Abstract:The valve is the key part of filling and emptying system of ship lock. It is significantly affected by hydrodynamic load during operation，which can easily induce cavitation and vibration and threaten the safe operation of valve. When the filling and emptying valve in the emergency case of closing under hydrodynamic load，the water flow in culvert presents negative water-hammer waves，the pressure in front of the valve rises rapidly，while the pressure behind the valve drops sharply，and the working condition of the valve deteriorates. In this article，through the field-observation，the operation characteristics of the filling and emptying valve of the 4th gate on the north lane of the Three Gorges ship lock are monitored when it is closed in an emergency，including the change of flow rate and water level of valve well，characteristics of valve cavitation，flow-induced vibration and hoisting capacity. The response regularity of the maximum acting head when valve in the emergency case of closing under hydrodynamic load is analyzed.The result shows that the filling and emptying valve of the Three Gorges ship lock is safe and reliable under the emergency case of closing.

Abstract:In order to solve the problem of the prototype observation for the complex flow field at the entrance area of downstream approach channel of navigation structures，we invent a new method to measure the flow velocity and field more precisely，and obtain the transverse velocity，longitudinal velocity and reflux velocity at the entrance area of the downstream approach channel of the ship lift under different flow conditions and reveal the characteristics of the flow field at the entrance area of the approach channel with permeable guide wall，which provides an important basis for navigation safety evaluation of ship lift and optimization of route and navigation method. Comparing the results of prototype observation and model test，we put forward some suggestions for the model test of navigable flow condition and the evaluation of ship navigation safety，which can provide reference for related research.

Abstract:Combined with the project design of the sector gate of the lower lock head of Yuxi first ship lock to be rebuilt and expanded，we research the static and dynamic optimal design of sector lock gate with a span of 34 m，which is the largest span in the sector gate of the domestic ship lock. Based on the finite element analysis and checking calculation of the preliminary design of the sector lock gate，we apply APDL of ANSYS to re-develop the 3D finite element model of the sector lock gate，and carry out the static optimization design and dynamic characteristic optimization with the aim of the minimum mass of the gate. The results show that by static optimization，the mass of triangular gate structure decreases 12.5% to 14.2%. Through dynamic optimization，the first order natural vibration frequency of gate is improved，which meets the constraint condition of not less than 5 Hz.

Abstract:Combining with the conceptual design of the reconstruction and extension of the sector lock gate of the first line ship lock in the Yuxi River，we propose a new type of double energy-consuming anti-collision system with aluminum foam sandwich panel and supporting bar with spring to improve the anti-collision performance of the sector lock gate. By the numerical simulation of the ship impact on a new anti-collision system of the sector lock gate，we know the mechanical characteristics and energy conversion law of the anti-collision system. Through the parameter analysis of the aluminum foam sandwich panel thickness and the stiffness of supporting bar with spring and comparison with the traditional anti-collision system，it is shown that the combined use of aluminum foam sandwich plate and supporting bar with spring can reduce the weight of the anti-collision system and reduce the impact force of the ship.

Abstract:In order to study the effects of topographic inhomogeneity on wave breaking process，a series of experiments were conducted with normal，oblique and multidirectional irregular waves breaking on three-dimensional lens topography to study the breaker indices. The existing formulas of wave breaking on two-dimensional topography were compared with the experimental results to study the differences of breaker indices of the two topographies. The results showed that the values of breaker indices of three-dimensional lens topography were larger than the calculated values，which was caused by the wave focusing effect of lens topography. Further，the general forms of existing formulas were used to fit the experimental data and the parameters in the calculation formula of the crushing index suitable for three-dimensional lens topography were given. The results can provide the basis for engineering designing.

Abstract:Wave interaction with submerged permeable breakwater involves wave reflection，wave transformation，wave overtopping and wave breaking，which is a complex nonlinear problem of turbulent flow and seepage flow．Based on the improved MPS method，we apply Drew’s governing equations of two phase flow in porous media，derive source term equation of Poisson pressure equation of seepage water pressure suitable for particle method，introduce SPS turbulence model into the model to simulate the turbulent effect inside and outside porous media，establish a vertical two-dimensional MPS method numerical calculation model of turbulent seepage flow，simulate wave propagation and deformation over the submerged permeable breakwater，and analyze the distribution characteristics of velocity and pressure fields and well wave energy dissipation around the submerged permeable breakwater. The results show that the model can reproduce the complex flow field and pressure distribution around the submerged permeable breakwater，alleviate the problem of pressure oscillation and particle distribution at the fluid-solid interface，and achieve high simulation accuracy.

Abstract:The pebble is often used in river model in the past. In view of the ecological environment protection of pebble prohibition and the characteristics of easy access and high roughness of gravel，we study the resistance of gravel. We obtain the representative element weight of homogeneous gravel particles and the average constant volume particle size of multiple types of gravel by statistical analysis method，carry out the experiment of the steady flow in open channel with the dense bed gravel and cement slurry wall，apply the river bed and bank resistance of hydraulic radius segmentation method，segment the bed rock surface roughness，and obtain the relationship of class evenly spread gravel dense roughness ns and average constant volume size .The results show that the representative element weight of four-grades homogeneous gravel is 1 kg to 2 kg，and the value can be determined according to the particle size；ns=0.013 91/6V.

Abstract:The internal friction angle is one of the soil shear strength indexes which reflects the friction characteristics of soil，and is an important input parameter in geotechnical engineering design，especially for sand. Based on a mass of laboratory tests，in-situ tests，research studies and engineering practices，many empirical values and theoretical calculation formulas for the internal friction angle of sand are presented in domestic and foreign standards. By comparing the determination methods in domestic standards，American standards API & Engineer Manual，European standards Eurocode & BS 6349 and a series of international literature，the differences of various methods have been summarized. It is concluded that in the absence of laboratory test results，in-situ testing method to determine the internal friction angle is reasonable and feasible，which can provide some reference for related design work in domestic and overseas projects.

Abstract:Based on the research status of the testing method of structural displacement，we propose the idea of measuring dynamic displacement of wharf without benchmark，and establish the corresponding test and analysis system. We select the passive servo sensor to collect the dynamic signal，and study vibrational response law of the sensor to different loading forms by the simulation test system，propose a correction method to obtain actual value of structure displacement based on inverse analysis by the simulation model of the test system and signals of sensors aiming at the working condition of quasi-static displacement，develop the dynamic displacement testing technology without benchmark for dock structure under variable load，and carry out field dynamic displacement test to verify the reliability of the proposed technology combining with the research on wharf displacement limit based on comfort level and the analysis and calculation of finite element modeling. The results show that the technology is simple to operate，reliable in results，less affected by the environment，and can realize remote automatic monitoring

Abstract:Based on the actual requirements of plane layout of port area，the port area under the cover of the breakwater is subjected to wave physical model tests. And based on the numerical simulation of the MIKE21-BW model，the wave heights of irregular waves incident on the berth behind a vertical wharf at a certain angle are studied. Both numerical simulation and physical model experiment can take into account wave’s the diffraction，reflection and refraction from sea to shore. Comparing the wave height data extracted by the terminal front through the above two methods，the results are in good agreement，indicating that the MIKE21-BW can be applied to the study of nearshore wave propagation and wave condition in the port area providing a scientific research basis for the layout of the port area.

Abstract:Aiming at the site selection for Taipingwan port area of Dalian Port and for the purpose of making up for the haul distance disadvantage of Dalian Port’s hinterland，solving the contradictions among the port，industry and city，conforming to the port integration orientation of Liaoning Province，promoting the revitalization of Northeast China，optimizing the transportation layout，and undertaking the industrial transfer，there exists an urgent need to carry out a planning on Taipingwan port area. Adopting the methods of qualitative and quantitative analyses，comparisons and selections，and mathematical models，we understand the characteristics of the proposed site including weak development of the shoreline，favorable conditions of wind，wave and tide，simple flow field，clear water and less sand，stable seabed，bed rock’s high bearing capacity，and favorable water depth condition，etc.，based on which，we come to the conclusion of selecting corresponding water and land area to form Taipingwan port area along the coastline from Taipingjiao to Taipingjiao southern coastline. Taipingwan port area will be an important part of Dalian Port，the crucial support for the revitalization of Northeast China and development and opening of Liaoning coastal economic belt，as well as an important carrier for the integration，layout adjustment，transformation and upgrading of ports in Liaoning Province.

Abstract:The replacement and maintenance of the anticorrosive system which is about to reach the design protection period is the necessary way to ensure the reliability and good technical condition of the structure. Aiming at the replacement and maintenance of the sacrificial anode cathodic protection system for steel pipe piles in the old quay of coastal port，referring to the experience of similar projects and relevant codes and standards，we discuss key difficulties，including replacement and maintenance design procedures，the influence，determination and correction of seawater resistivity，protection area and protection current density calculation，sacrificial anode layout and installation，etc. Then，we put forward solutions to the key technical problems to ensure that the anticorrosive system for steel pipe piles is continuous and effective，and to practical ensure the normal use and safe operation of port facilities.

Abstract:Considering the current situation that there is no a consensus code for seismic design of port structures to unify manage difficultly in America，American Society of Civil Engineers （ASCE） is accredited by the American National Standards Institute （ANSI） to develop ASCECOPRI 61-14 Seismic Design of Piers and Wharves on the basis of local design criterions for some existing ports. This code provides detailed provisions for seismic level，seismic performance objects，seismic design methods and seismic design and construction requirements of components，and includes the latest achievements of seismic research in the world in recent years，and it is significant to promote the development of seismic design for pile-supported wharves. In order to help domestic engineering technicians understand this code with ease，we introduce the compilation background and design philosophy，and interpret and explain each part of the code in detail combining with engineering experience. Moreover，we briefly compare the differences between this standard and domestic code，which can provide the references for the further revision of backward domestic code.

Abstract:Aiming at the planning of the highway collecting and distributing system of Taipingwan port area of Dalian Port，according to the idea of separation of passenger and freight and in view of the intensive development，we establish the collecting and distributing pattern of “3 Transverse and 3 Longitudinal” mostly in 3 dredging port highways，use the combination of qualitative and quantitative method，four stages predicted method，OD matrix method to analyze the future port freight needs，and obtain the planning and construction scheme of collecting and distributing. The results show that the port area’s freight volume includes the coastal economic zone and hinterland of the port area in the future，and the staged development model that Yongning Street progressively transform into affording all of the passenger transport tasks from the near to the distant. The planning and construction scheme is that 3 dredging port highways become the bi-directional and six lines highway at least，Yongning Street can also become the bi-directional and eight lines highway，and the highway port is planned between Yongning Street and the first distributing port.

Abstract:The design of supporting terminals for hydropower stations often faces constraints such as complex terrain and geology，limited layout space，and large change in water level for loading and unloading operations. In view of the problems faced by the design of the supporting terminals of hydropower stations under complex conditions，taking the upstream supporting terminals of a hydropower station in the western region as an example，we probe into key issues concerning the overall plan layout of the terminals. Based on the functional positioning of the terminals in the reservoir area，we propose related solutions such as multi-site selection，function-based terminal zoning，control the amount of excavation works，and reasonable external traffic，and discuss the loading and unloading process schemes of barge-based fish collection and sewage ship.The result may serve as reference for similar projects.

Abstract:The key design issues of the axis direction and structural form of the open terminal at south coast of Mediterranean sea are analyzed. For the axis direction，the main controlling factor is found comprehensively after considering the wind，wave and current ，and the channel，connecting structure and the impact with surrounding are also been considered，then the axis orientation is confirmed. In view of the structural form，the conventional advantages and disadvantages of the gravity type and the pile foundation type are given. Combined with the actual project，how to consider the geological conditions，operation and maintenance and new technical factors in the structure selection is explained. More importantly，the unconventional double cylinders section plan and its advantages are introduced to provide reference for similar projects.

Abstract:Multi buoy moorings （MBM） are commonly adopted in offshore mooring for large oil tankers berthing in open seas，but there are no practical applications in China. We carry out the force analysis of anchor chains which are main structural components of an MBM system，analyze and calculate the force of single chain and composite chains under free or constrained condition by catenary equation，summarize a set of systematic analysis method for the force of chains，and apply the method to an MBM project in the Middle East for case calculation. The results show that the proposed theoretical formula and design method can provide references for the anchor chain design of MBM berth.

Abstract:In order to reach the goal of extending the deepwater channel to Nanjing，the navigation channel regulation projects were carried out at Fujiangsha waterway by the phaseⅡof 12.5 m deepwater channel project in the Yangtze River below Nanjing. Regulation project is mainly including spur dike at the left edge of Fujiangsha，submerged dike at the head of Shuangjiansha，spur dike at the north side of submerged dike and spur dike at the south side. Based on the measured data after the implementation of the channel regulation project of Fujiangsha waterway，this paper makes a comparative analysis with the predicted results of the digital and physical model in the design stage，and comprehensively analyzes the realization of river regime changes，flow field changes，and channel maintenance volume and other aspects before and after the project. The results show that：1）After the implementation of the project，the scour trend of Shuangjiansha head has been well controlled. So the siltation near the sand head on the upstream side and the spur dike on the north side of the submerged dike is obvious，and the volume of sand body is obviously increased. 2）The scour and siltation in the upper middle section of the left edge of Fujiangsha is relatively stable and generally presents the siltation trend，and there is scour in the lower part. The volume and area of sand body on the left edge of Fujiangsha are generally increased. Remediation project has better effect of bank protection and sand fixation. 3）The overall distributary pattern of Fujiangsha waterway has not changed significantly，only the flow field around the regulation building has been adjusted. 4）The amount of channel maintenance has increased. The project has achieved the expected goal of channel regulation，the project regulation scheme is reasonable，and the effect of channel regulation is in line with the expectation. It can be used as a reference for channel regulation of tidal branches in the middle and lower reaches of the Yangtze River.

Abstract:In view of the problem of water resources utilization in the design of ship locks，this paper summarizes the development trends at home and abroad from the perspective of water-saving technology. It focuses on the conceptual classification of water-saving technologies used in the Panama Canal locks and studies the application characteristics of each water-saving technology in conjunction with the lock’s multi-objective optimization design concept. The water-saving technologies used in the Panama Canal locks is realized by gravity，and the water-saving benefit is directly related to the water-saving technology and operation mode，which is essentially the optimal design of the spatial storage of water. The multi-factor analysis method is used to discuss the water consumption rate formulas of different water-saving technologies under the corresponding ship lock operation modes，so as to calculate the water-saving rate. It has important reference significance for the comprehensive development and utilization of water resources，energy-saving and emission reduction of water transportation and the future development of water-saving technology of ship locks.

Abstract:For the bearing capacity of ship reception chamber under earthquake，we study the coupling dynamic response of chamber-water-ship. Based on the ANSYS software，we establish a finite element model of ship reception chamber by the modified Housner theory to simulate the coupling action between ship and water，compare and analyze the dynamic responses of the system under three conditions including ship reception chamber at the bottom，middle and top. The results show that under the same earthquake condition，when the position of the ship reception chamber changes from bottom to top，the maximum stress，lateral and longitudinal acceleration all increase accordingly. The maximum lateral and longitudinal displacement and acceleration at the top are 263.31 mm and 0.174 mm，3371.97 mm/s2 and 1.47 mm/s2 respectively，and the maximum equivalent stress is 52.76 MPa.In the design of ship reception chamber，the working condition of ship reception chamber at the top can be taken as the design basis.

Abstract:In view of the damage of the waterway regulation structure under the new water-sediment condition，we take revetment works as example to simulate the erosion and siltation characteristics of the revetment works under different hydrodynamic strength and different sediment saturation by the generalized flume experiment. The test results show that with the increase of the ratio of mean velocity in section to the incipient velocity of sediment （U/Uc），the frontal erosion of the revetment works increase exponentially. With the increase of the ratio of sediment concentration to sediment carrying capacity （S/S*），the frontal erosion of the revetment works decrease in a logarithmic manner. When U/Uc＞3 or S/S*＜40%，the scouring range and scouring depth of the revetment front increase rapidly. Based on this，when U/Uc＞3 or S/S*＜40%，the monitoring of the interannual and intraannual changes in the surrounding works’ flow velocity should be strengthened. The research results can provide a technical support for the design of waterway regulation engineering and the maintenance work of waterway regulation structures.

Abstract:In recent years，a series of steel wire mesh stone cage ecological revetment projects are carried out in the middle and lower reaches of the Yangtze River，but there is no follow-up investigation and evaluation on the ecological restoration effect after the completion of these projects. Based on the investigation of vegetation and matrix of six steel wire mesh stone cage revetments before and after the flood season in 2019，we analyze the annual and interannual successions of vegetation. Combined with the hydrologic data，matrix characteristics and field observation，we screen four vegetation characteristic factors and seventeen environmental impact factors for correlation analysis. The results show that after restoration，the relatively single vegetation succession seeded at the completion of the revetment protection area is replaced by a multi-species community dominated by herbage plants，and the ecological restoration effect of the revetment protection site is good. The time of revetment，the percentage of clay，silt and sand in the matrix and the duration of inundation are the main factors affecting the succession of vegetation in the engineering area.

Abstract:Combining with the natural condition of Jiangyin channel，we analyze riverbed evolvement，channel conditions and economic benefits of Jiangyin waterway，research the feasibility of opening up subchannel in lower section of Jiangyin waterway，and propose the corresponding opening scheme. The results show that the lower section of Jiangyin waterway has the conditions of opening up a certain grade subchannel according to the existing natural condition and using a certain water level. Although the conditions of Jiangyin waterway are good in recent years，the channel relationship is complex. It is suggested to open subchannel of grade I-4，the channel dimension is determined according to the requirements of navigable 3，000-tons sea vessel and 7，000-tons inland vessel，and the virtual navigation mark is used to navigation mark.

Abstract:The rivers have many other functions，such as generating power，supplying water，preventing flood and protecting ecological areas，and how to balance multiple goals and achieve synergistic development and quantification of channel carrying capacity in channel construction has become one of the most important problems today. By using the modified variance coefficient，we carry out coordinated and adaptive regulation of channel carrying capacity combining with the horizontal evaluation value of channel carrying capacity on ecological，economic and multi-function utilization of river，calculate the maximum channel size under multi-objective coordination，take AE channel as an example to verify the rationality and operability of the evaluation model and calculation method. The results show that the maximum channel size calculated can alleviate the contradiction between current channel construction and economy，ecology and rivers，and multi-purpose utilization. The calculation model is reasonable and feasible.

Abstract:The submerged dike，spur dike and bottom protection zone are applied in the Luochengzhou waterway regulation project on the 12.5 m deepwater channel of the Yangtze River below Nanjing to prevent the right branch from further scouring and development，enhance the power of shallow section of left branch and improve the channel conditions. In order to demonstrate the regulation effect of the implementation of Luochengzhou waterway regulation project，we compare the shoal and channel evolution，the flow and sediment diversion ratios of branched channels，the shoal consolidation effect and the improvement of channel navigation conditions before and after the implementation of the Luochengzhou waterway regulation project based on the measured topographic and hydrological data. The results show that after the implementation of the project，the sediment deposited in the head of sandbar and the shelter area of the spur dike，and the trend of erosion and retreat of the head of sandbar are effectively curbed. The diversion ratio of the left branch increases by about 4%，the velocity of flow in the spur dike’s pick-up area increases by about 0.2 m/s，and the water depth increases from 10.5 m to 12.5 m. The regulation aims are achieved in general through the regulation buildings，but attention should be paid to the impact of the deposition at Sanyiqiao marginal bank on the deepwater channel.

Abstract:The quality of the flow conditions in the entrance area directly affects the safety of navigation. In view of the problems such as the large transverse velocity and the poor flow conditions in the entrance area and the connecting section of the upstream of Fengguang hydro-junction’s expanded locks，we carry out the model experiment of Fengguang hydro-junction，based on which，we shorten the length of the navigation wall in the entrance area of the upstream by 40 m，adjust the spacing of diversion piers to 5 m，and increase the number from 4 to 7，and the distance between the end of the downstream diversion pier and the navigation wall is 7 m. The test results show that after the navigation wall is shortened，the distance between the entrance area and the upstream river bend increases，and after the distance between the diversion piers reduces，the water permeability between the piers decreases，thus water flow condition is obviously improved and meets the requirements of the code. The ship model navigation test shows that the maximum navigable flow is Q10%=6 077 m3/s，the ship model can pass through the lock safely and stably，and the control parameters meet the requirements of the specification.

Abstract:Establishing a simplified model for ship lock passing，using the stochastic simulation method combining the Monte Carlo method and 2D bin-packing heuristic algorithm，we compute the passing capacity of different ship lock design schemes at different scales，discuss the results for different simulation implementations considering different factors，and optimize the reasonable design scheme. The results show that when using the ship’s first-come-first-served strategy，the lock chamber utilization rate of ship locks of the same width is about the same，and the tonnage index of one-pass ship lock increases as the ship lock chamber length increases. When the ship selection service strategy is adopted，the tonnage index of the first pass is higher than the calculated index of the first-come-first-served service strategy，and the average number of times to ship lock the gate shows a single increase trend after the ship lock reaches the busy state. The L4 ship lock design scheme shows advantages in ship type adaptability，pass ability，service quality level and other indicators. When calculating the pass capacity on the basis of the random simulation of the ship lock，it is necessary to reasonably determine the specification formula parameters in conjunction with the actual operation of the ship lock

Abstract:The Zhegan canal is a connecting project between the Yangtze River system and the Qiantang River system，which opens up an east passage to the sea for Jiangxi Province. Aiming at the route problems of Zhegan canal Yueling part，we carry out a comparison and selection of the canal route and local route of the watershed section. Analyzing the route layout，regional influence，water supply，connection section，building，project implementation，resettlement land occupation，etc.，and considering comprehensively route length，crossing elevation and shipping volume，we recommend the canal route，i.e. Longrao stream plan：by constructing the Damaiyu junction，Togngongshan junction，Jiudu junction，Hongqigang ship lock and Dongshanwu ship lock to control the lowest water level and excavate the canal. Three planes are compared and selected in the watershed section，and the reservoir plan with better route length and resettlement land occupation is recommended.

Abstract:According to the Inland river navigation development plan of Sichuan Province，there are 14 steps planned in the Jialing River，and the section from Guangyuan to Zhaohua will reach the Grade IV waterway standard by 2030. However，due to the Comprehensive planning for the Yangtze River basin，the Shuidong dam junction of the Jialing River was cancelled，the water level between Tingzikou and Shangshipan junction cannot be connected. The designed water level variation range of Tingzikou hydropower station is as high as 20 m，which results in a fluctuating backwater area of about 28 km at the end of the reservoir. The natural flow of this waterway section is very small，and the planned grade IV waterway cannot be achieved only through waterway regulation. Therefore，this paper adopts the method of good river section correlation to establish the river correlation under the characteristic flow between the beach dangerous riverbed after regulation section shape and the good river section，and infer the stable navigation depth that may be achieved by the beach dangerous riverbed regulation under different flows，so as to find the minimum flow of the engineering reach that meets the water depth standard of Class IV channel. Then the paper analyzes the time of occurrence of this flow based on the data from the hydrological station，combined with the characteristic water level backwater mileage of the Tingzikou Power Station，studies the navigation guarantee rate by segment，and proposes the flow rate and guarantee rate for the variable backwater area at the rear of the Tingzikou Reservoir to reach the planned level IV channel.

Abstract:On the basis of the investigation of the economic development of the hinterland，the development of the port and the needs of enterprises，the impact of the 12.5 m deep water channel II phase project of the Yangtze River below Nanjing on the development of Jiangyin Port is studied by a research method combining qualitative analysis and quantitative calculation.The analysis concludes：1）The implementation of the 12.5 m deep water channel II phase project has greatly improved the navigation conditions from Nanjing to Nantong section of the Yangtze River and created favorable conditions for CAPE ships to enter Jiangyin Port. 2）The large-scale ships have greatly increased the actual load rate，which have not only enabled Jiangyin Port to achieve a substantial increase in throughput，but also reduced the logistics cost of enterprises. It has promoted the optimization and adjustment of the ship transportation organization，and reduced the pollution and carbon emissions of ships，and promoted the green development of the port.

Abstract:Based on the prototype data of water and sediment from 1972 to 2016 at Fuyang sluice station of Shaying River，using tools such as SPSS，MATLAB，etc.，and adopting R/S analysis and wavelet analysis methods，we study the characteristics and change trend of water and sediment from Sanbacun reach. Based on the measured topographic data of the project reach in 2017 and 2019，we analyze the recent changes of river regime and characteristics of riverbed erosion and deposition to reveal the main characteristics and laws of riverbed evolution in this reach. The results show that under the premise of no systematic increase or decrease of runoff，the sediment discharge and sediment concentration in the river course are obviously decreased；The sediment discharge and sediment concentration in the river reach of the project are predicted to be decreased in the future；Under the natural evolution condition，the floodplain of the river course of the project section is basically stable，the main channel is slightly scoured，the scour range is small，and the river course is relatively stable；The project will not fundamentally change the scouring and silting characteristics of the reach. In the long run，the main stream of the bend after the project tends to open a new channel，and the riverbed will still maintain the trend of scouring and cutting down.

Abstract:The navigational condition of the Nanjing Yangtze River Bridge is complicated with high safety risk. It is of great significance to master the navigation rules of ships for maritime surveillance and waterway design. Applying a parallel approach developed for calculating the density of ship trajectories in the Nanjing Yangtze River Bridge waters based on AIS big data，we recognize the distribution of the regular routes of ships of different sizes in different seasons，and find that most ships follow the navigation rules of the Nanjing Yangtze River Bridge waters in general. Compared to small ships，large ships are more formal in sailing across the bridge. When passing through the bridge span，the position of large ships is more centered，the angle between the large ships′ bow direction and the normal direction of the bridge axis is larger. Meanwhile，the overlap between the lane boundary of the large ships and the designed waterway is much higher than that of small ships. We also find that the ships prefer to take a northerly route in the flood season and a southerly route in the dry season. With the decrease of water level，ship tracks gradually change to the south.

Abstract:In the reclamation project in the coastal areas of Fujian，the main soil particles are medium-coarse sand types. In the process of transportation of this type of soil，large resistance is more likely to cause pipe blockage，which will delay the construction process. Under this working condition，it is very important to grasp the real-time information of the conveying resistance in the pipeline. However，under coarse particle conditions，commonly used empirical methods such as the Durand formula method have poor calculation accuracy. In this paper，based on the existing pipeline transportation research and the test data of the actual coastal engineering in Fujian，the Gaussian process regression method and support vector machine method are used to establish the prediction model of the pressure drop in the pipeline. Both regression models can get more ideal effects during the training period，the R2 index of the model is above 0.80. In the prediction period of the model，the R2 index of the support vector machine regression model is 0.78，and the R2 index of the Gaussian process regression prediction model reaches 0.95. The results show that the machine learning prediction model based on Gaussian process regression can better predict the dredging parameters of the medium-coarse sand dredging project.

Abstract:With the deepening of the Belt and Road Initiative，a lot of Chinese companies undertake construction projects in Africa，such as port，highway and industrial park. With the development of the project，the drainage near the project site needs to be constantly changed and the drainage planning near the project site is particularly important. Based on the Civil 3D terrain analysis module，confluence analysis module and confluence region boundary analysis module，this paper presents a design method for analyzing the large-area drainage and planning of large-area drainage. Based on Kribi Deep Sea Port Project，this paper expounds the application of this method，which provides reference for the whole area design planning for other large projects.

Abstract:In the area with a thick permeable stratum，the dry condition construction under the coastal environment can be achieved by combination of earth-rock cofferdam without water-proof curtain and deep-well dewatering technology. In order to study the influence of deep-well dewatering conditions on the stability of cofferdams，this paper analyzes and discusses the seepage distribution and slope stability of high earth-rock cofferdam during the operation of dewatering wells by GeoStudio based on Egypt port of Sokhna Container Terminal Basin 2 Project. It is established that the relationship curve between different target dewatering levels and the minimum safety factor of the overall slope stability，and compare with the stability of the cofferdam under the condition of open drainage of water collection. The results show that：1）The seepage is obviously controlled by the dewatering well in the process of developing towards the land side. As there is no seep point in the toe of the cofferdam，the stability can meet the safety requirements. 2）When the target dewatering level rises，the stability of the cofferdam tends to decrease. 3）When the target dewatering level falls to a certain depth，the phreatic line reaches a certain depth，and the stability of the cofferdam is almost not affected by seepage while the stability coefficient no longer increases. 4）The analysis results can provide a reasonable design approach for similar projects.

Abstract:The Dares Salaam project in Tanzania locates in the coral gravel sandstone area. PHC piles with diameter of 800 mm and 1 000 mm are used as pile foundation. Carrying out the geotechnical test on coral gravel sandstone and studying on the law of pile sinking with difference diameter of PHC pile，we obtain the peak friction angle of PHC pile-soil interface of coral gravel sandstone debris and the residual friction angle. Summarizing the law of piling of 200 foundation piles with 1.5m long pile shoe and with diameter of 800 mm and 1 000 mm respectively，we get to know the depth of piles into the strongly weathered coral reef limestone and law for pile sinking. The penetration ability of the 1 000 mm-diameter pile is stronger，and its elevation control shall be taken as the main criterion，while penetration shall be the complementary for sinking stopping. But both are main criteria for 800 mm-diameter piles. The research results provide a guidance for PHC sinking and theoretical research under similar geologic conditions.