Abstract:To improve the wave attenuation performance of floating breakwaters，an arc-wall-floating breakwater is proposed.Based on the theory of uncompressible fluids and VOF method，a two-dimensional numerical model is established by using the computational fluid mechanics software Star-ccm+，and the accuracy of the numerical model is verified.The numerical model is used to simulate and study the hydrodynamic properties of arc-wall-floating breakwaters under different horizontal widths，relative heights and relative wave heights.The influence of various parameters on the transmission coefficient，reflection coefficient and motion response of the breakwater is concluded，and the structural parameters of the breakwater with the best wave attenuation performance are identified.The results show that the transmission coefficient increases with the increase of the horizontal width，and the transmission coefficient can be stably maintained below 0.6 when the period is less than 1.4 s.The reflection coefficient decreases to a certain extent when the period is 1.6 s or 1.8 s.The motion response increases with the increase of horizontal widths and relative heights.

Abstract:Ocean waves are generally a mixture of wind-wave and swell.Due to the significant differences in their growth，decay，propagation，and destruction mechanisms，the separation of wind-wave and swell is of great significance for marine research and engineering application.Based on the measured data in the offshore of Hambantota，Sri Lanka，this paper discusses the selection of the wave age threshold in the traditional methods and analyzes the wave characteristics of the offshore of Hambantota.Finally，the method based on wave age is used to verify the newly proposed method based on the overshoot phenomenon that does not rely on meteorology information.The results show that the optimal threshold of wave age is 1.7.The offshore of Hambantota is dominated by the swell propagating from distant storms.The method based on the overshoot phenomenon is consistent with the method based on wave age in the identification of the swell propagating from distant storms but gives different results for the wind-wave and local swell at the high frequency，which can be explained by the fact that the change of physical wave characteristics is slower than that of wind.

Abstract:This paper summarizes and compares the existing formulas for the wave force reduction of crest walls on vertical breakwaters and rubble mound breakwaters under oblique wave attacks.The paper takes a new rubble mound breakwater of a port in North Africa as an example and compares the calculation results with the results of two-dimensional and three-dimensional physical model tests.The results show that for rubble mound breakwaters under oblique wave attack of 30 degrees，the unit-length reduction coefficient of wave force calculated by van Gent formula fits best with the measured value，and the unit-length wave force reduction formula of each vertical breakwater is conservative in the calculation of crest wall on rubble mound breakwaters.The longitudinal reduction coefficient of total wave force calculated by Mares-Nasarre formula is in good agreement with the measured value，but the difference in reduction effects between horizontal and uplift forces is not considered，and there is still some deviation from the experimental results.The longitudinal reduction formula of the total wave force of the vertical breakwater proposed by LI Yucheng et al.is not applicable to the calculation of the crest wall on rubble mound breakwaters.The research can provide a reference for similar port projects.

Abstract:The circular underground diaphragm wall supporting structure with three-dimensional arch effect is gradually used in foundation pit projects because of its better resistance to deformation and load-bearing capacity.But it also faces problems such as complex force deformation of the wall，various calculation methods，and uncertainty in the value of circumferential stiffness.In this paper，taking the 65 m diameter circular accident emergency pool ground connection wall support in Lanshan port area as an example，the two-dimensional m-value method and the three-dimensional m-value method were used to model and analyze considering the annular equivalent stiffness respectively，and compared with the actual measured data.The results show that the structures have strong spatial effects，and the lateral deformation and vertical bending moment derived from two-dimensional calculation are relatively large，while three-dimensional calculation can more realistically simulate the excavation process.When the two-dimensional m-value method is used，it is more appropriate to take 0.8 for the circumferential stiffness reduction factor，and 0.5 for the three-dimensional m-value method.When the circular ground link wall support is used，it is more reasonable to use static earth pressure after the wall.

Abstract:Sloping breakwater is a common type of wave protection structure with simple structure，strong adaptability to foundation and mature construction technology，and is widely used in coastal engineering.Conventional sloping breakwater design is usually combined with structural safety，engineering cost and other needs，according to the requirements of the code to select the appropriate wave prevention standards，determine the corresponding wave run-up and wave overtopping discharge，and finally select the appropriate section structure.In addition to the above factors，the design of breakwaters with driving function，especially those projects greatly affected by wind and waves，should take driving safety and landscape requirements into consideration.In this thesis，combined with the use of practical projects and the results of different physical model test schemes，the design scheme of adding a wide platform on the outer side of existing structure is put forward to effectively reduce the amount of wave overtopping discharge.It has been tested in practice and meets the requirements of use.

Abstract:This paper focuses on the project of LEKKI Port in Nigeria.In view of the poor shield and water depth conditions in the sea area where the project is located，obvious coastal flushing and silting，long wave period，high wave，and concentrated wave direction，this paper studies the core issues such as the management and balance of upstream and downstream beaches after the construction of the project and the construction of new container terminals with high requirements for berth stability.The paper uses the methods of numerical simulation and physical model tests to determine the general layout points such as the overall layout ideas of the project，the direction of the entrance channel and breakwater，and the location of the terminal front line.As a consequence，the general layout scheme is presented to be scientific，economic，and reasonable.This paper also proposes and summarizes a new idea and design scheme summary for the overall layout of wharf construction under strong wave surging and flushing conditions，which can be used as a reference for port construction in similar conditions.

Abstract:With the development of liquefied natural gas (LNG)ship types，there is a new demand for small-scale refueling.To effectively promote green and low-carbon development，it is a trend to retrofit the existing large LNG wharf to adapt to the berthing of new small LNG bunker vessels.This article proposes a retrofit method for adding a berthing pile cluster system based on the existing large butterfly-arranged LNG terminal.The space model is used to simulate the structure，analyze its force and system displacement，and verify the influence of large mooring LNG ships on the system.Finally，the article proposes a set of design processes for the structure.The wharf after retrofit can berth and refuel a variety of small LNG refueling ships or carriers，with better adaptability，safety and reliability，superior durability，short retrofit period，and low investment，which has good application value and broad promotion prospects.

Abstract:With the growth of global extreme stormy weather，the damaged breakwaters of built ports have increased year by year.To summarize the research results in the field of breakwater damage mechanism and repair，thirty-four cases of domestic and foreign breakwaters damaged in recent years are collected in this paper.The four main factors that cause damage to sloping breakwater are summarized.Typical cases for each factor are introduced to propose reasonable suggestions for sloping breakwater repair and design.For a sloping breakwater with severe damage to the outer protective structure，it is recommended to use the existing structure as the core and construct a new protective armor structure for repair.For new projects with high wave heights and complex terrain，it is advisable to consider the life-cycle cost，including construction and maintenance expenses，and carefully consider the convenience of maintenance and repair.It is recommended to select a suitable cross-sectional form and artificial blocks with high robustness and ease of repair.

Abstract:Taking an iron ore loading port engineering in the Arctic area of Canada as an example，aiming at the characteristics of the waterborne transport and freight volume limited by the ice condition of the sea area，this paper carries out the preliminary simulation analysis to propose the design vessel combination for different seasons based on the natural conditions and in-situ status，determines the general layout plan for functional zones including ore dock，stockyard，temporary construction dock，freight dock，and oil tank farm suited to local conditions，and orderly connects the functional zones by roads，embankments，and causeways.Besides，the paper analyzes the specifications and direction of different equipment modules based on the characteristics of the finished products of the process equipment in this project transported ashore by self-propelled modular transporters and reasonably plans the transport routes of self-propelled modular transporters as well.

Abstract:Taking the ATI Barge Terminal project in Philippines with pile supported structure in strong seismic area as an example，this paper introduces the design innovations of marine structures such as the prefabricated U-type concrete channel structure，close-piled type wave wall，and triangle brace type single pile steel mooring dolphin，which solve the conflict problem of reinforcing bar at the cast-in-place joints of prefabricated structures.A special wave retaining structure adapted to strong earthquake area and a new steel structure wharf expansion scheme are proposed，which can provide reference for similar engineering design.

Abstract:In view of the shortage of calculation methods for anchor chain design in the existing water transport codes and manuals，this paper performs theoretical derivation and proposes numerical solution methods.By catenary theory derivation，the paper obtains the basic curve equation of the drag form of the anchor chain and lists the supplementary equations for anchor chains not dragging the ground and anchor chains with a settlement in the middle.The results show that this method can be combined with mathematical software to accurately solve the curve equation，anchor angle，anchor distance，anchor tension，and other parameters under various working conditions，such as anchor chain dragging，no dragging，and settlement in the middle.

Abstract:Based on the measured data，the evolution characteristics and activities of deep pools in the Xuliujing reach of the lower reaches of the Yangtze River are analyzed.The results show that before 2003，the lowest point of the main trough was generally within -40 m，and there was no obvious deep pool.After 2003，under the influence of the construction of Sutong Bridge and other projects，deep pools below -40 m appeared.Since then，with the reduction of upstream sand and the implementation of the regulation project of Xuliujing node on both banks，the deep pool has been scoured to about -50 m after 2007 and below -70 m by 2020.Relevant research shows that the impact range of bridge works on hydrodynamic forces and riverbed scouring and silting is generally 5~6 km.In addition，the lower section of Xuliujing River is an extended section with slow flow，and there is no obvious trend of scouring and moving down for deep pools，which will not cause significant impact on the layout of Haitai tunnels downstream.However，considering the development of deep pool flushing，it is necessary to strengthen the monitoring of deep pool changes.

Abstract:Relying on the navigation project of Wujiang River，the hydraulics observation and ship test of the intermediate channel containing the long-distance navigation tunnel are carried out.Wave regulation of time and space of intermediate channel and ship navigation characteristics are revealed.The observation presents the intermediate channel wave propagation speed is about 5.0~6.8 ms.The wave amplitude is inversely proportional to the water width.The water surface at the two ends of the intermediate channel fluctuates the most，second in the navigation tunnel，and the large aqueduct intersection area fluctuates the least.The amplitude of the wave generated in the intermediate channel by the open and close of the chamber gate is within 2 cm，while that caused by ship navigation is basically within 10 cm.The main wave period is between 120 and 160 s.The water surface fluctuation has little impact on the underkeel clearance of the ship navigation.The normal navigation speed of the ship in the intermediate channel reaches the design index，and the maximum sinkage occurs in the continuous acceleration stage of the ship out of the chamber.The measured maximum sinkage of the upward and down is about 25 and 13 cm respectively.The maximum navigation sinkage of the ship in the intermediate channel is basically within 10 cm.The underkeel clearance is rich and the design of the navigable tunnel section is generally reasonable.

Abstract:Taking Shanghai LNG pipeline project，the major crossing project of the Yangtze Estuary，as an example，the paper studies the interaction between the crossing project and the planned regulation buildings in the Yangtze Estuary and the relevant engineering measures.Shanghai LNG pipeline project intersects with the planned Ruifengsha regulation project and the Baozhen beach protection project，the tunnel construction will have a certain impact on each other.To fully consider the above impacts，prepare the corresponding safety protection，and ensure that the implementation of the planned project will not be affected，it is necessary to carry out a special study on the impact of the project on the planned renovation buildings of the North South Port and the measures to solve it.This paper uses the mature η-ζ method to calculate the internal force of the tunnel structure.The results show that the deformation of the LNG pipeline project will exceed the control standard when the planned Ruifengsha regulation project and Baozhen beach protection project implement，and corresponding protective measures should be taken.It also shows that the short-term plan can eliminate the impact of the beach protection project in the planned Baozhen Town on the tunnel line A，but not the impact of the planned Ruifengsha regulation project on the tunnel line B.Therefore，the long-term plan should be implemented simultaneously during the construction of the Ruifengsha regulation project.

Abstract:The Chayuqi shoal section in the upper reaches of the Yangtze River is the rapids and shallow shoal at the outlet of the branch.It is difficult for ships to drive upstream，and maintenance dredging is required every year to maintain unobstructed.According to the characteristics of the rapids at the entrance of the Chayuqi and the shallowness of the transition section，we study the flow characteristics by the plane 2D flow mathematical model，and propose corresponding regulation measures.The results show that the built longitudinal dike of Chayuqi should be removed and the regulation measures to enhance the scour duration of the shallow area can effectively alleviate the navigation obstruction.The characteristics of the rapids disappear after the implementation of the regulation scheme，and the average velocity in the transition section near the multi-year average flow level increases，which is beneficial to reduce the siltation in the shallow area，and the channel scale meets the planning requirements.

Abstract:The Yuan River is a primary tributary of the Ganjiang River.The middle and lower reaches of the Yuan River are meandering，which belong to a transitional river between hills and plains.The average bed slope is 0.2‰，and the flood rise and fall fast.The proposed Longweizhou project is the last step of the Yuan River channel upgrading project.The upstream and downstream reaches of the dam site are continuous bends，and there exists protruding banks deflecting flow and point bars.The complex boundary conditions make it difficult to design the ship-lock.The overall physical model of Longweizhou project is constructed to carry out the tests of navigable water flow conditions of the ship-lock.Under the current boundary conditions，the ship-lock is difficult to achieve safe navigation under the 20-year flood conditions required by the standard.Thus，the study of improvement measures is carried out to determine the operation regulation of lock gates and maximum navigable discharge suitable for ship navigation in combination with the flood characteristics of the Yuan River，which provides the basis for engineering design and management.When constructing high-grade ship-locks on rivers with short flood duration，it is recommended to adopt the maximum navigable discharge for ship-locks management and optimizing the design of the partition wall，berthing dolphin and navigation wall to ensure navigational safety and save investment costs on the basis of satisfying the cargo volume through the ship-lock.

Abstract:In order to further clarify the changing law of the sailing resistance of a ship in a navigable tunnel，this paper proposes a sailing resistance estimation formula for large ships and builds a physical model to carry out ship model tests to verify and analyze the formula.The results show that the measured resistance value and the formula have a high degree of fitting，and the verification effect is great.The change of the cross-sectional area of the tunnel water area has a greater disturbance to the sailing resistance，and the sensitivity of the sailing resistance to the cross-sectional area of the tunnel water area is higher than that to the ship speed.The sailing resistance is proportional to the square of the ship speed and decreases with the increase in the navigable section coefficient.

Abstract:To guarantee the service safety of reversed radial gate in water conveyance gallery of Three Gorges ship lock，the planning maintenance is conducted in the suspended shipping periods of 2021 and 2022，respectively.The coating failure and corrosion situations of reversed radial gate in water conveyance gallery are detected and evaluated during these periods.The reasons for anti-corrosion coating blistering and steel gate corrosion are analyzed in detail.The results show that the blistering and flaking of anti-corrosion coatings are presented widely on these reversed radial gates of Three Gorges ship lock.In special，local corrosion occurs on the steel gates as well as their components.The total area of coating damage and corrosion is in a proportion of about 20 percent of the detected region for each reversed radial gate.The retained organic coating and thermal-sprayed zinc layer can still play a role in preventing the reversed radial gate against corrosion，giving rise to a fact that the large area maintenance is not an urgent requirement.However，the local corrosion and coating failure areas need to be repaired in time followed by the strengthened detection and maintenance so as to avoid the threat to the safety of reversed radial gate.Meanwhile，the research in terms of high elastic，impact-resistant materials repairment and the sacrificial anode cathodic protection application is suggested to conduct on the reversed radial gate of Three Gorges ship lock，which is expected to suppress the coupling damage from erosion，cavitation erosion and galvanic corrosion.

Abstract:Since the navigable clearance scale of the railway bridges in the Laibin-Guiping Channel cannot meet the navigation requirements，and the first and second railway bridges are old and have geological diseases，the investment in the reconstruction of railway bridges is huge，and thus this paper determines the water level calculation control condition under the condition that the railway-related reach is not renovated.Based on the hydrological test data and water level calculation results，this paper establishes the water level-flow correlation between the channel in the railway-related reach and the upstream Qianjiang hydrologic station.Through the analysis of the flow assurance rate，the paper determines that the annual navigation days affected by the insufficient navigable height scale of railway bridges and channel width are 35.3.According to the characteristics of small ship flow in the near future，this paper determines the scheme of single-way navigation in the near future and double-way navigation except railway bridges in the medium and long term and arranges emergency berthing points at upstream and downstream respectively.The paper also puts forward suggestions on navigation safety guarantee measures and navigation rules such as layout monitoring，bridge anti-collision，navigation aid，and traffic safety signs，which can be used for reference in similar railway-related channel designs.

Abstract:The Lanzhou urban reach of the Yellow River is subject to the comprehensive regulation of Liujiaxia Hydropower Station and Xiaoxia Hydropower Station，and the hydrological conditions of the reach are complex.To reasonably determine the design navigable water level，according to the hydrological characteristics of the river section and the relationship between the water level-flow of Lanzhou Station，the design flow is determined based on the comprehensive duration method，the assurance rate frequency method and the graphical fitting method.The Manning formula is used to determine the corresponding design water level at the end of the reach in combination with the hub dispatching operation mode.A one-dimensional mathematical model is built to study the design navigable water level of the reach.The design navigable water level of Lanzhou urban reach of the Yellow River is obtained.The results show that under the design maximum navigable flow，the engineering reach is in a natural state，and the design maximum navigable water level along the way can be calculated according to the combination of the 3 a return period flow and the tailgate water level calculated by the Manning formula method.Under the designed minimum navigable flow rate，the engineering reach is affected by the backwater of Xiaoxia Hydropower Station.Therefore，it is advisable to calculate the designed minimum navigable water level along the route based on a combination of 90% guaranteed flow rate and the water level in front of the Xiaoxia Hydropower Station dam.

Abstract:Laohuliang Beach in the upper Yangtze River is a major navigation-obstructing shoal from Chongqing to Yichang reach.Several marine accidents have occurred recently，which seriously affect the safety of navigation and shipping efficiency.In view of the above problems，this paper performs a physical model test and a ship model test.On the basis of deeply revealing the navigation-obstructing flow characteristics and navigation safety problems of Laohuliang Beach，the paper compares and studies the flow conditions and navigation states after the implementation of different channel regulation schemes.The results show that the schemes can reduce the influence of bad flow patterns on the safe navigation of ships.After comprehensive comparison，the optimal scheme is put forward，which provides a scientific basis for the design of channel regulation projects on this beach and can be used as a reference for other similar channel regulation research.

Abstract:By optimizing the operation of the filling and emptying valve of a high-head lock，the berthing conditions of ships in the lock chamber and the flow conditions of the valve section of the water-delivery corridor can be improved.This is an essential technical means to solve the problem that the mooring force exceeds the designed value due to the large size of the ship passing the lock.Combined with the operation status of the filling and emptying valve of a large ship lock through adjusting the opening of the dynamic water closing (opening)valve，the residual head of the dynamic water shutoff valve under different working conditions of the filling and emptying valve operation process and the hydraulic field test，the optimized operation process of the water filling valve with the water filling and discharging time and inertia superelevation(drop)meeting the design and specification requirements is selected.The field test shows that the recommended operation process of the water conveyance valve can effectively improve the berthing conditions of the ship in the lock chamber and the hydraulic conditions of the water conveyance corridor.The maximum mooring force of the ship during bilateral water filling is 39.3% lower than the current working condition.When the miter door is opened，the maximum mooring force of the ship is reduced by nearly 59% compared with the current working condition.

Abstract:Longxu Waterway is a natural river under the hub dam.In view of the channel regulation and construction problems under the environment of large-density navigation of multi-line locks，this paper studies the construction layout scheme.Through the analysis of riverbed hydrology，navigation environment，shipping conditions，and channel regulation design scheme，the paper uses mathematical and physical models and concludes that large-density ship navigation，bridge navigation restrictions，and construction precipitation are three difficult points in the construction layout of Longxu Waterway regulation.Therefore，the paper formulates the construction layout principles of “widening the channel，half-section layered construction，half-section navigation，and navigation traffic control” to alleviate the contradiction between construction and navigation and ensure the smooth progress of construction and the safety of ship navigation.The research ideas can be used as a reference for similar projects.

Abstract:To analyze the influence of daily regulation operation of Xiangjiaba Hydropower Station on the navigable flow conditions of downstream Zhongzui Wharf，a 1100 normal physical model is established to simulate the typical daily regulation operation of Xiangjiaba Hydropower Station，and the change process of navigable hydraulic factors such as velocity，water level and gradient of the water area of Zhongzui Wharf caused by daily regulation unsteady flow is analyzed.At the same time，combining the flow field distribution data and self-propelled ship model test，the influence of daily regulation on ship navigation and berthing in and out of the port is studied.The results show that when the power station conducts daily regulation according to the proposed water level variation，the water level variation of the wharf reach does not exceed the allowable value of the power station operation regulation，the flow conditions meet the requirements of ship navigation，and the ships can normally enter and leave the port for berthing operation，with little impact on the wharf operation.The research results can provide reference for daily regulation and operation of power stations.

Abstract:The project section of Pinglu Canal Youth Hub is located in a curved channel，with numerous bridges and dense buildings at the dam site.The reservoir area of Youth Hub is the drinking water source protection area of Qinzhou City.The operation of the ship lock is affected by the salt water flowing upstream.The influencing factors of dam site selection and general arrangement are complicated.This paper compares the site selection and general arrangement of the dam with multiple schemes from the aspects of topography and geology，navigation condition，flood impact，landing condition，impact on surrounding buildings and project investment，etc.Based on the physical model test，the paper optimizes the channel arrangement of the upstream entrance area and connecting section and improves the navigable flow conditions of upstream and downstream entrance areas.Under the condition that the carrying capacity is not lower than the upstream cascade，the water-saving scheme of mutual irrigation and mutual discharge can increase the maximum navigable flow with lower project investment and a better general arrangement scheme.

Abstract:The downstream tail water level of Changsha Hub is far lower than the designed minimum water level in the dry season.In order to analyze its impact and study countermeasures，this paper adopts methods such as data statistics and analysis，comprehensively analyzes the impact of downstream low water level and corresponding water head parameters on the operation of the hub dam，navigation of the ship lock and operation of the power station，and proposes countermeasures as follow.The original maximum working head of the dam should be raised from 9.3 m to 11.2 m.The minimum ecological flow of 348 m3s should be ensured through hub short-term dispatching and basin joint dispatching.“Segmentation，zoning，orderliness，time control，and quantity limit” should be adopted to comprehensively control sand mining in the downstream river channel.“More holes and less flow” should be adopted to release water，and underwater photography and dam safety monitoring should be adopted regularly to ensure dam safety.To prevent the ship from stranding，the water conveyance valve of the ship lock should be opened in a way of “first slow and then fast” to ensure the safety of the mooring line when the floating bollard hits the bottom.A 3000-ton three-line ship lock should be built to ensure the safe navigation of the ship lock.The unit should operate under the operating water head of 7.0 m，and the unit should not be started when the downstream water level is lower than 19.55 m.The forebay of the power station should be cleaned in time to ensure the safe operation of the power station.

Abstract:In the background of smart port construction，building information modeling (BIM)technology plays an increasingly significant role in promoting the digital transformation of ports，and the data chassis of wharf infrastructure is built as a carrier to realize the multi-dimensional application of digital twins of wharf infrastructure.To explore the effective method of digital management and twin application of a high-piled wharf，based on Revit and its secondary development technology，and according to the structural characteristics of the high-piled wharf，this paper proposes a twinning modeling method connecting the BIM model and finite element model to build the BIM model of the high-piled wharf.The paper also develops an efficient model conversion program to accurately generate the finite element model of a high-piled wharf and verifies the correctness and rationality of the modeling method and conversion process by case application.

Abstract:In view of the limitations of two-dimensional design in dealing with spatial complex structural design and calculation problems，building information modeling (BIM technology)is used to carry out the structural design of the floating mooring column of ship lock in the visual environment.Based on the BIM model，the finite element simulation calculation and analysis are carried out to the design research on the floating mooring column structure of ship lock.Two kinds of BIM models including fixed and articulated of ship lock floating mooring column are built，and studied respectively from the aspects of structure and mechanical property analysis.The results show that the mooring trolley of floating mooring column of articulated ship lock can solve the problem of poor adaptability of mooring height well.The multi-layer mooring trolley is flexibly connected by connecting rod，which reduces the supporting reaction of buried parts and improves the structure safety and later maintenance greatly.The design is tested by several ship lock engineering applications，and it can provide references for the similar engineering design and improvement.

Abstract:This article takes the dry bulk terminal yard as a representative and proposes a multi-sensor intelligent perception fusion technology framework for the perception problem of large-scale equipment automated operations in the complex dynamic environment of the yard.Based on the fusion of multiple sensors such as LiDAR，inertial sensor (IMU)，and real time kinematic (RTK)，the article uses the original RTK data information to optimize the bit pose of front-end odometer output.It also uses dynamic object removal technology to achieve robust and accurate dynamic element sensing and utilizes the octree cube query to achieve efficient and real-time global map updates to finally establish a highly accurate and up-to-date bulk yard map and support the subsequent yard operations.The intelligent perception fusion technology framework is applied to a real-world large dry bulk terminal.The results prove that the technology can achieve its high accuracy and real-time performance effect for the yard’s dynamic environment，effectively improving the perception ability of automated operations in dry bulk terminals.

Abstract:The design structure of the lap section between Shenzhong Link immersed tube tunnel foundation trench and 3 supporting channels is complicated.There are some problems such as poor integrity and continuity of section analysis，complicated analysis process and poor three-dimensional visualization effect in analyzing the excavation quality of base channel lap section by section method.To solve the above problems，three-dimensional foundation trench and channel design interface are established，and terrain collapse tool，three-dimensional chromatic aberration diagram tool，section analysis tool，overcut and undercut calculation tool are developed and customized for the second time.The three-dimensional model of base channel lap section is established by using three-dimensional design interface of foundation trench and channels and tools，and the quantitative three-dimensional visualization analysis of the excavation quality of base channel lap section is realized，including overall plane analysis of the overcut depth and undercut thickness by using three-dimension color block and numerical value of overcut and undercut，any vertical and horizontal section analysis of excavation quality，fast calculation of overcut and undercut engineering quantity in any local area.The results show that the overcut and undercut engineering quantity difference between the model and the section method is within ±1%，which meets the requirements of engineering application，and has the advantages of good integrity and continuity of the section analysis，fast calculation speed and high precision，and good three-dimensional visualization effect.It is especially suitable for the construction quality analysis of complex lap section with multiple superposition between the foundation trench and channel or the channel and channel.

Abstract:Sixty years ago，the Ministry of Communications of the People’s Republic of China approved the ministerial standard (trial)JTB 2003-63 Technical Specification for Concrete in Port Construction，which created the construction specification requirements to ensure the safety，suitability and durability of port construction buildings，among which the durability requirement was put forward，and the requirement of maximum water-cement ratio was put forward in the design of concrete mix ratio.It showed the modern concrete design concept of “strength-durability”.Improving the durability of the structure is always the goal of a hundred years or even a thousand years.The construction specifications are generally stipulated from the aspects of raw materials，mix ratio design，concrete construction and special concrete construction.The review analysis is carried out in this paper only from the improvement of freeze-thaw resistance and cracking resistance.Air-entraining is the basic measure to improve the freeze-thawing resistance of the northern port concrete，and the expansion agent and fiber are the optional measures to reduce or avoid the cracking that leads to structural deterioration to ensure the durability of the concrete structure.Its application technology is developed and gradually included in the specification，which improves the construction quality and prolongs the service life of the harbor concrete structure.

Abstract:To study the ecological reef clearing technology in the environmentally sensitive area of the Yangtze River channel，the field test of underwater reef clearing with high frequency hydraulic breaking hammer is carried out to study the underwater reef clearing characteristics of high frequency hydraulic breaking hammer and optimize the reef breaking parameters.The test results show that the speed of the drilling rod embedded in the reef gradually decreases with the increase of the contact surface between the drilling rod and the reef.With the increase of strike time，the embedment depth of the drilling rod experiences three stages in turn：steep increase，slow increase and constant，corresponding to the high efficiency rock breaking，low efficiency rock breaking and ineffective rock breaking stages of the high frequency hydraulic breaking hammer in turn.The single optimal strike time of high frequency hydraulic breaking hammer is 20 seconds and the optimal strike distance is 0.3 meters.The research results have important reference value for enriching underwater ecological reef clearing technology in environmentally sensitive areas.

Abstract:Relying on a deep foundation pit project of the Qingyuan water control project second-line ship lock in the channel capacity expansion and upgrade project of North River，by carrying out real-time monitoring of the horizontal displacement，settlement，and vibration of existing ship lock and deep soil horizontal displacement between ship locks，this paper analyzes the disturbance characteristics of the second-line ship lock deep foundation pit excavation on adjacent first-line ship lock.The results show that in the process of second-line ship lock foundation pit excavation，the horizontal displacement and settlement of the lock chamber of the existing first-line ship lock follows the distribution law of large on both sides and small in the middle.When the excavation depth of the foundation pit is greater than 5 m，the settlement rate of the first-line ship lock increases significantly，and uneven settlement is likely to occur on both sides of the first-line ship lock.The soil horizontal displacement is closely related to the setting of the temporary axial force of the internal support，and the maximum cumulative deformation is 11.6 mm.The maximum vibration velocity of the first-line ship lock vibration monitoring point is 0.079 6 cms.During the second-line ship lock deep foundation pit excavation，the deformation disturbance on the adjacent first-line ship lock is controlled within a safe range，and the safety of the structure and operation of the ship lock is ensured.The research results can be used as a reference for the monitoring of ship locks.

Abstract:In view of the construction of cast in-situ piles under the environment of deep water and rock foundation，the lack of overburden soil leads to the difficulty in the placement of auxiliary steel pipe pile of overwater construction platform and steel casing of cast in-situ piles.Taking the construction of a high pile wharf as an example，this paper studies the construction technology practice and proposes the solution of hole-drilling and pile-inserting.The study results show that：1)To solve the problem of building overwater construction platforms，new technologies can be used，such as punching holes on the platform and vortically drilling holes on the vessel，so as to drill holes before pile inserting for auxiliary steel pipe pile in advance and analyze the characteristics of each technology，applicability，effectiveness，and economy.2)The embedding problem of steel casing is solved by the technology of vortically drilling holes on the platform before inserting.This technology well solves the problem regarding the embedded length of the pile and ensures the quality of the cast in-situ pile.It can serve as a reference for similar projects.

Abstract:The phase Ⅱ cofferdam of the Yakou Navigation Complex project on Hanjiang River is an overflow cofferdam with silty fine sand as the main filling material，supplemented by geotextile and plain concrete slabs to resist water scouring.After the flood in 2021，the concrete slabs on the cofferdam overflow surface suffer from local failure such as local void and fracture of connecting steel bars between slabs.This paper uses the nonlinear finite element method to conduct numerical simulation of the stress and deformation of the overflow cofferdam and analyzes the causes of the local failure of the cofferdam to propose preventive measures.The results show that under the combined action of gravity and water load，the non-uniform settlement deformation of the cofferdam overflow dam slope surface is too large，resulting in varying degrees of void between the anti-scour concrete slabs and the cofferdam body filling material.The stress state of the connecting reinforcement between the slabs changes from tension to shear，and local shear failure occurs due to insufficient strength，which ultimately leads to a reduction of the integrity of the concrete slabs and insufficient anti-flow scour capacity.Reducing the non-uniform settlement is the key to preventing such failure.Therefore，it is necessary to strengthen the filling and rolling to improve the compactness of the material，thus enhancing the anti-settlement deformation capacity of the dam body.Geomembrane reverse filter is set under the concrete slabs to improve the capacity of anti-seepage deformation and anti-flow scour.

Abstract:Effect of dynamic compaction method in silty fine sand ground with high fines content is uncertain.The effective reinforcement depth of dynamic compaction in hydraulic filled sand and natural sand is also different.The characteristics of hydraulic filled silty to fine sand are studied in a typical project，and in-situ trial construction is carried out for compaction energy of 5 MN·m.Verification results including standard penetration test，cone penetration test and plate loading test of the whole site after dynamic compaction are analyzed.The results show that dynamic compaction is applicable in hydraulic filled silty to fine sand with average fines content of 22.7%.The effective reinforcement depth of 5 MN·m dynamic compaction is about 11 m，which is much larger than that proposed in standard JGJ 120—2012.Requirements for characteristic bearing capacity of ≥150 kPa，compression modulus of ≥10 MPa can be satisfied after dynamic compaction，and also the standard for liquefaction resistance under seismic fortification intensity of 7 degrees can be met.When thin layers of cohesive hydraulic fills existing above sandy hydraulic fills，the adverse impact on treatment effect can be minimized by filling the craters with sands during compaction.Good effect can be achieved by dynamic compaction in hydraulic filled silty to fine sand with high fines content.The correction factor of effective reinforcement depth of dynamic compaction can be taken as 0.49.