Abstract:Regarding the problem of how to formulate a reasonable development path and development strategy under the background of port enterprise transformation and upgrading，this paper studies the development direction of coastal port enterprises in China in terms of transformation and upgrading during the 14th Five-Year Plan period.After analyzing the current development stage of coastal port enterprises，the paper adopts the trend analysis method and empirical reference method and proposes that the key direction of the transformation and upgrading of coastal port enterprises during the 14th Five-Year Plan period should mainly focus on strengthening the main business of ports，diversifying business，and developing port supply chain services.In addition，it is necessary to formulate appropriate specific measures based on the direction considered promising by large，small，and medium-sized port enterprises and their self-conditions.The conclusion provides a reference for the transformation and upgrading of port enterprises during the 14th Five-Year Plan period.

Abstract:Scientific prediction of the latest policy opportunities，demand characteristics，and port construction priorities faced by ports in the Yangtze River Delta is of great significance for the mid-term adjustment of the 14th Five Year Plan waterway transportation plan and the optimization of regional port and port construction priorities.This article focuses on analyzing the key policy opportunities related to the construction of ports in the Yangtze River Delta region，scientifically predicting the development trend and structural characteristics of cargo transportation demand in regional ports，and proposing the key points for port terminal construction in the Yangtze River Delta region.In the next three years，the key construction path for regional ports is to promote the upgrading and renovation of small and medium-sized ports and old ports，plan ahead with the construction of storage and transportation facilities behind the ports，advance the improvement of container port facilities and the subsequent development of shoreline resources，and orderly promote the construction of specialized ports for major equipment，commercial vehicles，etc.The relevant conclusions will have reference value for adjusting port planning in the Yangtze River Delta region and promoting the integrated development of regional ports.

Abstract:In order to explore the evolution law of port economic hinterland under integrated development of regional ports，this paper studies Dalian Port and Yingkou Port before and after port resource integration and uses the improved hinterland plume model to calculate the scope of port hinterland in 2018 and 2020.Then，the paper draws the spatial distribution of simple and mixed hinterlands of each port by Arcgis software and analyzes the integrated development strategy for ports according to the evolution characteristics of port hinterland scope.The research results show that after port integration，the gap in the comprehensive influence between ports becomes smaller.The gap in the hinterland scope between Dalian Port and Yingkou Port decreases，and the scope of the mixed hinterland expands.Under the background of integrated development of ports，each port focuses on balancing and coordinating hinterland scope during development，so as to avoid homogeneous competition and realize reasonable division of labor.

Abstract:It is difficult to implement the traditional pile foundation permeable breakwater in frozen areas.In order to meet the requirements of coordinated development of engineering construction and ecological environment，this paper proposes a kind of permeable breakwater of the inclined baffle for frozen areas and studies the wave absorbing effect and mechanical performance of the permeable breakwater under the action of irregular waves by physical model test.The results show that when there is a strong crossing wave，the transmission wave height consists of crossing waves and permeable waves，and the transmission coefficient decreases with the increase in water level.The model test proves that the permeable breakwater of the inclined baffle has an excellent wave absorbing effect，and the force of the baffle structure is uniform.

Abstract:In view of the relationship between the wave propagation law and the channel，this paper studies the influence of wave incident angle and grid side length of channels on wave propagation law based on the wave numerical model.The results show that after channel dredging，when the wave incident angle is 15°，the maximum change rate of wave height between the wave-facing side and the back side of the channel can reach 6.6%，and when the minimum grid side length of the channel is 0.12 relative to the width of the channel slope，the channel slope can be simulated accurately，and numerical simulation is quick.

Abstract:Long-period wave oscillation leads to extremely terrible wave conditions in the harbor，which seriously jeopardizes the normal docking and operation of ships in the port.The oscillations and amplifications of long-period waves in a harbor are studied by physical model tests.The results show that long-period oscillations obviously occur in the harbor basin under short waves，and the long-period wave height reaches to 0.4 m under 5.47 m incident wave height.Wave energy in the port is amplified in the port at the wave period nearly equivalent to 633，320 and 200 s. Through the comparison of wave energy inside and outside the harbor,it is found that the wave energy outside the harbor at a frequency below 0.008 Hz is far less than the wave inside the harbor, and the long-wave energy inside the harbor area near 320 s and 200 s is amplified by 5 times.The results can be beneficial for the prevention of long-period waves in similar projects.

Abstract:The difficulty of pollution management in navigable waters restricts the green development of water transport traffic，and sediment is an important factor affecting the phosphorus load of navigable waters.This paper analyses the isothermal phosphorus adsorption characteristics of channel sediment through sediment adsorption indoor tests and field tests，proposes acidic activation and calcareous activation methods，compares the phosphorus adsorption characteristics and differential kinetic processes of activated sediment，and demonstrates and explores the applicability of the activated phosphorus removal method for polluted sediment.The results show that the particle size and content of the channel sediment are important factors affecting the equilibrium phosphorus adsorption，and that reducing the particle size or content of the sediment can increase the equilibrium phosphorus adsorption up to 0.944 mg/g.The isothermal adsorption and kinetic adsorption analysis show that the phosphorus adsorption by acidic activated sediment is mainly physical adsorption，while the phosphorus adsorption by calcareous activated sediment is mainly chemical adsorption.The maximum phosphorus saturation adsorption by calcareous activated sediment is up to 16.5 mg/g.The maximum phosphorus saturation adsorption capacity can reach 16.50 mg/g，which is 8.1 and 17.5 times higher than that of acid-activated sediment and natural sediment respectively under the same sediment content.Sediment activation can enhance the performance of natural sediment in phosphorus adsorption，which can provide basic research support for water quality improvement and pollution control in navigable waters as a potential method for phosphorus removal in water bodies.

Abstract:There are many important liquefied natural gas (LNG) ports planned in the waters of Zhoushan Islands，which play a key role in ensuring the natural gas supply in the Yangtze River Delta.The LNG terminals have the characteristics of high self-construction requirements and strong external exclusivity，and it is technically difficult to construct such terminals in the open island and reef waters represented by the Zhoushan Islands.Taking Zhoushan Liuheng and Yangshan LNG terminals as examples，this paper systematically analyzes the influence of open island and reef waters on the planning and layout of LNG terminals，discusses key issues in terminal and channel layout，and demonstrates the safety spacing of joint layout of multiple large LNG berths.Considering the influence of ship navigation safety and navigation efficiency in LNG terminals，this paper proposes the LNG terminal planning and layout scheme.The results show that when multiple large LNG berths are arranged in an open water environment，the safety spacing should be appropriately increased compared with when the cover conditions are better，and attention should be paid to the influence of crosswind and inclined top flow to ensure the safety of ship navigation.It is also necessary to control the reasonable scale of LNG transportation，adopt optimal navigation measures，and improve ship navigation efficiency.

Abstract:Regaring the problems of incomplete scope，updated version and limited application of ship type in the calculation of ship flow force，this paper selects four current mainstream industry specifications of China，the United Kingdom，the United States and OCIMF（Oil Companies International Marine Forum）for analysis and research，and takes the general cargo ship of 20，000 tons as a case for comparative analysis.The results show that there are great differences in the calculation principle，expression form and calculation results of industrial standards in different countries.The American standard has relatively comprehensive and reasonable considerations，while the British standard has certain advantages in ease of use.The distribution of transverse and longitudinal component curves is different.It is suggested that the above calculation method should be reasonably selected according to the applicable ship type，the degree of information of ship data，the mainstream direction angle and the management requirements.The numerical simulation method should be adopted when possible.

Abstract:To study the back analysis of the adverse inducement of wharf structure damage，we carry out a test on the physical model of the inland river overhead vertical wharf，and analyze the strain law of the wharf under two kinds of damage inducement，namely overloading and irregular berthing.Combining with the back analysis of the damage inducement of the overhead vertical wharf in the Three Gorges reservoir area，we put forward a back analysis model of the damage inducement based on random forest，and evaluate the model by the tests data of the physical model.The results show that the distribution law of axial strain of foundation pile near the river and near the shore are obtained by physical model test，and the axial strain characteristics near the river are more obvious than those near the shore，so it is more suitable for back analysis input source.The random forest back analysis model can accurately predict the type，position and intensity of the horizontal and vertical actions of the physical model.The accuracy of the damage type reaches 0.98，and the accuracy of the damage location reaches 0.99，moreover the accuracy of damage intensity reaches 0.99.

Abstract:This study takes the container yard with twin automated yard cranes as the research object.A multi-agent-based simulation model of yard operation is established to study the efficiency and energy consumption of yard with relay mode.The model simulates the complex operation process of twin yard cranes under the uncertainty of arrival time of automatic guided vehicles and external trucks，and realizes the quantitative calculation of power and energy consumption of yard machinery.Through the quantitative analysis of the indexes of efficiency and energy consumption，the influence of the handshake area location on the yard efficiency and machinery energy consumption for different working conditions is explored.The results show that the yard operation simulation model can effectively simulate the operation process and interaction behavior of yard equipment，and obtain the index values of efficiency and energy consumption for different working conditions.In addition，the handshake area location corresponding to the maximum efficiency and minimum energy consumption are different，and the handshake area should be reasonably designed according to the specific working conditions to achieve the dual goals of efficiency and energy consumption.

Abstract:The conventional vertical revetment faces a serious reflection of the front wall subject to wave action under the topographic restrictions，and the vertical caisson structure is uneconomical due to a large amount of reinforcement and concrete used in the front wall.In order to solve these problems，this paper carries out experimental research on different structures with openings under the wave action and calculates the bending moment distribution of the front wall.The paper uses the physical wave model experiment and finite element numerical simulation analysis to obtain the distribution of wave pressure and internal force of the front wall of the structure.The results show that the new porous structure can effectively reduce the wave pressure and avoid serious wave reflection superposition.At the same time，the front wall is only subject to part of the wave force，resulting in small internal force and deformation，and this trend is positively related to the increase in openings within a certain range.The reinforcement of the front wall component of the porous structure can be optimized to achieve economic results.

Abstract:In view of inconsistent volume design ideas and various volume design schemes of sumps in liquefied natural gas (LNG) terminals，this paper studies the leakage through holes and evaporation diffusion of LNG terminals and adopts numerical calculation method to establish the calculation model of leakage and evaporation amounts.The paper also carries out calculations according to the actual engineering data and compares the calculation results.The results show that if the leakage duration is less than 5 min，the relationship between the leakage amount and the leakage aperture is not obvious；if the leakage aperture is less than 25 mm，the relationship between the leakage amount and the leakage duration is not obvious.In addition，the difference between the leakage point pressure and the flow velocity in the pipe has no significant influence on the leakage amount.Evaporation duration greatly affects LNG evaporation amount，but the ambient temperature has no significant effect on LNG evaporation amount.The leakage amount at the terminal is much larger than the evaporation amount，so the influence of the evaporation amount can be ignored in the volume design of the sump.This paper obtains reasonable and reliable LNG collection amount by calculating the leakage amount of the terminal according to the leakage duration of 10 min and the leakage aperture of 50 mm.

Abstract:In view of the problems such as incomplete reference standards，version updates，and limited ship type applications in ship wind load calculation，this paper selects four current mainstream industry standards of China，the United Kingdom，the United States，and OCIMF for analysis and takes a 20，000-ton general cargo ship as a case for comparison.The results show that the calculation results are quite different.For the lateral component force，the results by standards of the United Kingdom and the United States are close，and that by the standard of China is obviously larger.For the longitudinal component，the results by the standard of the United Kingdom are significantly greater than those by the standard of the United States in the case of stern wind，and the results by standards of China and the United Kingdom are close in the case of bow wind，and both are smaller than those by the standard of the United States.The paper suggests that the calculation methods should be reasonably selected according to factors such as the applicable ship type，the fullness of ship data，the main wind angle，and management requirements，and the numerical simulation method should be used when conditions permit.

Abstract:As new technologies，especially detection and identification technologies，develop and become mature，yard interaction zone configuration in automated container terminals needs to be comprehensively updated.In view of this，this paper proposes optimization and upgrading schemes of detection,monitoring，identification，and other related system configuration according to the development of the detection and identification system as well as the interaction zone process.The paper adopts a three-dimensional (3D) software camera to simulate monitored images，uses a point cloud calculation method to simulate positioning data，and employs the image recognition method to identify the simulated image，which thus demonstrates the feasibility of the scheme.The configuration optimization and upgrading scheme of the yard interaction zone in automated container terminals can be applied to the actual interaction zone upgrading.Finally suggestion for further upgrades is put forward.The configuration of the interaction zone can be more upgraded and supports more function after the corresponding technology is mature.

Abstract:This paper introduces the design method of the port plane layout in the Russian port design code，namely Standards for the design of sea channels，fairways and maneuvering areas and analyzes the design differences between the Russian code and the Chinese code，namely Design Code of General Layout for Sea Ports through the case calculation.There are similarities between the two codes in terms of port plane layout，while differences in the basin width，berthing water width，and channel width remain，which is of guiding significance for similar practical engineering applications.

Abstract:In view of the characteristics of river-sea-rail container terminal with multi-shoreline and large depth，combined with the outstanding characteristics and advanced experience of the existing automated container terminals，we put forward a multi-modal automated container terminal handling process scheme，and expound the handling process scheme in detail.The overall layout of the scheme adopts the double U-shaped vertical layout + side handling mode，which realizes the seamless connection of river-sea-rail transport with multi-shoreline berths，and has the advantages of simple traffic organization and high traffic turnover efficiency.It effectively solves the problem that the typical handling system can not adapt the automated container terminal engineering well.

Abstract:There is lack of systematic studies to the minimum water depth on sill needed by vessels passing through locks in China.By analyzing existing studies results，the minimum water depth on sill needed by vessels passing through locks shall be composed of draft of the vessel and additional water depth.The additional water depth is composed of squat of the vessel and the minimum clearance.Main factors influencing the squat of vessels passing through locks are blockage coefficient，speed of vessel and water depth.From application conditions of existing studies，formulas to estimate the squat through locks and limit speed of vessels are presented.The minimum clearance is used to compensate biases of the squat estimation and to take fluctuations of translatory waves into account.The main source of translatory waves is the unsteady flow from the operation of hub.In normal case the minimum clearance could be 30cm.When the influence of translatory waves will be significant on the water depth on sill，a special study shall be needed.

Abstract:How to reduce the scour pit depth is an important issue in bridge design and maintenance.To further explore the influence of the installation position of the lattice promoting sedimentation on the sedimentation and restoration effect of local scour pits around piles and piers，this paper investigates the change characteristics of sedimentation and restoration efficiency with the installation position and aperture size of the lattice promoting sedimentation by flume test.The results show that the sedimentation and restoration efficiency is less affected by the intensity of incoming flow and more affected by the relative installation position of the lattice.To improve the stability and sedimentation and restoration effect of the lattice promoting sedimentation，it is necessary to install the lattice promoting sedimentation as high as possible below the trough of the sand wave，so as to obtain the maximum sedimentation capacity and increase the sedimentation depth.The effect of the installation position of the lattice on the sedimentation and restoration effect of scour pits is significant with the decreasing aperture size of the lattice.Finally，this paper proposes a formula for calculating the final sedimentation depth under the protection of the lattice promoting sedimentation，which can provide a reference for the future engineering application of the lattice promoting sedimentation.

Abstract:The right-branch entrance section of Baguazhou implements the full-section concrete soft mattress project.However，Baguazhou right branch is the main branch，with deep water，rapid currents，and complicated terrain changes，so the full-section layout construction in the riverbed is difficult.In order to illustrate the application effect of the soft mattress in the project，this paper uses the multi-beam bathymetry system to collect underwater topographic data in the project area many times and detects the quality of the soft mattress layout through the multi-beam effect map.Furthermore，the paper uses geographic information system (GIS) spatial analysis technology to quantitatively analyze the riverbed changes in the project area in different periods，so as to better grasp the effect of project remediation and operation.The results show that after the completion of the project，the riverbed of the project has changed from scouring to silting，and the maximum siltation range can reach 7.87 m.The project prevents the further expansion of the entrance section.After the severe flood in 2020，the overall siltation volume and siltation area of the project riverbed continue to increase，with the siltation area ratio increasing from 66.6% to 83.9% and the siltation volume increasing from 414，000 m3 to 545，000 m3.The full-section soft mattress project is running stably and has played a role in engineering protection.

Abstract:In view of the impact of the implementation of the Hengsha east siltation and reclamation Phase 8 project on the nearby waters，the river regime analysis method is used to quantitatively analyze the changes of water，sediment and topographic erosion and deposition during 2017-2021 after the implementation of the project.The results show as follows：1) In the flood season，the diversion ratio of ebb tide in the North Passage is between 52.4% and 55.9%，and there is no overall trend change.2) North Passage，the lower section of North Channel and Hengsha Shoal continue the erosion and deposition trend since 2010.3) The thalweg of the lower section of North Channel is southward and smoother.4) Hengsha channel volume remains stable.In addition，the head of the N23 submerged breakwater and the northern edge of the Hengsha shoal near the submerged breakwater are scoured obviously，which requires continued attention.

Abstract:The navigation characteristics of ships in intermediate channels are closely related to the navigation efficiency of navigable buildings and the safety of ship navigation.A scale test of tugboat model is used to study the navigation characteristics of the ship in the middle channel of the navigable building of the Goupitan Hydropower Station，and the sinking amount characteristics of the ship under different sailing speeds are analyzed.The relationship between the maximum sinking amount of the ship in the intermediate channel and the sailing speed，underwater area of channel，area below the water surface of midship section of ship and initial water depth is established，and a dimensionless formula that can accurately predict the maximum sinking amount of the ship is established.The research results show that：1) Under the same speed，the sinking amount of the ship out of the cabin is much larger than that of the entering cabin，and the ships exit process is the control condition of the ships sinking amount.2) When the section coefficient of the intermediate channel is less than 3.0，the change in section coefficient has a more significant impact on the sinking amount of ships ，and the smaller the section coefficient，the more significant the impact on the sinking volume of ships；when the section coefficient of the intermediate channel is greater than 4.0，the influence of the increase of the section coefficient on the sinking volume of the ship decreases rapidly.

Abstract:The existing research on the scale of the Yangtze River waterway focuses on the minimum maintenance scale of the waterway under low water conditions，and lacks corresponding research on the scale of the waterway during medium flood periods.This article is based on the characteristics of water level and terrain changes since the use of the 175 m water storage in the Three Gorges Dam.It proposes to use the lowest water level from the 175 m experimental water storage in the Three Gorges Dam to the end of 2021 as a verification method for overlaying the available water level with the most unfavorable terrain during the recent mid flood period.Key waterways are screened and combined with actual measurement scales to explore the potential for channel scale improvement.The results indicate that the verification method has good adaptability to the potential analysis of channel scale during medium flood periods.On the basis of low water maintenance，the Wuhan to Anqing section of the lower reaches of the Yangtze River has the potential to use natural water levels to enhance channel maintenance scale during medium flood periods.

Abstract:The existing navigation facilities generally refer to the ship lock and ship lift.The ship lock has high traffic efficiency，but it consumes more water.The ship lift does not consume water，but it has low traffic efficiency and complex structure.Therefore，in view of some limitations of the existing navigation facilities，this paper proposes a new type of hydraulic lift，which can save water and energy to the maximum extent and has good traffic efficiency when applied to navigation facilities.This navigation facility uses the lift in the shaft (mother ship) to carry the navigation ship (sub ship) to achieve lifting.The sub ship is in the pool on the deck of the mother ship.When the water level in the pool is flush with the upstream and downstream water levels，the vessels in the pool will then enter and exchange with upstream and downstream vessels，so as to achieve the purpose of navigation of upstream and downstream vessels.The navigation facility can have the functions of ship lock and ship lift，and has good universality and applicability.

Abstract:Navigable tunnel is a typical narrow channel with shallow water depth.When a ship sails in such channels，the asymmetric water areas on both sides of the ship，as well as the reflection superposition of the traveling wave and shockwave caused by the filling and emptying system，will cause asymmetrical lateral forces on the hull and increase the difficulty of controlling the hull.In order to solve the wave effect when the ship sails in the tunnel，this paper proposes a wave absorber with columns and transverse plates and adopts a physical model to carry out ship model tests，so as to analyze the energy-absorbing effect of the absorber.It has been verified that the absorber can reduce the wave amplitude effectively.

Abstract:The expanding scale of sand mining in rivers has affected the stability of riverbed structure and its evolution process.In this study，based on the measured topographic data of Jiangjin to Fuling river section from 2007 to 2019，the distribution of sand mining pits in the fluctuating backwater area of the Three Gorges Reservoir is investigated，and the recovery process of sand mining pits in the key river section is analyzed.The results show that the sand mining volume in the fluctuating backwater area is about 163 million m3 from 2007 to 2019，the intense sand mining activities are mainly concentrated from 2007 to 2016 in the Jiangjin to Changshou river section，and the sand mining pits are mainly distributed in the river side beaches.With the implementation of the upstream mining ban measures in 2016，the sand mining activities at the end of the Three Gorges reservoir are significantly declined，while the further reduction of the sand inflow from the Three Gorges has caused the tiny change of the river topography in the end of the reservoir，and the sand mining pits could not be return to their original form according to the present sediment supply level.

Abstract:In view of the influence of the gate opening mode on the flow characteristics and navigation flow conditions of the downstream approach channel entrance area of the junction，taking the second ship lock of Jinweizhou junction in the Xiangjiang River as an example，we build a two-dimensional flow mathematical model that can better simulate the complex river boundary conditions.On the basis of fully understanding the flow conditions of the downstream approach channel entrance area under the conventional design discharge and sluice opening mode，we carry out a combination test study of multiple sluice opening and discharge modes.The results show that the flow at the entrance area of the downstream approach channel of the second ship lock is greatly affected by the operation mode of the junction.The rational arrangement of the side hole (22# sluice hole) can increase the energy loss of the reflux flow at the entrance area，thereby reducing the reflux flow at the entrance area，and at the same time，the longitudinal and transverse flows can also meet the code requirements.To ensure the safety of ship navigation，it is suggested that the project should adopt the mode of the conventional gate opening and side hole improving flow as far as possible when discharging flood.

Abstract:This paper discusses the feasibility of applying three new surveying and mapping methods in the prototype observation of the western waterway，namely the Thousand Seekers Knowing Inch Elevation Anomaly Budget Method，the Thousand Seekers GPS Float Method and the Temporary Water Scale Suspension Method，by analyzing the experimental data of the important tributaries of the upper reaches of the Yangtze River in China，including the reservoir tail section of the Jinsha River Xiangjiaba Power Station and the important waterway prototype observation projects in the municipal sections of the Min River Yibin and Meishan.The results show that the elevation anomalies of the whole survey area obtained by the elevation anomaly budget method can replace the traditional RTK point correction measurement level height.Additionally，the GPS float method can replace the traditional total station front rendezvous method to obtain the surface flow velocity and direction，as well as the river core specific drop，while the temporary water scale suspension method can replace the traditional temporary water scale method for hydrological observation.The experimental data prove that the measurement quality of the new surveying and mapping methods reaches or even exceeds that of the traditional surveying and mapping methods.These approaches can meet the quality requirements of the survey specification and design，while also reducing production costs and improving working efficiency compared to traditional methods，achieving twice the result with half the effort.These methods have significant potential for promotion and use.

Abstract:Most of the existing 10 shipping hubs in Lianjiang，such as Jietan，have exceeded their service life，and there are hidden safety hazards in terms of plane layout，main structure，foundation treatment，and construction quality of buildings.Therefore，this paper proposes disposal plans for hidden safety hazards，including hub scrapping and demolition，reconstruction after risk removal，and unified cascade layout adjustment.Through technical and economic comparison，the paper recommends the unified cascade layout adjustment plan.This plan aims to build a comprehensive hub with navigation as the main function，which also considers power generation，irrigation，water supply，flood control，urban landscape，and other functions，so as to comprehensively utilize water resources and maximize benefits，which can provide a reference for the disposal of hidden safety hazards of hubs in similar rivers in the future.

Abstract:Earth-rock cofferdam is a common cofferdam support method，and its stability and impermeability effect have an important impact on the safety of water conservancy projects.Taking the upstream and downstream horizontal earth-rock cofferdam project of Yanzhou Hub phase I in Changde City as the research object，in view of the three aspects of rock mass fragmentation and fragmentation，soft interlayer and landslide in the area，a multi-layer interactive protection construction scheme to cope with this working condition is innovatively designed，and the stability performance of the slope and rock protection of the earth-rock cofferdam is further analyzed and studied.Firstly，the construction difficulties caused by the hydrogeological conditions of the Yanzhou Hub cofferdam project are introduced in detail.Then，the cofferdam structure and impermeability design are studied by theoretical analysis.Finally，the stability of the earth-rock cofferdam is studied by numerical analysis.The engineering construction results show that the design scheme provided in this paper can well meet the requirements of cofferdam deformation control under harsh geological conditions in this area，which can provide reference for the design and construction of similar projects.

Abstract:There are many factors affecting the selection of geotechnical engineering parameters，and the problems involved in hydropower and shipping hub projects are more complex.The indexes obtained by conventional test methods often cannot reflect the real environmental conditions.In this paper，in-situ tests of the direct shear test and load test in Naji shipping hub，Yuliang shipping hub and Laokou shipping hub are carried out in the vertical shaft，foundation pit etc，and original samples are taken from the site for laboratory tests to obtain the basic data of the physical and mechanical parameters of gravel layer.FRWS software is used for back analysis of m values.The results show that the vertical and horizontal subgrade coefficients of cobble layer increase with the increase of cobble layer density.The subgrade coefficients of gravel bed obtained by load test are larger than the empirical values given in the code，but the values are within the reasonable range.The m values obtained by back analysis are smaller than the empirical values of m in the code which belong to the empirical value of pile foundation.So the final results shall be subject to the back analysis results.

Abstract:The second phase cofferdam of Yakou navigation hub adopts a new composite structure featuring river sand filling，slope protection with tube of sand filling，composite geomembrane anti-seepage，geotextile anti-filtration，and polypropylene fabric anti-scouring，and the overtopped condition is easy to induce the instability of cofferdam.Based on the experimental data，this paper analyzes the stability and safety of cofferdam under complex working conditions from the perspectives of seepage，stress and deformation，and stability and compares the stability of geotextile，polypropylene fabric，and tube of sand filling layer.The results show that the effect of an overtopped cofferdam on the slope foot seepage gradient is obvious，and the local resistance to seepage damage can be enhanced after reinforcement.The overtopped condition is the most unfavorable to the stability of the side slope of the foundation pit of the cofferdam，but the overall stability and stress and deformation meet the requirements of the code after reinforcement.The friction between polypropylene fabric and tube of sand filling is small，and there is the possibility of interlayer displacement，but the geotextile between polypropylene fabric and tube of sand filling can effectively improve the stability between layers.After the test of the severe Hanjiang River flood in the autumn of 2021，the cofferdam can run stably and safely under water retaining and overtopped conditions.

Abstract:Under the promotion of the national “One Belt and One Road” initiative，the pretension prestressed high-strength concrete (PHC) pipe pile has been comprehensively applied in various overseas engineering projects. However，there are large differences between the specifications and design theories in foreign areas，which makes the mechanical properties of PHC piles based on Chinese standards are difficultly be adapted by the designers abroad.This paper compares the concrete structures and piles prescribed in the standards of China，America，British，Europe and Japan，especially the axial-bending capacities for PHC piles，which are mostly significant to the design.After comparisons，it is found that the simplified equations given by Chinese standards，at the expenses of some accuracy，can draw smooth curves for axial-bending capacities of PHC piles.However，due to the large differences of the definition of design axial capacities in different foreign standards，it is hard to give integrated and smooth curves.

Abstract:To obtain the response of the supporting structure of the foundation pit nearby water and thus evaluate the safety of the supporting structure，this paper establishes a random finite element model of the foundation pit nearby water by considering the spatial variability of the soil.The paper also transforms the feature units whose parameters conform to the random field distribution in the model into images to construct multi-channel grayscale image data and inputs the data into the constructed convolutional neural network (CNN) for training.In addition，the paper studies the random finite element calculation results of the foundation pit nearby water，predicts the deformation responses of the foundation pit nearby water with different random field parameters，and then obtains the response of the supporting structure of the foundation pit nearby water with statistical significance.The results show that the analysis method of foundation pit nearby water based on deep learning and random field can predict the response probability distribution of the supporting structure accurately.

Abstract:Due to the lack of engineering examples and research on steel pipe piles in marine dense gravelly soil bearing stratum，relying on a port project in Peru，we study the pile driving and bearing characteristics of steel pipe piles in gravelly soil bearing stratum.We carry out the model test in advance in China to obtain the parameters of simulated pile sinking，and conduct the drivability analysis of pile sinking to improve the construction plan work.Then，we carry out the pile sinking test，high strain test and static load tests on the site，and test the side resistance and end resistance at the same time.The results show that the bearing capacity，unit area side resistance and end resistance of open steel pipe pile increase with the increase of soil penetration after entering the dense gravel soil bearing layer，but the increase range gradually decreases.After entering the bearing layer for 1 m，the penetration of the pile will be difficult，and then the unit area end resistance will gradually stabilize.Limit unit area end resistance of gravelly soil is not less than 10.5 MPa.The end resistance of the steel pipe pile is mainly provided by the pile end resistance，the reaction force provided by the soil plug bearing capacity is small，the pile soil plug coefficient is relatively low.

Abstract:In response to the problem of sediment leakage from the outflow field during the operation of the trailing suction dredger，we study the outer sediment flow characteristics of the rake head work process.By the numerical simulation method，we analyze the sediment leakage between the front and rear ends of the external flow field of the rake head，and the sediment concentration distribution in the external flow field under different working conditions，and obtain the effect of vacuum and velocity changes on the sediment distribution in the external flow field.The results show that the sediment leakage in the flow field behind the rake head is more serious in the external flow field.The leakages in the vertical and horizontal directions of the flow field are in the form of turbulent flow and laminar flow respectively.The vacuum degree and sailing speed are positively correlated with the leakage amount of the dredge pump.

Abstract:Different dredged soil will affect the productivity of cutter suction dredgers，especially the silt with high density，large sand，local silty clay mass，mixed sand，and clay particles，which will cause difficult dredging of cutter suction dredgers.Based on the data of slightly dense-dense silt excavated by Tianqi cutter suction dredger，this paper analyzes the productivity and specific cutting energy and establishes the relationship among the characteristic index of typical dredged silt，productivity，and specific cutting energy.The result shows that there is a quadratic polynomial relationship between productivity and silt standard penetration number，and there is an exponential relationship between specific cutting energy and the standard penetration number.The productivity formula obtained is in good agreement with the actual engineering data，which can provide a reference for dredging similar soil.

Abstract:Based on the Euler two-fluid model，the unsteady numerical simulation of solid-liquid two-phase flow of large dredging pump of cutter suction dredger is carried out.Through the analysis of the effects of particle size，particle concentration and particle density on the flow field characteristics of dredging pump including the two-phase streamline and solid particle concentration distribution，it provides guidance for improving the optimal design of dredging pump.The simulation results show that the physical properties of particles have little effect on the streamline distribution of liquid phase，and the driving effect of liquid relative to solid phase decreases with the increase of particle size.With the increase of particle density，the driving effect of liquid relative to solid does not weaken.With the increase of particle concentration，the driving effect of liquid relative to solid phase increases.With the increase of particle size and density，the uneven distribution of particles increases.With the increase of particle concentration，the uniformity of particle concentration distribution strengthened，and the concentration near the blade wall increased significantly.By comparing the particle concentration distribution of the two dredging pumps，the reasonable design of the impeller channel can reduce the agglomeration of particles on the surface of the channel and the abrasion of the dredging pump.