Channel is located in the core area of the middle reaches of the Pearl River.The Pearl River Estuary it crosses is one of the busiest waterways water areas with the largest ship density in China.The bridge section of the channel,with a total length of approximately 17 km,adopts a long-span design to cross several important navigational channels including the Lingding Channel,Longxue South Channel,and Hengmen East Channel.After the project is completed,it will become a permanent cross-sea structure,changing the original navigational environment of the bridge area waters.It is necessary to give full play to the navigation aids in the bridge area to ensure the navigation safety of bridges and ships.At present,the current domestic and international standards mainly impose principled requirements for bridge navigation aids,which are evidently lacking in practical guidance for the complex navigational environment and numerous design and installation constraints of large-scale cross-sea bridges.This paper takes the design scheme of the navigation aids in the bridge area of the Shenzhen-Zhongshan Channel as an example.Focusing on the different navigational needs of the main bridge section and the non-navigable bridge sections of large-scale cross-sea bridges,it analyzes the main factors affecting the design of navigation aids in the bridge area,and proposes the main issues and corresponding solutions in the design process of navigation aids for large-scale cross-sea bridges.The navigation efficiency is maximized through the effective connection between bridge navigation aids and water navigation aids.At the same time,it provides reference and guidance for the revision of industry standards and the design of navigation aids for other large-scale cross-sea bridges.

Abstract:In view of the problem of the challenges of excessive internal-external temperature differences,and significant cracking risks in flow-surface concrete of navigation-power hub projects during phased diversion construction caused by low-temperature river water cooling shock,an equivalent heat conduction model incorporating the negative heat source effect of cooling pipes is developed by integrating field monitoring data with three-dimensional finite element simulations.Adiabatic temperature rise inversion is employed to analyze temperature and stress fields under different temperature control strategies.An innovative multi-measure collaborative approach is proposed,combining mid-term cooling (target temperature:25 ℃),surface flow curing,and controlled pouring temperature (≤22 ℃),while quantifying the critical cooling rate threshold for crack prevention through sensitivity analysis.The results show that by normal temperature control measure,the internal along-river stress reaches 1.82 MPa (safety factor:1.27) and surface stress 1.46 MPa (safety factor:1.10),both violating anti-cracking specifications.Mid-term cooling combined with flow curing reduced surface stress to 0.46 MPa(safety factor:3.49).Introducing pouring temperature control further lowers the peak concrete temperature from 44.2 ℃ to 40.4 ℃,decreases internal stress to 1.45 MPa (safety factor:1.60),and increases the surface safety factor to 3.91.Sensitivity analysis reveals a critical cooling rate threshold of 1.0 ℃/d,exceeding this threshold caused the safetyfactor to plummet from 1.86 to 1.20.This paper establishes a systematic framework integrating thermodynamic parameter inversion,multi-field simulation,and multi-measure optimization,providing quantifiable design criteria for crack prevention in navigation-power hub projects.The proposed strategy enhances crack resistance significantly and improves structural durability.

Abstract:Breccia has the characteristics of softening when exposed to water,which has a great impact on the bearing capacity of cast-in-place piles.Based on the static load test results of self-balanced method of two composite piles of steel pipe pile and cast-in-place pile in Phase I project of Yantian Port East,the bearing characteristics of composite pile of steel pipe pile and cast-in-place pile in breccia geology are studied.The results show that:1) The compressive shaft friction of cast-in-place pile in the strong weathered breccia and middle weathered breccia are not less than 150.06 and 248.67 kPa,respectively,and the pile-end resistance in middle weathered breccia is not less than 2,578.86 kPa.2) The pull-out resistance reduction coefficients of the strong weathered breccia and the middle weathered breccia are about 0.85 and 0.94,respectively.3) After the pile-soil relative displacement in the middle weathered breccia is greater than 0.50 mm,the growth rate of the shaft friction tend to stabilize,and the shaft friction of the pile is not fully activated before the pile-soil relative displacement is less than 3.68 mm.4) The theoretical calculation values of the vertical compressive ultimate bearing capacity of the test pile S1#?and S2#?are not less than 28,108.58 and 29,768.71 kN,with safety coefficients of not less than 1.34 and 1.42,respectively.The relevant results can provide reference for the pile length design of similar geological port terminals and other project.

Abstract:The spatial resolution of structural vibration modes directly affects the accuracy of damage identification results based on these modes.Digital image correlation (DIC),with its non-contact,full-field measurement capabilities within the field of view,offers a high-density measurement approach.However,limited by the camera's field of view,the DIC method cannot directly perform complete testing on large,slender structures such as pile foundations.To address this challenge,a 3D-DIC stitching measurement-based method for pile foundation vibration mode testing is proposed.The method involves segmented testing to obtain full-field vibration responses of different regions of the pile foundation,uses image feature matching to derive spatial transformation matrices for each region,and achieves the stitching and fusion of full-field modal vibration modes with high spatial resolution.Combined with dynamic fingerprint indicators,the method enables the identification of local damage in pile foundations,and the physical model experiments based on the 3D-DIC stitching measurement method are carried out.The results demonstrate that the vibration modes identified by this approach closely align with finite element simulation results,and provide richer structural detail information compared to traditional acceleration sensor testing.